Nanotechnology最新文献

This paper describes the electroenzymatic reduction of CO2 to formate catalyzed by formate dehydrogenase from Candida boidinii (CbFDH) immobilized on carbon nanotube-modified gold electrodes. Cyclic voltammetry indicates that CbFDH could catalyze CO2 reduction to formate without protonated nicotinamide adenine dinucleotide (NADH) as a cofactor, exhibiting diffusion-controlled, quasi-reversible kinetics on both multi-walled carbon nanotube (MWCNT) and single-walled carbon nanotube (SWCNT) substrates. Surface-enhanced infrared absorption (SEIRA) spectra indicate that CbFDH adopts a near-parallel orientation on the CNT-modified gold surface, positioning its active site for the direct electron transfer between CO2 and tht the conductive carbon support. The IR spectra reveal an increase in the formate band's intensity in the potential region from -0.3 V to -0.6 V vs. Ag/AgCl, confirming efficient CO2 reduction. Below -0.6 V vs. Ag/AgCl, the hydrogen evolution reaction competitively suppresses formate yield. This study demonstrates that CNTs serve as an effective support for enzyme immobilization and confirms that CO2 could be directly reduced to formate at the CNT-modified electrode without a cofactor at potentials close to the equilibrium potential (minimum of overpotential). This represents a novel and unexpected finding.

The development of potent subunit vaccines requires adjuvant systems capable of eliciting robust cellular (Th1) immunity while maintaining high biocompatibility. Herein, We engineered a novel "safety-by-design" nanoadjuvant platform via the supramolecular co-assembly of cholesteryl-conjugated Mannan (MN-CLS) and cholesteryl-conjugated branched polyethylenimine (BPEI-CLS). This design induced the spontaneous formation of polyplex micelles driven by a "dual-lock" mechanism: electrostatic attraction between the cationic BPEI and anionic Mannan, reinforced by hydrophobic associations between cholesterol domains. Structural characterization (1H-NMR, FT-IR) confirmed successful synthesis, and the resulting micelles exhibited superior thermodynamic stability with a significantly reduced Critical Micelle Concentration (CMC). FRET and DLS analyses verified a unified core-shell architecture of approximately 200 nm, which is suitable for APC-mediated cellular uptake and subsequent lymph node delivery. Crucially, in vitro assays demonstrated that MN-CLS/CLS-BPEI micelles significantly reduced cytotoxicity compared to native BPEI and BPEI-CLS while maintaining colloidal stability. This platform is expected to effectively synergizes the receptor-targeting specificity of Mannan with the immunostimulatory potential of BPEI, presenting a promising, biocompatible adjuvant system for next-generation vaccines.

Porous carbon was prepared using hazardous waste and employed for the adsorption of volatile organic compounds. It can be utilized to reuse hazardous waste to enhance energy utilization efficiency. Through comparative analysis of theoretical and experimental values, a synergistic effect was demonstrated at a blending ratio of 25%. At a blending ratio of 50%, the apparent activation energy was minimized to 154.27 kJ mol^-1, which was consistent with a diffusion-controlled mechanism. Based on pyrolysis characteristic analysis, three peak temperatures from the DTG curve were selected to prepare a series of porous carbons. The maximum specific surface area achieved for the prepared porous carbon was 1865 m²g^-1. Three groups of samples were selected for adsorption experiments. An ethyl acetate adsorption capacity of 1075.7 mg g^-1was attained (quasi-first-order kineticsR²= 0.98). However, when the coal proportion exceeded 50%, the adsorption capacity plummeted to 361.52 mg g^-1, which was attributed to overlapping potential fields in micropores. This technology provides a practical solution for the efficient valorization of hazardous wastes such as penicillin mycelial residue. It converts two solid wastes into high-performance adsorbent materials for environmental pollution control, thereby reducing the consumption of virgin resources and promoting the development of a circular economy.

This study explores the potential of porous silicon nanoparticles (pSiNPs) as advanced nanocarriers to enhance the therapeutic efficacy and reduce the cytotoxicity of niclosamide for COVID-19 treatment. Niclosamide, an FDA-approved drug used to treat tapeworm infections, has been suggensted as a potential treatment for COVID-19. However, its clinical application is limited by its significant cytotoxicity and low bioavailability. To address these challenges, three types of pSiNPs-pSiNP-H, pSiNP-COOH, and pSiNP-NH 2 -were synthesized. Niclosamide was successfully loaded onto each type of pSiNPs, achieving a loading efficiency over 30%. Among them, the antiviral activity of niclosamide-loaded pSiNP-NH 2 was assessed against the Delta variant of SARS-CoV-2 in Vero E6 cells using plaque assays and real-time PCR. Results demonstrated that niclosamide-loaded pSiNP-NH 2 significantly suppressed viral replication more efficiently than free niclosamide at equivalent doses, while minimizing host cell cytotoxicity. These findings suggest that pSiNP-NH 2 could serve as a potent drug delivery platform, improving the therapeutic index of niclosamide for COVID-19 treatment.

Augmented, virtual, and mixed reality devices increasingly rely on compact and efficient optical elements to guide and shape light into the user's eye. A key enabling technology for these devices is the use of surface relief gratings (SRGs) as optical in- and out-couplers within diffractive optical waveguides. A critical performance requirement is achieving uniform illumination of the eye-box, which ensures image clarity and consistency across the viewing area. To manufacture such high-performance SRGs, nanoimprint lithography (NIL) combined with direct etching techniques has proven effective. However, nanoimprint methods require the prior fabrication of a master stamp, which is a highly precise template that defines the nanoscale surface features to be replicated during the NIL process. This work demonstrates the nanopatterning capabilities of slanted and blazed SRGs in terms of sidewall angle, modulation of pitch and critical dimension, continuous depth variation and shape fidelity control by using advanced electron beam lithography and reactive ion beam trimming etching techniques.

Electrospun carbon nanofibers (CNFs) have remarkable properties such as high surface area, a three-dimensional conductive interconnected network, porous and self-supporting structure, making them promising anode materials for advanced lithium-ion batteries (LIBs). However, the development of a well-organized porous architecture is crucial to further enhance their electrochemical performance. In this study, multichannel CNFs (m-CNFs) were fabricated via electrospinning of polyacrylonitrile (PAN) and cellulose acetate (CA) blend solutions followed by thermal treatment processes namely, stabilization and carbonization. Initially, solid CNFs (s-CNFs) were fabricated by using PAN alone in order to investigate the influence of thermal treatment processes on both morphology and electrochemical performance. Additionally, the effect of PAN:CA ratio on the morphology of the PAN/CA based CNFs was studied by varying the PAN:CA weight ratios in the electrospinning solutions. The phase separation behavior of CA within the continuous PAN matrix facilitated the formation of multichannel porous nanofibers and inter-fiber junctions after thermal treatment. Increasing CA content yielded a more prominent multichannel structure formation with intense fiber junctions. Electrochemical evaluation of the self-supporting CNF electrodes revealed that s-CNFs carbonized at 650 °C exhibited a higher specific capacity of 538 mAh g^-1after 100 cycles at 50 mA g^-1, compared to those carbonized at 550 °C and 750 °C. In contrast, m-CNFs anode showed remarkable cycling capacity as 634 mAh g^-1after 100 cycles at 50 mA g^-1and superior rate capability as 226 g^-1at a high current density of 2 A g^-1. As a result, a unique multichannel porous structure obtained under optimized thermal treatment conditions contributed to accelerated ion transport kinetics and improved accessibility of lithium storage sites. This study highlights the potential of multichannel CNFs as efficient, self-supporting anode materials for high-performance LIBs.

Iron oxide nanoparticles (IONPs) are widely used for biomedical applications, and their nanoscale physicochemical properties and surface chemistry strongly influence biological interactions and overall performance. Their easily modified surfaces enable diverse biomedical applications, making it crucial to understand how different surfactants or coatings affect their properties and biological interactions. In this study, IONPs were synthesized by co-precipitation and subsequently functionalized with oleic acid, dextran, or ascorbic acid to investigate coating-dependent differences in physicochemical behavior and cellular responses. Comprehensive structural, magnetic, and colloidal characterizations were performed to ensure well-defined nanoparticle (NP) features. Biological evaluations included cytotoxicity assessments in both monolayer (2D) and spheroid (3D)in vitromodels incorporating healthy and cancer-derived mammalian cell lines from different tissue origins. Direct cytotoxicity was evaluated using WST-1, resazurin, and Annexin V/propidium iodide assays, and indirect cytotoxic effects were examined using NP-conditioned media. The findings revealed that cytotoxicity varied not only with the surface coating but also with the assay format and culture model, emphasizing the need for multi-parameter assessment when evaluating NP biocompatibility. Among the tested coatings, ascorbic acid-modified IONPs exhibited the greatest reduction in hydrodynamic size (22.9 nm) and demonstrated no detectable cytotoxic effects across multiple assays and cell lines, while maintaining key magnetic characteristics. These results highlight that nanoscale surface design can be strategically leveraged to achieve a favorable balance between magnetic performance and biological safety. The study underscores the importance of coating-driven modulation in guiding the development of next-generation magnetic NPs for biomedical applications.

The dynamic magnetization of magnetic nanoparticles (MNPs) arises from coupled Néel and Brownian relaxations, which are influenced by intrinsic particle properties such as size, saturation magnetization, magnetic anisotropy, and damping. While experimental AC magnetization measurements can reveal the collective dynamic behavior of MNP ensembles, extracting accurate nanoparticle-specific parameters from such data remains a challenge due to experimental limitations and model oversimplifications. To address this, we apply a stochastic Langevin model that explicitly captures the time-dependent magnetization response of MNPs under alternating magnetic fields by incorporating both thermal fluctuations and stochastic relaxation processes. This model provides a physically grounded framework for simulating magnetization hysteresis under experimental conditions, enabling parameter estimation through direct data fitting. In this work, we fit the stochastic Langevin model to experimentally measured hysteresis loops of different MNPs collected under a 20 mT, 5 kHz AC field. By coupling the model with Bayesian optimization and Gaussian process regression, we identify optimal values of key magnetic parameters: saturation magnetization (Ms), effective anisotropy (Ka), and Gilbert damping parameter (α). Furthermore, theMsis experimentally measured and employed as a validation parameter. Accordingly, the determination of theαand theKais based on two complementary criteria: (1) the best agreement between the simulated and experimental AC response magnetization hysteresis loops, quantified by the coefficient of determination (R2), and (2) the closest correspondence between the estimated and experimentally measuredMsvalues, evaluated using the mean absolute percentage error. Our approach is validated on four commercial MNP products (SHS30, IPG30, SHP25, and SHP15, from Ocean Nanotech, LLC), yielding high-fidelity fits to experimental data and robust estimation of their magnetic properties.

We realize strongly confined quantum dots (QDs) in InAs nanowires (NWs) by combining epitaxial crystal-phase control with chemical wet etching. A strong axial confinement is first introduced by growing closely spaced wurtzite (WZ) tunnel barriers in NWs to enclose a zinc blende (ZB) QD. The NW cross-section is then reduced by isotropic etching to obtain very small QDs, with a maximum observed charging energy>30 meV. Using low-temperature electrical characterization and finite-element method simulations, we study how charging energies and the onset of electron filling scale with QD diameter. For extremely small diameters, we identify a regime where stray capacitances become non-negligible, limiting further increase in charging energy by diameter reduction alone. This approach to increasing confinement is particularly relevant for understanding the strong spin-orbit interaction observed in crystal-phase QDs, possibly linked to polarization charges at the WZ/ZB interfaces. Small diameter QDs allow considerably weaker interfering electric fields when studied, but the QDs cannot be realized with epitaxial growth alone due to a loss of crystal phase control.

A common strategy in cancer therapy involves using a nanoscale carrier to simultaneously deliver phototherapeutic agents and chemotherapeutic drugs. However, traditional delivery carriers are toxic and immunogenic, and their preparation involves complex procedures, limiting their widespread application. Exosomes (Exo) are spherical, lipid bilayer vesicles that have a diameter of 50-150 nm. They are naturally secreted by various cells and can cross multiple biological barriers, making them attractive alternatives. Dunaliella salina-derived exosome-like nanovesicles (DENV) represent promising drug nanocarriers due to their excellent biocompatibility, low immunogenicity, low cost, and large-scale, rapid production. However, the role of DENV in triple-negative breast cancer, which has the highest rates of metastasis and recurrence, is unknown. In this study, DENVs were prepared by ultracentrifugation. Indocyanine green (ICG) and 5-fluorouracil (5-FU) were co-loaded into DENV (DENV-ICG/5-FU) via electroporation. DENV-ICG/5-FU exhibited good photothermal performance and stability. At a pH of 5.0 and exposure to 808 nm near-infrared (NIR) light at 1 W/cm2 for 5 minutes, the cumulative release of 5-FU from the DENV-ICG/5-FU was 86.45%. In addition, DENV-ICG/5-FU was internalized into 4T1 breast cancer cells. Under NIR irradiation, it inhibited proliferation and migration and induced apoptosis of 4T1 cells. Results from flow cytometry and DCFH-DA analyses indicated that NIR irradiation significantly increased both the proportion of cells in the G1 phase and the generation of ROS. Mechanism studies showed that under NIR irradiation, DENV-ICG/5-FU enhanced the expression of the pro-apoptotic protein Bax. In summary, these findings suggest that DENV could be ideal vehicles to co-deliver phototherapeutic agents and chemotherapeutic drugs for synergistic tumor treatment.