Nanoscale Advances最新文献

Hybrid nanoscintillators, which feature a heavy inorganic nanoparticle conjugated with an organic emitter, represent a promising avenue for advancements in diverse fields, including high-energy physics, homeland security, and biomedicine. Many research studies have shown the suitability of hybrid nanoscintillators for radiation oncology, showing potential to improve therapeutic results compared to traditional protocols. In this work, we studied SiO₂/ZnO nanoparticles functionalized with porphyrin as a photosensitizer, capable of producing cancer cytotoxic reactive oxygen species for possible use in radio-oncological therapeutics. Radioluminescence measurements under increasing energy of the ionizing radiation beam up to 10 keV show sensitization of porphyrin moieties on SiO₂/ZnO. This can be attributed to an increase in energy deposition promoted by the ZnO nanoparticles, which have a higher density and atomic number. This assumption was confirmed by computational simulations of energy deposition after the first interaction of ionizing radiation with SiO₂, ZnO, and air. Indeed, Monte Carlo simulations evidence that, despite a decrease in the absolute number of X-rays interacting within the system while increasing the energy of the beam, at 10 keV, the presence of ZnO is dominant to enhance energy deposition. Hence, these experimental and computational studies evidence the importance of each hybrid nanosystem component in the scintillation process. This work shows how an appropriate choice of constituents, in terms of physicochemical properties and architecture, can favour energy deposition mechanisms under X-ray irradiation and thus can boost the hybrid nanosystems' performance for diverse biomedical scintillation-based applications.

In this study, we show that on-chip grown, vertically aligned MoS₂ films that are decorated with Ni(OH)₂ catalyst are suitable materials to be applied as working electrodes in electrochemical sensing. The constructed sensors display a highly repeatable response to dopamine, used as a model analyte, in a large dynamic range from 1 μM to 1 mM with a theoretical detection limit of 0.1 μM. In addition, to facilitate practical implementation of the sensor chips, we also demonstrate a low power wireless cyber-physical system that we designed and accommodated for cyclic voltammetry measurements. The developed cost-effective and portable instrument enables straightforward data acquisition, transfer and visualization through an Android mobile interface, and has an accuracy comparable to reference analysis of our sensors using a commercial table-top laboratory potentiostat.

Hydrothermal carbonization (HTC) of carbohydrates has been reported as a sustainable and green technique to produce carbonaceous micro- and nano-materials. These materials have been developed for several applications, including catalysis, separation science, metal ion adsorption and nanomedicine. Carbon nanoparticles (CNPs) obtained through HTC are particularly interesting for the latter application since they exhibit photothermal properties when irradiated with near-infrared (NIR) light, act as an antioxidant by scavenging reactive oxygen species (ROS), and present good colloidal stability and biocompatibility. However, due to the highly disordered structure, there is still a poor understanding of the mechanism of synthesis of CNPs. Consequently, the modulation of the CNP properties by controlling the synthetic parameters is still a challenge. In this work, a novel and simplified HTC synthetic strategy to obtain non-aggregated glucose derived CNPs in the 15-150 nm size range with precise control of the diameter is presented, together with an advance in the understanding of the reaction mechanism behind the synthesis. Modifications of the synthetic parameters and a post-synthesis hydrothermal process were applied to increase the bulk order of CNPs, resulting in an increase of the photothermal and ROS scavenging activities, without affecting the morphological and colloidal properties of the nanomaterial.

The diffusion motions of individual polymer aggregates in disordered porous media were visualized using the single-particle tracking (SPT) method because the motions inside porous media play important roles in various fields of science and engineering. In the aggregates diffused on the surfaces of pores, continuous adsorption and desorption processes were observed. The relationship between the size of the aggregates and pore size was analysed based on diffusion coefficients, moment scaling spectrum (MSS) slope analysis, and diffusion anisotropy analysis. The obtained diffusion coefficients were different for different aggregates and pore sizes. The MSS slope analysis indicated that more than 85% of the aggregates showed confined diffusion for all the conditions investigated. The diffusion anisotropy analysis suggested that the diffusion of the aggregates exhibited anisotropic behaviour. The interactions between the aggregates and the pores were complex, causing the aggregates to exhibit motions distinct from those associated with surface diffusion on smooth surfaces.

In alignment with the global movement toward reducing animal testing, several reconstructed human epidermis (RHE) models have been created for conducting skin irritation tests. These models have undergone development, verification, validation, and integration into OECD TG 439. Our team has introduced a novel in-house RHE named GB-RHE, and we adhere to OECD TG 439 to pre-validate the model and test its potential employment for nanoparticle irritation studies. GB-RHE exhibits morphological, biochemical, and physiological attributes equivalent to the human epidermis, featuring well-differentiated multilayered viable keratinocytes with a robust barrier function. The performance of the GB-RHE model was evaluated using ten reference chemicals, following the performance standard of OECD TG 439. The results demonstrated commendable predictive capacity and showed that titanium dioxide nanoparticles (TiO₂ NPs) are 'non-irritant' to the human epidermis following the globally harmonized classification system. However, although the histological analysis did not show morphological changes, transmission electron micrographs demonstrated that TiO₂ NPs can be internalized, reaching the external viable layers of the epidermis. This study demonstrates that in addition to the potential of the GB-RHE model to evaluate skin irritation, this model also has the potential to evaluate the skin toxicity of NPs and carry out cell internalization studies.

Sensing of hazardous gases has an important role in ensuring safety in a variety of industries as well as environments. Mainly produced by the combustion of fossil fuels and other organic matter, ethanol is a dangerous gas that endangers human health and the environment. Stability and sensing sensitivity are major considerations when designing gas sensors. Here, a superior ethanol sensor with a high response and fast recovery was synthesized by "wrapping" CdS nanoparticles on metallic Ti₃C₂T _x MXene using a simple method. CdS nanoparticles were uniformly covered on the Ti₃C₂T _x MXene surface, forming a "rice crust"-like heterostructure. The sensor displayed good detection of ethanol gas at room temperature. Response signals up to 31% were obtained for ethanol molecules (20 ppm) with quick recovery (41 s). The performance of the ethanol sensor was evaluated across a range of concentrations (5-100 ppm) and relative humidity (60% and 90% RH) at room temperature. Our method could open up a new strategy for the development of ethanol sensors.

Using the first principle calculations, we propose a boron and nitrogen cluster incorporated graphene system for efficient valley polarization. The broken spatial inversion symmetry results in high Berry curvature at K and K' valleys of the hexagonal Brillouin zone in this semiconducting system. The consideration of excitonic quasiparticles within the GW approximation along with their scattering processes using the many-body Bethe-Salpeter equation gives rise to an optical gap of 1.72 eV with an excitonic binding energy of 0.65 eV. Owing to the negligible intervalley scattering, the electrons in opposite valleys are selectively excited by left- and right-handed circularly polarized light, as evident from the oscillator strength calculations. Therefore, this system can exhibit the circular-dichroism valley Hall effect in the presence of an in-plane electric field. Moreover, such excitonic qubits can be exploited for information processing.

Pt-CeO₂ nanosponges (1 wt% Pt) with high surface area (113 m² g^-1), high pore volume (0.08 cm³ g^-1) and small-sized Pt nanoparticles (1.8 ± 0.4 nm) are prepared by thermal decomposition of a cerium oxalate precursor and examined for catalytic oxidation of CO, volatile organic compounds (VOCs), and NH₃. The cerium oxalate precursor Ce₂(C₂O₄)₃·10H₂O is prepared by aqueous precipitation from Ce(NO₃)₃·6H₂O and K₂C₂O₄·H₂O and thermally converted to CeO₂ nanosponges by heating in air. Optimal conditions for decomposition in terms of surface area and porosity are observed at 350 °C for 20 min. Finally, the CeO₂ nanosponges are decorated with small-sized Pt nanoparticles, using a wet-chemical impregnation with Pt(ac)₂ in methanol. Electron microscopy with tomography, electron spectroscopy and further methods (TG, XRD, FT-IR, sorption analysis) are used to characterize the catalyst composition and especially the structure and porosity of the Pt-CeO₂ nanosponges as well as the uniform distribution of the Pt nanoparticles. The Pt-CeO₂ nanosponges show good thermal stability (up to 400 °C) and, already as a new, non-optimized catalyst, promising activity for catalytic oxidation of CO, VOCs, NH₃ as indicated by high activities in terms of low and stable light-out and light-off temperatures as well as a high selectivity to N₂ (for NH₃ oxidation) with >80% at 170-250 °C.

Photocatalytic reduction of CO₂ to produce organic fuels is a promising strategy for addressing carbon reduction and energy scarcity. Transition metal carbides (Ti₃C₂T _X ) are of particular interest due to their unique layered structures and excellent electrical conductivity. However, the practical application of Ti₃C₂T _X is limited by the poor separation efficiency of photogenerated charge carriers and the low migration ability of photogenerated electrons. Herein, Ag/Ag₂S/Ti₃C₂T _X heterojunctions were synthesized by depositing Ag/Ag₂S nanoparticles onto layered Ti₃C₂T _X substrates using a combination of co-precipitation and photoreduction methods. Fluorescence spectra, UV diffuse reflection, and photoelectric chemical characterizations demonstrated that Ag/Ag₂S/Ti₃C₂T _X heterojunctions provided effective channels for the reverse and synergistic migration of electrons and holes, leading to improved spatial separation. Notably, the Ag component in the composite acts as an electron acceptor and reactive center, significantly enhancing the migration ability of photogenerated electrons. The total alcohol yield over Ag/Ag₂S/Ti₃C₂T _X (125.3 μmol g_catal. ^-1) was 5.1 times higher than that on Ag₂S (24.7 μmol g_catal. ^-1) and 2.1 times higher than on Ti₃C₂T _X (60.7 μmol g_catal. ^-1). This study offers valuable insights into designing efficient photocatalytic CO₂ reduction catalysts.

Mesenchymal stem cell (MSC)-based bone tissue regeneration has gained significant attention due to the excellent differentiation capacity and immunomodulatory activity of MSCs. Enhancing osteogenesis regulation is crucial for improving the therapeutic efficacy of MSC-based regeneration. By utilizing the regenerative capacity of bone ECM and the functionality of nanoparticles, we recently engineered bone-based nanoparticles (BNPs) from decellularized porcine bones. The effects of internalization of BNPs on MSC viability, proliferation, and osteogenic differentiation were first investigated and compared at different time points. The phenotypic behaviors, including cell number, proliferation, and differentiation were characterized and compared. By incorporating a LNA/DNA nanobiosensor and MSC live cell imaging, we monitored and compared Notch ligand delta-like 4 (Dll4) expression dynamics in the cytoplasm and nucleus during osteogenic differentiation. Pharmacological interventions are used to inhibit Notch signaling to examine the mechanisms involved. The results suggest that Notch inhibition mediates the osteogenic process, with reduced expression of early and late stage differentiation markers (ALP and calcium mineralization). The internalization of BNPs led to an increase in Dll4 expression, exhibiting a time-dependent pattern that aligned with enhanced cell proliferation and differentiation. Our findings indicate that the observed changes in BNP-treated cells during osteogenic differentiation could be associated with elevated levels of Dll4 mRNA expression. In summary, this study provides new insights into MSC osteogenic differentiation and the molecular mechanisms through which BNPs stimulate this process. The results indicate that BNPs influence osteogenesis by modulating Notch ligand Dll4 expression, demonstrating a potential link between Notch signaling and the proteins present in BNPs.