Publications
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Fabrication and characterization of large-area suspended MoSe2 crystals down to the monolayer
Varghese S., Reig D.S., Mehew J.D., Block A., El Sachat A., Chávez-Ángel E., Sledzinska M., Ballesteros B., Sotomayor Torres C.M., Tielrooij K.-J. JPhys Materials; 4 (4, 046001) 2021. 10.1088/2515-7639/ac2060. IF: 0.000
Many layered materials, such as graphene and transition metal dichalcogenides, can be exfoliated down to atomic or molecular monolayers. These materials exhibit exciting material properties that can be exploited for several promising device concepts. Thinner materials lead to an increased surface-to-volume ratio, with mono- and bi-layers being basically pure surfaces. Thin crystals containing more than two layers also often behave as an all-surface material, depending on the physical property of interest. As a result, flakes of layered materials are typically highly sensitive to their environment, which is undesirable for a broad range of studies and potential devices. Material systems based on suspended flakes overcome this issue, yet often require complex fabrication procedures. Here, we demonstrate the relatively straightforward fabrication of exfoliated MoSe2 flakes down to the monolayer, suspended over unprecedentedly large holes with a diameter of 15 µm. We describe our fabrication methods in detail, present characterization measurements of the fabricated structures, and, finally, exploit these suspended flakes for accurate optical absorption measurements. © 2021 The Author(s).
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Gadolinium-Incorporated Carbon Nanodots for T1-Weighted Magnetic Resonance Imaging
Ji D.-K., Reina G., Liang H., Zhang D., Guo S., Ballesteros B., Ménard-Moyon C., Li J., Bianco A. ACS Applied Nano Materials; 4 (2): 1467 - 1477. 2021. 10.1021/acsanm.0c02993. IF: 5.097
The design and development of contrast agents for magnetic resonance imaging (MRI) with improved chemical stability and higher contrasting capability for clinical translation compared to conventional contrast agents are still of great interest. In this study, a facile and universal approach was explored for controllable functionalization of red-emissive carbon nanodots (RCNDs) with diethylenetriaminepentaacetic anhydride (DTPA) for chelation of gadolinium. A series of accurate characterizations were used to control each step of the synthesis. The functionalization did not alter the band gap of the carbon nanodots, preserving their inherent far-red fluorescence. The as-prepared RCND-DTPA-Gd displayed a high colloidal stability with negligible Gd leakage. The nanodots also showed a better magnetic resonance relaxivity than commercial MRI agents. RCND-DTPA-Gd had good biocompatibility in vivo even at high doses. The systemically injected RCND-DTPA-Gd were found to be efficiently excreted through the renal route, a feature that further minimizes the potential toxicity risks. All these properties suggest that carbon nanodots can be well designed as efficient carriers of Gd, resulting in potential clinical tools as dual MRI/fluorescence functional probes for imaging applications. The approach described here could pave the pathway to a flexible strategy for the controllable functionalization of small-sized nanoparticles including carbon dots, rendering them more versatile. This work is expected to promote the future translation of carbon nanodots into clinical trials. © 2021 American Chemical Society. All rights reserved.
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Graphene oxide prevents lateral amygdala dysfunctional synaptic plasticity and reverts long lasting anxiety behavior in rats
Franceschi Biagioni A., Cellot G., Pati E., Lozano N., Ballesteros B., Casani R., Coimbra N.C., Kostarelos K., Ballerini L. Biomaterials; 271 (120749) 2021. 10.1016/j.biomaterials.2021.120749. IF: 12.479
Engineered small graphene oxide (s-GO) sheets were previously shown to reversibly down-regulate glutamatergic synapses in the hippocampus of juvenile rats, disclosing an unexpected translational potential of these nanomaterials to target selective synapses in vivo. Synapses are anatomical specializations acting in the Central Nervous System (CNS) as functional interfaces among neurons. Dynamic changes in synaptic function, named synaptic plasticity, are crucial to learning and memory. More recently, pathological mechanisms involving dysfunctional synaptic plasticity were implicated in several brain diseases, from dementia to anxiety disorders. Hyper-excitability of glutamatergic neurons in the lateral nucleus of the amygdala complex (LA) is substantially involved in the storage of aversive memory induced by stressful events enabling post-traumatic stress disorder (PTSD). Here we translated in PTSD animal model the ability of s-GO, when stereotaxically administered to hamper LA glutamatergic transmission and to prevent the behavioral response featured in long-term aversive memory. We propose that s-GO, by interference with glutamatergic plasticity, impair LA-dependent memory retrieval related to PTSD. © 2021 The Authors
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Graphene quantum dots: From efficient preparation to safe renal excretion
Hadad C., González-Domínguez J.M., Armelloni S., Mattinzoli D., Ikehata M., Istif A., Ostric A., Cellesi F., Alfieri C.M., Messa P., Ballesteros B., Da Ros T. Nano Research; 14 (3): 674 - 683. 2021. 10.1007/s12274-020-3096-y. IF: 8.897
Carbon nanomaterials offer excellent prospects as therapeutic agents, and among them, graphene quantum dots (GQDs) have gained considerable interest thanks to their aqueous solubility and intrinsic fluorescence, which enable their possible use in theranostic approaches, if their biocompatibility and favorable pharmacokinetic are confirmed. We prepared ultra-small GQDs using an alternative, reproducible, top-down synthesis starting from graphene oxide with a nearly 100% conversion. The materials were tested to assess their safety, demonstrating good biocompatibility and ability in passing the ultrafiltration barrier using an in vitro model. This leads to renal excretion without affecting the kidneys. Moreover, we studied the GQDs in vivo biodistribution confirming their efficient renal clearance, and we demonstrated that the internalization mechanism into podocytes is caveolae-mediated. Therefore, considering the reported characteristics, it appears possible to vehiculate compounds to kidneys by means of GQDs, overcoming problems related to lysosomal degradation. [Figure not available: see fulltext.]. © 2020, The Author(s).
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Heat-up colloidal synthesis of shape-controlled cu-se-s nanostructures—role of precursor and surfactant reactivity and performance in n2 electroreduction
Mourdikoudis S., Antonaropoulos G., Antonatos N., Rosado M., Storozhuk L., Takahashi M., Maenosono S., Luxa J., Sofer Z., Ballesteros B., Thanh N.T.K., Lappas A. Nanomaterials; 11 (12, 3369) 2021. 10.3390/nano11123369. IF: 5.076
Copper selenide-sulfide nanostructures were synthesized using metal-organic chemical routes in the presence of Cu-and Se-precursors as well as S-containing compounds. Our goal was first to examine if the initial Cu/Se 1:1 molar proportion in the starting reagents would always lead to equiatomic composition in the final product, depending on other synthesis parameters which affect the reagents reactivity. Such reaction conditions were the types of precursors, surfactants and other reagents, as well as the synthesis temperature. The use of ‘hot-injection’ processes was avoided, focusing on ‘non-injection’ ones; that is, only heat-up protocols were employed, which have the advantage of simple operation and scalability. All reagents were mixed at room temperature followed by further heating to a selected high temperature. It was found that for samples with particles of bigger size and anisotropic shape the CuSe composition was favored, whereas particles with smaller size and spherical shape possessed a Cu2−xSe phase, especially when no sulfur was present. Apart from elemental Se, Al2Se3 was used as an efficient selenium source for the first time for the acquisition of copper selenide nanostructures. The use of dodecanethiol in the presence of trioctylphosphine and elemental Se promoted the incorporation of sulfur in the materials crystal lattice, leading to Cu-Se-S compositions. A variety of techniques were used to characterize the formed nanomaterials such as XRD, TEM, HRTEM, STEM-EDX, AFM and UV-Vis-NIR. Promising results, especially for thin anisotropic nanoplates for use as electrocatalysts in nitrogen reduction reaction (NRR), were obtained. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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Shedding plasma membrane vesicles induced by graphene oxide nanoflakes in brain cultured astrocytes
Musto M., Parisse P., Pachetti M., Memo C., Di Mauro G., Ballesteros B., Lozano N., Kostarelos K., Casalis L., Ballerini L. Carbon; 176: 458 - 469. 2021. 10.1016/j.carbon.2021.01.142. IF: 9.594
Microvesicles (MVs) generated and released by astrocytes, the brain prevalent cells, crucially contribute to intercellular communication, representing key vectorized systems able to spread and actively transfer signaling molecules from astrocytes to neurons, ultimately modulating target cell functions. The increasing clinical relevance of these signaling systems requires a deeper understanding of MV features, currently limited by both their nanoscale dimensions and the low rate of their constituent release. Hence, to investigate the features of such glial signals, nanotechnology-based approaches and the applications of unconventional, cost-effective tools in generating MVs are needed. Here, small graphene oxide (s-GO) nanoflakes are used to boost MVs shedding from astrocytes in cultures and s-GO generated MVs are compared with those generated by a natural stimulant, namely ATP, by atomic force microscopy, light scattering, attenuated total reflection–fourier transform infra-red and ultraviolet resonance Raman spectroscopy. We also report the ability of both types of MVs, upon acute and transient exposure of patch clamped cultured neurons, to modulate basal synaptic transmission, inducing a stable increase in synaptic activity accompanied by changes in neuronal plasma membrane elastic features. © 2021 The Author(s)
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Superelasticity preservation in dissimilar joint of NiTi shape memory alloy to biomedical PtIr
Shamsolhodaei A., Oliveira J.P., Panton B., Ballesteros B., Schell N., Zhou Y.N. Materialia; 16 (101090) 2021. 10.1016/j.mtla.2021.101090. IF: 0.000
Laser microwelding was used to join, for the first time, superelastic NiTi to biomedical PtIr which can be used in multicomponent biomedical devices. By process optimization, it was possible to control the formation of the B2 NiTiPt phase, with no intermetallic compounds being formed. The NiTiPt phase inside the fusion zone had a strong metallurgical bonding with the NiTi base material due to the smooth transition of its grain orientation towards 〈111〉 B2 NiTi. The major finding of the present work is the preservation of the NiTi superelastic response in the welded joint as evidenced by the load/unloading cycling up to 6% strain, significantly higher than typically required for biomedical applications. © 2021
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Tailoring the Architecture of Cationic Polymer Brush-Modified Carbon Nanotubes for Efficient siRNA Delivery in Cancer Immunotherapy
Li D., Ahmed M., Khan A., Xu L., Walters A.A., Ballesteros B., Al-Jamal K.T. ACS Applied Materials and Interfaces; 13 (26): 30284 - 30294. 2021. 10.1021/acsami.1c02627. IF: 9.229
The facile and controlled fabrication of homogeneously grafted cationic polymers on carbon nanotubes (CNTs) remains poorly investigated, which further hinders the understanding of interactions between functionalized CNTs with different nucleic acids and the rational design of appropriate gene delivery vehicles. Herein, we describe the controlled grafting of cationic poly(2-dimethylaminoethylmethacrylate) brushes on CNTs via surface-initiated atom transfer radical polymerization integrated with mussel-inspired polydopamine chemistry. The binding of nucleic acids with different brush-CNT hybrids discloses the highly architectural-dependent behavior with dense short brush-coated CNTs displaying the highest binding among all the other hybrids, namely, dense long, sparse long, and sparse short brush-coated CNTs. Additionally, different chemistries of the brush coatings were shown to influence the biocompatibility, cellular uptake, and silencing efficiency in vitro. This platform provides great flexibility for the design of polymer brush-CNT hybrids with precise control over their structure-activity relationship for the rational design of nucleic acid delivery systems. © 2021 American Chemical Society. All rights reserved.
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The role of temperature on the degree of end-closing and filling of single-walled carbon nanotubes
Kierkowicz M., Pach E., Fraile J., Domingo C., Ballesteros B., Tobias G. Nanomaterials; 11 (12, 3365) 2021. 10.3390/nano11123365. IF: 5.076
Carbon nanotubes (CNTs), owing to their high surface area-to-volume ratio and hollow core, can be employed as hosts for adsorbed and/or encapsulated molecules. At high temperatures, the ends of CNTs close spontaneously, which is relevant for several applications, including catalysis, gas storage, and biomedical imaging and therapy. This study highlights the influence of the annealing temperature in the range between 400 and 1100◦C on the structure and morphology of single-walled CNTs. The nitrogen adsorption and density functional theory calculations indicate that the fraction of end-closed CNTs increases with temperature. Raman spectroscopy reveals that the thermal treatment does not alter the tubular structure. Insight is also provided into the efficacy of CNTs filling from the molten phase, depending on the annealing temperature. The CNTs are filled with europium (III) chloride and analyzed by using electron microscopy (scanning electron microscopy and highresolution transmission electron microscopy) and energy-dispersive X-ray spectroscopy, confirming the presence of filling and closed ends. The filling yield increases with temperature, as determined by thermogravimetric analysis. The obtained results show that the apparent surface area of CNTs, fraction of closed ends, and amount of encapsulated payload can be tailored via annealing. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
