ICN2 Publications

2019

  • Electrochemical detection of plant virus using gold nanoparticle-modified electrodes

    Khater M., de la Escosura-Muñiz A., Quesada-González D., Merkoçi A. Analytica Chimica Acta; 1046: 123 - 131. 2019. 10.1016/j.aca.2018.09.031.

    Nanobioelectronics and Biosensors

    Tristeza is one of the destructive diseases of citrus causing by citrus tristeza virus (CTV). Historically, CTV has been associated with serious outbreaks of quick decline of citrus, therefore CTV monitoring is important aspect for avoiding such re-emerging epidemics, which would threat citrus production through the world. In this context, we have designed for the first time a label-free impedimetric biosensor for the detection of nucleic acid of CTV. The sensing platform based on a screen-printed carbon electrode (SPCE) was modified by electrodeposited gold nanoparticles (AuNPs), which allowed to efficiently immobilizing thiolated ssDNA probes as well to enhance the electrode conductivity. The growth of AuNPs was optimized and characterized using scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). We investigated the behavior of thiolated ssDNA probe layer and its hybridization with target DNA onto AuNP surfaces by EIS measurements in Fe(CN6)4-/Fe(CN6)3- red-ox system. The main sensor design aspects such as AuNPs size, probe DNA concentration and immobilization time together with DNA hybridization time were optimized so as to achieve the best performance. Impedance values of DNA hybridization increased with Citrus tristeza-related synthetic DNA concentration, showing a logarithmic relation in the range of 0.1–10 μM. The results also indicate that the biosensor was able to selectively detect CTV nucleic acids in the presence of other non-specific DNAs. Moreover, we have demonstrated the good performance of the system in a real plant sample matrix. In addition, the sensor reproducibility enhanced after the hybridization onto MCH/poly (AT) thiolated DNA probes which was confirmed by intra- and inter-day variability assays. © 2018 Elsevier B.V.


  • Graphene-supported palladium phosphide PdP2 nanocrystals for ethanol electrooxidation

    Liu J., Luo Z., Li J., Yu X., Llorca J., Nasiou D., Arbiol J., Meyns M., Cabot A. Applied Catalysis B: Environmental; 242: 258 - 266. 2019. 10.1016/j.apcatb.2018.09.105.

    Advanced Electron Nanoscopy

    We present a procedure to produce single-phase PdP2 nanocrystals (NCs). The approach involves the reaction of palladium(II) acetylacetonate and hexamethylphosphoroustriamide to nucleate defective Pd5P2 nanoparticles that subsequently, with further phosphorous incorporation, crystallize into PdP2. The synthesized PdP2 NCs were supported on reduced graphene oxide (rGO) and applied as electrocatalysts for ethanol oxidation. The activity of PdP2 toward the ethanol oxidation reaction (EOR) was over a threefold higher than that of Pd NCs prepared under similar conditions. Even better performance was obtained from PdP2 NCs supported on rGO, which showed current densities up to 51.4 mA cm−2 and mass activities of 1.60 A mg-1 Pd, that is 4.8 and 15 times higher than Pd NCs. Besides, PdP2 NCs and PdP2/rGO catalysts showed improved stability during EOR than Pd NCs and Pd/rGO. © 2018 Elsevier B.V.


  • Non-cytotoxic carbon nanocapsules synthesized via one-pot filling and end-closing of multi-walled carbon nanotubes

    Martincic M., Vranic S., Pach E., Sandoval S., Ballesteros B., Kostarelos K., Tobias G. Carbon; 141: 782 - 793. 2019. 10.1016/j.carbon.2018.10.006.

    Electron Microscopy Unit

    Filled carbon nanotubes (CNTs) find application in a variety of fields that expand from sensors to supercapacitors going through targeted therapies. Bulk filling of CNTs in general results in samples that contain a large amount of non-encapsulated material external to the CNTs. The presence of external material can dominate the properties of the resulting hybrids and can also induce side effects when employed in the biomedical field. Unless the encapsulated payloads have a strong interaction with the inner CNT walls, an additional step is required to block the ends of the CNTs thus allowing the selective removal of the non-encapsulated compounds while preserving the inner cargo. Herein we present a fast, easy and versatile approach that allows both filling (NaI, KI, BaI2, GdCl3 and SmCl3) and end-closing of multi-walled CNTs in a single-step, forming “carbon nanocapsules”. Remarkably the encapsulation of GdCl3 and SmCl3 leads to the formation of tubular van der Waals heterostructures. The prepared nanocapsules are efficiently internalized by cells without inducing cytotoxicity, thus presenting a safe tool for the delivery of therapeutic and dianostic agents to cells. The synergies of novel carbon and inorganic hybrid materials can be explored using the present approach. © 2018 Elsevier Ltd


  • Production and printing of graphene oxide foam ink for electrocatalytic applications

    Baptista-Pires L., de la Escosura-Muñiz A., Balsells M., Zuaznabar-Gardona J.C., Merkoçi A. Electrochemistry Communications; 98: 6 - 9. 2019. 10.1016/j.elecom.2018.11.001.

    Nanobioelectronics and Biosensors

    A graphene-based ink printed as a foam-like structure with open pores is reported. The production of the ink is easier and faster than using existing methods and the obtained product is stable in water suspension. Electrocatalytic applications of 3D structured electrodes printed onto plastic substrates were explored. © 2018 Elsevier B.V.


  • Sustainable synthesis of luminescent CdTe quantum dots coated with modified silica mesoporous nanoparticles: Towards new protein scavengers and smart drug delivery carriers

    Oliveira E., Santos H.M., Jorge S., Rodríguez-González B., Novio F., Lorenzo J., Ruiz-Molina D., Capelo J.L., Lodeiro C. Dyes and Pigments; 161: 360 - 369. 2019. 10.1016/j.dyepig.2018.09.047.

    Nanostructured Functional Materials

    The synthesis and full characterization of a family of sustainable luminescent nanoparticles, CdTeQDs@MNs, made of quantum dots coated by modified mesoporous silica nanoparticles is reported. The presence of the luminescent QDs allows the imaging of the nanoparticles during cell internalization, as well as the visualization of selective release of doxorubicin inside the cell (via pH stimuli). The modified mesoporous silica nanoparticles lead to pore size improvement allowing better encapsulation and controlled release, of different active principles studied such as, small molecules (rhodamine B), drugs (doxorubicin), and isolated proteins such as bovine serum albumin, lysozyme, carbonic anhydrase, ovalbumin, α-lactalbumin, hemoglobin, myoglobin and cytochrome C. Finally, and as a proof-of-concept the efficacy of these novel platforms was demonstrated through the successful extraction and recognition of proteins in raw serum of osteoarthritis and prosthesis patients, without any previous protein depletion. © 2018 Elsevier Ltd