Small Methods最新文献

Flame-retardant separators present a viable strategy to address safety concerns in lithium-metal batteries (LMBs). However, the high loading and inhomogeneous distribution of flame-retardant microparticles within these separators can significantly impede ion transport, thereby degrading the electrochemical performance of LMBs. Herein, a nanoparticle-based flame-retardant separator is reported that exhibits enhanced flame-retardant efficiency and high cycling stability for LMBs. The separator consists of a nanoporous poly(vinylidene fluoride) (PVDF) matrix and uniformly dispersed ammonium polyphosphate (APP) nanoparticles (151 ± 27 nm, 10 wt.% loading). The nano-sized APP facilitates the formation of a uniform and intact char layer from the PVDF matrix at lower temperatures, thereby enhancing its barrier effect. Consequently, in pouch cells employing the PVDF/nano-APP separator, the peak heat release rate and total heat release are reduced by 30.3% and 27.1%, respectively, compared to those using conventional PP separators. Additionally, the APP nanoparticles help preserve the nanoporous structure of PVDF, allowing the corresponding LMBs to maintain 94.6% capacity retention over 2000 cycles. The flame-retardant nanocomposite separators show great potential for developing high-safety LMBs.

Hybrid architectures that combine atomically thin semiconductors, such as transition metal dichalcogenides (TMDs), with molecular systems provide a powerful platform for engineering optical properties and controlling photoexcitations. In this work, Förster resonance energy transfer is realized between 2D and molecular excitons. Well-defined hybrid structures are fabricated using lithographic methods together with DNA origami self-assembly, which enables the precise positioning of fluorescent dyes under TMD monolayers. By selecting specific dye molecules, spatial modulation of MoS₂ photoluminescence is achieved, with either enhancement or quenching. Beyond demonstrating controlled energy transfer at the molecular scale, this approach establishes a robust framework for engineering excitonic interactions and offers opportunities for programmable design of nanophotonic and nanoelectronic devices based on 2D materials and their van der Waals heterostructures.

Methylammonium lead iodide (MAPbI₃) has been considered as the most influential component to boost the rapid development of perovskite photovoltaic devices during the past decade. However, the volatility of organic compounds (Methylammonium ions) causes excessive residual PbI₂ during the fabrication and storage process of MAPbI₃ films. The doping of various reduced graphene oxide (L-AA-rGO) is systematically induced into MAPbI₃ precursor ink to regulate the crystallization process, resulting in obtaining a high-quality perovskite film. The higher content of oxygen-containing functional groups (carboxyl and hydroxyl) and flexible sp³ skeleton structure is successfully obtained in L-AA-rGO(LT), which is favored to form stable coordination bonds with uncoordinated Pb²⁺ ions via lone pairs of electrons. Therefore, this functional L-AA-rGO(LT) not only passivates deep-level defects Pb⁰ with its functional groups, but also absorbs the perovskite lattice structure with its special sp³ carbon network to release its residual stress within the perovskite film. This work provides a new method to develop the efficiency and stability of MAPbI₃ perovskite solar cells via doping functional L-AA-rGO.

Red blood cells (RBCs) have emerged as promising carriers for therapeutic and diagnostic agents due to their long circulation time, biocompatibility, and immune-evasive properties. Hypotonic encapsulation is the most widely employed technique; however, the correlation between nanoparticle sizes and the hypotonic osmolarities required for efficient encapsulation remains unclear. In this study, the size-dependent osmolarity requirements governing nanoparticles into RBCs are investigated. Using monodisperse gold nanoparticles as model systems, the optimal osmolarity correlated with nanoparticle diameter is identified as 150 mOsm for particles ≤33 nm, 100 mOsm for particles 66-91 nm, and 50 mOsm for particles ≈133 nm. These conditions maximized encapsulation efficiency while maintaining RBC membrane integrity and preserving the expression of key surface proteins, including CD47. The applicability of this approach is further validated using nanoparticles of diverse compositions and zeta potentials. In vitro assays demonstrated minimal hemolysis and significantly reduced macrophage uptake across all formulations. Complementary in vivo imaging reveals prolonged systemic circulation and biodistribution profiles that closely resemble those of native RBCs. This study establishes a standardized, size-adaptive hypotonic encapsulation protocol, offering a versatile and scalable platform for engineering RBC-based carriers with broad translational potential in nanomedicine.

Sulfur-induced restructuring of active phases has been identified as one of the dominant reasons why the catalysts are quickly deactivated, posing a significant threat on the long-term use under practical reaction conditions. Three typical strategies have been proposed for designing the SO₂-resistant nanocatalysts. Herein, a new strategy is discovered to preserve the clean PtO_x surfaces in SO₂-containing reaction stream, expected to effectively minimize the sulfur-induced deactivation. In situ CO-DRIFTS, FT-IR, Raman, XPS, HAADF-STEM, sulfur content determination, and DFT are employed to confirm the PtO restructuring behaviors propelled by the bismuth-promoted S^2- spillover effect. In situ SO₂-DRIFTS and theoretical calculation results reveal that the adsorption and dissociation of SO₂ on the PtO_x surfaces are significantly inhibited once the PtO-Bi₂S₃ interfaces are formed by migrating the adsorbed S^2- species to the surfaces of Bi₂O₃. The bismuth-induced dynamic restructuring of PtO surfaces allows to dramatically decrease the activity loss for catalytic CO oxidation and maintain the intrinsic activity following the formate pathway during the introduction of SO₂ molecules. These findings provide a new strategy to design the SO₂-resistant nanocatalysts.

Organic matter (OM) constitutes a major fraction of atmospheric aerosols. However, achieving molecular-level and high-temporal-resolution analysis of OM remains a significant analytical challenge. Here, an observation system, is developed the versatile aerosol concentration enrichment system coupled to online extraction and liquid chromatography-mass spectrometry (VACE-OE-LC-MS), for online observation of OM in PM_2.5. This system enables molecular-level detection and quantification of particle-bound organic compounds, with chromatographic separation allowing the identification of structural isomers. It integrates a modified VACE module for particle enrichment, an OE module for collecting particles, extracting analytes, and concentrating the extracts, and an LC-MS module for compound analysis. The VACE module delivers a ≈10-fold enrichment of particle concentration. The OE module innovatively employs N,N-dimethylacetamide (DMA) with a swirling aerosol collector, achieving collection efficiencies of 64.0-99.1% and maintaining stable operation for at least 8 h. In field observations, the system successfully quantifies 11 nitroaromatic compounds (NACs) at a 3-h resolution, revealing diurnal concentration patterns that conventional 12-24-h sampling cannot capture. Overall, this system offers enhanced temporal resolution while maintaining molecular specificity relative to traditional offline methods, providing a powerful analytical tool for investigating the formation, evolution, and transformation of OM in atmospheric aerosols.

Triboelectric nanogenerators (TENGs), as an emerging energy conversion technology, inevitably encounter various extreme environmental application scenarios, such as high temperatures, corrosion, and deep-sea environments, which may damage the device structure or reduce the surface potential, thereby causing a decline in the output performance of TENGs. Therefore, significant efforts are dedicated to improving the performance of TENGs, enabling sensors to maintain their original performance under extremely harsh environmental conditions. This article reviews and focuses on the latest research progress of triboelectric sensors with high environmental adaptability in extreme environments such as high humidity, high temperature, high salt, corrosion, and deep-sea environments, aiming to gain insights from the selection of functional materials, advanced structural design, fabrication processes, application scenarios, and integration strategies. Finally, it looks forward to the challenges faced by triboelectric sensors in extremely harsh environmental conditions and proposes solutions as well as future research directions. It is hoped that this review provides a systematic reference for the technological breakthroughs of triboelectric sensors in extremely harsh environments, promoting their transition from laboratory research to practical applications, providing feasible paths for technological upgrades in key industrial fields, and accelerating the industrialization process of this technology.

To address the long-standing challenges of slow response, weak signal, and poor mechanical robustness in conventional flexible humidity sensors, A novel flexible multifunctional sensor is developed based on a "lotus-leaf acoustic wave collaborative lead-free piezoelectric" technology strategy. Specifically, a lotus leaf surface is used as a template, which is replicated with PVDF and then combined with a cellulose matrix embedded with niobium-based perovskite crystals, resulting in a sandwich-structured, flexible, lead-free piezoelectric composite film. Under acoustic wave excitation, the local piezoelectric coupling at the bio-inspired papilla interfaces significantly accelerates water adsorption/desorption kinetics, achieving an exceptional humidity response/recovery time of 0.98/1.2 s and a high sensitivity of 97%. The sensor demonstrates superior performance compared to commercial hygrometers. In addition, it has a high response signal of 130 V and a voltage sensitivity of 4.33 V N^-1 under a stress of 40 N, thus achieving dual parameter sensing. This humidity sensor, with its sub second response, high sensitivity, and dual-mode sensing capability of force and humidity, is expected to capture the slightest humidity and mechanical changes in real-time medical monitoring, motion tracking, and environmental IoT, providing unprecedented secure and green core components for intelligent health, and sustainable sensing systems.

Enzyme-instructed self-assembly (EISA) of peptides offers a versatile strategy for developing intracellular nanomedicines, yet the role of C-terminus fluorophores in modulating these assemblies remains insufficiently defined. Here four different fluorophores, NBD, DANS, DBD, and Cy5 are conjugated at the C-terminus of a phosphobiphenyl dipeptide to evaluate their influence on intracellular distribution, assembly morphology, and cytotoxicity. Confocal imaging reveals that NBD-, DANS-, and DBD-conjugated precursors predominantly localize to the endoplasmic reticulum, whereas Cy5 directed assemblies to mitochondria, highlighting the decisive effect of fluorophores on subcellular targeting of peptides. Transmission electron microscopy and confocal studies further show that the fluorophores markedly alter assembly pathways: NBD-conjugated precursors form dense yet still irregular aggregates, DANS-conjugated precursors form denser and more continuous aggregates, DBD-conjugated precursors yield fibrous networks, and Cy5-conjugated precursors exhibit minimal ordered assembly. These divergent morphologies correlate with cytotoxic profiles in Saos2 osteosarcoma cells, with DBD-conjugated precursors be the most potent. These results demonstrate that fluorophores can have a significant influence on the behavior of enzymatic self-assemblies and indicate that engineering the C-terminus of peptides is an effective approach for exploring EISA to develop nanomedicines.

To address the limitations of traditional lead shielding (toxicity, weight) and unmodified bismuth fillers (poor dispersion), this study develops an improved "one-pot" ball milling method. This one-pot strategy effectively achieves in-situ silane (vinyltrimethoxysilane, A171) modification and transforms bismuth powder into a flake-like morphology. Here, A171 bonds covalently to the bismuth surface via Si─O─Bi linkages, thereby converting bismuth from hydrophilic to hydrophobic. This dual functionalization enables uniform dispersion of Bi in polydimethylsiloxane (PDMS) at a high filler loading of 70 wt% while retaining excellent mechanical flexibility (tensile strength 0.42 MPa, elongation 166%), thermal stability (30 °C higher than that of pure PDMS), and fatigue resistance. The flake-like modified Bi (M-Bi) forms a 3D shielding network that extends X-ray propagation paths. The resulting 0.2 cm-thick 70M-Bi@PDMS composite exhibits 92% X-ray shielding efficiency for 60 keV X-rays, with corresponding linear (μ) and mass (µm) attenuation coefficients of 13.30 cm^-1 and 3.50 cm² g^-1, respectively, and 75% shielding efficiency at 80 keV. In terms of radiation shielding performance, it outperforms commercial lead shielding materials. This work provides a potentially scalable method for developing lead-free, lightweight, and flexible X-ray shielding materials for wearable applications.