Inorganic Nanoparticles Group

Group Leader: Víctor F. Puntes

Publications

2019

  • Beyond the Scavenging of Reactive Oxygen Species (ROS): Direct Effect of Cerium Oxide Nanoparticles in Reducing Fatty Acids Content in an In Vitro Model of Hepatocellular Steatosis

    Parra-Robert M., Casals E., Massana N., Zeng M., Perramón M., Fernández-Varo G., Morales-Ruiz M., Puntes V., Jiménez W., Casals G. Biomolecules; 9 (9) 2019. 10.3390/biom9090425. IF: 4.694

    Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic accumulation of lipids. Antisteatotic effects of cerium oxide nanoparticles (CeO2NPs) have recently been shown in animal models of liver disease. However, it is unclear whether the activity of CeO2NPs is related solely to the decrease in oxidative stress or, in addition, they directly decrease liver fatty acid accumulation. To address this question, in this work, we used an in vitro model of hepatocellular steatosis, exposing HepG2 cells to oleic and palmitic acid. Cell uptake of CeO2NPs and their effect on oxidative stress and viability of hepatic cells cultured with H2O2 were also evaluated. Results show that CeO2NPs were uptaken by HepG2 cells and reduced oxidative stress and improved cell viability. Treatment with oleic and palmitic acid increased lipogenesis and the content of different fatty acids. CeO2NPs reduced palmitic and stearic acid and most fatty acids consisting of more than 18 carbon atoms. These effects were associated with significant changes in elongase and desaturase activity. In conclusion, CeO2NPs directly protected HepG2 cells from cell injury in oxidative stress conditions and reduced fatty acid content in steatotic conditions by inducing specific changes in fatty acid metabolism, thus showing potential in the treatment of NAFLD.


  • Cerium oxide nanoparticles display antilipogenic effect in rats with non-alcoholic fatty liver disease

    Carvajal S., Perramón M., Oró D., Casals E., Fernández-Varo G., Casals G., Parra M., González de la Presa B., Ribera J., Pastor Ó., Morales-Ruíz M., Puntes V., Jiménez W. Scientific Reports; 9 (1, 12848) 2019. 10.1038/s41598-019-49262-2. IF: 4.011

    Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide, ranging from steatosis to non-alcoholic steatohepatitis (NASH). Recently, cerium oxide nanoparticles (CeO2NPs) have emerged as a new antioxidant agent with hepatoprotective properties in experimental liver disease. The aim of the current investigation was to elucidate whether CeO2NPs display beneficial effects in an experimental model of NAFLD.Therefore, fifteen Wistar rats were subjected to a methionine and choline deficient diet (MCDD) for 6 weeks and intravenously treated with CeO2NP or vehicle during the weeks three and four of the diet. The effect of CeO2NPs on serum biochemistry, hepatic steatosis, inflammation, fatty acid content and expression of reactive oxygen species (ROS) and lipid metabolism related genes was assessed. MCDD fed rats showed increased inflammation, enhanced hepatic lipid accumulation of both saturated and unsaturated fatty acids (FAs) and overexpression of genes related to fatty liver and ROS metabolism. Treatment with CeO2NPs was able to reduce the size and content of hepatocyte lipid droplets, the hepatic concentration of triglyceride- and cholesterol ester-derived FAs and the expression of several genes involved in cytokine, adipokine and chemokine signaling pathways. These findings suggest that CeO2NPs could be of beneficial value in NAFLD. © 2019, The Author(s).


  • Coating aerosolized nanoparticles with low-volatile organic compound (LVOC) vapors modifies surface functionality and oxidative reactivity

    Zhao J., Suárez G., Tran N., Puntes V., Riediker M. NanoImpact; 14 (100150) 2019. 10.1016/j.impact.2019.100150. IF: 0.000

    Engineered nanoparticles (ENPs) released into the environment have a high probability of interacting with other pollutants before human exposure. These interactions can modify the physicochemical characteristics of ENPs’ surface functionality. The toxicity of ENPs can thus largely depend on the coatings picked up in the environment rather than particle core alone. We built a dynamic system to simulate this barely-studied scenario and open up a novel and convenient way to form hydrophobic coatings directly on airborne ENPs. We coated airborne ENPs with low-volatile organic compounds (LVOCs)—common pollutants that exhibit a high affinity for surfaces. Measurement of airborne particle size distribution showed an increase in particle size after coating. The coating thickness was adjustable by controlling the parameters of LVOC generator, namely the reaction temperature and the flow rate through LVOC reservoir, to create 5–90 nm coatings. Transmission electron microscopy images and nanotracking analyses of ENPs suspended in liquid were used to further characterize the coating thickness. Both methods suggested that the system yielded stable, replicable, and well controlled surface coatings. ROS generation of the coated ENPs significantly depended on the type and thickness of LVOC coating. Chemically non-reactive coatings led to significantly reduced ROS generation of silver-ENPs with a 20 nm inert coating quenching close to 100% of ROS generation; this was attributed to the blocked reactive zones on the ENP surfaces. Chemically reactive anthracene coatings, in contrast, first passivated the surface but then contributed to the redox cycle, leading to an increased generation of ROS, which was at a 90 nm coating thickness comparable to that of bare ENPs. Our results add to the understanding of ENP surface functionality—an important aspect of nanotoxicity. Furthermore, the high controllability of our ENP coating system makes it useful for other applications in inducing hydrophobic coating on airborne ENPs. © 2019 Elsevier B.V.


  • Detection of resistance protein A (MxA) in paper-based immunoassays with surface enhanced Raman spectroscopy with AuAg nanoshells

    Russo L., Sánchez-Purrà M., Rodriguez-Quijada C., Leonardo B.M., Puntes V., Hamad-Schifferli K. Nanoscale; 11 (22): 10819 - 10827. 2019. 10.1039/c9nr02397f. IF: 6.970

    Myxovirus protein A (MxA) is a biomarker that can be used to distinguish between viral and bacterial infections. While MxA lateral flow assays (LFAs) have been successfully used for viral vs. bacterial differential diagnosis for children, the clinically relevant level of MxA for adults has been reported to be 100 times lower, which is too low for traditional LFAs. We present results applying the use of surface enhanced Raman spectroscopy (SERS) to detect MxA. AuAg nanoshells (AuAg NSs) were used to enhance the Raman signal of mercaptobenzoic acid (4-MBA), enabling readout by SERS. The AuAg NSs were conjugated to antibodies for the biomarker of interest, resulting in a "nanotag", that could be used in a dipstick immunoassay for detection. We first optimized the nanotag parameters using anti-human IgG/human IgG as a model antibody/antigen system, and then demonstrated detection of MxA using anti-MxA antibodies. We show that SERS readout of immunoassays for MxA can quantify MxA levels at clinically relevant levels for adult viral infection. © 2019 The Royal Society of Chemistry.


  • Functionalized cerium oxide nanoparticles mitigate the oxidative stress and proinflammatory activity associated to the portal vein endothelium of cirrhotic rats

    Ribera J., Rodríguez-Vita J., Cordoba B., Portolés I., Casals G., Casals E., Jiménez W., Puntes V., Ruiz M.M. PLoS ONE; 14 (6, e0218716) 2019. 10.1371/journal.pone.0218716. IF: 2.776

    Background and aims The occurrence of endothelial alterations in the liver and in the splanchnic vasculature of cirrhotic patients and experimental models of liver diseases has been demonstrated. However, the pathological role of the portal vein endothelium in this clinical context is scarcely studied and, therefore, deserves attention. In this context, we aimed to investigate whether pathological endothelial activation occurs in the portal vein of cirrhotic rats. Methods Cirrhosis was induced in wistar rats by CCl4 inhalation. We generated immortalized endothelial cells from the portal vein of control (CT-iPVEC) and cirrhotic rats (CH-iPVEC) by retroviral transduction of the SV40 T antigen. We assessed differential gene expression and intracellular reactive oxygen species (ROS) levels in iPVECs and in portal veins of control and cirrhotic rats. Finally, we assessed the therapeutic effectiveness of cerium oxide nanoparticles (CeO2NP) on reversing PVEC activation and macrophage polarization. Results CH-iPVECs overexpressed collagen-I, endothelin-1, TIMP-1, TIMP-2, IL-6 and PlGF genes. These results were consistent with the differential expression showed by whole portal veins from cirrhotic rats. In addition, CH-iPVECs showed a significant increase in intracellular ROS and the capacity of potentiating M1 polarization in macrophages. The treatment of CH-iPVECs with CeO2NPs blocked intracellular ROS formation and IL-6 and TIMP-2 gene overexpression. In agreement with the in vitro results, the chronic treatment of cirrhotic rats with CeO2NPs also resulted in the blockade of both ROS formation and IL-6 gene overexpression in whole portal veins. Conclusions Endothelial cells from portal vein of cirrhotic rats depicted an abnormal phenotype characterized by a differential gene expression and the induction of M1 polarization in macrophages. We identified the excess of intracellular reactive oxygen species (ROS) as a major contributor to this altered phenotype. In addition, we demonstrated the utility of the nanomaterial cerium oxide as an effective antioxidant capable of reverse some of these pathological features associated with the portal vein in the cirrhosis condition. © 2019 Ribera et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


  • Internalization and toxicological mechanisms of uncoated and PVP-coated cerium oxide nanoparticles in the freshwater alga: Chlamydomonas reinhardtii

    Pulido-Reyes G., Briffa S.M., Hurtado-Gallego J., Yudina T., Leganés F., Puntes V., Valsami-Jones E., Rosal R., Fernández-Piñas F. Environmental Science: Nano; 6 (6): 1959 - 1972. 2019. 10.1039/c9en00363k. IF: 7.704

    Due to the wide range of applications of cerium oxide nanoparticles (CeO2NPs), a risk assessment of their biological effects using environmentally relevant species becomes highly important. There are contradictory reports on the effects of CeO2NPs, which may be related to the use of different types of nanoparticles (NPs) and coatings. CeO2NPs may act as an oxidant causing toxicity or as an antioxidant able to scavenge free radicals. As a consequence of such complexity, the toxicological behaviour of these NPs is still poorly understood. Moreover, little is known about the internalization process of CeO2NPs in algae. There is evidence of CeO2NP-internalization by the green alga Chlamydomonas reinhardtii, but the mechanism and route of uptake are still unknown. In this study, we used uncoated and different polyvinylpyrrolidone (PVP)-coated CeO2NPs with the aim of identifying their toxicological mechanisms to C. reinhardtii and exploring their possible internalization. Our results showed that PVP coated-CeO2NPs significantly increased the formation of reactive oxygen species in exposed cells, indicating that oxidative stress is an important toxicity mechanism for these particles. Direct contact and damage of the cellular membrane was identified as the mechanism causing the toxicity of uncoated NPs. From experiments with endocytosis inhibitors, clathrin-dependent endocytosis was revealed as the main internalization route for all NPs. However, as uncoated CeO2NPs led to severe cellular membrane damage, direct passage of NPs through membrane holes could not be discarded. To our knowledge, this is the first report with evidence of direct linking between NP internalization and a specific endocytic pathway. The results presented here will help to unravel the toxicological mechanism and behaviour of CeO2NPs and provide input information for the environmental health and safety assessment of CeO2NPs. © 2019 The Royal Society of Chemistry.


  • Kidney nanotoxicity studied in human renal proximal tubule epithelial cell line TH1

    Sramkova M., Kozics K., Masanova V., Uhnakova I., Razga F., Nemethova V., Mazancova P., Kapka-Skrzypczak L., Kruszewski M., Novotova M., Puntes V.F., Gabelova A. Mutation Research - Genetic Toxicology and Environmental Mutagenesis; 845 (403017) 2019. 10.1016/j.mrgentox.2019.01.012. IF: 2.256

    Progressive expansion of nanomaterials in our everyday life raises concerns about their safety for human health. Although kidneys are the primary organs of xenobiotic elimination, little attention has been paid to the kidneys in terms of nanotoxicological studies up to now. Here we investigate the cytotoxic and genotoxic potential of four solid-core uncoated inorganic nanoparticles (TiO2NPs, SiO2NPs, Fe3O4NPs and AuNPs) using the human renal proximal tubule epithelial TH1 cells. To mimic the in vivo conditions more realistic, TH1 cells were exposed in vitro to inorganic NPs under static as well as dynamic conditions for 3 h and 24 h. The medium throughput alkaline comet assay (12 minigels per slide) was employed to evaluate the impact of these NPs on genome integrity and their capacity to produce oxidative lesions to DNA. The accumulation and localization of studied inorganic NPs inside the cells was monitored by transmission electron microscopy (TEM) and the efficacy of internalization of particular NPs was determined by atomic absorption spectroscopy (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). From all the tested NPs, only Fe3O4NPs induced a slight cytotoxicity in TH1 cells exposed to high concentrations (>700 μg/ml) for 24 h. On the other hand, the inorganic NPs did not increase significantly the level of DNA strand breaks or oxidative DNA damage regardless of the treatment mode (static vs. dynamic conditions). Interestingly, substantial differences were observed in the internalized amount of inorganic NPs in TH1 cells exposed to equivalent (2.2 μg/ml) concentration. Fe3O4NPs were most efficiently taken up while the lowest quantity of particles was determined in TiO2NPs-treated cells. As the particle size and shape of individual inorganic NPs in culture medium was nearly identical, it is reasonable to suppose that the chemical composition may contribute to the differences in the efficacy of NPs uptake. © 2019 The Authors


  • Robust one-pot synthesis of citrate-stabilized Au@CeO 2 hybrid nanocrystals with different thickness and dimensionality

    Bastús N.G., Piella J., Perez S., Patarroyo J., Genç A., Arbiol J., Puntes V. Applied Materials Today; 15: 445 - 452. 2019. 10.1016/j.apmt.2019.03.003. IF: 8.013

    Well-defined colloidal Au@CeO 2 hybrid nanocrystals (NCs) comprising different core/shell morphologies have been synthesized via a novel and simple one-pot aqueous approach. The method allows producing hybrid morphologies composed by an active and accessible Au core coated by a porous CeO 2 shell with varying shell thickness and dimensionality by simply adjusting the Au 3+ /Ce 3+ precursor ratio. These hybrid NCs are highly monodisperse and well-dispersed in water, showing intense surface plasmon resonance bands that offer unique opportunities for advanced material applications, such as plasmonics and catalysis. © 2019 Elsevier Ltd


2018

  • Aging reduces the toxicity of pristine but not sulphidised silver nanoparticles to soil bacteria

    Schultz C.L., Gray J., Verweij R.A., Busquets-Fité M., Puntes V., Svendsen C., Lahive E., Matzke M. Environmental Science: Nano; 5 (11): 2618 - 2630. 2018. 10.1039/C8EN00054A. IF: 6.087

    In the environment engineered nanoparticles (ENPs) are subject to chemical and physical transformation processes. Thus, to understand their impact, it is important to consider how bioavailability and toxicity are influenced by these “aging” transformations with relation to environmental conditions and ENP properties. Here, two soil bacteria were exposed to Ag ENPs in ISO media (± fulvic acid) and soil pore water extracts with pH 6 and pH 8. The ENPs tested were 49 nm unfunctionalised, citrate stabilised (Ag-citr), 58 nm PVP-coated (Ag-PVP) and 36 nm sulphidised (Ag2S-PVP); AgNO3 was used as a positive control. Exposures were carried out using pristine (unaged) and 24 h aged ENPs, and the 24 h soluble fraction. Overall, toxicity was ranked AgNO3 > Ag-PVP ≥ Ag-citr ≫ Ag2S. Aging of AgNO3, Ag-PVP and Ag-citr in the ISO medium caused little change from unaged exposures and growth inhibition was mainly caused by soluble silver. Added fulvic acid decreased silver toxicity after aging and reduced the contribution of dissolution; as was the case in the soil pore waters where toxicity could not be attributed to ionic silver. Ag2S toxicity to A. globiformis in both ISO variants increased after aging, yet followed the same patterns as the metallic ENPs in the pore waters. For all ENPs pH effects were species dependent. Together this data showed that aging reduced toxicity in media with organic matter and despite soluble silver being the main driver of pristine ENP toxicity in the standard ISO medium, dissolution did not fully explain toxicity in the presence of organic matter. © The Royal Society of Chemistry.


  • Characterization of nanoparticle batch-to-batch variability

    Mülhopt S., Diabaté S., Dilger M., Adelhelm C., Anderlohr C., Bergfeldt T., de la Torre J.G., Jiang Y., Valsami-Jones E., Langevin D., Lynch I., Mahon E., Nelissen I., Piella J., Puntes V., Ray S., Schneider R., Wilkins T., Weiss C., Paur H.-R. Nanomaterials; 8 (5, 311) 2018. 10.3390/nano8050311. IF: 3.504

    A central challenge for the safe design of nanomaterials (NMs) is the inherent variability of NM properties, both as produced and as they interact with and evolve in, their surroundings. This has led to uncertainty in the literature regarding whether the biological and toxicological effects reported for NMs are related to specific NM properties themselves, or rather to the presence of impurities or physical effects such as agglomeration of particles. Thus, there is a strong need for systematic evaluation of the synthesis and processing parameters that lead to potential variability of different NM batches and the reproducible production of commonly utilized NMs. The work described here represents over three years of effort across 14 European laboratories to assess the reproducibility of nanoparticle properties produced by the same and modified synthesis routes for four of the OECD priority NMs (silica dioxide, zinc oxide, cerium dioxide and titanium dioxide) as well as amine-modified polystyrene NMs, which are frequently employed as positive controls for nanotoxicity studies. For 46 different batches of the selected NMs, all physicochemical descriptors as prioritized by the OECD have been fully characterized. The study represents the most complete assessment of NMs batch-to-batch variability performed to date and provides numerous important insights into the potential sources of variability of NMs and how these might be reduced. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.


  • Effects of Systematic Variation in Size and Surface Coating of Silver Nanoparticles on Their In Vitro Toxicity to Macrophage RAW 264.7 Cells

    Makama S., Kloet S.K., Piella J., van den Berg H., de Ruijter N.C.A., Puntes V.F., Rietjens I.M.C.M., van den Brink N.W. Toxicological sciences : an official journal of the Society of Toxicology; 162 (1): 79 - 88. 2018. 10.1093/toxsci/kfx228. IF: 4.181

    In literature, varying and sometimes conflicting effects of physicochemical properties of nanoparticles (NPs) are reported on their uptake and effects in organisms. To address this, small- and medium-sized (20 and 50 nm) silver nanoparticles (AgNPs) with specified different surface coating/charges were synthesized and used to systematically assess effects of NP-properties on their uptake and effects in vitro. Silver nanoparticles were fully characterized for charge and size distribution in both water and test media. Macrophage cells (RAW 264.7) were exposed to these AgNPs at different concentrations (0-200 µg/ml). Uptake dynamics, cell viability, induction of tumor necrosis factor (TNF)-α, ATP production, and reactive oxygen species (ROS) generation were assessed. Microscopic imaging of living exposed cells showed rapid uptake and subcellular cytoplasmic accumulation of AgNPs. Exposure to the tested AgNPs resulted in reduced overall viability. Influence of both size and surface coating (charge) was demonstrated, with the 20-nm-sized AgNPs and bovine serum albumin (BSA)-coated (negatively charged) AgNPs being slightly more toxic. On specific mechanisms of toxicity (TNF-α and ROS production) however, the AgNPs differed to a larger extent. The highest induction of TNF-α was found in cells exposed to the negatively charged AgNP_BSA, both sizes (80× higher than control). Reactive oxygen species induction was only significant with the 20 nm positively charged AgNP_Chit.


  • Fluorescently labelled nanomaterials in nanosafety research: Practical advice to avoid artefacts and trace unbound dye

    Murray R.A., Escobar A., Bastús N.G., Andreozzi P., Puntes V., Moya S.E. NanoImpact; 9: 102 - 113. 2018. 10.1016/j.impact.2017.11.001. IF: 0.000

    Fluorescence labelling has become a fundamental tool in nanotoxicological research. There are, however, certain drawbacks when dealing with the labelling of nanomaterials. Very often the leaching of dye from the nanomaterial or the presence of unbound dyes in solution leads to the incorrect quantification and localisation of nanomaterials in cells. In this review article we will discuss possible situations, which may give rise to incorrect quantification of the fluorescence associated with nanomaterials and their consequences in the evaluation of the fate of the nanomaterial and its intracellular dose. Issues related to the labelling strategies, dye photostability, impact of the dye on the properties of the nanomaterial surface, and the presence of unbound dye will be discussed. We will also show how Fluorescence Correlation Spectroscopy can be used to trace the presence of free label in solution. In addition, we will discuss the interaction of fluorescence molecules with metallic nanoparticles which can lead to an enhancement or quenching of fluorescence depending on the distance between the dye and the nanoparticle surface. Finally, we will compare the fluorescence emission originating from quantum dots and organic molecules. © 2017 Elsevier B.V.


  • Influence of soil porewater properties on the fate and toxicity of silver nanoparticles to Caenorhabditis elegans

    Schultz C.L., Lahive E., Lawlor A., Crossley A., Puntes V., Unrine J.M., Svendsen C., Spurgeon D.J. Environmental Toxicology and Chemistry; 37 (10): 2609 - 2618. 2018. 10.1002/etc.4220. IF: 3.179

    Engineered nanoparticles (NPs) entering the environment are subject to various transformations that in turn influence how particles are presented to, and taken up by, organisms. To understand the effect of soil properties on the toxicity of nanosilver to Caenorhabditis elegans, toxicity assays were performed in porewater extracts from natural soils with varying organic matter content and pH using 3–8 nm unfunctionalized silver (Ag 3–8Unf), 52-nm polyvinylpyrrolidone (PVP)-coated Ag NPs (Ag 52PVP), and AgNO 3 as ionic Ag. Effects on NP agglomeration and stability were investigated using ultraviolet-visible (UV-vis) spectroscopy and asymmetric flow field-flow fractionation (AF4); Ag + showed greater overall toxicity than nanosilver, with little difference between the NP types. Increasing soil organic matter content significantly decreased the toxicity of Ag 3–8Unf, whereas it increased that of AgNO 3 . The toxicity of all Ag treatments significantly decreased with increasing porewater pH. Dissolution of both NPs in the porewater extracts was too low to have contributed to their observed toxic effects. The UV-vis spectroscopy revealed low levels of agglomeration/aggregation independent of soil properties for Ag 3–8Unf, whereas higher organic matter as well as low pH appeared to stabilize Ag 52PVP. Overall, both soil organic matter content and pH affected NP fate as well as toxicity to C. elegans; however, there appears to be no clear connection between the measured particle characteristics and their effect. Environ Toxicol Chem 2018;37:2609–2618. © 2018 SETAC. © 2018 SETAC


  • Inter-laboratory comparison of nanoparticle size measurements using dynamic light scattering and differential centrifugal sedimentation

    Langevin D., Lozano O., Salvati A., Kestens V., Monopoli M., Raspaud E., Mariot S., Salonen A., Thomas S., Driessen M., Haase A., Nelissen I., Smisdom N., Pompa P.P., Maiorano G., Puntes V., Puchowicz D., Stępnik M., Suárez G., Riediker M., Benetti F., Mičetić I., Venturini M., Kreyling W.G., van der Zande M., Bouwmeester H., Milani S., Rädler J.O., Mülhopt S., Lynch I., Dawson K. NanoImpact; 10: 97 - 107. 2018. 10.1016/j.impact.2017.12.004. IF: 0.000

    Nanoparticle in vitro toxicity studies often report contradictory results with one main reason being insufficient material characterization. In particular the characterization of nanoparticles in biological media remains challenging. Our aim was to provide robust protocols for two of the most commonly applied techniques for particle sizing, i.e. dynamic light scattering (DLS) and differential centrifugal sedimentation (DCS) that should be readily applicable also for users not specialized in nanoparticle physico-chemical characterization. A large number of participants (40, although not all participated in all rounds) were recruited for a series of inter-laboratory comparison (ILC) studies covering many different instrument types, commercial and custom-built, as another possible source of variation. ILCs were organized in a consecutive manner starting with dispersions in water employing well-characterized near-spherical silica nanoparticles (nominal 19 nm and 100 nm diameter) and two types of functionalized spherical polystyrene nanoparticles (nominal 50 nm diameter). At first each laboratory used their in-house established procedures. In particular for the 19 nm silica particles, the reproducibility of the methods was unacceptably high (reported results were between 10 nm and 50 nm). When comparing the results of the first ILC round it was observed that the DCS methods performed significantly worse than the DLS methods, thus emphasizing the need for standard operating procedures (SOPs). SOPs have been developed by four expert laboratories but were tested for robustness by a larger number of independent users in a second ILC (11 for DLS and 4 for DCS). In a similar approach another SOP for complex biological fluids, i.e. cell culture medium containing serum was developed, again confirmed via an ILC with 8 participating laboratories. Our study confirms that well-established and fit-for-purpose SOPs are indispensable for obtaining reliable and comparable particle size data. Our results also show that these SOPs must be optimized with respect to the intended measurement system (e.g. particle size technique, type of dispersant) and that they must be sufficiently detailed (e.g. avoiding ambiguity regarding measurand definition, etc.). SOPs may be developed by a small number of expert laboratories but for their widespread applicability they need to be verified by a larger number of laboratories. © 2017 Elsevier B.V.


  • Low-Cost Strategy for the Development of a Rapid Electrochemical Assay for Bacteria Detection Based on AuAg Nanoshells

    Russo L., Leva Bueno J., Bergua J.F., Costantini M., Giannetto M., Puntes V., De La Escosura-Muñiz A., Merkoçi A. ACS Omega; 3 (12): 18849 - 18856. 2018. 10.1021/acsomega.8b02458.

    A low-cost strategy for the simple and rapid detection of bacterial cells in biological matrixes is presented herein. Escherichia coli and Salmonella typhimurium were chosen as model bacteria for the development of an electrochemical assay based on hollow AuAg nanoshells (NSs). By taking advantage of their electrocatalytic properties for the in situ generation of the electrochemical signal without the need of any other kind of reagent, substrate, or redox enzyme, high sensitivities (down to 102 CFU/mL) were achieved. Moreover, the recognition and discrimination of the model bacterial cells in the sample matrix was possible by relying solely on nonspecific affinity interactions between their cell walls and AuAg NSs surface, avoiding the use of expensive and fragile biological receptor. Compared to traditional, laboratory-based analytical tests available, this assay provides a promising proof-of-concept alternative that allows to obtain good sensitivities and selectivity in very short times in addition to the low cost. © 2018 American Chemical Society.


  • Nanosafety: Towards safer nanoparticles by design

    Bastús N.G., Puntes V. Current Medicinal Chemistry; 25 (35): 4587 - 4601. 2018. 10.2174/0929867324666170413124915. IF: 3.469

    Background: Nanosafety aims for a solution through the safer design (and re-design) of nanostructured materials, optimizing both performance and safety, by resolving which structural features lead to the desired properties and modifying them to avoid their detrimental effects without losing their desired nanoscale properties in the process. Starting with known toxic NPs, the final aim should be the re-design of such detrimental specific NP characteristics and to redefine the way they should be manipulated from the beginning to the end of their life cycle. Methods: The researchers reviewed literature in the area of novel nanosafety strategies addressing the “safe-by-design” paradigm. Results: The potential hazards of engineered NPs are not only determined by the physicochemical properties of the engineered NPs per se but also on the interactions of these NPs with immediate surrounding environments. The aim of promoting the timely and safe development of NPs cannot be achieved via traditional studies as they address one material at one time. The development of a safer design strategy of engineered NPs requires an understanding of both intrinsic (synthetic) properties together with their extrinsic responses to external stimuli. Conclusions: We have summarized recent developments of novel nanosafety strategies addressing the “safe-by-design” paradigm for optimizing both performance and safety, allowing the comparison of results of different studies and ultimately providing guidelines for the re-design of safer NPs. The resulting discussion is intended to provide guidelines for synthetic nanochemists on how to design NPs to be safe during their full life cycle while maintaining their parental desired properties. © 2018 Bentham Science Publishers.


  • Nanotechnology for maternal foetal medicine

    Eudald Casals, Muriel F. Gusta, Lena Montana, Manel Mendoza, Nerea Maiz, Elena Carreras, Victor Puntes International Journal of Pediatrics and Neonatal Health; 2 (5): 55 - 64. 2018. ISSN: 2572-4355.

    Last decade has seen a flourishing in the study of the properties of inorganic nanoparticles (NPs) for their application in medicine. Inorganic NPs behave as “artificial atoms” since their high density of electronic states -which controls many physical properties- can be extensively and easily tuned by adjusting composition, size, shape and surface state. Consequently, nanotechnology’s ability to shape matter at the scale of biomolecules has opened the door to a new generation of diagnostics, imaging agents and drugs for detecting and treating disease. But perhaps even more important, nanotechnology is allowing to combine a series of advances into a single NP, creating nanosized objects that at the same time may contain drugs designed to kill tumoral cells or pathogenic invaders, together with targeting compounds designed to home-in on malignancies and target tissue, and be imaging agents designed to light up even the earliest stage of disease. Besides, it is becoming widely known that none of the existing single-modality treatments such as chemotherapy, radiotherapy, immunotherapy, gene therapy or thermotherapy can cure complex fatal diseases such as cancer or preeclampsia by itself. Consequently, a combination of treatments, such as combination of chemotherapy (combining more than one drug), chemotherapy and gene therapy, thermotherapy, radiotherapy or biotherapy, are being investigated for their synergistic effects that may dramatically improve outcomes and reduce the side effects of each single modality treatment. This is because therapeutic effects are designed to add up while side effects do not. In this context, NPs appear as ideal platforms for multimodal therapy in the special case of maternal fetal medicine where treatment for the mother and the foetus has to be differential


  • Plasmonic assemblies of gold nanorods on nanoscale patterns of poly(ethylene glycol): Application in surface-enhanced Raman spectroscopy

    Karabel Ocal S., Patarroyo J., Kiremitler N.B., Pekdemir S., Puntes V.F., Onses M.S. Journal of Colloid and Interface Science; 532: 449 - 455. 2018. 10.1016/j.jcis.2018.07.124. IF: 5.091

    Approaches are needed for the tailored assembly of plasmonic building blocks on the surface of substrates to synergistically enhance their properties. Here we demonstrate selective immobilization and assembly of gold nanorods (NRs) on substrates modified and patterned with end-grafted poly(ethylene glycol) (PEG) layers. The ligand exchange from the initial cetyltrimethylammonium bromide to sodium citrate was necessary for the immobilization of gold NRs onto PEG grafted substrates. Linear nanopatterns of PEG were fabricated using electrospun nanofibers as masks in oxygen plasma etching. The selective immobilization of citrate-stabilized gold NRs with a length of ∼50 nm and a width of 20 nm on the nanopatterned PEG layers led to linear and registered arrays of rods. The number of gold NRs per line depended on the width of the patterns and approached 1 when the width of the patterns was comparable to the length of the rods. The confinement of the binding regions led to a ∼3 fold increase in the number of gold NRs immobilized per unit area. The selective and dense immobilization of gold NRs on the nanoscale patterns of PEG resulted in spatially defined and strong surface-enhanced Raman scattering activity enabling detection of molecules at concentrations as low as 1 nM. © 2018


  • Sequential Deconstruction-Reconstruction of Metal-Organic Frameworks: An Alternative Strategy for Synthesizing (Multi)-Layered ZIF Composites

    Avci C., Yazdi A., Tarrés M., Bernoud E., Bastús N.G., Puntes V., Imaz I., Ribas X., Maspoch D. ACS Applied Materials and Interfaces; 10 (28): 23952 - 23960. 2018. 10.1021/acsami.8b05098. IF: 8.097

    Here, we report the synthesis of (multi)-layered zeolitic imidazolate framework (ZIF-8/-67) composite particles via a sequential deconstruction-reconstruction process. We show that this process can be applied to construct ZIF-8-on-ZIF-67 composite particles whose cores are the initially etched particles. In addition, we demonstrate that introduction of functional inorganic nanoparticles (INPs) onto the crystal surface of etched particles does not disrupt ZIF particle reconstruction, opening new avenues for designing (multi)-layered ZIF-on-INP-on-ZIF composite particles comprising more than one class of inorganic nanoparticles. In these latter composites, the location of the inorganic nanoparticles inside each single metal-organic framework particle as well as of their separation at the nanoscale (20 nm) is controlled. Preliminary results show that (multi)-layered ZIF-on-INP-on-ZIF composite particles comprising a good sequence of inorganic nanoparticles can potentially catalyze cascade reactions. Copyright © 2018 American Chemical Society.


  • Time- and Size-Resolved Plasmonic Evolution with nm Resolution of Galvanic Replacement Reaction in AuAg Nanoshells Synthesis

    Russo L., Merkoçi F., Patarroyo J., Piella J., Merkoçi A., Bastús N.G., Puntes V. Chemistry of Materials; 30 (15): 5098 - 5107. 2018. 10.1021/acs.chemmater.8b01488. IF: 9.890

    The rational design of advanced nanomaterials with enhanced optical properties can be reached only with the profound thermodynamic and kinetic understanding of their synthetic processes. In this work, the synthesis of monodisperse AuAg nanoshells with thin shells and large voids is achieved through the development of a highly reproducible and robust methodology based on the galvanic replacement reaction. This is obtained thanks to the systematic identification of the role played by the different synthetic parameters involved in the process (such as surfactants, co-oxidizers, complexing agents, time, and temperature), providing an unprecedented control over the material's morphological and optical properties. Thus, the time- and size-resolved evolution of AuAg nanoshells surface plasmon resonance band is described for 15, 30, 60, 80, 100, and 150 nm-sized particles spanning almost through the entire visible spectrum. Its analysis reveals a four-phase mechanism coherent with the material's morphological transformation. Simulations based on Mie's theory confirm the observed optical behavior in AuAg nanoshells formation and provide insights into the influence of the Au/Ag ratio on their plasmonic properties. The high degree of morphological control provided by this methodology represents a transferable and scalable strategy for the development of advanced-generation plasmonic nanomaterials. © 2018 American Chemical Society.


  • Tunable electrochemistry of gold-silver alloy nanoshells

    Russo L., Puntes V., Merkoçi A. Nano Research; 11 (12): 6336 - 6345. 2018. 10.1007/s12274-018-2157-y. IF: 7.994

    The widespread and increasing interest in enhancing biosensing technologies by increasing their sensitivities and lowering their costs has led to the exploration and application of complex nanomaterials as signal transducers and enhancers. In this work, the electrochemical properties of monodispersed AuAg alloy nanoshells (NSs) with finely tunable morphology, composition, and size are studied to assess their potential as electroactive labels. The controlled corrosion of their silver content, caused by the oxidizing character of dissolved oxygen and chlorides of the electrolyte, allows the generation of a reproducible electrochemical signal that is easily measurable through voltammetric techniques. Remarkably, the underpotential deposition of dissolved Ag+ catalyzed on AuAg NS surfaces is observed and its dependence on the nanoparticle morphology, size, and elemental composition is studied, revealing a strong correlation between the relative amounts of the two metals. The highest catalytic activity is found at Au/Ag ratios higher than ≈ 10, showing how the synergy between both metals is necessary to trigger the enhancement of Ag+ reduction. The ability of AuAg NSs to generate an electrocatalytic current without the need for any strong acid makes them an extremely promising material for biosensing applications. [Figure not available: see fulltext.]. © 2018, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.


2017

  • Assembly of Plasmonic Nanoparticles on Nanopatterns of Polymer Brushes Fabricated by Electrospin Nanolithography

    Kiremitler N.B., Pekdemir S., Patarroyo J., Karabel S., Torun I., Puntes V.F., Onses M.S. ACS Macro Letters; 6 (6): 603 - 608. 2017. 10.1021/acsmacrolett.7b00288. IF: 6.185

    This paper presents electrospin nanolithography (ESPNL) for versatile and low-cost fabrication of nanoscale patterns of polymer brushes to serve as templates for assembly of metallic nanoparticles. Here electrospun nanofibers placed on top of a substrate grafted with polymer brushes serve as masks. The oxygen plasma etching of the substrate followed by removal of the fibers leads to linear patterns of polymer brushes. The line-widths as small as ∼50 nm can be achieved by precise tuning of the diameter of fibers, etching condition, and fiber-substrate interaction. Highly aligned and spatially defined patterns can be fabricated by operating in the near-field electrospinning regime. Patterns of polymer brushes with two different chemistries effectively directed the assembly of gold nanoparticles and silver nanocubes. Nanopatterned brushes imparted strong confinement effects on the assembly of plasmonic nanoparticles and resulted in strong localization of electromagnetic fields leading to intense signals in surface-enhanced Raman spectroscopy. The scalability and simplicity of ESPNL hold great promise in patterning of a broad range of polymer thin films for different applications. © 2017 American Chemical Society.


  • Bacterial endotoxin (lipopolysaccharide) binds to the surface of gold nanoparticles, interferes with biocorona formation and induces human monocyte inflammatory activation

    Li Y., Shi Z., Radauer-Preiml I., Andosch A., Casals E., Luetz-Meindl U., Cobaleda M., Lin Z., Jaberi-Douraki M., Italiani P., Horejs-Hoeck J., Himly M., Monteiro-Riviere N.A., Duschl A., Puntes V.F., Boraschi D. Nanotoxicology; 11 (9-10): 1157 - 1175. 2017. 10.1080/17435390.2017.1401142. IF: 6.428

    Nanoparticles (NPs) are easily contaminated by bacterial endotoxin (lipopolysaccharide [LPS]). The presence of LPS can be responsible for many immune/inflammatory effects attributed to NPs. In this study, we examined the effects of LPS adsorption on the NP surface on the formation of a biocorona in biological fluids and on the subsequent inflammation-inducing activity of NPs. Different gold (Au) NPs with sizes ranging from 10 to 80 nm and with different surface functionalization (sodium citrate, lipoic acid, and branched polyethyleneimine (BPEI), or polyethylene glycol (PEG)) were exposed to E. coli LPS under different conditions. The binding capacity of LPS to the surface of AuNPs was dose- and time-dependent. LPS attached to sodium citrate and lipoic acid coatings, but did not adhere to BPEI- or PEG-coated NPs. By computational simulation, the binding of LPS to AuNPs seems to follow the Langmuir absorption isotherm. The presence of LPS on AuNP surface interfered and caused a decrease in the formation of the expected biomolecular corona upon incubation in human plasma. LPS-coated AuNPs, but not the LPS-free NPs, induced significant inflammatory responses in vitro. Notably, while free LPS did also induce an anti-inflammatory response, LPS bound to NPs appeared unable to do so. In conclusion, the unintentional adsorption of LPS onto the NP surface can affect the biocorona formation and the inflammatory properties of NPs. Thus, for an accurate interpretation of NP interactions with cells, it is extremely important to be able to distinguish the intrinsic NP biological effects from those caused by biologically active contaminants such as endotoxin. © 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.


  • Cancer resistance to treatment and antiresistance tools offered by multimodal multifunctional nanoparticles

    Casals E., Gusta M.F., Cobaleda-Siles M., Garcia-Sanz A., Puntes V.F. Cancer Nanotechnology; 8 (1, 7) 2017. 10.1186/s12645-017-0030-4.

    Chemotherapeutic agents have limited efficacy and resistance to them limits today and will limit tomorrow our capabilities of cure. Resistance to treatment with anticancer drugs results from a variety of factors including individual variations in patients and somatic cell genetic differences in tumours. In front of this, multimodality has appeared as a promising strategy to overcome resistance. In this context, the use of nanoparticle-based platforms enables many possibilities to address cancer resistance mechanisms. Nanoparticles can act as carriers and substrates for different ligands and biologically active molecules, antennas for imaging, thermal and radiotherapy and, at the same time, they can be effectors by themselves. This enables their use in multimodal therapies to overcome the wall of resistance where conventional medicine crash as ageing of the population advance. In this work, we review the cancer resistance mechanisms and the advantages of inorganic nanomaterials to enable multimodality against them. In addition, we comment on the need of a profound understanding of what happens to the nanoparticle-based platforms in the biological environment for those possibilities to become a reality. © 2017, The Author(s).


  • Cationic liposomal vectors incorporating a bolaamphiphile for oligonucleotide antimicrobials

    Mamusa M., Sitia L., Barbero F., Ruyra A., Calvo T.D., Montis C., Gonzalez-Paredes A., Wheeler G.N., Morris C.J., McArthur M., Berti D. Biochimica et Biophysica Acta - Biomembranes; 1859 (10): 1767 - 1777. 2017. 10.1016/j.bbamem.2017.06.006. IF: 3.498

    Antibacterial resistance has become a serious crisis for world health over the last few decades, so that new therapeutic approaches are strongly needed to face the threat of resistant infections. Transcription factor decoys (TFD) are a promising new class of antimicrobial oligonucleotides with proven in vivo activity when combined with a bolaamphiphilic cationic molecule, 12-bis-THA. These two molecular species form stable nanoplexes which, however, present very scarce colloidal stability in physiological media, which poses the challenge of drug formulation and delivery. In this work, we reformulated the 12-bis-THA/TFD nanoplexes in a liposomal carrier, which retains the ability to protect the oligonucleotide therapeutic from degradation and deliver it across the bacterial cell wall. We performed a physical-chemical study to investigate how the incorporation of 12-bis-THA and TFD affects the structure of POPC- and POPC/DOPE liposomes. Analysis was performed using dynamic light scattering (DLS), ζ-potential measurements, small-angle x-ray scattering (SAXS), and steady-state fluorescence spectroscopy to better understand the structure of the liposomal formulations containing the 12-bis-THA/TFD complexes. Oligonucleotide delivery to model Escherichia coli bacteria was assessed by means of confocal scanning laser microscopy (CLSM), evidencing the requirement of a fusogenic helper lipid for transfection. Preliminary biological assessments suggested the necessity of further development by modulation of 12-bis-THA concentration in order to optimize its therapeutic index, i.e. the ratio of antibacterial activity to the observed cytotoxicity. In summary, POPC/DOPE/12-bis-THA liposomes appear as promising formulations for TFD delivery. © 2017 Elsevier B.V.


  • Confining Functional Nanoparticles into Colloidal Imine-Based COF Spheres by a Sequential Encapsulation–Crystallization Method

    Rodríguez-San-Miguel D., Yazdi A., Guillerm V., Pérez-Carvajal J., Puntes V., Maspoch D., Zamora F. Chemistry - A European Journal; 23 (36): 8623 - 8627. 2017. 10.1002/chem.201702072. IF: 5.317

    Here, a two-step method is reported that enables imparting new functionalities to covalent organic frameworks (COFs) by nanoparticle confinement. The direct reaction between 1,3,5-tris(4-aminophenyl)benzene and 1,3,5-benzenetricarbaldehyde in the presence of a variety of metallic/metal-oxide nanoparticles resulted in embedding of the nanoparticles in amorphous and non-porous imine-linked polymer organic spheres (NP@a-1). Post-treatment reactions of NP@a-1 with acetic acid under reflux led to crystalline and porous imine-based COF-hybrid spheres (NP@c-1). Interestingly, Au@c-1 and Pd@c-1 were found to be catalytically active. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim


  • Conserved effects and altered trafficking of Cetuximab antibodies conjugated to gold nanoparticles with precise control of their number and orientation

    García-Fernández L., Garcia-Pardo J., Tort O., Prior I., Brust M., Casals E., Lorenzo J., Puntes V.F. Nanoscale; 9 (18): 6111 - 6121. 2017. 10.1039/c7nr00947j. IF: 7.367

    Gold nanoparticles (17 nm) have been functionalized with the antiangiogenic monoclonal antibody drug Cetuximab at a well-defined orientation and coverage density of antibodies. Functionalization has been carried out through site-directed chemistry via the selective oxidation of the carbohydrate moiety of antibodies linked to a thiolated hydrazide. A431 tumor cells have been exposed to these conjugates for in vitro evaluation of their effects. In addition to epithelial growth factor receptor blocking, trafficking and signaling alterations were also observed. Thus, the blocking effects of Cetuximab were increased and sustained for a longer time when associated with the nanoparticles. Enhancing antibody therapy effects by decreasing the needed dose and prolonging its effect by avoiding receptor recycling may serve to obtain increased therapeutic benefits for immunotherapy. © The Royal Society of Chemistry 2017.


  • Core-shell Au/CeO2 nanoparticles supported in UiO-66 beads exhibiting full CO conversion at 100 °c

    Yazdi A., Abo Markeb A., Garzón-Tovar L., Patarroyo J., Moral-Vico J., Alonso A., Sánchez A., Bastus N., Imaz I., Font X., Puntes V., Maspoch D. Journal of Materials Chemistry A; 5 (27): 13966 - 13970. 2017. 10.1039/c7ta03006a. IF: 8.867

    Hybrid core-shell Au/CeO2 nanoparticles (NPs) dispersed in UiO-66 shaped into microspherical beads are created using the spray-drying continuous-flow method. The combined catalytic properties of nanocrystalline CeO2 and Au in a single particle and the support and protective function of porous UiO-66 beads make the resulting composites show good performances as catalysts for CO oxidation (T50 = 72 °C; T100 = 100 °C) and recyclability. © 2017 The Royal Society of Chemistry.


  • Critical review of existing nanomaterial adsorbents to capture carbon dioxide and methane

    Alonso A., Moral-Vico J., Abo Markeb A., Busquets-Fité M., Komilis D., Puntes V., Sánchez A., Font X. Science of the Total Environment; 595: 51 - 62. 2017. 10.1016/j.scitotenv.2017.03.229. IF: 4.900

    Innovative gas capture technologies with the objective to mitigate CO2 and CH4 emissions are discussed in this review. Emphasis is given on the use of nanoparticles (NP) as sorbents of CO2 and CH4, which are the two most important global warming gases. The existing NP sorption processes must overcome certain challenges before their implementation to the industrial scale. These are: i) the utilization of the concentrated gas stream generated by the capture and gas purification technologies, ii) the reduction of the effects of impurities on the operating system, iii) the scale up of the relevant materials, and iv) the retrofitting of technologies in existing facilities. Thus, an innovative design of adsorbents could possibly address those issues. Biogas purification and CH4 storage would become a new motivation for the development of new sorbent materials, such as nanomaterials. This review discusses the current state of the art on the use of novel nanomaterials as adsorbents for CO2 and CH4. The review shows that materials based on porous supports that are modified with amine or metals are currently providing the most promising results. The Fe3O4-graphene and the MOF-117 based NPs show the greatest CO2 sorption capacities, due to their high thermal stability and high porosity. Conclusively, one of the main challenges would be to decrease the cost of capture and to scale-up the technologies to minimize large-scale power plant CO2 emissions. © 2017 Elsevier B.V.


  • Diverse Applications of Nanomedicine

    Pelaz B., Alexiou C., Alvarez-Puebla R.A., Alves F., Andrews A.M., Ashraf S., Balogh L.P., Ballerini L., Bestetti A., Brendel C., Bosi S., Carril M., Chan W.C.W., Chen C., Chen X., Chen X., Cheng Z., Cui D., Du J., Dullin C., Escudero A., Feliu N., Gao M., George M., Gogotsi Y., Grünweller A., Gu Z., Halas N.J., Hampp N., Hartmann R.K., Hersam M.C., Hunziker P., Jian J., Jiang X., Jungebluth P., Kadhiresan P., Kataoka K., Khademhosseini A., Kopeček J., Kotov N.A., Krug H.F., Lee D.S., Lehr C.-M., Leong K.W., Liang X.-J., Ling Lim M., Liz-Marzán L.M., Ma X., Macchiarini P., Meng H., Möhwald H., Mulvaney P., Nel A.E., Nie S., Nordlander P., Okano T., Oliveira J., Park T.H., Penner R.M., Prato M., Puntes V., Rotello V.M., Samarakoon A., Schaak R.E., Shen Y., Sjöqvist S., Skirtach A.G., Soliman M.G., Stevens M.M., Sung H.-W., Tang B.Z., Tietze R., Udugama B.N., VanEpps J.S., Weil T., Weiss P.S., Willner I., Wu Y., Yang L., Yue Z., Zhang Q., Zhang Q., Zhang X.-E., Zhao Y., Zhou X., Parak W.J. ACS Nano; 11 (3): 2313 - 2381. 2017. 10.1021/acsnano.6b06040. IF: 13.942

    The design and use of materials in the nanoscale size range for addressing medical and health-related issues continues to receive increasing interest. Research in nanomedicine spans a multitude of areas, including drug delivery, vaccine development, antibacterial, diagnosis and imaging tools, wearable devices, implants, high-throughput screening platforms, etc. using biological, nonbiological, biomimetic, or hybrid materials. Many of these developments are starting to be translated into viable clinical products. Here, we provide an overview of recent developments in nanomedicine and highlight the current challenges and upcoming opportunities for the field and translation to the clinic. © 2017 American Chemical Society.


  • Domain Formation and Conformational Changes in Gold Nanoparticle Conjugates Studied Using DPD Simulations

    Raman A., Jaime C., Puntes V.F. Langmuir; 33 (50): 14502 - 14512. 2017. 10.1021/acs.langmuir.7b03318. IF: 3.833

    A gold nanoparticle (AuNP) conjugate formed with 11-mercaptoundecanoic acid (MUA) and thiolated polyethylene glycol (SH-PEG) is simulated using dissipative particle dynamics (DPD) methods, obtaining an excellent agreement with previous experimental observations. The simulations cover the isolated components (AuNP, MUA, and SH-PEG), as well as pairs of components, and finally the all three components at the same time. In this latter case, changes in the order of addition of MUA and SH-PEG over the AuNP are also considered. The AuNP is formed by independent gold beads and keeps an almost spherical shape throughout the simulation. MUA forms micelles of four to six MUA units when dispersed in water, while SH-PEG stays individually and well solvated. When exposed to AuNP, both molecules show a tendency to form patches on the surface. SH-PEG displays two different conformations (radial and tangential) depending on its relative concentration and the presence of other molecules at the NP surface. When combined at subsaturation concentrations, MUA arrives faster to the AuNP surface than SH-PEG and forms patches while SH-PEG occupies the remaining free surface. In these conditions, the order of addition of the different components partially alters these results. When SH-PEG is added over an already formed MUA/AuNP partial layer, it adopts a radial conformation over the MUA formed patches; on the contrary, if MUA is added over an already formed SH-PEG/AuNP partial layer, much less SH-PEGs adopt a radial conformation and MUA patches are significantly smaller. © 2017 American Chemical Society.


  • Formation of the Protein Corona: The Interface between Nanoparticles and the Immune System

    Barbero F., Russo L., Vitali M., Piella J., Salvo I., Borrajo M.L., Busquets-Fité M., Grandori R., Bastús N.G., Casals E., Puntes V. Seminars in Immunology; 34: 52 - 60. 2017. 10.1016/j.smim.2017.10.001. IF: 9.611

    The interaction of inorganic nanoparticles and many biological fluids often withstands the formation of a Protein Corona enveloping the nanoparticle. This Protein Corona provides the biological identity to the nanoparticle that the immune system will detect. The formation of this Protein Corona depends not only on the composition of the nanoparticle, its size, shape, surface state and exposure time, but also on the type of media, nanoparticle to protein ratio and the presence of ions and other molecular species that interfere in the interaction between proteins and nanoparticles. This has important implications on immune safety, biocompatibility and the use of nanoparticles in medicine. © 2017 Elsevier Ltd


  • Hollow metal nanostructures for enhanced plasmonics: Synthesis, local plasmonic properties and applications

    Genç A., Patarroyo J., Sancho-Parramon J., Bastús N.G., Puntes V., Arbiol J. Nanophotonics; 6 (1): 193 - 213. 2017. 10.1515/nanoph-2016-0124. IF: 4.492

    Metallic nanostructures have received great attention due to their ability to generate surface plasmon resonances, which are collective oscillations of conduction electrons of a material excited by an electromagnetic wave. Plasmonic metal nanostructures are able to localize and manipulate the light at the nanoscale and, therefore, are attractive building blocks for various emerging applications. In particular, hollow nanostructures are promising plasmonic materials as cavities are known to have better plasmonic properties than their solid counterparts thanks to the plasmon hybridization mechanism. The hybridization of the plasmons results in the enhancement of the plasmon fields along with more homogeneous distribution as well as the reduction of localized surface plasmon resonance (LSPR) quenching due to absorption. In this review, we summarize the efforts on the synthesis of hollow metal nanostructures with an emphasis on the galvanic replacement reaction. In the second part of this review, we discuss the advancements on the characterization of plasmonic properties of hollow nanostructures, covering the single nanoparticle experiments, nanoscale characterization via electron energy-loss spectroscopy and modeling and simulation studies. Examples of the applications, i.e. sensing, surface enhanced Raman spectroscopy, photothermal ablation therapy of cancer, drug delivery or catalysis among others, where hollow nanostructures perform better than their solid counterparts, are also evaluated. © 2016 Aziz Genç, Jordi Arbiol et al., published by De Gruyter.


  • Inclusion of oligonucleotide antimicrobials in biocompatible cationic liposomes: A structural study

    Mamusa M., Barbero F., Montis C., Cutillo L., Gonzalez-Paredes A., Berti D. Journal of Colloid and Interface Science; 508: 476 - 487. 2017. 10.1016/j.jcis.2017.08.080. IF: 4.233

    Hypothesis Transcription factor decoys (TFD) are short oligonucleotides designed to block essential genetic pathways in bacteria and defeat resistant infections. TFD protection in biological fluids and their delivery to the site of infection require formulation in appropriate delivery systems. In this work, we build on a classical phosphatidylcholine/phosphatidylethanolamine (POPC/DOPE) scaffold to design TFD-loaded cationic liposomes by combining the DNA-complexing abilities of a bolaamphiphile, (1,1′-(dodecane-1,12-diyl)-bis-(9-amino-1,2,3,4-tetrahydroacridinium) chloride (12-bis-THA), with the biocompatible cationic lipid ethyl-phosphatidylcholine (DPePC). The goal is to perform a structural study to determine the impact of the bolaamphiphile and TFD incorporation on the liposome structure, the capacity for TFD encapsulation, and the colloidal stability in saline media and cell culture environments. Experiments The systems are characterized by means of dynamic light scattering, small-angle X-ray scattering, and ζ-potential measurements, to provide a clear picture of the liposome structure. Circular dichroism (CD) spectroscopy is used to assess the compaction of the oligonucleotide in a psi form, while steady-state fluorescence and fluorescence correlation spectroscopies give insight into the entrapment rate and distribution of the TFD in the liposomes. Findings We found that the combination of the two cationic species, 12-bis-THA and DPePC, allows encapsulation of 90% of the TFD. Results of CD experiments revealed that the TFD is condensed, therefore likely protected from the lytic action of serum nucleases. Finally, the systems showed colloidal stability in aqueous dispersion with ionic strength comparable to biologically relevant media. © 2017 Elsevier Inc.


  • Intrinsic and extrinsic properties affecting innate immune responses to nanoparticles: The case of cerium oxide

    Casals E., Gusta M.F., Piella J., Casals G., Jiménez W., Puntes V. Frontiers in Immunology; 8 (AUG, 970) 2017. 10.3389/fimmu.2017.00970. IF: 6.429

    We review the apparent discrepancies between studies that report anti-inflammatory effects of cerium oxide nanoparticles (CeO2 NPs) through their reactive oxygen specieschelating properties and immunological studies highlighting their toxicity. We observe that several underappreciated parameters, such as aggregation size and degree of impurity, are critical determinants that need to be carefully addressed to better understand the NP biological effects in order to unleash their potential clinical benefits. This is because NPs can evolve toward different states, depending on the environment where they have been dispersed and how they have been dispersed. As a consequence, final characteristics of NPs can be very different from what was initially designed and produced in the laboratory. Thus, aggregation, corrosion, and interaction with extracellular matrix proteins critically modify NP features and fate. These modifications depend to a large extent on the characteristics of the biological media in which the NPs are dispersed. As a consequence, when reviewing the scientific literature, it seems that the aggregation state of NPs, which depends on the characteristics of the dispersing media, may be more significant than the composition or original size of the NPs. In this work, we focus on CeO2 NPs, which are reported sometimes to be protective and anti-inflammatory, and sometimes toxic and pro-inflammatory. © 2017 Casals, Gusta, Piella, Casals, Jiménez and Puntes.


  • Modeling the Optical Responses of Noble Metal Nanoparticles Subjected to Physicochemical Transformations in Physiological Environments: Aggregation, Dissolution and Oxidation

    Piella J., Bastús N.G., Puntes V. Zeitschrift fur Physikalische Chemie; 231 (1): 33 - 50. 2017. 10.1515/zpch-2016-0874. IF: 1.012

    Herein, we study how optical properties of colloidal dispersions of noble metal nanoparticles (Au and Ag) are affected by processes such as aggregation and oxidative dissolution. The optical contributions of these processes to the extinction spectra in the UV-vis region are often overlapped, making difficult its interpretation. In this regard, modeling the UV-vis spectra (in particular absorbance curve, peaks position, intensity and full width at half maximum-FWHM) of each process separately offers a powerful tool to identify the transformation of NPs under relevant and complex scenarios, such as in biological media. The proper identification of these transformations is crucial to understand the biological effects of the NPs. © 2017 Walter de Gruyter GmbH, Berlin/Boston.


  • One-Pot Synthesis of Cationic Gold Nanoparticles by Differential Reduction

    Sperling R.A., Garciá-Fernández L., Ojea-Jiménez I., Piella J., Bastús N.G., Puntes V. Zeitschrift fur Physikalische Chemie; 231 (1): 7 - 18. 2017. 10.1515/zpch-2016-0864. IF: 1.012

    The size-controlled synthesis of cationic particles by differential reduction of HAuCl4 precursor in the presence of NaBH4 and 1-aminoundecane-12-thiol (AUT) is reported. The number of seed particles is determined by the fraction of the initially Au precursor reduced by NaBH4 present in the reaction mixture, which are then grown larger by the AUT, acting as both weak reducing agent and stabilizing surfactant. By this methodology, size controlled synthesis is achieved in a two-step one-pot synthesis at room temperature. © 2017 Walter de Gruyter GmbH, Berlin/Boston.


  • Probing the surface reactivity of nanocrystals by the catalytic degradation of organic dyes: The effect of size, surface chemistry and composition

    Piella J., Merkoçi F., Genç A., Arbiol J., Bastús N.G., Puntes V. Journal of Materials Chemistry A; 5 (23): 11917 - 11929. 2017. 10.1039/c7ta01328k. IF: 8.867

    We herein present a comprehensive study on how the catalytic performance and reusability of Au nanocrystals (NCs) are affected by systematic variations of crystal size, surface coating and composition. The reductions of different organic dyes (4-nitrophenol, rhodamine B and methylene blue) by borohydride ions were used as model catalytic reactions. The catalytic performance of the Au NCs ranged between 3.6 to 110 nm was found to be dependent on crystal size, indicating that Au surface atoms have a distinct size-dependent reactivity in this reaction. Similarly, the catalytic performance was found to be strongly dependent on the nature of the coating molecule, obtaining lower catalytic activities for molecules strongly bound to the Au surface. Finally, the catalytic performance was found to be dependent on the chemical composition of the NC (Au, Ag, Pt) and the model dye used as a testing system, with the highest degradation rate found for methylene blue, followed by 4-nitrophenol and rhodamine B. We believe that this study provides a better understanding of the catalytic performance of Au NCs upon controlled modifications of the structural and morphological parameters, and a working environment that can be used to facilitate the selection of the optimum NC size, coating molecule and evaluation system for a particular study of interest. © 2017 The Royal Society of Chemistry.


  • Safer by design strategies

    Cobaleda-Siles M., Guillamon A.P., Delpivo C., Vázquez-Campos S., Puntes V.F. Journal of Physics: Conference Series; 838 (1, 012016) 2017. 10.1088/1742-6596/838/1/012016. IF: 0.000

    Throughout the EU funded FP7 project GUIDENano, we are trying to control and monitor the evolution of nano-enable products during their lifecycle. Small alterations of the nanoparticle (NP) state may have critical consequences on the NP behaviour and performance. For this reason it is important to highlight the importance of an extensive and proper characterization to define the NP physico-chemical characteristics under several environmental conditions. Furthermore, this characterization is necessary to ensure that obtained results are reproducible and allow understanding the behaviour of the NP on biological systems. In this paper different strategies reported in the literature regarding the safety-by-design concept are summarized. Several strategies from the synthetic point of view that help us to modulate the main factors which determine the safety of nanomaterials are proposed. © Published under licence by IOP Publishing Ltd.


  • Seeded Growth Synthesis of Au-Fe3O4 Heterostructured Nanocrystals: Rational Design and Mechanistic Insights

    Fantechi E., Roca A.G., Sepúlveda B., Torruella P., Estradé S., Peiró F., Coy E., Jurga S., Bastús N.G., Nogués J., Puntes V. Chemistry of Materials; 29 (9): 4022 - 4035. 2017. 10.1021/acs.chemmater.7b00608. IF: 9.466

    Multifunctional hybrid nanoparticles comprising two or more entities with different functional properties are gaining ample significance in industry and research. Due to its combination of properties, a particularly appealing example is Au-Fe3O4 composite nanoparticles. Here we present an in-depth study of the synthesis of Au-Fe3O4 heterostructured nanocrystals (HNCs) by thermal decomposition of iron precursors in the presence of preformed 10 nm Au seeds. The role of diverse reaction parameters on the HNCs formation was investigated using two different precursors: iron pentacarbonyl (Fe(CO)5) and iron acetylacetonate (Fe(acac)3). The reaction conditions promoting the heterogeneous nucleation of Fe3O4 onto Au seeds were found to significantly differ depending on the precursor chosen, where Fe(acac)3 is considerably more sensitive to the variation of the parameters than Fe(CO)5 and more subject to homogeneous nucleation processes with the consequent formation of isolated iron oxide nanocrystals (NCs). The role of the surfactants was also crucial in the formation of well-defined and monodisperse HNCs by regulating the access to the Au surface. Similarly, the variations of the [Fe]/[Au] ratio, temperature, and employed solvent were found to act on the mean size and the morphology of the obtained products. Importantly, while the optical properties are rather sensitive to the final morphology, the magnetic ones are rather similar for the different types of obtained HNCs. The surface functionalization of dimer-like HNCs with silica allows their dispersion in aqueous media, opening the path to their use in biomedical applications. © 2017 American Chemical Society.


  • Size-Dependent Protein-Nanoparticle Interactions in Citrate-Stabilized Gold Nanoparticles: The Emergence of the Protein Corona

    Piella J., Bastús N.G., Puntes V. Bioconjugate chemistry; 28 (1): 88 - 97. 2017. 10.1021/acs.bioconjchem.6b00575. IF: 4.818

    Surface modifications of highly monodisperse citrate-stabilized gold nanoparticles (AuNPs) with sizes ranging from 3.5 to 150 nm after their exposure to cell culture media supplemented with fetal bovine serum were studied and characterized by the combined use of UV-vis spectroscopy, dynamic light scattering, and zeta potential measurements. In all the tested AuNPs, a dynamic process of protein adsorption was observed, evolving toward the formation of an irreversible hard protein coating known as Protein Corona. Interestingly, the thickness and density of this protein coating were strongly dependent on the particle size, making it possible to identify different transition regimes as the size of the particles increased: (i) NP-protein complexes (or incomplete corona), (ii) the formation of a near-single dense protein corona layer, and (iii) the formation of a multilayer corona. In addition, the different temporal patterns in the evolution of the protein coating came about more quickly for small particles than for the larger ones, further revealing the significant role that size plays in the kinetics of this process. Since the biological identity of the NPs is ultimately determined by the protein corona and different NP-biological interactions take place at different time scales, these results are relevant to biological and toxicological studies.


2016

  • Assessing the Immunosafety of Engineered Nanoparticles with a Novel in Vitro Model Based on Human Primary Monocytes

    Li Y., Italiani P., Casals E., Valkenborg D., Mertens I., Baggerman G., Nelissen I., Puntes V.F., Boraschi D. ACS Applied Materials and Interfaces; 8 (42): 28437 - 28447. 2016. 10.1021/acsami.6b06278. IF: 7.145

    The possibility that nanomaterials could perturb the normal course of an inflammatory response is a key issue when assessing nanoimmunosafety. The alteration of the normal progress of an inflammatory response may have pathological consequences, since inflammation is a major defensive mechanism and its efficiency maintains the body's health. The immunosafety of engineered nanoparticles at nontoxic concentrations was investigated with the use of a human primary monocyte-based in vitro system, which reproduces in a simplified fashion the full course of the physiological inflammatory response, from initiation and development to resolution. The kinetics of expression and production of inflammatory and anti-inflammatory cytokines and the proteomic profiles were used for describing the inflammatory defensive response. We assessed the ability of gold and silver nanoparticles to trigger inflammation and to interfere with the course of an ongoing defensive reaction. While neither nanoparticle type was able to directly activate monocytes, silver nanoparticles could exacerbate the inflammatory response of monocytes but did not interfere with the resolution of the inflammatory reaction. These findings support the use of human primary monocyte-based in vitro assays for realistically investigating the effects of engineered nanoparticles on human innate immune responses, in order to predict the immunological risk of nanomaterials and implement safe nanoparticle-based applications. © 2016 American Chemical Society.


  • Cerium oxide nanoparticles reduce steatosis, portal hypertension and display anti-inflammatory properties in rats with liver fibrosis

    Oró D., Yudina T., Fernández-Varo G., Casals E., Reichenbach V., Casals G., De La Presa B.G., Sandalinas S., Carvajal S., Puntes V., Jiménez W. Journal of Hepatology; 64 (3): 691 - 698. 2016. 10.1016/j.jhep.2015.10.020. IF: 10.590

    Background & Aims Cerium oxide nanoparticles (CeO2NPs) have proven to behave as free radical scavengers and/or anti-inflammatory agents. The aim of the study was to determine whether CeO2NPs display hepatoprotective properties in experimental chronic liver disease. Methods Systemic and hepatic effects of nanoparticles were assessed in CCl4-treated rats receiving CeO2NPs or vehicle twice weekly for two weeks and CCl4 treatment was continued for 8 additional weeks. Thereafter, mean arterial pressure and portal pressure (PP) were assessed and serum samples obtained to measure standard hepatic and renal function tests. Organ and subcellular distribution of NPs were assessed using mass spectrometry (ICP-MS) and transmission electron microscopy. Liver samples were obtained to evaluate steatosis, α-SMA expression, macrophage infiltration, apoptosis and mRNA expression of oxidative stress, inflammatory or vasoactive related genes. Results Most CeO2NPs were located in the liver and it reduced hepatic steatosis, ameliorated systemic inflammatory biomarkers and improved PP without affecting mean arterial pressure. In addition, a marked reduction in mRNA expression of inflammatory cytokines (TNFα, IL1β, COX-2, iNOS), ET-1 and messengers related to oxidative (Epx, Ncf1, Ncf2) or endoplasmic reticulum (Atf3, Hspa5) stress signaling pathways was observed in the liver of rats receiving CeO2NPs. This was associated with reduced macrophage infiltration and reduced abundance of caspase-3, α-SMA and inflammatory cytokines. Conclusions CeO2NPs administration to CCl4-treated rats protects against chronic liver injury by reducing liver steatosis and portal hypertension and markedly attenuating the intensity of the inflammatory response, thereby suggesting that CeO2NPs may be of therapeutic value in chronic liver disease. © 2015 European Association for the Study of the Liver.


  • Enhanced detection with spectral imaging fluorescence microscopy reveals tissue- and cell-type-specific compartmentalization of surface-modified polystyrene nanoparticles

    Kenesei K., Murali K., Czéh Á., Piella J., Puntes V., Madarász E. Journal of Nanobiotechnology; 14 (1, 55) 2016. 10.1186/s12951-016-0210-0. IF: 4.239

    Background: Precisely targeted nanoparticle delivery is critically important for therapeutic applications. However, our knowledge on how the distinct physical and chemical properties of nanoparticles determine tissue penetration through physiological barriers, accumulation in specific cells and tissues, and clearance from selected organs has remained rather limited. In the recent study, spectral imaging fluorescence microscopy was exploited for precise and rapid monitoring of tissue- and cell-type-specific distribution of fluorescent polystyrene nanoparticles with chemically distinct surface compositions. Methods: Fluorescent polystyrene nanoparticles with 50-90 nm diameter and with carboxylated- or polyethylene glycol-modified (PEGylated) surfaces were delivered into adult male and pregnant female mice with a single intravenous injection. The precise anatomical distribution of the particles was investigated by confocal microscopy after a short-term (5 min) or long-term (4 days) distribution period. In order to distinguish particle-fluorescence from tissue autofluorescence and to enhance the detection-efficiency, fluorescence spectral detection was applied during image acquisition and a post hoc full spectrum analysis was performed on the final images. Results: Spectral imaging fluorescence microscopy allowed distinguishing particle-fluorescence from tissue-fluorescence in all examined organs (brain, kidney, liver, spleen and placenta) in NP-treated slice preparations. In short-time distribution following in vivo NP-administration, all organs contained carboxylated-nanoparticles, while PEGylated-nanoparticles were not detected in the brain and the placenta. Importantly, nanoparticles were not found in any embryonic tissues or in the barrier-protected brain parenchyma. Four days after the administration, particles were completely cleared from both the brain and the placenta, while PEGylated-, but not carboxylated-nanoparticles, were stuck in the kidney glomerular interstitium. In the spleen, macrophages accumulated large amount of carboxylated and PEGylated nanoparticles, with detectable redistribution from the marginal zone to the white pulp during the 4-day survival period. Conclusions: Spectral imaging fluorescence microscopy allowed detecting the tissue- and cell-type-specific accumulation and barrier-penetration of polystyrene nanoparticles with equal size but chemically distinct surfaces. The data revealed that polystyrene nanoparticles are retained by the reticuloendothelial system regardless of surface functionalization. Taken together with the increasing production and use of nanoparticles, the results highlight the necessity of long-term distribution studies to estimate the potential health-risks implanted by tissue-specific nanoparticle accumulation and clearance. © 2016 The Author(s).


  • Galvanic Replacement onto Complex Metal-Oxide Nanoparticles: Impact of Water or Other Oxidizers in the Formation of either Fully Dense Onion-like or Multicomponent Hollow MnOx/FeOx Structures

    López-Ortega A., Roca A.G., Torruella P., Petrecca M., Estradé S., Peiró F., Puntes V., Nogués J. Chemistry of Materials; 28 (21): 8025 - 8031. 2016. 10.1021/acs.chemmater.6b03765. IF: 9.407

    Multicomponent metal-oxide nanoparticles are appealing structures from applied and fundamental viewpoints. The control on the synthetic parameters in colloidal chemistry allows the growth of complex nanostructures with novel morphologies. In particular, the synthesis of biphase metal-oxide hollow nanoparticles has been reported based on galvanic replacement using an organic-based seeded-growth approach, but with the presence of H2O. Here we report a novel route to synthesize either fully dense or hollow core/shell metal-oxide nanoparticles (MnOx/FeOx) by simply adding or not oxidants in the reaction. We demonstrate that the presence of oxidants (e.g., O2 carried by the not properly degassed H2O or (CH3)3NO) allows the formation of hollow structures by a galvanic reaction between the MnOx and FeOx phases. In particular, the use of (CH3)3NO as oxidant allows for the first time a very reliable all-organic synthesis of hollow MnOx/FeOx nanoparticles without the need of water (with a somewhat unreliable oxidation role). Oxidants permit the formation of MnOx/FeOx hollow nanoparticles by an intermediate step where the MnO/Mn3O4 seeds are oxidized into Mn3O4, thus allowing the Mn3+ → Mn2+ reduction by the Fe2+ ions. The lack of proper oxidative conditions leads to full-dense onion-like core/shell MnO/Mn3O4/Fe3O4 particles. Thus, we show that the critical step for galvanic replacement is the proper seed oxidation states so that their chemical reduction by the shell ions is thermodynamically favored. © 2016 American Chemical Society.


  • Influence of Nanomaterial Compatibilization Strategies on Polyamide Nanocomposites Properties and Nanomaterial Release during the Use Phase

    Fernández-Rosas E., Vilar G., Janer G., González-Gálvez D., Puntes V., Jamier V., Aubouy L., Vázquez-Campos S. Environmental Science and Technology; 50 (5): 2584 - 2594. 2016. 10.1021/acs.est.5b05727. IF: 5.393

    The incorporation of small amounts of nanofillers in polymeric matrices has enabled new applications in several industrial sectors. The nanofiller dispersion can be improved by modifying the nanomaterial (NM) surface or predispersing the NMs to enhance compatibility. This study evaluates the effect of these compatibilization strategies on migration/release of the nanofiller and transformation of polyamide-6 (PA6), a thermoplastic polymer widely used in industry during simulated outdoors use. Two nanocomposites (NCs) containing SiO2 nanoparticles (NPs) with different surface properties and two multiwalled carbon nanotube (MWCNT) NCs obtained by different addition methods were produced and characterized, before and after accelerated wet aging conditions. Octyl-modified SiO2 NPs, though initially more aggregated than uncoated SiO2 NPs, reduced PA6 hydrolysis and, consequently, NM release. Although no clear differences in dispersion were observed between the two types of MWCNT NCs (masterbatch vs direct addition) after manufacture, the use of the MWCNT masterbatch reduced PA6 degradation during aging, preventing MWCNT accumulation on the surface and further release or potential exposure by direct contact. The amounts of NM released were lower for MWCNTs (36 and 108 mg/m2) than for SiO2 NPs (167 and 730 mg/m2), being lower in those samples where the NC was designed to improve the nanofiller-matrix interaction. Hence, this study shows that optimal compatibilization between NM and matrix can improve NC performance, reducing polymer degradation and exposure and/or release of the nanofiller. © 2016 American Chemical Society.


  • Interaction of gold nanoparticles and nickel(II) sulfate affects dendritic cell maturation

    Deville S., Baré B., Piella J., Tirez K., Hoet P., Monopoli M.P., Dawson K.A., Puntes V.F., Nelissen I. Nanotoxicology; 10 (10): 1395 - 1403. 2016. 10.1080/17435390.2016.1221476. IF: 7.913

    Despite many investigations have focused on the pristine toxicity of gold nanoparticles (GNPs), little is known about the outcome of co-exposure and interaction of GNPs with heavy metals which can possibly detoxify or potentiate them. Here, the combined exposure of nickel (II) sulfate (NiSO4) and GNPs on the maturation response of dendritic cells (DCs) was explored. Exposure to GNPs or NiSO4 separately induced cell activation. When cells were exposed to a mixture of both, however, the observed cell activation pattern indicated a competitive rather than an additive effect of both inducers with levels similar to those induced by NiSO4 alone. Quantification of the GNP uptake by DCs demonstrated a significant decrease in intracellular gold content during co-incubation with NiSO4. An extensive physiochemical characterization was performed to determine the interaction between GNPs and NiSO4 in the complex physiological media using nanoparticle tracking analyses, disc centrifugation, UV–visible spectroscopy, ICP-MS analyses, zeta potential measurements, electron microscopy, and proteomics. Although GNPs and NiSO4 did not directly interact with each other, the presence of NiSO4 in the physiological media resulted in changes in GNPs' charge and their associated protein corona (content and composition), which may contribute to a decreased cellular uptake of GNPs and sustaining the nickel-induced DC maturation. The presented results provide new insights in the interaction of heavy metals and NPs in complex physiological media. Moreover, this study highlights the necessity of mixture toxicology, since these combined exposures are highly relevant for human subjection to NPs and risk assessment of nanomaterials. © 2016 Informa UK Limited, trading as Taylor & Francis Group.


  • Nanoparticle Interaction with Biomolecules: How it Shapes the Nano-Effects on Immunity

    Victor Puntes Current Bionanotechnology; 2 (1): 11 - 19. 2016. 10.2174/2213529402666160601124203. IF: 0.000

    The different modes in which small and large molecules can be associated to a nanoparticle surface, either covalently or loosely linked, in an ordered or disordered fashion, and with mixtures of other molecules, play a determining role in the nature of the interactions between nano-objects and the immune system. The immune system may detect or not detect the nanoparticles, and tolerate them or initiate a defensive response, due to the nanoparticles themselves, to bystanders, sometime pollutants, or secondary effects, as those induced by the corrosion of the nanoparticle and the concomitant release of cations. In vitro, this can be translated in the acquisition of effector functions, such as the synthesis of cytokines, or in a lack of effect, if the NPs pass undetected.


  • One-pot polyol synthesis of highly monodisperse short green silver nanorods

    Patarroyo J., Genç A., Arbiol J., Bastús N.G., Puntes V. Chemical Communications; 52 (73): 10960 - 10963. 2016. 10.1039/c6cc04796c. IF: 6.567

    Green silver nanorods (Ag NRs) of a low aspect ratio (2.8) have been produced in high yields via an optimized, simple, and robust one-pot polyol method in the presence of tannic acid, which favors the nucleation of decahedral seeds needed for the production of monodisperse Ag NRs. These Ag NRs were further used as sacrificial templates to produce Au hollow nanostructures via galvanic replacement reaction with HAuCl4 at room temperature. © 2016 The Royal Society of Chemistry.


  • Properties of silver nanoparticles influencing their uptake in and toxicity to the earthworm Lumbricus rubellus following exposure in soil

    Makama S., Piella J., Undas A., Dimmers W.J., Peters R., Puntes V.F., van den Brink N.W. Environmental Pollution; 218: 870 - 878. 2016. 10.1016/j.envpol.2016.08.016. IF: 4.839

    Physicochemical properties of nanoparticles influence their environmental fate and toxicity, and studies investigating this are vital for a holistic approach towards a comprehensive and adequate environmental risk assessment. In this study, we investigated the effects of size, surface coating (charge) of silver nanoparticles (AgNPs) – a most commonly-used nanoparticle-type, on the bioaccumulation in, and toxicity (survival, growth, cocoon production) to the earthworm Lumbricus rubellus. AgNPs were synthesized in three sizes: 20, 35 and 50 nm. Surface-coating with bovine serum albumin (AgNP_BSA), chitosan (AgNP_Chit), or polyvinylpyrrolidone (AgNP_PVP) produced negative, positive and neutral particles respectively. In a 28-day sub-chronic reproduction toxicity test, earthworms were exposed to these AgNPs in soil (0–250 mg Ag/kg soil DW). Earthworms were also exposed to AgNO3 at concentrations below known EC50. Total Ag tissue concentration indicated uptake by earthworms was generally highest for the AgNP_BSA especially at the lower exposure concentration ranges, and seems to reach a plateau level between 50 and 100 mg Ag/kg soil DW. Reproduction was impaired at high concentrations of all AgNPs tested, with AgNP_BSA particles being the most toxic. The EC50 for the 20 nm AgNP_BSA was 66.8 mg Ag/kg soil, with exposure to <60 mg Ag/kg soil already showing a decrease in the cocoon production. Thus, based on reproductive toxicity, the particles ranked: AgNP_BSA (negative) > AgNP_PVP (neutral) > Chitosan (positive). Size had an influence on uptake and toxicity of the AgNP_PVP, but not for AgNP_BSA nor AgNP_Chit. This study provides essential information on the role of physicochemical properties of AgNPs in influencing uptake by a terrestrial organism L. rubellus under environmentally relevant conditions. It also provides evidence of the influence of surface coating (charge) and the limited effect of size in the range of 20–50 nm, in driving uptake and toxicity of the AgNPs tested. © 2016 Elsevier Ltd


  • Quantifying the Sensitivity of Multipolar (Dipolar, Quadrupolar, and Octapolar) Surface Plasmon Resonances in Silver Nanoparticles: The Effect of Size, Composition, and Surface Coating

    Bastús N.G., Piella J., Puntes V. Langmuir; 32 (1): 290 - 300. 2016. 10.1021/acs.langmuir.5b03859. IF: 3.993

    The effect of composition, size, and surface coating on the sensitivity of localized multipolar surface plasmon resonances has been spectroscopically investigated in high-quality silver colloidal solutions with precisely controlled sizes from 10 to 220 nm and well-defined surface chemistry. Surface plasmon resonance modes have been intensively characterized, identifying the size-dependence of dipolar, quadrupolar, and octapolar modes. Modifications of the NP's surface chemistry revealed the higher sensitivity of large sizes, long molecules, thiol groups, and low-order resonance modes. We also extend this study to gold nanoparticles, aiming to compare the sensitivity of both materials, quantifying the higher sensitivity of silver. © 2015 American Chemical Society.


  • Shell or Dots - Precursor Controlled Morphology of Au-Se Deposits on CdSe Nanoparticles

    De La Cueva L., Meyns M., Bastús N.G., Rodríguez-Fernández J., Otero R., Gallego J.M., Alonso C., Klinke C., Juárez B.H. Chemistry of Materials; 28 (8): 2704 - 2714. 2016. 10.1021/acs.chemmater.6b00287. IF: 9.407

    The most prevalent image of the morphology of Au-CdSe hybrid nanoparticles (HNPs) is that of dumbbells or matchsticks with CdSe nanoparticles (NPs) acting as seed material onto which spherical Au dots are deposited. On the basis of a system with only three reaction components, CdSe seeds, n-dodecyltrimethylammonium bromide-complexed AuCl3, and dodecanethiol, we demonstrate how the morphology of the Au deposits on the semiconductor NPs, either in the form of dots on the vertices or in the form of a shell around the NP surface, can be determined by controlling the oxidation state of the metal precursor. Furthermore, we apply X-ray photoelectron spectroscopy to show that the resultant deposits are composed of partially oxidized Au, corresponding to a Au-Se compound regardless the deposit morphology. To obtain a detailed characterization of the HNPs with different morphologies and to gain mechanistic insights into the deposition process, (cryogenic) high-resolution transmission electron microscopy, mass spectrometry, cyclic voltammetry, and computational simulations have been performed. Our results emphasize that the knowledge of the surface chemistry of the seed particles as well as a defined picture of the metal precursors is necessary to understand heterodeposition processes. © 2016 American Chemical Society.


  • Size-Controlled Synthesis of Sub-10-nanometer Citrate-Stabilized Gold Nanoparticles and Related Optical Properties.

    Piella J., Bastús N.G., Puntes V. Chemistry of Materials; 28 (4): 1066 - 1075. 2016. 10.1021/acs.chemmater.5b04406. IF: 9.407

    Highly monodisperse, biocompatible and functionalizable sub-10-nm citrate-stabilized gold nanoparticles (Au NPs) have been synthesized following a kinetically controlled seeded-growth strategy. The use of traces of tannic acid together with an excess of sodium citrate during nucleation is fundamental in the formation of a high number (7 × 1013 NPs/mL) of small ∼3.5 nm Au seeds with a very narrow distribution. A homogeneous nanometric growth of these seeds is then achieved by adjusting the reaction parameters: pH, temperature, sodium citrate concentration and gold precursor to seed ratio. We use this method to produce Au NPs with a precise control over their sizes between 3.5 and 10 nm and a versatile surface chemistry allowing studying the size-dependent optical properties in this transition size regime lying between clusters and nanoparticles. Interestingly, an inflection point is observed for Au NPs smaller than 8 nm in which the sensitivity of the localized surface plasmon resonance (LSPR) peak position as a function of NPs size and surface modifications dramatically increase. These studies are relevant in the design of the final selectivity, activity and compatibility of Au NPs, especially in those (bio)applications where size is a critical parameter (e.g., biodistribution, multiplex labeling, and protein interaction). © 2016 American Chemical Society.


  • The influence of the MOF shell thickness on the catalytic performance of composites made of inorganic (hollow) nanoparticles encapsulated into MOFs

    Yazdi A., Merkoçi F., Bastús N., Imaz I., Puntes V., Maspoch D. Catalysis Science & Technology; 6 (24): 8388 - 8391. 2016. 10.1039/C6CY02071B. IF: 5.287

    Herein we report the encapsulation of hollow Pt or Pd nanoparticles into ZIF-8, making a series of composites in which the ZIF-8 shell thickness has been systematically varied. By using these composites as catalysts for the reduction of 4-nitrophenol and Eosin Y, we show that the MOF shell thickness plays a key role in the catalytic performance of this class of composites.


  • Toxicity of nickel in the marine calanoid copepod Acartia tonsa: Nickel chloride versus nanoparticles

    Zhou C., Vitiello V., Casals E., Puntes V.F., Iamunno F., Pellegrini D., Changwen W., Benvenuto G., Buttino I. Aquatic Toxicology; 170: 1 - 12. 2016. 10.1016/j.aquatox.2015.11.003. IF: 3.557

    Nickel compounds are widely used in industries and have been massively introduced in the environment in different chemical forms. Here we report the effect of two different chemical forms of nickel, NiCl2 and nickel nanoparticles (NiNPs), on the reproduction of the marine calanoid copepod Acartia tonsa. The behavior of nickel nanoparticles was analyzed with different techniques and with two protocols. In the "sonicated experiment" (SON) NiNP solution was sonicated while in the "non-sonicated experiment" (NON-SON) the solution was vigorously shaken by hand. Final nominal concentrations of 5, 10 and 50mgL-1 and 1, 5 and 10mgL-1 NiNPs were used for the acute and semichronic tests, respectively. Nanoparticle size did not change over time except for the highest concentration of 50mgL-1 NiNPs, in which the diameter increased up to 843nm after 48h. The concentration of Ni dissolved in the water increased with NP concentration and was similar for SON and NON-SON solutions. Our results indicate that sonication does not modify toxicity for the copepod A. tonsa. Mean EC50 values were similar for NON-SON (20.2mgL-1) and SON experiments (22.14mgL-1) in the acute test. Similarly, no differences occurred between the two different protocols in the semichronic test, with an EC50 of 7.45mgL-1 and 6.97mgL-1 for NON-SON and SON experiments, respectively. Acute and semichronic tests, conducted exposing A. tonsa embryos to NiCl2 concentrations from 0.025 to 0.63mgL-1, showed EC50 of 0.164 and 0.039mgL-1, respectively. Overall, A. tonsa is more sensitive to NiCl2 than NiNPs with EC50 being one order of magnitude higher for NiNPs. Finally, we exposed adult copepods for 4 days to NiCl2 and NiNPs (chronic exposure) to study the effect on fecundity in terms of daily egg production and naupliar viability. Egg production is not affected by either form of nickel, whereas egg viability is significantly reduced by 0.025mgL-1 NiCl2 and by 8.5mgL-1 NiNPs. At NiNP concentration below the acute EC50 (17mgL-1) only 9% of embryos hatched after 4 days. Interestingly, the percentage of naupliar mortality (>6;82%) observed in the semichronic test at the nominal concentration of 10mgL-1 NiNPs corresponding to almost 0.10mgL-1 of dissolved Ni, was similar to that recorded at the same Ni salt concentration. Electron microscopical analyses revealed that A. tonsa adults ingest NiNPs and excrete them through fecal pellets. To the best of our knowledge, this is the first study investigating the toxicity of two different forms of Ni on the reproductive physiology of the copepod A. tonsa and showing the ability of the calanoid copepod to ingest nanoparticles from seawater. © 2015 Elsevier B.V.


  • Tuning the Plasmonic Response up: Hollow Cuboid Metal Nanostructures

    Genç A., Patarroyo J., Sancho-Parramon J., Arenal R., Duchamp M., Gonzalez E.E., Henrard L., Bastús N.G., Dunin-Borkowski R.E., Puntes V.F., Arbiol J. ACS Photonics; 3 (5): 770 - 779. 2016. 10.1021/acsphotonics.5b00667. IF: 5.404

    We report the fine-tuning of the localized surface plasmon resonances (LSPRs) from ultraviolet to near-infrared by nanoengineering the metal nanoparticle morphologies from solid Ag nanocubes to hollow AuAg nanoboxes and AuAg nanoframes. Spatially resolved mapping of plasmon resonances by electron energy loss spectroscopy (EELS) revealed a homogeneous distribution of highly intense plasmon resonances around the hollow nanostructures and the interaction, that is, hybridization, of inner and outer plasmon fields for the nanoframe. Experimental findings are accurately correlated with the boundary element method (BEM) simulations demonstrating that the homogeneous distribution of the plasmon resonances is the key factor for their improved plasmonic properties. As a proof of concept for these enhanced plasmonic properties, we show the effective label free sensing of bovine serum albumin (BSA) of single-walled AuAg nanoboxes in comparison with solid Au nanoparticles, demonstrating their excellent performance for future biomedical applications. © 2016 American Chemical Society.


2015

  • Assessment of a panel of interleukin-8 reporter lung epithelial cell lines to monitor the pro-inflammatory response following zinc oxide nanoparticle exposure under different cell culture conditions

    Stoehr L.C., Endes C., Radauer-Preiml I., Boyles M.S.P., Casals E., Balog S., Pesch M., Petri-Fink A., Rothen-Rutishauser B., Himly M., Clift M.J.D., Duschl A. Particle and Fibre Toxicology; 12 (1, 29) 2015. 10.1186/s12989-015-0104-6. IF: 8.649

    Background: Stably transfected lung epithelial reporter cell lines pose an advantageous alternative to replace complex experimental techniques to monitor the pro-inflammatory response following nanoparticle (NP) exposure. Previously, reporter cell lines have been used under submerged culture conditions, however, their potential usefulness in combination with air-liquid interface (ALI) exposures is currently unknown. Therefore, the aim of the present study was to compare a panel of interleukin-8 promoter (pIL8)-reporter cell lines (i.e. green or red fluorescent protein (GFP, RFP), and luciferase (Luc)), originating from A549 lung epithelial type II-like cells cells, following NPs exposure under both submerged and ALI conditions. Methods: All cell lines were exposed to zinc oxide (ZnO) NPs at 0.6 and 6.2 μg/cm2 for 3 and 16 hours under both submerged and ALI conditions. Following physicochemical characterization, the cytotoxic profile of the ZnO-NPs was determined for each exposure scenario. Expression of IL-8 from all cell types was analyzed at the promoter level and compared to the mRNA (qRT-PCR) and protein level (ELISA). Results: In summary, each reporter cell line detected acute pro-inflammatory effects following ZnO exposure under each condition tested. The pIL8-Luc cell line was the most sensitive in terms of reporter signal strength and onset velocity following TNF-aα treatment. Both pIL8-GFP and pIL8-RFP also showed a marked signal induction in response to TNF-aα, although only after 16 hrs. In terms of ZnO-NP-induced cytotoxicity pIL8-RFP cells were the most affected, whilst the pIL8-Luc were found the least responsive. Conclusions: In conclusion, the use of fluorescence-based reporter cell lines can provide a useful tool in screening the pro-inflammatory response following NP exposure in both submerged and ALI cell cultures. © 2015 Stoehr et al.


  • Chitosan functionalisation of gold nanoparticles encourages particle uptake and induces cytotoxicity and pro-inflammatory conditions in phagocytic cells, as well as enhancing particle interactions with serum components

    Boyles M.S.P., Kristl T., Andosch A., Zimmermann M., Tran N., Casals E., Himly M., Puntes V., Huber C.G., Lütz-Meindl U., Duschl A. Journal of Nanobiotechnology; 13 (1, 84) 2015. 10.1186/s12951-015-0146-9. IF: 4.115

    Background: Gold nanoparticles (AuNPs) are a popular choice for use in medical and biomedical research applications. With suitable functionalisation AuNPs can be applied in drug delivery systems, or can aid in disease diagnosis. One such functionalisation is with chitosan, which enables efficient interaction and permeation of cellular membranes, providing an effective adjuvant. As both AuNPs and chitosan have been shown to have low toxicity and high biocompatibility their proposed use in nanomedicine, either individually or combined, is expanding. However, further toxicological and immunological assessments of AuNP-chitosan conjugates are still needed. Therefore, we have evaluated how AuNP functionalisation with chitosan can affect uptake, cytotoxicity, and immunological responses within mononuclear cells, and influence the interaction of AuNPs with biomolecules within a complex biofluid. The AuNPs used were negatively charged through citrate-coating, or presented either low or high positive charge through chitosan-functionalisation. Uptake by THP-1 cells was assessed via transmission electron microscopy and electron energy loss spectroscopy, pro-inflammatory responses by ELISA and qRT-PCR, and cell death and viability via lactate dehydrogenase release and mitochondrial activity, respectively. Interactions of AuNPs with protein components of a frequently used in vitro cell culture medium supplement, foetal calf serum, were investigated using mass spectrometry. Results: Although cells internalised all AuNPs, uptake rates and specific routes of intracellular trafficking were dependent upon chitosan-functionalisation. Accordingly, an enhanced immune response was found to be chitosan-functionalisation-dependent, in the form of CCL2, IL-1β, TNF-α and IL-6 secretion, and expression of IL-1β and NLRP3 mRNA. A corresponding increase in cytotoxicity was found in response to chitosan-coated AuNPs. Furthermore, chitosan-functionalisation was shown to induce an increase in unique proteins associating with these highly charged AuNPs. Conclusions: It can be concluded that functionalisation of AuNPs with the perceived non-toxic biocompatible molecule chitosan at a high density can elicit functionalisation-dependent intracellular trafficking mechanisms and provoke strong pro-inflammatory conditions, and that a high affinity of these NP-conjugates for biomolecules may be implicit in these cellular responses. © 2015 Boyles et al.


  • Design and pharmacokinetical aspects for the use of inorganic nanoparticles in radiomedicine

    Puntes V. British Journal of Radiology; 89 (1057, 20150210) 2015. 10.1259/bjr.20150210. IF: 2.026

    The potential use of nanoparticles (NPs) in medicine is determined by the pharmacokinetical and biodistribution aspects that govern NP behaviour. In this context, diagnosis (low irradiation dose) and therapy (high irradiation dose) is about the same for the NP, as much as to deliver toxic doses of radiation or toxic doses of a chemotherapeutic agent. The NP effects also have to be correlated with how they interact, evolve and are transformed during their exposure to the human body, during their administration, distribution, metabolization and expulsion. Indeed, owing to interactions between NPs and components from the biological medium, NPs are known to suffer different types of alterations, such as loss of colloidal stability (aggregation and sedimentation), protein adsorption (and consequent exposure to or escape from the immune system) and chemical transformation (oxidation, corrosion and dissolution). Their original performance and these alterations have a major impact on NP behaviour and have to be taken into account for any intended use of them in medicine, also including their use for enhanced radiodiagnosis, radiotherapy and radiochemotherapy. © 2015 The Authors. Published by the British Institute of Radiology.


  • Enhanced reactivity of high-index surface platinum hollow nanocrystals

    González E., Merkoçi F., Arenal R., Arbiol J., Esteve J., Bastús N.G., Puntes V. Journal of Materials Chemistry A; 4 (1): 200 - 208. 2015. 10.1039/c5ta07504a. IF: 7.443

    The precise morphological control of the surface of inorganic nanocrystals (NCs) is critical for the understanding of the unique properties of the materials at the nanoscale and useful in a wide range of applications, such as catalysis, where the development of highly active and low-cost materials represents a landmark for the development of industrial technologies. Here we show how combining solid state chemistry and colloidal synthesis allows us to prepare exotic materials, in particular, PtAg@Pt single-crystal hollow NCs with high-index planes synthesized at room temperature by controlled corrosion of silver templates, which minimize Pt consumption and maximize surface reactivity. © The Royal Society of Chemistry 2016.


  • Exploring new synthetic strategies for the production of advanced complex inorganic nanocrystals

    Bastús N.G., Gonzalez E., Esteve J., Piella J., Patarroyo J., Merkoçi F., Puntes V. Zeitschrift fur Physikalische Chemie; 229 (1-2): 65 - 83. 2015. 10.1515/zpch-2014-0611. IF: 1.356

    The design of new protocols for the colloidal synthesis of complex nanocrystals (NCs) with advanced functionalities, comprising both hybrid and hollow structures, and the study of their fundamental properties is of paramount importance for the development of a new generation of nanostructured materials. The possibility of tailoring the dimensional regime of NCs, along with its composition and structure, represents a landmark achievement in the control of their unique physico-chemical properties. These properties, alongside with the ability to cheaply produce high quality NCs in fairly large amounts by wet-chemistry techniques, leads to their potential applicability from materials science to nanomedicine. Within this context, this review is focused on describing a successful framework for designing synthetic strategies for the production of advanced complex NCs, integrating the development of new synthetic methods with its structural characterization, monitoring of their properties, and study of its reactivity. As a result, it is expected to provide new routes to produce robust and easy-to-process NCs in a wide range of sizes, shapes and configurations that can be explored to achieve the combination of all degrees of control, aiming to produce a complete and diverse library of material combinations that will expand its applicability in a wide diversity of fields. © 2014 Walter de Gruyter Berlin/Boston.


  • High aspect ratio gold nanorods grown with platinum seeds

    Varón M., Arbiol J., Puntes V.F. Journal of Physical Chemistry C; 119 (21): 11818 - 11825. 2015. 10.1021/acs.jpcc.5b01263. IF: 4.772

    Using Au chloride as precursor, Pt nanocrystals as seeds, ascorbic acid as a reducer, and CTAB as surfactant and complexing agent, extremely long Au nanorods have been grown. The influence of different parameters such as the composition of the seeds, the amount of Pt, or the type of Pt present in solution has been analyzed. These large Au NRs have been exhaustively characterized by (S)TEM, SEM and optical microscopy as well as UV-vis spectroscopy and their morphology correlated with the growth mechanism. © 2015 American Chemical Society.


  • Longitudinal domain wall formation in elongated assemblies of ferromagnetic nanoparticles

    Varón M., Beleggia M., Jordanovic J., Schiøtz J., Kasama T., Puntes V.F., Frandsen C. Scientific Reports; 5 ( 14536) 2015. 10.1038/srep14536. IF: 5.578

    Through evaporation of dense colloids of ferromagnetic ∼13â €‰nm Co particles onto carbon substrates, anisotropic magnetic dipolar interactions can support formation of elongated particle structures with aggregate thicknesses of 100-400â €‰nm and lengths of up to some hundred microns. Lorenz microscopy and electron holography reveal collective magnetic ordering in these structures. However, in contrast to continuous ferromagnetic thin films of comparable dimensions, domain walls appear preferentially as longitudinal, i.e., oriented parallel to the long axis of the nanoparticle assemblies. We explain this unusual domain structure as the result of dipolar interactions and shape anisotropy, in the absence of inter-particle exchange coupling.


  • Optimising the use of commercial LAL assays for the analysis of endotoxin contamination in metal colloids and metal oxide nanoparticles

    Li Y., Italiani P., Casals E., Tran N., Puntes V.F., Boraschi D. Nanotoxicology; 9 (4): 462 - 473. 2015. 10.3109/17435390.2014.948090. IF: 3.821

    Engineered nanoparticles (NP) are generally contaminated by bacterial endotoxin, a ubiquitous bacterial molecule with significant toxic and inflammatory effects. The presence of endotoxin, if not recognised, can be responsible for many of the in vitro and in vivo effects attributed to NPs. The Limulus Amoebocyte Lysate (LAL) assay, the test requested by regulatory authorities for assessing endotoxin contamination in products for human use, is not immediately applicable for testing endotoxin in NP preparations, mainly due to the possible interference of NPs with the assay readouts and components. In this study, we have compared different commercially available LAL assays for detecting endotoxin in gold, silver and iron oxide NPs. Different NP chemistry, concentrations and surface coatings could differently interfere with the LAL assays' results. After accurate testing of the possible interaction/interference of NPs with the various assay components, the modified chromogenic LAL assay proved the most suitable assay for measuring endotoxin in NP samples, provided the appropriate controls are performed. Thus, endotoxin determination can be performed in NP preparation with commercial LAL assays only after assay validation, i.e. once possible interference of NPs with the assay components and readouts has been excluded. © 2014 Informa UK Ltd. All rights reserved: reproduction in whole or part not permitted.


  • SERS efficiencies of micrometric polystyrene beads coated with gold and silver nanoparticles: The effect of nanoparticle size

    Mir-Simon B., Morla-Folch J., Gisbert-Quilis P., Pazos-Perez N., Xie H.-N., Bastús N.G., Puntes V., Alvarez-Puebla R.A., Guerrini L. Journal of Optics (United Kingdom); 17 (11, 114012) 2015. 10.1088/2040-8978/17/11/114012. IF: 2.059

    Rapid advances in nanofabrication techniques of reproducibly manufacturing plasmonic substrates with well-defined nanometric scale features and very large electromagnetic enhancements paved the way for the final translation of the analytical potential of surface-enhanced Raman scattering (SERS) to real applications. A vast number of different SERS substrates have been reported in the literature. Among others, discrete particles consisting of an inorganic micrometric or sub-micrometric core homogeneously coated with plasmonic nanoparticles stand out for their ease of fabrication, excellent SERS enhancing properties, long-term optical stability and remarkable experimental flexibility (manipulation, storage etc). In this article, we performed a systematic experimental study of the correlation between the size of quasi-spherical gold and silver nanoparticle and the final optical property of their corresponding assembles onto micrometric polystyrene (PS) beads. The size and composition of nanoparticles play a key role in tuning the SERS efficiency of the hybrid material at a given excitation wavelength. This study provides valuable information for the selection and optimization of the appropriate PS@NPs substrates for the desired applications. © 2015 IOP Publishing Ltd.


  • The oxidative potential of differently charged silver and gold nanoparticles on three human lung epithelial cell types

    Schlinkert P., Casals E., Boyles M., Tischler U., Hornig E., Tran N., Zhao J., Himly M., Riediker M., Oostingh G.J., Puntes V., Duschl A. Journal of Nanobiotechnology; 13 (1, 1) 2015. 10.1186/s12951-014-0062-4. IF: 4.115

    Background: Nanoparticle (NPs) functionalization has been shown to affect their cellular toxicity. To study this, differently functionalized silver (Ag) and gold (Au) NPs were synthesised, characterised and tested using lung epithelial cell systems. Methods: Monodispersed Ag and Au NPs with a size range of 7 to 10 nm were coated with either sodium citrate or chitosan resulting in surface charges from -50 mV to +70 mV. NP-induced cytotoxicity and oxidative stress were determined using A549 cells, BEAS-2B cells and primary lung epithelial cells (NHBE cells). TEER measurements and immunofluorescence staining of tight junctions were performed to test the growth characteristics of the cells. Cytotoxicity was measured by means of the CellTiter-Blue ® and the lactate dehydrogenase assay and cellular and cell-free reactive oxygen species (ROS) production was measured using the DCFH-DA assay. Results: Different growth characteristics were shown in the three cell types used. A549 cells grew into a confluent mono-layer, BEAS-2B cells grew into a multilayer and NHBE cells did not form a confluent layer. A549 cells were least susceptible towards NPs, irrespective of the NP functionalization. Cytotoxicity in BEAS-2B cells increased when exposed to high positive charged (+65-75 mV) Au NPs. The greatest cytotoxicity was observed in NHBE cells, where both Ag and Au NPs with a charge above +40 mV induced cytotoxicity. ROS production was most prominent in A549 cells where Au NPs (+65-75 mV) induced the highest amount of ROS. In addition, cell-free ROS measurements showed a significant increase in ROS production with an increase in chitosan coating. Conclusions: Chitosan functionalization of NPs, with resultant high surface charges plays an important role in NP-toxicity. Au NPs, which have been shown to be inert and often non-cytotoxic, can become toxic upon coating with certain charged molecules. Notably, these effects are dependent on the core material of the particle, the cell type used for testing and the growth characteristics of these cell culture model systems. © Schlinkert et al.


  • Use of cerium oxide (CeO2) nanoparticles for the adsorption of dissolved cadmium (II), lead (II) and chromium (VI) at two different pHs in single and multi-component systems

    Contreras A.R., Casals E., Puntes V., Komilis D., Sánchez A., Font X. Global Nest Journal; 17 (3): 536 - 543. 2015. . IF: 0.468

    Cerium oxide (CeO2) nanoparticles (NPs) were used for the removal of cadmium (II), lead (II) and chromium (VI) ions in single aqueous solutions and in solutions with mixtures of the three metals. The adsorption studies were carried out at pH 5 and 7 using a systematic factorial experimental design that considered the metal concentration from 1 mg l-1 to 10 mg l-1 and NP concentration from 0.064 g l-1 to 0.640 g l-1. The highest adsorption capacity was obtained in the removal of lead (II) (128.1 mg g-1), followed by cadmium (II) (93.4 mg g-1) and finally chromium (VI) (34.4 mg g-1). Data were fitted to a polynomial function obtaining the best reduced models. The type of system (single, multi-component) did not affect sorption capacity, whilst pH affected the sorption of Cd and Cr, but not that of lead. CeO2 nanoparticles proved to be effective adsorbents in removing all three heavy metals in multi-component systems, which opens a new window for their use as sorbent materials in complex waters contaminated with mixtures of heavy metals. © 2015 Global NEST Printed in Greece. All rights reserved.


2014

  • Common strategies and technologies for the ecosafety assessment and design of nanomaterials entering the marine environment

    Corsi, I.; Cherr, G.N.; Lenihan, H.S.; Labille, J.; Hassellov, M.; Canesi, L.; Dondero, F.; Frenzilli, G.; Hristozov, D.; Puntes, V.; Della Torre, C.; Pinsino, A.; Libralato, G.; Marcomini, A.; Sabbioni, E.; Matranga, V. ACS Nano; 8 (10): 9694 - 9709. 2014. 10.1021/nn504684k. IF: 12.033


  • Gene expression profiles reveal distinct immunological responses of cobalt and cerium dioxide nanoparticles in two in vitro lung epithelial cell models

    Verstraelen, S.; Remy, S.; Casals, E.; De Boever, P.; Witters, H.; Gatti, A.; Puntes, V.; Nelissen, I. Toxicology Letters; 228 (3): 157 - 169. 2014. 10.1016/j.toxlet.2014.05.006. IF: 3.355


  • Interaction of differently functionalized fluorescent silica nanoparticles with neural stem- and tissue-type cells

    Izak-Nau, E.; Kenesei, K.; Murali, K.; Voetz, M.; Eiden, S.; Puntes, V.F.; Duschl, A.; Madarász, E. Nanotoxicology; 8 (SUPPL. 1): 138 - 148. 2014. 10.3109/17435390.2013.864427. IF: 7.336


  • Little Adjustments Significantly Improve the Turkevich Synthesis of Gold Nanoparticles

    Schulz, F.; Homolka, T.; Bastús, NG.; Puntes, V. F.; Weller,H.; Vossmeyer, T. Langmuir : the ACS journal of surfaces and colloids; 30 (35): 10779 - 10784. 2014. 10.1021/la503209b. IF: 4.384


  • Nanoparticles for imaging, sensing, and therapeutic intervention

    Bogart, L.K.; Pourroy, G.; Murphy, C.J.; Puntes, V.; Pellegrino, T.; Rosenblum, D.; Peer, D.; Lévy, R. ACS Nano; 8 (4): 3107 - 3122. 2014. 10.1021/nn500962q. IF: 12.033


  • Optimising the use of commercial LAL assays for the analysis of endotoxin contamination in metal colloids and metal oxide nanoparticles.

    Li, Y.; Italiani, P.; Casals, E.; Tran, N.; Puntes, V. F.; Boraschi, D. Nanotoxicology; 14: 1 - 12. 2014. . IF: 7.336


  • Programmed iron oxide nanoparticles disintegration in anaerobic digesters boosts biogas production

    Casals, E.; Barrena, R.; García, A.; González, E.; Delgado, L.; Busquets-Fité, M.; Font, X.; Arbiol, J.; Glatzel, P.; Kvashnina, K.; Sánchez, A.; Puntes, V. Small; 10 (14): 2801 - 2808. 2014. 10.1002/smll.201303703. IF: 7.514


  • Synthesis of highly monodisperse citrate-stabilized silver nanoparticles of up to 200 nm: Kinetic control and catalytic properties

    Bastús, N.G.; Merkoçi, F.; Piella, J.; Puntes, V. Chemistry of Materials; 26 (9): 2836 - 2846. 2014. 10.1021/cm500316k. IF: 8.535


2013

  • Absence of Ce3+ sites in chemically active colloidal ceria nanoparticles

    Cafun, J.-D.; Kvashnina, K.O.; Casals, E.; Puntes, V.F.; Glatzel, P. ACS Nano; 7 (12): 10726 - 10732. 2013. 10.1021/nn403542p. IF: 12.062


  • Altered characteristics of silica nanoparticles in bovine and human serum: the importance of nanomaterial characterization prior to its toxicological evaluation

    Izak-Nau, E.; Voetz, M.; Eiden, S.; Duschl, A.; Puntes, V.F. Particle and Fibre Toxicology; 2013. 10.1186/1743-8977-10-56. IF: 9.178


  • Characterizing Nanoparticles Reactivity: Structure-Photocatalytic Activity Relationship

    Piella, J.; Bastús, N. G.; Casals, E.; Puntes, V. Journal of Physics: Conference Series; 429: 1. 2013. 10.1088/1742-6596/429/1/012040. IF: 0.000


  • Dipolar magnetism in ordered and disordered low-dimensional nanoparticle assemblies

    Varón, M.; Beleggia, M.; Kasama, T.; Harrison, R.J.; Dunin-Borkowski, R.E.; Puntes, V.F.; Frandsen, C. Scientific Reports; 2013. 10.1038/srep01234. IF: 2.927


  • Engineered Inorganic Nanoparticles for Drug Delivery Applications

    Ojea-Jiménez, I.; Comenge, J.; García-Fernández, L.; Megson, Z.A.; Casals, E.; Puntes, V.F. Current Drug Metabolism; 14 (5): 518 - 530. 2013. 10.2174/13892002113149990008. IF: 4.405


  • Exploring release and recovery of nanomaterials from commercial polymeric nanocomposites

    Busquets-Fité, M.; Fernandez, E.; Janer, G.; Vilar, G.; Vázquez-Campos, S.; Zanasca, R.; Citterio, C.; Mercante, L.; Puntes, V. Journal of Physics: Conference Series; 429: 1. 2013. 10.1088/1742-6596/429/1/012048. IF: 0.000


  • Monitoring migration and transformation of nanomaterials in polymeric composites during accelerated aging

    Vilar, G.; Fernández-Rosas, E.; Puntes, V.; Jamier, V.; Aubouy, L.; & Vázquez-Campos, S Journal of Physics: Conference Series; 429: 2. 2013. 10.1088/1742-6596/429/1/012044. IF: 0.000


  • Radiochemical synthesis of105gAg-labelled silver nanoparticles

    Ichedef, C.; Simonelli, F.; Holzwarth, U.; Bagaria, J.P.; Puntes, V.F.; Cotogno, G.; Gilliland, D.; Gibson, N. Journal of Nanoparticle Research; 15 (11) 2013. 10.1007/s11051-013-2073-8. IF: 2.175


  • Spontaneous formation of hollow cobalt oxide nanoparticles by the Kirkendall effect at room temperature at the water-air interface

    Varón, M.; Ojea-Jimenez, I.; Arbiol, J.; Balcells, L.; Martínez, B.; Puntes, V.F. Nanoscale; 5: 2429 - 2436. 2013. 10.1039/c2nr32657d. IF: 6.233


  • Stability of polymer encapsulated quantum dots in cell culture media

    Ojea-Jiménez, I.; Piella, J.; Nguyen, T. L.; Bestetti, A.; Ryan, A. D.; Puntes, V. Journal of Physics: Conference Series; 429: 3. 2013. 10.1088/1742-6596/429/1/012009. IF: 0.000


  • The social context of nanotechnology and regulating its uncertainty: A nanotechnologist approach

    Jamier, V.; Gispert, I.; Puntes, V. Journal of Physics: Conference Series; 429: 4. 2013. 10.1088/1742-6596/429/1/012059. IF: 0.000


2012

  • Citrate-Coated Gold Nanoparticles As Smart Scavengers for Mercury(II) Removal from Polluted Waters

    Ojea-Jiménez, I.; López, X.; Arbiol, J.; Puntes, V. ACS Nano; 6: 2253 - 2260. 2012. .


  • Controlled positioning of nanoparticles on graphene by noninvasive AFM lithography

    Bellido, E.; Ojea-Jiménez, I.; Ghirri, A.; Alvino, C.; Candini, A.; Puntes, V.; Affronte, M.; Domingo, N.; Ruiz-Molina, D. Langmuir : the ACS journal of surfaces and colloids; 28: 12400 - 12409. 2012. 10.1021/la3023419.


  • Detoxifying Antitumoral Drugs via Nanoconjugation: The Case of Gold Nanoparticles and Cisplatin

    Comenge, J.; Sotelo, C.; Romero, F.; Gallego, O.; Barnadas, A.; García-Caballero Parada, T.; Domínguez, F.; Puntes, V.F. Plos One. Open acces; 7(10): e47562. 2012. .

    Open Access


  • Effect of cerium dioxide, titanium dioxide, silver, and gold nanoparticles on the activity of microbial communities intended in wastewater treatment.

    García, A.; Delgado, L.;Torà, JA.; Casals, E.; González, E.; Puntes, V.; Font, X.; Carrera, J.; Sánchez, A. Journal of Hazardous Materials; 199-200: 64 - 72. 2012. 10.1016/j.jhazmat.2011.10.057.


  • Engineered nonviral nanocarriers for intracellular gene delivery applications

    Ojea-Jiménez, I.; Tort, O.; Lorenzo, J.; Puntes, V.F. Biomedical materials (Bristol, England); 7(5): 54106. 2012. 10.1088/1748-6041/7/5/054106.


  • Facile Preparation of Cationic Gold Nanoparticle-Bioconjugates for Cell Penetration and Nuclear Targeting

    Ojea-Jiménez, I.; García-Fernández, L.; Lorenzo, J.; Puntes, V. F. ACS Nano; 6 (9): 7692 - 7702. 2012. .


  • Inorganic nanoparticle biomolecular corona: Formation, evolution and biological impact

    Casals, E.; Puntes, V.F. Nanomedicine; 7: 1917 - 1930. 2012. 10.2217/nnm.12.169.


  • Inorganic nanoparticles and the environment: Balancing benefits and risks

    Casals, E.; González, E.; Puntes, V. Comprehensive Analytical Chemistry; 59: 265 - 290. 2012. 10.1016/B978-0-444-56328-6.00008-6.


  • Inorganic nanoparticles and the immune system: detection, selective activation and tolerance.

    Bastús, N.G.; Sánchez-Tilló, E.; Pujals, S.; Comenge, J.; Giralt, E.; Celada, A.; Lloberas, J.; Puntes, V.F. Proceedings of SPIE - The International Society for Optical Engineering; 823217: 1. 2012. 10.1117/12.917327.


  • Molecular modeling of the reduction mechanism in the citrate-mediated synthesis of gold nanoparticles

    Ojea-Jiménez, I.; Campanera, J.M. Journal of Physical Chemistry C; 116: 23682 - 23691. 2012. 10.1021/jp305830p.


  • Physicochemical Characteristics of Protein¿NP Bioconjugates: The Role of Particle Curvature and Solution Conditions on Human Serum Albumin Conformation and Fibrillogenesis Inhibition

    Goy-López, S.; Juárez, J.; Alatorre-Meda, M.; Casals, E.; Puntes, V.F.; Taboada, P.; Mosquera, V. Langmuir : the ACS journal of surfaces and colloids; 28(24): 9113 - 9126. 2012. 10.1021/la300402w.


  • Potential use of CeO2 , TiO2 and Fe3O4 nanoparticles for the removal of cadmium from water

    Contreras, A.R.; García, A.; González, E.; Casals, E.; Puntes, V.F.; Sánchez, A.; Fonta, X.; Recillas, S. Desalination and Water Treatment; 41 (1-3): 296 - 300. 2012. 10.1080/19443994.2012.664743.

    Open Access


  • Preliminary study of phosphate adsorption onto cerium oxide nanoparticles for use in water purification; nanoparticles synthesis and characterization

    Recillas, S.; García, A.; González, E.; Casals, E.; Puntes, V.F.; Sánchez, A.; Font, X. Water Science and Technology; 66(3): 503 - 509. 2012. 10.2166/wst.2012.185.

    Open Access


  • Rational nanoconjugation improves biocatalytic performance of enzymes: Aldol addition catalyzed by immobilized rhamnulose-1-phosphate aldolase

    Ardao, I.; Comenge, J.; Benaiges, M.D.; Álvaro, G.; Puntes, V.F. Langmuir : the ACS journal of surfaces and colloids; 28: 6461 - 6467. 2012. 10.1021/la3003993.


  • Reactivity of inorganic nanoparticles in biological environments: Insights into nanotoxicity mechanisms

    Casals, E.; Gonzalez, E.; Puntes, V.F. Journal of Physics D - Applied Physics; 45 2012. 10.1088/0022-3727/45/44/443001.


  • Synthesis of co-organosilane-Au nanocomposites via a controlled interphasic reduction

    Ojea-Jiménez, I.; Lorenzo, J.; Rebled, J.M.; Sendra, J.; Arbiol, J.; Puntes, V. Chemistry of Materials; 24: 4019 - 4027. 2012. 10.1021/cm300757j.


2011

  • Acute toxicity of cerium oxide, titanium oxide and iron oxide nanoparticles using standardized tests

    García, A.; Espinosa, R.; Delgado, L.; Casals, E.; González, E.; Puntes, V.; Barata, C.; Font, X.; Sánchez, A.; Barata, C Desalination; 269: 136 - 141. 2011. 10.1016/j.desal.2010.10.052.


  • Analysis of time-dependent conjugation of gold nanoparticles with an antiparkinsonian molecule by using curve resolution methods

    Amigo, J.M.; Bastús, N.G.; Hoen, R.; Vázquez-Campos, S.; Varón, M.; Royo, M.; Puntes, V.F. Analytica Chimica Acta; 2011. .


  • Carving at the nanoscale: Sequential galvanic exchange and Kirkendall growth at room temperature

    González, E.; Arbiol, J.; Puntes, V.F. SCIENCE; 334: 1377 - 1380. 2011. 10.1126/science.1212822.


  • Ecotoxicity of, and remediation with, engineered inorganic nanoparticles in the environment

    Sánchez, A.; Recillas, S.; Font, X.; Casals, E.; González, E.; Puntes, V.F. TrAC - Trends in Analytical Chemistry; 2011. .


  • Hardening of the nanoparticle-protein corona in metal (Au, Ag) and oxide (Fe 3O 4, CoO, and CeO 2) nanoparticles

    Casals, E.; Pfaller, T.; Duschl, A.; Oostingh, G.J.; Puntes, V.F. Small; 7: 3479 - 3486. 2011. 10.1002/smll.201101511.


  • Influence of the Sequence of the Reagents Addition in the Citrate-Mediated Synthesis of Gold Nanoparticles

    Ojea-Jiménez, I.; Bastús, N.G.; Puntes, V.F. Journal of Physical Chemistry C; 2011. 10.1021/jp2017242.


  • Kinetically Controlled Seeded Growth Synthesis of Citrate-Stabilized Gold Nanoparticles of up to 200 nm: Size Focusing versus Ostwald Ripening

    Bastús, N.G.; Comenge, J.; Puntes, V.F. Langmuir : the ACS journal of surfaces and colloids; 2011. .


  • Large 2D self-assembled domains of cobalt nanoparticles onto silicon wafers

    Peña, L.; Varón, M.; Konstantinovic, Z.; Balcells, L.; Martínez, B.; Puntes, V. Journal of Materials Chemistry; 21: 16973 - 16977. 2011. 10.1039/c1jm11647a.


  • Nano-immunosafety: issues in assay validation

    Boraschi, D.; Oostingh, G.J.; Casals, E.; Italiani, P.; Nelissen, I.; Puntes, V.F:; Duschl, A. Journal of Physics: Conference Series; 2011. .


  • Nanoparticle microinjection and Raman spectroscopy as tools for nanotoxicology studies

    Candeloro, P.; Tirinato, L.; Malara, N.; Fregola, A.; Casals, E.; Puntes, V.; Perozziello, G.; Gentile, F.; Coluccio, M.L.; Das, G.; Liberale, C.; De Angelis, F.; Di Fabrizio, E. The Analyst; 2011. .


  • Problems and challenges in the development and validation of human cell-based assays to determine nanoparticle-induced immunomodulatory effects

    Oostingh, G.J.; Casals, E.; Italiani, P.; Colognato, R.; Stritzinger, R.; Ponti, J.; Pfaller, T.; Kohl, Y.; Ooms, D.; Favilli, F.; Leppens, H.; Lucchesi, D.; Rossi, F.; Nelissen, I.; Thielecke, H.; Puntes, V.F.; Duschl, A.; Boraschi, D. Particle and Fibre Toxicology; 2011. .


  • Pt nanocrystal evolution in the presence of Au(iii)-salts at room temperature: Spontaneous formation of AuPt heterodimers

    Lim, S.I.; Varon, M.; Ojea-Jiménez, I.; Arbiol, J.; Puntes, V. Journal of Materials Chemistry; 21: 11518 - 11523. 2011. 10.1039/c1jm10313j.


  • Synthesis and evaluation of gold nanoparticle -modified polyelectrolyte capsules under microwave irradiation for remotely controlled release for cargo

    del Mercato, L.L.; Gonzalez, E.; Abbasi, A.Z.; Parak, W.J.; Puntes, V.F. Journal of Materials Chemistry; 2011. .


  • Use of CeO2, TiO2 and Fe3O4 nanoparticles for the removal of lead from water: Toxicity of nanoparticles and derived compounds

    Recillas, S.; García, A.; González, E.; Casals, E.; Puntes, V.F.; Sánchez, A.; Font, X. Desalination; 2011. .


2010

  • Chromium VI adsorption on cerium oxide nanoparticles and morphology changes during the process

    Recillas, S.; Colón, J.; Casals, E.; González, E.; Puntes, V.; Sánchez, A.; Font, X. Journal of Hazardous Materials; 2010. .


  • Coordination polymer particles as potential drug delivery systems

    Imaz, I.; Rubio-Martínez, M.; García-Fernández, L.; García, F.; Ruiz-Molina, D.; Hernando, J.; Puntes, V.; Maspoch, D. Chemical Communications; 46: 4737 - 4739. 2010. 10.1039/c003084h.


  • Correlating Physico-Chemical with Toxicological Properties of Nanoparticles: The Present and the Future

    Rivera Gil, P.; Oberdörster, G.; Elder, A.; Puntes, V.F.; Parak, W.J. ACS Nano; 2010. .


  • Dipolar driven spontaneous self assembly of superparamagnetic CO nanoparticles into micrometric rice-Grain like structures

    Varón, M.; Peña, L.; Balcells, L.; Skumryev, V.; Martinez, B.; Puntes, V. Langmuir : the ACS journal of surfaces and colloids; 26: 109 - 116. 2010. 10.1021/la902169s.


  • Exploring the limitations of the use of competing reducers to control the morphology and composition of Pt and PtCo nanocrystals

    Lim, S.I.; Varón, M.; Ojea-Jiménez, I.; Arbiol, J.; Puntes, V. Chemistry of Materials; 22: 4495 - 4504. 2010. 10.1021/cm101436p.


  • Small gold nanoparticles synthesized with sodium citrate and heavy water: Insights into the reaction mechanism

    Ojea-Jiménez, I.; Romero, F.M.; Bastús, N.G.; Puntes, V. Journal of Physical Chemistry C; 114: 1800 - 1804. 2010. 10.1021/jp9091305.


  • Synthesis of platinum cubes, polypods, cuboctahedrons, and raspberries assisted by cobalt nanocrystals

    Lim, S.I.; Ojea-Jiménez, I.; Varon, M.; Casals, E.; Arbiol, J.; Puntes, V. Nano Letters; 10: 964 - 973. 2010. 10.1021/nl100032c.


  • The suitability of different cellular in vitro immunotoxicity and genotoxicity methods for the analysis of nanoparticle-induced events

    Pfaller, T.; Colognato, R.; Nelissen, I.; Favilli, F.; Casals, E.; Ooms, D.; Leppens, H.; Ponti, J; Stritzinger, R.; Puntes, V.F.; Boraschi, D.; Duschl, A.; Oostingh, G.J. Nanotoxicology; 2010. 10.3109/17435390903374001.


  • Time evolution of the nanoparticle protein corona

    Casals, E.; Pfaer, T.; Dusch, A.; Oostingh, G.J.; Puntes, V.F. ACS Nano; 2010. .


2009

  • Homogeneous Conjugation of Peptides onto Gold Nanoparticles Enhances Macrophage Response

    Bastús, N. G.; Sánchez-Tillo, E.; Pujals, S.; Farrera, C.; López, C. ; Giralt, E. ; Celanda, A. ; Lloberas, J.; Puntes, V. ACS Nano; 3 (6): 1335 - 1344. 2009. 10.1021/nn8008273 CCC: $40.75.


  • Identifying Spinel Phases in Nearly Monodisperse Iron Oxide Colloidal Nanocrystal

    Corrias, A.; Mountjoy, G.; Loche, D.; Puntes, V.; Falqui, A.; Zanella, M.; Parak, W.J.; Casula, M.F. Journal of the American Chemical Society; 113 (43): 18667. 2009. 10.1021/jp9047677 CCC: $40.75.


  • Impact of engineered nanoparticles on immune-related genes and processes in human alveolar epithelial cells

    Nelissen, I.; Verstraelen, S.; De Boever, P.; Casals, E.; Ooms, D.; Leppens, H.; Hollanders, K.; Van Den Heuvel, R.; Schoeters, G.; Puntes, V.; Witters, H. Toxicology Letters; 189: 186 - 189. 2009. dx.doi.org/10.1016/j.toxlet.2009.06.649.


  • In vitro investigation of immunomodularoty effects caused by engineered inorganic nanoparticles- the impact of experimental design and cell choice

    Pfaller, T.; Puntes, V. F.; Casals, E.; Duschl, A.; Oostingh, G.J. Nanotoxicology; 3 (1): 46 - 59. 2009. 10.1016/j.toxlet.2009.06.649 .


  • Inorganic engineered nanoparticles and their impact on the immune response

    Sperling, R. A.; Casals, E.; Comenge, J.; Bastús, N. G. ; Puntes, V. Current Drug Metabolism; 10: 895 - 904. 2009. http://dx.doi.org/10.2174/138920009790274577.


  • Instability of Cationic Gold Nanoparticle Bioconjugates: The Role of Citrate Ions

    Ojea-Jimenez, I. ; Puntes, V. Journal of the American Chemical Society; 131 (37): 13320 - 133327. 2009. 10.1021/ja902894s.


  • Nano-cotton fabrics with high ultraviolet protection

    Roshan, P.; Bautista, L.; De la Varga, M .; Botet, J.M. ; Casals, E.; Puntes, V.F. ; Marsal, F. Textile Research Journal; 13: 101177. 2009. 10.1177/0040517509342316.


  • Nanopànic o Nanoeufòria?: Nanoinfo

    Puntes, V.F. ; Garcia Horn, A. Mètode; 63: 25 - 30. 2009. .


  • Peptides conjugated to gold nanoparticles induce macrophage activation

    Bastús, N. G.; Sánchez-Tillo, E.; Pujals, S.; Farrera, C.; Kogan, M. J.; Giralt, E.; Celada, A.; Lloberas, J.; Puntes, V. F. Molecular Immunology; 46 (4): 743 - 748. 2009. 10.1016/j.molimm.2008.08.277 .


  • Scientist still wondering-Industry are selling

    Gatti, A.; Puntes, V. Nano; 46 (4): 743 - 748. 2009. .


  • Shuttling Gold Nanoparticles into Tumoral Cells with an Amphipathic Proline-Rich Peptide

    Pujals, S. ; Bastus, N. G.; Pereiro, E.; López-Iglesias, C.; Puntes, V. F.; Kogan, M. J.; Giralt, E. Chemistry: a European Journal; 10 (6): 1025 - 1031. 2009. 10.1002/cbic.200800843 .


2008

  • Distribution and potential toxicity of engineered inorganic nanoparticles and carbon nanostructures in biological systems

    Casals E.; Vazquez-Campos S.; Bastus N.G.; Puntes V. TrAC - Trends in Analytical Chemistry; 27 (8): 672 - 683. 2008. 10.1016/j.trac.2008.06.004.


  • Gold Nanoparticles and Microwave Irradiation Inhibit Beta-Amyloid Amyloidogenesis

    Araya Eyleen; Olmedo Ivonne; Bastus Neus G.; Guerrero Simon; Puntes Victor F.; Giralt Ernest; Kogan Marcelo J Nanoscale Research Letters; 3 (11): 435 - 443. 2008. 10.1007/s11671-008-9178-5.

    Open Access


  • Low-Temperature Synthesis of CoO Nanoparticles via Chemically Assisted Oxidative Decarbonylation

    Lagunas A.; Mairata i Payeras A.; Jimeno C.; Puntes V. F.; Pericàs M. A. Chemistry of Materials; 20 (1): 92 - 100. 2008. 10.1021/cm7018636.


  • Nanoparticles for cosmetics: how safe is safe?

    M. Guix-Noguera; C. Carbonell; J. Comenge; L. García-Fernández; A. Alarcón-Pardo; E. Casals; V. Puntes Contributions to Science; 4: 2. 2008. 10.2436/20.7010.01.52.


  • Reactivity of engineered inorganic nanoparticles and carbon nanostructures in biological media

    Neus G. Bastús; Eudald Casals; Socorro Vázquez-Campos; Victor Puntes Nanotoxicology; 2 (3): 99 - 112. 2008. 10.1080/17435390802217830.


  • Shuttling Gold Nanoparticles into Tumoral Cells with an Amphipathic Pro rich Peptide

    Pujals S; Bastús NG; Pereiro E; López-Iglesias E; Puntes VF; Kogan MJ; Giralt E Chemistry: a European Journal; 10: 1025 - 1031. 2008. 10.1002/cbic.200800843.