ACS Nano最新文献

Intense noise poses a threat to spiral ganglion neurons (SGNs) in the inner ear, often resulting in limited axonal regeneration during noise injury and leading to noise-induced hearing loss (NIHL). Here, we propose an ultrasound-triggered nitric oxide (NO) release to enhance the sprouting and regeneration of injured axons in SGNs. We developed hollow silicon nanoparticles to load nitrosylated N-acetylcysteine, producing HMSN-SNO, which effectively protects NO from external interferences. Utilizing low-intensity ultrasound stimulation with bone penetration, we achieve the controlled release of NO from HMSN-SNO within the cochlea. In mice with NIHL, a rapid and extensive loss of synaptic connections between hair cells and SGNs is observed within 24 h after exposure to excessive noise. However, this loss could be reversed with the combined treatment, resulting in a hearing functional recovery from 83.57 to 65.00 dB SPL. This positive outcome is attributed to the multifunctional effects of HMSN-SNO, wherein they scavenge reactive oxygen species (ROS) to reverse the pathological microenvironment and simultaneously upregulate the CREB/BDNF/EGR1 signaling pathway, thereby enhancing neuroplasticity and promoting the regeneration of neuronal axons. These findings underscore the potential of nanomedicine for neuroplasticity modulation, which holds promise for advancing both basic research and the further treatment of neurological diseases.

Background: Atrial fibrillation (AF) often remains undiagnosed, and it independently raises the risk of ischemic stroke, which is largely reversible by oral anticoagulation. Although randomized trials using longer term screening approaches increase identification of AF, no studies have established that AF screening lowers stroke rates.

Objectives: To address this knowledge gap, the GUARD-AF (Reducing Stroke by Screening for Undiagnosed Atrial Fibrillation in Elderly Individuals) trial screened participants in primary care practices using a 14-day continuous electrocardiographic monitor to determine whether screening for AF coupled with physician/patient decision-making to use oral anticoagulation reduces stroke and provides a net clinical benefit compared with usual care.

Methods: GUARD-AF was a prospective, parallel-group, randomized controlled trial designed to test whether screening for AF in people aged ≥70 years using a 14-day single-lead continuous electrocardiographic patch monitor could identify patients with undiagnosed AF and reduce stroke. Participants were randomized 1:1 to screening or usual care. The primary efficacy and safety outcomes were hospitalization due to all-cause stroke and bleeding, respectively. Analyses used the intention-to-treat population.

Results: Enrollment began on December 17, 2019, and involved 149 primary care sites across the United States. The COVID-19 pandemic led to premature termination of enrollment, with 11,905 participants in the intention-to-treat population. Median follow-up was 15.3 months (Q1-Q3: 13.8-17.6 months). Median age was 75 years (Q1-Q3: 72-79 years), and 56.6% were female. The risk of stroke in the screening group was 0.7% vs 0.6% in the usual care group (HR: 1.10; 95% CI: 0.69-1.75). The risk of bleeding was 1.0% in the screening group vs 1.1% in the usual care group (HR: 0.87; 95% CI: 0.60-1.26). Diagnosis of AF was 5% in the screening group and 3.3% in the usual care group, and initiation of oral anticoagulation after randomization was 4.2% and 2.8%, respectively.

Conclusions: In this trial, there was no evidence that screening for AF using a 14-day continuous electrocardiographic monitor in people ≥70 years of age seen in primary care practice reduces stroke hospitalizations. Event rates were low, however, and the trial did not enroll the planned sample size.(Reducing Stroke by Screening for Undiagnosed Atrial Fibrillation in Elderly Individuals [GUARD-AF]; NCT04126486).

The surging demand for electronics is causing detrimental environmental consequences through massive electronic waste production. Urgently shifting toward renewable and eco-friendly materials is crucial for fostering a green circular economy. Herein, we develop a multifunctional bionanocomposite using an algae-derived carbohydrate biopolymer (alginate) and boron nitride nanosheet (BNNS) that can be readily employed as a multifunctional dielectric material. The adopted rational design principle includes spatial locking of superhigh loading of BNNS via hydrogel casting followed by layer-by-layer assembly via solvent evaporation, successive cross-link engineering, and hot pressing. We harness the hierarchical assembly of BNNS and the molecular interaction of alginates with BNNS to achieve synergistic material properties with excellent mechanical robustness (tensile strength ∼135 MPa, Young's modulus ∼18 GPa), flexibility, thermal conductivity (∼4.5 W m^-1 K^-1), flame retardance, and dielectric properties (dielectric constant ∼7, dielectric strength ∼400 V/μm, and maximum energy density ∼4.33 J/cm³) that outperform traditional synthetic polymer dielectrics. Finally, we leverage the synergistic material properties of our engineered bionanocomposite to showcase its potential in green electronic applications, for example, supercapacitors and flexible interconnects. The supercapacitor device consisting of aerosol jet-printed single-walled carbon nanotube electrodes on our engineered bionanocomposite demonstrated a volumetric capacitance of ∼7 F/cm³ and robust rate capability, while the printed silver interconnects maintained conductivity in various deformed states (i.e., bending or flexing).

Aqueous Zn-ion batteries have garnered significant attention as promising and safe energy storage systems. Due to the inevitable dendrite and corrosion in metallic Zn anodes, alternative anodes of intercalation-type materials are desirable, but they still suffer from low energy efficiency, unsatisfactory capacity, and insufficient cycle life. Here, we develop a high-performance anode for aqueous Zn-ion batteries via a lattice expansion strategy in combination with a Zn²⁺/H⁺ synergistic mechanism. The anatase TiO₂ with expanded lattice exhibits an appropriate deintercalation potential of 0.18 V vs Zn/Zn²⁺ and a high reversible capacity (227 mAh g^-1 at 2.04 A g^-1) with an outstanding rate capability and excellent cycle stability. The high electrochemical performance is attributed to a decrease in the Zn²⁺/H⁺ diffusion barriers, which results from lattice expansion and also a H⁺-promoted Zn²⁺ intercalation effect. The anode intercalates Zn²⁺/H⁺ via a solid-solution mechanism with a minor volume change, which contributes to the high reversibility and thus high energy efficiency. When paired with different types of cathodes, including NV, I₂, and activated carbon, to construct corresponding full cells, high specific energy, high specific power, long cycle life, and extremely high energy efficiency can be achieved. This study provides a prospect for developing high-performance Zn-ion batteries.

Distillation membranes with hydrophobic surfaces and defined pores are considered a promising solution for seawater desalination. Most existing distillation membranes exhibit three-dimensional (3D) stacking bulk structures, where the zigzag water-repellent channels often lead to limited permeability and high energy costs. Here, we created two-dimensional nanowebs directly from the polymer/sol solution to construct dual-asymmetric Janus membranes. By tailoring the phase separation rate, the polymer phase evolved into continuous hydrophilic webs in situ weld on the microporous hydrophobic layer. The webs possess true-nanoscale architectures (internal fiber diameter of ∼20 nm, pore size of ∼140 nm) with enhanced roughness, serving as a superspreading surface to reach a water contact angle of 0° in 1.7 s. Benefiting from the architecture and wettability dual asymmetries, the obtained Janus membrane shows high-efficiency desalination performance (salt rejection >99%, flux of 11 kg m^-2 h^-1, and energy efficiency of 79%) with a thickness of 6.7 μm. Such a fascinating nanofibrous web-based Janus membrane may inspire the design of advanced liquid separation materials.

Regulating the surface termination of a confined space to achieve ultrafast ion transport remains an ongoing challenge. Two-dimensional (2D) MXenes possess adjustable structures and interlayer spacing, which provide an ideal platform for in-depth investigation of ion transport in 2D confined space; however, the strong interaction of the negatively charged terminations in MXenes hinders the transport of intercalated cations. In this work, we proposed a strategy that precisely regulates the surface modification of Ti₃C₂T_x MXene with the weak polarity of boron atoms (SCB-MXene) via the distinct effect of supercritical CO₂. This not only could effectively substitute -OH termination in MXene but also can prevent the loss of -O active sites, and then, both ultrafast ion transport and high volumetric capacitance can be achieved simultaneously. Ideally, a volumetric capacitance up to 742.7 C cm^-3 at 1000 mV s^-1 for the SCB-MXene film as pseudocapacitive materials that provides an energy density of 66.3 Wh L^-1 even at an ultrahigh power density of 132.5 kW L^-1 is obtained, which is a prominent record of energy density and power density reported up to now. Subsequently, it can be used in large-scale energy storage and conversion devices.

Optical matter, a transient arrangement formed by the interaction of light with micro/nanoscale objects, provides responsive and highly tunable materials that allow for controlling and manipulating light and/or matter. A combined experimental and theoretical exploration of optical matter is essential to advance our understanding of the phenomenon and potentially design applications. Most studies have focused on nanoparticles composed of a single material (either metallic or dielectric), representing two extreme regimes, one where the gradient force (dielectric) and one where the scattering force (metallic) dominates. To understand their role, it is important to investigate hybrid materials with different metallic-to-dielectric ratios. Here, we combine numerical calculations and experiments on hybrid metal-dielectric core-shell particles (200 nm gold spheres coated with silica shells with thicknesses ranging from 0 to 100 nm). We reveal how silica shell thickness critically influences the essential properties of optical binding, such as interparticle distance, reducing it below the anticipated optical binding length. Notably, for silica shells thicker than 50 nm, we observed a transition from a linear arrangement perpendicular to polarization to a hexagonal arrangement accompanied by a circular motion. Further, the dynamic swarming assembly changes from the conventional dumbbell-shaped to lobe-like morphologies. These phenomena, confirmed by both experimental observations and dynamic numerical calculations, demonstrate the complex dynamics of optical matter and underscore the potential for tuning its properties for applications.

Nanowires composed of a 1:1 stoichiometry of transition metals and chalcogen ions can be fabricated from two-dimensional transition metal dichalcogenides (TMDs) by using electron beam irradiation. Wires fabricated through in situ experiments can be geometrically connected to TMD sheets in various ways, and their physical properties can vary accordingly. Understanding the structural transformation caused by electron beams is critical for designing wire-sheet structures for nanoelectronics. In this study, we report the behavior of nanowires formed inside a monolayer MoS₂ sheet by combining phase-contrast images and large-scale atomistic modeling. We investigate the effect of vacancies on the dynamic evolution of wires, such as rotations with different edge structures and breaking, by considering the interactions between MoS wires and MoS₂ nanosheets. The obtained insights can be applied to other monolayer TMDs to guide the behavior of TMD wires and fabricate favorable geometries for various applications.

Hydrochromic materials undergo magical color changes when interacting with water and are receiving widespread attention for their frontier applications such as sensing and information security. The hydrochromic effect is observable in perovskite materials via the mechanism of water-induced fluorescence quenching. However, due to water isolation, achieving a hydrochromic effect in perovskite-polymer composite remains elusive, notwithstanding its importance as a potentially commercial-ready material. Here, we demonstrate a hydrochromic effect of perovskite-polymer-based porous composite via a nonsolvent-induced phase separation method, comprising of FA₂PbBr₄/poly(vinylidene fluoride) (FA = formamidinium). The naturally formed pores serve as microchannels, facilitating moisture diffusion. The penetrated water induces a phase transition of perovskite material from the nonfluorescent two-dimensional FA₂PbBr₄ to the fluorescent three-dimensional FAPbBr₃. This work has developed the hydrochromic perovskite-polymer composites, enabling various commercial-ready chromatic applications as conceptually demonstrated custom-made fingerprint labels, quick response code anticounterfeiting labels, encrypted document protections, and water-ink inkjet printing.