Small Methods最新文献

Organic molecule-based triplet-triplet annihilation upconversion (TTA-UC) has already shown enormous potential for applications in bioimaging, disease diagnostics, and additive manufacturing with its ultrahigh upconversion efficiency and low excitation intensity. However, TTA-UC relies on intermolecular Dexter energy transfer, rendering its upconversion strongly concentration-dependent. Here, a strategy is presented to decouple the concentration dependence of TTA-UC in small, uniform nanoparticles (NPs), addressing a critical limitation in its practical applications. By encapsulating ultralow-concentration TTA-UC pairs (sensitizer/annihilator: 244 nm/6.5 µm) in solid micellar NPs, an exceptional upconversion quantum efficiency of 15.9% (100% normalized) is achieved in aqueous media, which surpasses the reported results of NIR upconversion nanomaterials by two orders of magnitude. The TTA-UC NPs present ultra-low critical micellar concentration which suppresses micelle dissociation. Through rational annihilator T₁ energy level engineering, efficient, lifetime-tunable upconversion emission (96.0-47.8 µs range) is further demonstrated within water-dispersible NPs while maintaining multicolor output under single-wavelength excitation. Further, unprecedented TTA-UC-based time-resolved temperature sensing with a thermal sensitivity of 4.1% K^-1 is constructed. This study establishes a versatile platform for developing high-performance TTA-UC materials, opening new avenues for their implementation in nanophotonics and background-free sensing.

A planar layered MOF material, PTCDA-Ni, is prepared through a coordination reaction of PTCDA (3,4,9,10-perylenetetracarboxylic acid) with Ni ions, and the PTCDA-Ni is activated by solvent exchange activation with trichloromethane (TCM), acetone (AC), and co-activation with AC and microwaves (AC&Mw) to obtain three MOFs materials (PTCDA-Ni@TCM, PTCDA-Ni@AC, PTCDA-Ni@AC&Mw). The results show that the activated PTCDA-Ni has a different degree of enhancement in the specific surface area, the size of the pore size, and its stacking aggregation compared with the unactivated PTCDA-Ni. Meanwhile, the activation strategy can reduce the content of guest molecules in the pore structure, exposing more active sites and then improving the electrochemical properties. As a result, the capacity retention of PTCDA-Ni electrode before activation is 60.8% after 200 cycles at a current density of 0.1 A·g^-1, while under the same conditions, the capacity retention of PTCDA-Ni@TCM, PTCDA-Ni@AC, and PTCDA-Ni@AC&Mw electrodes are significantly improved to 92.1%, 96.9%, and 96.9%, respectively. The results of the GITT test and the CV curves at different scanning speeds similarly show that the activation strategy can increase the migration rate of lithium ions and further improve its electrochemical performance, which will open up a new idea for the design of anode materials for high-performance LIBs.

The integration of multidimensional optical sensing and computing within a single device is critical for next-generation optoelectronics but remains challenging due to material limitations and complex architectures. 2D van der Waals heterostructures(vdWHs) offer a promising platform for such multifunctionality. Here, a gate-tunable Te-WSe₂ heterojunction device is demonstrated that simultaneously achieves high-performance polarization-sensitive photodetection and reconfigurable multimode optoelectronic logic operations. By exploiting the strong in-plane anisotropy of Te and the gate-tunable band alignment at the heterointerface, the device exhibits a widely adjustable rectification ratio exceeding 10⁵, a high responsivity of 667.9 mA W^-1, and a gate-tunable polarization anisotropy ratio(AR) from 1.27 to 17.8. Operating in a photovoltaic mode, the device achieves a specific detectivity over 10¹¹ Jones and a fast response time of ≈25 µs. Furthermore, secure optical communication and multimode logic gates are demonstrated, where optical and electrical inputs are programmatically processed to execute encryption and Boolean operations. This work overcomes key limitations in polarization photodetection and provides a pathway toward compact, intelligent optoelectronic systems for advanced information processing.

Achieving high sensitivity, signal uniformity, and cost-effective large-scale fabrication of large-area surface-enhanced Raman scattering (SERS) substrates continues to pose a significant challenge. In order to break through the limitations of conventional SERS substrates and to meet the demands of high-throughput production, a strategy integrating programmable cyclic deposition with high-precision nanoskiving techniques is presented for the fabrication of large-area periodic nanowire arrays with adjustable geometric parameters and versatile material compositions in this study. By precisely controlling the stacking sequence and nanoskiving parameters, the structural dimensions and material composition can be finely tuned, which significantly enhances the coupling efficiency between localized surface plasmon resonance and Rayleigh anomaly, thereby enabling the excitation of high-quality-factor surface lattice resonances. The resulting arrays exhibit excellent structural integrity, uniform electromagnetic field distribution, and good signal reproducibility (RSD = 1.9%) over ≈206 mm². Notably, Ag150-Gap20-Ag150-Gap115-Period435 periodic nanowire arrays as the substrate exhibit excellent sensitivity with a detection limit as low as 1 × 10^-12 M for the target. This strategy offers an efficient, scalable, and material-adaptive method for high-throughput fabrication of SERS substrates, thereby facilitating its application in environmental monitoring, food safety, and bioanalysis.

Electron diffraction emerges as a powerful technique for structural analysis of small crystals, especially those that are too small for single crystal X-ray analysis or too complex for powder diffraction. Its growing popularity is driven by the strong electron-matter interaction and the opportunity for single-crystal data collection from nanosized crystals. However, this strong interaction often comes with the caveat of possible damage to the sample by the electron beam, a drawback that can affect the crystal structure and compromise data quality. This review delves into the details of the effects of beam damage on electron diffraction data, particularly focusing on the fading of Bragg reflections that are known to be the most sensitive damage indicator. By compiling the observations from quantitative measurements across the available reports, a treatise is provided on the effects of electron beam damage on electron diffraction data. Comparison of various mitigation strategies is also provided which sets guidelines for optimization of data collection strategies for efficient exposure of beam-sensitive compounds. We hope that this review will provide valuable insights for the growing research community that resorts to electron diffraction for characterization of materials, sometimes as the only applicable method to determine the structure of very small crystals.

Sequencing-based spatial transcriptomics (sST) techniques with high resolution enable transcriptome-wide RNA capture at subcellular resolution. Although new cell segmentation methods for sST data are continually being developed, accurately assigning RNA spots to corresponding cells still presents significant challenges and there is a lack of quality control methods. This work introduces a deep learning method for quality control of cell segmentation and improvement of the segmentation result. The proposed method exploits the subcellular spatial distribution patterns of different types of RNA by a deep neural network to assess the quality of segmented cells. The method identifies partially segmented cells typically due to low RNA capture or strong RNA diffusion as well as merged cells due to high cell density. In addition, the quality control method is combined with a Transformer-based cell segmentation method and it is shown that the cell segmentation performance improves by automatically removing low-quality segmented cells from the training dataset. The method is applied to both synthetic data and real Stereo-seq data, demonstrating its potential for quality control and enhancement of cell segmentation in sST data.

Copper-induced cell death (cuproptosis) shows great promise against infections, especially antibiotic-resistant bacteria. However, common copper carriers like inorganic oxides/frameworks suffer from uncontrollable copper ion leakage. Inspired by copper finger protein, similar copper binding peptide with sequence of Met-Asp-His-Gly-Tyr-Tyr (MDHGYY) is designed and then forms nanoparticles with copper ions with loading efficiency of 66.5%. To enable controlled release, such peptides are oxidized into melanin-like nanoparticles by tyrosinase with NIR light responsiveness. The copper-loaded peptide nanoparticles remain stable without leaking but release copper ions upon NIR irradiation. They can disrupt the pyruvate metabolic pathway within bacteria, inducing dihydrolipoamide S-acetyltransferase oligomerization with pyruvate upregulation and acetyl-coenzyme A downregulation for cuproptosis. It also interfere with bacterial quorum sensing, downregulating quorum sensing genes (e.g., agrB, oppA). Overall, synergistic quorum sensing interference and bacterial cuproptosis provide a novel biomimetic strategy against antibiotic-resistant bacteria, and effectively promte diabetes wound healing.

Understanding the ion storage mechanism and the influence of structural features on the pseudocapacitive behavior of electroactive materials is critical for enhancing energy and power density. In this study, the pseudocapacitive behavior of V₂O₅ at the single-particle level is investigated using scanning electrochemical cell microscopy (SECCM). This method allows simultaneous identification of structural features and electrochemical pseudocapacitive behavior in the same particle. Analysis of cyclic voltammetry at various scan rates for individual V₂O₅ particles reveals that the pseudocapacitive behavior, comprising surface redox reactions and (de)intercalation, dominates the energy storage process. The capacitive contribution ratio increases with particle diameter, highlighting the size-dependent kinetics. Furthermore, the effect of particle porosity is examined, demonstrating that 550 nm-diameter hollow-V₂O₅ particles exhibit a lower average capacitive contribution (82.5% at 0.5 V s^-1) compared to the solid-V₂O₅ particles with a similar size. This structural effect on the energy storage process can be attributed to the restricted diffusion-controlled faradaic (battery-like) process within the bulk V₂O₅ particles under fast charging/discharging conditions. This study presents a promising method for probing pseudocapacitive behavior at the single-particle level and provides insights into ion storage mechanisms.

Superior aqueous dispersibility mitigates nanoparticle toxicity in biological systems while preventing agglomeration. Herein, a hydrogen-bond-mediated aqueous synthesis strategy is proposed, utilizing β-cyclodextrin (β-CD) and sodium citrate (SC) to directly fabricate metal oxide nanoparticles in a single step. This approach not only suppresses particle aggregation but also preserves the molecular integrity of surface modifiers under high-temperature reaction conditions. Taking the preparation of gadolinium oxide as an example. Through modifier molecules on Gd₂O₃ surfaces, the hydrophilicity is markedly enhanced, enabling stable dispersion in aqueous media, which is a critical prerequisite for biomedical applications. This green synthesis method, regulated by hydrogen-bonding interactions, overcomes safety concerns associated with organic solvents in traditional solvothermal techniques and gadolinium ion leakage in co-precipitation methods, while eliminating complex post-modification steps. The longitudinal relaxation rate (r1) of Gd₂O₃UPs-220, prepared by this method, achieves 8.43 mm^-1s^-1 at a magnetic field strength of 7.0 T, demonstrating excellent magnetic resonance imaging (MRI) enhancement performance. This synthetic strategy provides an approach for preparing water-dispersible metal oxides.

Combined chemotherapy (CT) and gene therapy (GT) represent a reliable modality toward drug-resistant tumor treatment. Yet, physical-chemical differences between chemodrugs and nucleic acids often hinder the construction of feasible delivery systems with synergistic activity. Herein, a smart supramolecular polymeric scaffold is reported to co-load chemodrug paclitaxel (PTX) and Bcl-2 small interfering RNA (siRNA), respectively via Hydrogen-bonding (H-bonding) association and electrostatic interaction, toward efficiently reversing drug resistance and significantly inhibiting tumor growth in a synergistic manner via GT-enhanced CT. Therefore, a cationic copolymer carrier, P(OEGA-co-DMAEA)-b-P(HFA-co-TU) (e.g., PODHT), serves as a structurally distinct drug-delivery platform. The hydrophobic section, P(HFA-co-TU) (poly((heptafluorobutyl acrylate)-co-acylthiourea)), incorporates pendant thiourea (TU) moieties that can selectively recognize hydrophobic PTX. Such molecular recognition and co-assembly are governed by TU/PTX double H-bonding association in concert with hydrophobic interactions. Moreover, the cationic shell consisting of P(OEGA-co-DMAEA) (poly(oligo(ethylene glycol) monomethyl ether acrylate-co-2-dimethylaminoethyl acrylate)) from resulting PTX-loaded micelles can steadily bind the negative siRNA via electrostatic interaction, finally to afford the targeted supramolecular micelleplexes PTX@PODHT/siRNA. Such nanoplatform not only possesses the enhanced co-loading capacity and transportation stability of distinct PTX and siRNA, but also can induce pH-responsive cargos release within the tumor zone, ultimately effectively inhibiting tumor growth via synergistic CT/GT.