Small Methods最新文献

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.

Passive daytime radiative cooling (PDRC) is one of the most promising ways for energy conservation and even carbon emission reduction to achieve carbon neutrality. However, developing colored PDRC materials that exhibit effective cooling performance while meeting aesthetic requirements for outdoor applications remains challenging. Polymer material with lightweight, low-cost, and universal high thermal emissivity, poses great potential of efficient radiative cooling materials. In this study, a hierarchical pore-particle-nested structure is engineered in a polymer framework, achieving a solar reflectance of 93.6% and a thermal emissivity of 91.1%. Moreover, the colored variants maintained high performance, with solar reflectance values of 80.6%, 84.8%, and 88.1% for the blue, pink, and yellow films, respectively. The pore-particle-nested structure enhances scattering of both direct and diffuse sunlight, enabling efficient colored PDRC films. With enhanced mechanical properties and hydrophobic performance, the structure provides a cost-effective strategy for developing practical outdoor PDRC materials.

The development of efficient, scalable metal-free catalysts is vital for sustainable chemical processes. Here, we report a tunable one-step thermal synthesis of 2D/2D graphitic carbon nitride/reduced graphene oxide (g-C₃N₄/RGO) nanohybrids and nitrogen-doped RGO (N-RGO) by varying the urea-to-GO mass ratio. Urea-rich mixtures yield RGO-intercalated g-C₃N₄, while GO-rich compositions produce N-RGO. GO promotes amine condensation and acts as a structural scaffold for g-C₃N₄ growth, while urea serves as a g-C₃N₄ precursor, nitrogen dopant, and reducing agent. XRD, FTIR, and XPS analyses confirm sheet exfoliation and the formation of interfacial CN covalent bonds, evidencing strong coupling between g-C₃N₄ and RGO. BET and electrochemical impedance results reveal that catalytic enhancement arises primarily from interfacial electronic coupling and accelerated charge transfer rather than surface area effects. The g-C₃N₄/RGO-60% composite exhibits optimal coupling and achieves 100% conversion of 4-nitrophenol to 4-aminophenol within 3 minutes (k = 1.33 min^-1), outperforming pristine RGO and g-C₃N₄ by 66- and 33-fold, respectively. N-RGO exhibits high efficiency (k = 0.94 min^-1), attributed to enhanced catalytic sites from nitrogen doping. This scalable, low-cost method enables precise tuning of structureproperty relationships, offering high-performance metal-free catalysts for both dark and light-driven environmental remediation and sustainable organic transformations.

In this paper, relativistic carrier mobilities and photoconduction properties in graphene/MoS₂ heterostructure (GM-HS) are mapped via photoconductive scanning noise microscopy with a conducting nanoprobe. Graphene on MoS₂ (HS) regions shows two-times reduced sheet conductance (G_Sh) without a significant increase in trap densities (N_T) compared to that in graphene on SiO₂ (Gr) regions, due to the electron-doping in graphene by underlying MoS₂. Interestingly, both regions exhibit G_Sh independent of N_T, which indicates that the relativistic nature of graphene is preserved in the overall GM-HS. The mobility map is obtained from conductivity maps at different gate biases, showing a rather low mobility in HS regions compared to that in Gr regions. Notably, the overall film exhibits a sharp increase in mobility at low carrier densities, as previously reported in graphene having relativistic carriers. Under the illumination with photon energies above the MoS₂ bandgap, HS regions exhibit pronounced negative photoresponses originating from the injection of photo-excited electrons from MoS₂ to graphene. Unexpectedly, under the illumination with photon energies below the MoS₂ bandgap, HS regions exhibit marginally negative photoresponses, possibly due to additional carriers de-trapped from trapping sites in MoS₂. Interestingly, photoconductance is independent of phototraps, indicating that the relativistic photoconduction is preserved in GM-HS.

Label-free characterization of nanoparticle surface functionalization at single-particle resolution is essential for a wide range of applications. Solid-state nanopore sensing provides a direct electrical readout that is intrinsically sensitive to the size, surface layer, and interfacial chemistry of single particles in liquid environments. The trapping-based nanopore sensing regime further enables probing surface-dependent particle-pore interactions with extended observation time. Here, a solid-state nanopore trap-based fingerprinting method is presented to differentiate single nanoparticles with distinct surface modifications. The method combines a "trap-release" measurement protocol with a multi-metric analysis workflow that extracts blockade distributions, sub-level statistics and frequency-domain signatures from trapping events, and constructs a unique fingerprint for each particle species. Applied to silica cores (≈25-30 nm) functionalized with APTES, NHS-PEG₄-Biotin and Tween-20, the approach generates distinct fingerprints that map to surface charge, coating conformation and configuration heterogeneity. Moreover, in situ detection of surface chemical transformation via specific streptavidin binding is demonstrated, with stoichiometry-dependent progression of the fingerprints. This platform provides a complementary tool to optical, spectral and ensemble assays for characterizing engineered nanoparticle surfaces and tracking interfacial molecular interactions in solution with label-free and single-particle sensitivity.

Cost-effective catalysts are pivotal in addressing energy and environmental challenges through the catalytic conversion of small molecules. Cyano-bridged metal frameworks (CMFs), as a subclass of reticular materials, demonstrate potential in small molecule conversion. However, CMFs are conventionally utilized as precursors for derivative synthesis, which inadvertently overshadows their intrinsic properties. Recent research has revealed that CMFs have emerged as direct catalysts. Accordingly, the feasibility is investigated of directly employing CMFs as catalysts for small molecule conversion and propose integrated design strategies encompassing element selection, structural modulation, and adaptation to working conditions. Specifically, insights is offered into the rational selection and combination of building units based on an updated understanding of CMFs' coordination environments. A crystallization-kinetics-guided, multi-dimensional assembly methodology is further proposed to achieve structural diversity and topological complexity. Finally, the application potential is demonstrated of CMFs in small molecule conversion through experimental evaluation and theoretical analysis of key intrinsic material properties. This study establishes a conceptual and methodological foundation for advancing CMFs toward broader applications in small molecule conversion.

Alloy-based anodes featuring high capacity and moderate operating potentials hold great promise for high-energy-density all-solid-state batteries (ASSBs). However, the significant volume fluctuations during cycling often lead to solid-solid interfacial failure, compromising reversibility and cycling stability. Multilevel architectural designs of composite alloy anodes have proven effective in enhancing electronic conductivity, ion transport, and interfacial stability. Herein, the influence of stacking sequence on the structural evolution and electrochemical performance of electrodes composed of silicon (Si) and aluminum (Al) is investigated. The results reveal that the plastic deformability of the upper layer active material (directly interfacing with the solid-state electrolyte) and its electrochemical potential window critically influence the reversibility, rate capability, and failure mechanism of the composite anode. Notably, when Si is employed as the upper layer, the anode delivers an initial Coulombic efficiency of 87.3% at 0.25 mA cm^-2, significantly exceeding that of the Al-upper configuration (59.3%). These results provide mechanistic understanding for the rational design of composite alloy anodes, highlighting the importance of component stacking for mitigating kinetic limitations and enhancing the performance of ASSBs.

Transition metals and their derivatives have demonstrated considerable potential in the field of electromagnetic wave absorption owing to their complementary dielectric and magnetic loss capabilities. However, achieving satisfactory impedance matching with pure transition metal-based materials remains challenging, which restricts the operational frequency bandwidth and limits the minimal thickness. Aerogels, with their unique 3D porous networks, high porosity, large surface area, and ultra-low density, offer an ideal supporting matrix for hosting transition metals and their derivatives. Such composite structures not only improve impedance matching but also introduce diverse attenuation mechanisms, thereby enabling superior electromagnetic wave absorption performance. This review begins with a systematic introduction to the fundamental mechanisms of electromagnetic wave absorption. It subsequently summarizes the design strategies for aerogel architectures from the perspective of gelation principles, categorizes various types of aerogel-based composites incorporated with transition metals and their derivatives, and highlights recent research advances in this emerging field. Finally, the current challenges and future prospects for the development of transition metal-based aerogel absorbers are outlined. This comprehensive overview is intended to illuminate the path for the rational design of next-generation, high-performance microwave absorbers with integrated multifunctionality.