ACS Applied Nano Materials最新文献

This work reports on the innovative application of layered sulfur nanosheets (S-NSs) in high-performance ammonia (NH₃) sensing and flexible piezoresistive sensing. To address the challenges of precise band structure tailoring in two-dimensional materials and the limited performance enhancement of piezoresistive sensors, we successfully synthesized S-NSs with an optimized band structure via a dual-ligand strategy employing sodium dodecyl benzenesulfonate (SDBS) and bovine serum albumin (BSA). The resulting material exhibited exceptional sensitivity in NH₃ detection, achieving a 20-fold enhancement in the response signal to an ultralow NH₃ concentration (10 ppt) compared to its single-ligand (BSA) counterpart along with a rapid response (5.2 s) and recovery (3.5 s). More importantly, we pioneered the integration of S-NSs with carbon nanotubes (CNTs) into a polyvinylidene fluoride (PVDF) matrix to construct a ternary “PVDF/CNTs/S-NSs” composite for piezoresistive sensing. This sensor demonstrated a remarkable 100-fold improvement in piezoresistive response relative to the control group without S-NSs, featuring high sensitivity, good linearity (0.3 to 1.4 kPa), a fast response time of as low as 220 ms, and enabling the effective monitoring of a wide range of human motions, including finger tapping, joint movement, and walking. This study not only provides a paradigm for designing ultrasensitive gas sensors through ligand engineering but also pioneeringly demonstrates the vast potential of S-NSs as a versatile nanomaterial for achieving cross-modal sensing capabilities, paving a material pathway for the development of next-generation flexible electronics.

MXenes are well-known as highly biocompatible two-dimensional nanomaterials with a wide range of biomedical applications, including antibacterial strategies. However, the coexistence of high biocompatibility and reported strong antibacterial effects presents a fundamental contradiction that requires critical evaluation. In this study, we systematically investigated the antibacterial properties of pure Ti₃C₂T_x, Nb₂CT_x, V₂CT_x, and Ti₃CNT_x MXene nanosheets of varying flake sizes using multiple in vitro assays and an in vivo wound model. High-resolution structural and chemical characterizations confirmed the use of high-quality, minimally oxidized MXene samples with well-defined surface terminations. Despite using multiple evaluation methods, including disk diffusion, broth microdilution, time-kill kinetics, ROS quantification, and electron microscopy, no significant antibacterial effects were observed at subtoxic concentrations. Furthermore, neither reactive oxygen species-mediated damage nor the hypothesized “nano-knife” mechanical disruption mechanism could be confirmed. This suggests that the previous observations of antibacterial properties resulted from incomplete removal of etching products or partial oxidation of MXene nanosheets. In contrast, we demonstrate that MXene-assisted photothermal therapy (PTT) under near-infrared laser irradiation offers highly effective and selective bacterial ablation. Ti₃C₂T_x MXene exhibited strong photothermal performance, achieving complete bacterial killing in vitro and significant wound healing efficacy in an in vivo rat model. Targeted PTT using antibody-functionalized MXene nanosheets enabled the eradication of Escherichia coli while sparing nontarget bacteria. These findings suggest that while intrinsic antibacterial properties of pristine MXenes are limited, their biocompatibility and photothermal responsiveness make them promising platforms for next-generation, externally triggered antibacterial therapies.

Hydrogen energy, as a zero-carbon-emission clean energy carrier, relies on electrocatalytic water splitting for its green production. However, the sluggish kinetics of the oxygen evolution reaction (OER) necessitate highly efficient catalysts. This study proposes an OER electrocatalyst design strategy by combining F/N codoped reduced graphene oxide (rGO) with anion-modified FeCo layered double hydroxide (LDH) to optimize electronic structure and surface polarity, enhancing charge transfer and intermediate adsorption capabilities. The resulting NF-rGO@Fe₁Co₁-LDH catalyst exhibits outstanding OER performance, with an onset overpotential of 235 mV, an overpotential of 324 mV at a current density of 500 mA cm^–2, and a maximum current density of up to 1021 mA cm^–2. It also demonstrates excellent stability during a 60-h test. In situ scanning electrochemical microscopy visually demonstrated the electrocatalytic activity of NF-rGO@Fe₁Co₁-LDH for OER, and the kinetic coefficient of NF-rGO@Fe₁Co₁-LDH was calculated to be 9.85 × 10^–3 cm² s^–1 based on the probe approach curve. In situ Raman spectroscopy confirmed that FeCo-LDH reconstructed into metal oxide hydroxide (MOOH) under applied potential, and MOOH served as the active species for electrocatalytic OER. This study provides insights for developing efficient and durable nonprecious metal OER catalysts.

Bacterial cellulose (BC) is a clinically established nanofibrillar wound dressing material that promotes healing by maintaining a moist and protected wound microenvironment. BC dressings can remain on wounds for extended periods, improving patient outcomes and reducing healthcare costs. However, BC lacks intrinsic antimicrobial properties, and infections in contaminated wounds remain a clinical concern, particularly in vulnerable patient populations. In this study, we present a benign and scalable self-assembly strategy to functionalize clinically used BC dressings with presynthesized colloidal silver nanoparticles (AgNPs) and antimicrobial peptides (C5), resulting in dual-action antimicrobial activity while preserving beneficial BC material properties. Colloidal AgNPs were efficiently adsorbed into the BC matrix by tailoring the interaction potential between the BC nanofibrils and the nanoparticles. Subsequent functionalization with C5 provided complementary antimicrobial mechanisms. The resulting dressings exhibited potent antimicrobial activity against Staphylococcus aureus, while maintaining high cytocompatibility with human primary keratinocytes and fibroblasts. By enabling tunable silver content, improved antimicrobial performance, and low cytotoxicity, the platform offers a promising route toward infection control in hard-to-heal wounds using clinically approved advanced BC dressings.

Developing efficient and stable photocatalysts for CO₂ reduction under visible light remains a significant challenge in solar energy conversion. In this study, we report a rational design of an amide-bonded ZnIn₂S₄/CoTCPP nanocomposite by covalently coupling amino-functionalized ZnIn₂S₄ (ZIS) with a cobalt porphyrin (CoTCPP) molecular catalyst. The formation of an amide linkage at the semiconductor–molecular interface promotes effective charge transfer and suppresses charge recombination, thus significantly enhancing photocatalytic CO₂ reduction. The optimized ZIS/CoTCPP-4 composite achieved a remarkable CO production rate of 2956.7 μmol·g^–1·h^–1 under solar-light irradiation, which was 32 times higher than that of pristine ZIS, representing one of the highest CO₂-to-CO photoreduction performances reported for ZnIn₂S₄-based photocatalysts. Furthermore, the establishment of a type-II heterojunction between ZIS and CoTCPP helps facilitate spatial charge separation and directional charge transfer, thereby enhancing photocatalytic efficiency. This work highlights the critical role of interfacial engineering via an amide linkage in enhancing light absorption and charge migration, providing an inspiration for constructing high-efficiency chemical bonded photocatalysts for solar-driven CO₂ conversion.

Accurate voltammetric determination of paracetamol (acetaminophen; ACT), nitrite (NO₂^–), and sildenafil (SILD) analytes in a single step is highly required yet challenging in biofluids and pharmaceutical matrices. Herein, samarium oxide (Sm₂O₃) with rod-like morphology was synthesized via a direct hydrothermal route, followed by thermal treatment at 400 °C. The Sm(OH)₃ nanorods (NRs) were initially formed and subsequently transformed into cubic crystals of Sm₂O₃ NRs with an average diameter of 50 nm and a length of 0.6 μm. The resulting Sm₂O₃ NRs exhibit well-defined surface cavities, high surface exposure, and preferential crystallographic growth, which are desired for enhancing electron-transfer processes. The Sm₂O₃ NRs were drop-cast onto screen-printed carbon electrodes (SPEs) and employed as a nonenzymatic platform for simultaneous electrochemical analysis of ACT, SILD, and NO₂^–. Well-resolved oxidation peaks of ACT, NO₂^–, and SILD were observed on the Sm₂O₃ NRs-SPEs at 0.57, 0.81, and 1.30 V (vs Ag/AgCl), respectively, in Britton–Robinson (B.R.) buffer of pH 2.0. The potential peak separation enabled sensitive individual and simultaneous analysis of the target analytes in wide concentration ranges of 2.65–2511.72 μmol/L ACT, 14.97–8849.79 μmol/L NO₂^–, and 0.49–1316.95 μmol/L SILD with low limit of detections (LODs) of 1.24 μmol/L, 1.477 μmol/L, and 97 nmol/L, respectively. Exceptional selectivity, stability, and recovery in pharmaceutical formulations and biological samples underscore the potential of Sm₂O₃ NRs-SPE as a promising electrochemical sensor for multianalytes.

We present a facile methodology for ammonia (NH₃) synthesis using a multiphase iron nanocatalyst (r-IOD (Fe@Fe₃O₄@Fe₂O₃)) under ambient conditions. Structural and physicochemical analyses of r-IOD were conducted using pXRD, Mössbauer spectroscopy, HRTEM, and XPS analyses, where r-IOD features a three-phase composite architecture, enabling room-temperature reduction of nitrate (NO₃^–) to NH₃. The NH₃ formation was confirmed by ¹⁵N isotope labeling and ¹H NMR analysis and quantified by UV-Vis spectroscopic analysis. Postreaction UV-DRS and XRD of r-IOD were also analyzed, indicating Fe-redox participation in the process of NO₃^– reduction.

In response to the urgent demand for sustainable and clean energy solutions, photoelectrochemical (PEC) water splitting is a leading approach for effectively producing green hydrogen (H₂). BiVO₄ photoanodes are among the best materials available for visible-light-driven water oxidation. However, their performance is hindered by rapid charge-carrier recombination and inadequate photostability. Therefore, the surface of nanodendritic BiVO₄ is modified with an iron oxyhydroxide (β-FeOOH) cocatalyst, which is obtained via a pH-controlled dip-coating method. A saturation photocurrent density of 2.73 mA cm^–2 at +1.4 V versus RHE under AM 1.5 G illumination is observed, which shows a 1.8-fold enhancement over that of pristine BiVO₄. The applied bias photon-to-current efficiency (ABPE) reflects a striking 3.45-fold increment for the heterojunction. The incident photon-to-current conversion efficiency (IPCE) measurements indicate that the heterojunction is twice as efficient as pristine BiVO₄. The BiVO₄/β-FeOOH heterojunction has significantly facilitated interfacial charge transfer, resulting in an increase in charge transfer efficiency from 35.73% to 58.24%, which reflects a noticeable reduction in electron–hole recombination. The oxidation of water molecules proceeds via a peroxo intermediate, which is confirmed by Fourier transform infrared (FTIR) spectroscopy. The Mott–Schottky analysis shows an enhanced charge carrier density, 3.61 times for the optimized BiVO₄/FeOOH heterostructure. According to the band edge alignment determined by ultraviolet photoelectron spectroscopy (UPS) analysis, a type-II heterojunction is formed between BiVO₄ and β-FeOOH, which efficiently separates the photogenerated excitons and promotes water oxidation, boosting its PEC performance. Hence, this study demonstrates that integrating the β-FeOOH cocatalyst is an effective strategy for overcoming the intrinsic limitations of BiVO₄, paving the way for advancing the development of efficient photoanodes for solar-driven H₂ production.

The extensive veterinary use of ronidazole (RZ), a nitroimidazole-class antiparasitic drug, has raised concerns regarding its environmental persistence, bioaccumulation in food products, and potential health risks. Herein, we report a highly sensitive electrochemical sensor based on a sulfur-doped tungsten oxide/hierarchical porous biocarbon (S-WO₃/HPBC) composite-modified glassy carbon electrode (GCE) for selective RZ detection. S-WO₃ was synthesized via a hydrothermal–ethanol crystallization–calcination route, while three-dimensional HPBC was derived from custard apple seeds through carbonization, KOH activation, and acid neutralization, providing a conductive, high-surface-area scaffold. The composite was assembled under reflux in a nitrogen atmosphere, ensuring homogeneous anchoring of S-WO₃ on HPBC. The intimate integration of S-WO₃ with HPBC generated a strong synergistic effect, resulting in abundant electroactive sites, accelerated charge transport, and enhanced electron-transfer kinetics. Differential pulse voltammetry revealed excellent sensing performance, with a limit of detection of 1.5 nM, a limit of quantification of 5.2 nM, and a sensitivity of 2.81 μA μM^–1 cm^–2. The sensor exhibited excellent repeatability, reproducibility, and selectivity, achieving recoveries of 94.6–99.91% in spiked real samples, including river water, sewage water, chicken extract, fish extract, human urine, and human blood serum. These findings highlight the synergistic contribution of S-WO₃ and HPBC, establishing S-WO₃/HPBC/GCE as a robust, cost-effective, and interference-free platform for reliable RZ monitoring in environmental, biological, and food matrices.

Systemic inflammation has been increasingly acknowledged as a pivotal factor contributing to neuropsychiatric disorders; however, therapeutic approaches specifically targeting neuroimmune interactions remain scarce. Atrial natriuretic peptide (ANP) exhibits strong anti-inflammatory effects but is limited by poor bioavailability and rapid enzymatic degradation. In this study, we developed an orally administered, gut-targeted armored nanomedicine, designated ANP-GBSA@CHI/TA, consisting of ANP-loaded albumin nanoparticles coated with graphene quantum dots and encapsulated within a multilayer shell of chitosan and tannic acid. Comprehensive physicochemical characterization confirmed the successful synthesis of core–shell nanoparticles with an average diameter of 246.8 ± 30.0 nm, demonstrating high encapsulation efficiency, excellent colloidal stability, and significant antioxidant activity, primarily attributable to the nanocarrier components. This formulation enhances intestinal retention and enables targeted delivery to inflamed tissues, as evidenced by in vivo imaging studies. In a lipopolysaccharide (LPS)-induced model of systemic inflammation model, administration of ANP-GBSA@CHI/TA markedly improved cognitive function in behavioral assays, decreased plasma concentrations of pro-inflammatory cytokines (IL-6, TNF-α), and attenuated microglial activation within the hippocampus. Mechanistic investigations revealed that the vagus nerve is indispensable for mediating these therapeutic effects, as subdiaphragmatic vagotomy abolished both the anti-inflammatory and cognitive benefits. Moreover, we demonstrated that ANP-GBSA@CHI/TA enhances hippocampal brain-derived neurotrophic factor (BDNF)/TrkB signaling, and pharmacological inhibition of this pathway significantly reverses the observed cognitive improvements and anti-inflammatory responses, highlighting its critical role in mediating treatment efficacy. Collectively, these findings indicate that this nanoplatform effectively attenuates neuroinflammation and mitigates cognitive deficits via vagus nerve-mediated modulation of the gut–brain axis immune response, thereby representing a promising therapeutic strategy for neuroinflammatory disorders.