Small Methods最新文献

The discovery and control of phases is a significant endeavor for materials science. PtSe₂, as a stable Pt─Se phase, is controllably synthesized for electronic, optoelectronic, and electrocatalytic applications, while research on another stable Pt─Se phase, Pt₅Se₄, is limited to calculations. Moreover, the growth mechanisms and phase transition of Pt─Se compounds remain unclear. Here, we report a two-step growth pathway of PtSe₂ with a stable Pt₅Se₄ phase as intermediate and reveal the Pt-Pt₅Se₄-PtSe₂ transition process. The synthesis of PtSe₂ and Pt₅Se₄ nanocrystals is achieved by controlling the degree of selenization. Theoretical calculations prove that Pt₅Se₄ phase is thermodynamically favorable under Se-deficient conditions and PtSe₂ nanocrystals are formed along with the diffusion of Pt and Se atoms. This work greatly enriches the knowledge on the growth mechanism and phase transition of Pt─Se compounds, and offers insights into the controlled synthesis of Pt₅Se₄ for future electrocatalysis and electronic devices.

3D flexible electrodes are essential to implement flexible pressure sensors in various flexible electronic applications. Conventional methods for fabricating these electrodes include electroless deposition, spray coating, and incorporating conductive nanomaterials into a polymer matrix. However, the electrodes fabricated using these methods are characterized by poor adhesion between the conductive layer and polymer surface and fail to maintain intrinsic mechanical properties of the polymer, such as elastic modulus and ductility. Herein, a transfer method in which conductive nanomaterials are embedded into the surface of polymer networks via optimal surface energy control is proposed, such as reducing adhesion between the mold and nanomaterials. This method induces mechanical interlocking between the surface of polymer networks and conductive nanomaterials, firmly anchoring them onto the polymer network surface. Moreover, the intrinsic mechanical properties of the fabricated 3D flexible electrodes remain unchanged. Flexible capacitive sensors prepared using the resulting electrodes exhibit a stable sensing performance (ΔC_0,5000/C₀ = 0.169%) even under repetitive pressure conditions (5000 cycles at 70 kPa). The proposed robust 3D flexible electrode fabrication method presents a promising strategy for the future development of flexible pressure sensors.

Fluorescence nanoscopy and single-molecule methods are entering the realm of structural biology, breaking new ground for dynamic structural measurements at room temperature and liquid environments. Here, single-molecule localization microscopy, polarization-dependent single-molecule excitation, and protein engineering are combined to determine the orientation of a fluorophore forming hydrogen bonds inside a protein cavity. The observed conformations are in good agreement with molecular dynamics simulations, enabling a new, more realistic interplay between experiments and simulations to identify stable conformations and the key interactions involved. Furthermore, jumps between conformations can be monitored with a precision of 3° and a time resolution of a few seconds, confirming the potential of this methodology for retrieving dynamic structural information of nanoscopic biological systems under physiologically compatible conditions.

RNA-cleaving DNAzymes are in vitro selected functional nucleic acids with inherent catalytic activities. Due to their unique properties, such as high specificity, substrate cleavage capability, and programmability, DNAzymes have emerged as powerful tools in the fields of analytical chemistry, chemical biology, and biomedicine. Nevertheless, the biological applications of DNAzymes are still impeded by several challenges, such as structural instability, compromised catalytic activity in biological environments and the lack of spatiotemporal control designs, which may result in false-positive signals, limited efficacy or non-specific activation associated with side effects. To address these challenges, various strategies have been explored to regulate DNAzyme activity through chemical modifications, enhancing their stability, selectivity, and functionality, thereby positioning them as ideal candidates for biological applications. In this review, a comprehensive overview of chemically modified DNAzymes is provided, discussing modification strategies and the effects of these modifications on DNAzymes. Specific examples of the use of chemically modified DNAzymes in biosensing and gene therapy are also presented and discussed. Finally, the current challenges in the field are addressed and offer perspectives on the potential direction for chemically modified DNAzymes.

With the rising incidence of benign prostatic hyperplasia (BPH) due to societal aging, accurate and early diagnosis has become increasingly critical. The clinical challenges associated with BPH diagnosis, particularly the lack of specific biomarkers that can differentiate BPH from other causes of lower urinary tract symptoms (LUTS). Here, matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) metabolomic detection platform utilizing urine and serum samples is applied to explore metabolic information and identify potential biomarkers in designed cohort. The nanoparticle-assisted platform demonstrated rapid analysis, minimal sample consumption, and high reproducibility. Employing a two-step grouping screening approach, the identification of urinary metabolic patterns (UMPs) is automated to distinguish healthy individuals from LUTS group, followed by the use of serum metabolic patterns (SMPs) to accurately identify BPH cases within the LUTS cohort, achieving an area under the curve (AUC) of 0.830 (95% CI: 0.802-0.851). Furthermore, eight BPH-sensitive metabolic markers are identified, confirming their uniform distribution across age groups (p > 0.05). This research contributes valuable insights for the early diagnosis and personalized treatment of BPH, enhancing clinical practice and patient care.

With increasing health awareness, monitoring human physiological signals for health status and disease prevention has become crucial. Non-invasive flexible wearable devices address issues like invasiveness, inconvenience, size, and continuous monitoring challenges in traditional devices. Among flexible sensors, optical fiber sensors (OFSs) stand out due to their excellent biocompatibility, anti-electromagnetic interference capabilities, and ability to monitor multiple signals simultaneously. This paper reviews the application of flexible optical fiber sensing technology (OFST) in monitoring human lung function, cardiovascular function, body parameters, motor function, and various physiological signals. It emphasizes the importance of continuous monitoring in personal health management, clinical settings, sports training, and emergency response. The review discusses challenges in OFST for continuous health signal monitoring and envisions its significant potential for future development. This technology underscores the importance of constant health signal monitoring and highlights the advantages and prospects of optical fiber sensing. Innovations in OFS for non-invasive continuous monitoring of physiological signals hold profound implications for materials science, sensing technology, and biomedicine.

Interfacial modification using self-assembled monolayers (SAMs) is crucial for defect passivation and energy level alignment in perovskite solar cells (PSCs), yet scaling SAMs remains a challenge. Organic SAMs are often too thin for large-area homogeneous layers through spin-coating and their hydrophobic nature complicates solution-based perovskite fabrication, hindering uniform film formation. This study introduces SAM based on phenothiazine core that involves synergistic co-adsorption of a hydrophilic phosphonic acid with phenothiazine core unit for use as a hole transport layer in p-i-n PSCs. The PTZ-PA SAM improves film formation, energy alignment, and hole extraction, achieving a power conversion efficiency above 23.2%. It also maintains stable performance for over 500 h under continuous illumination, indicating its potential for durable PSCs. PTZ-PA increases surface energy, overcoming non-wetting issues and enabling the formation of high-quality perovskite films with improved morphology and crystallinity. The phosphonic acid group coordinates with lead iodide in the perovskite, enhancing electronic charge transfer and mechanical absorption, which facilitates effective p-type charge-selective contacts.

Hydrogen plays a key role in maximizing the benefits of renewable energy, and the widespread adoption of water electrolyzers and fuel cells, which convert the chemical energy of hydrogen and electrical energy into each other, is strongly desired. Electrocatalysts used in these devices, typically in the form of nanoparticles, are crucial components because they significantly affect cell performance, but their raw materials rely on limited resources. In catalyst research, electrochemical experimental studies using model catalysts, such as single-crystal electrodes, have provided valuable information on reaction and degradation mechanisms, as well as catalyst development strategies aimed at overcoming the trade-off between activity and durability, across spatial scales ranging from the atomic to the nanoscale. Traditionally, these experiments are conducted using well-defined, simple model surfaces like bare single-crystal electrodes in pure systems. However, in recent years, experimental methods using more complex interfaces-while still precisely controlling elemental distribution, microstructure, and modification patterns-have been established. This paper reviews the history of those studies focusing on noble-metal-based electrocatalysts for oxygen reduction reactions and oxygen evolution reactions, which account for the majority of efficiency losses in fuel cells and water electrolyzers, respectively. Furthermore, potential future research themes in experimental studies using model electrodes are identified.

The unique optical, electrical, and thermal properties of 1D nanowires have sparked significant interest in growing high-quality 1D materials. Nanowire arrays and aligned growth offer scalability and maintain anisotropic properties, making them promising for research and applications. However, mass-producing high-quality nanowire arrays remains a challenge. A strategy is proposed for growing nanowire arrays based on homogeneous precursor as the substrate. Both calculations and experiments demonstrate that using a self-assembly micro-platform in advance facilitates epitaxial growth via chemical vapor deposition (CVD) to achieve highly oriented nanowire arrays. This is attributed to changes in crystallographic disregistry and adhesion energy. For instance, SnTe nanowire arrays are successfully grown using this method, with significantly lower thermal conductivity (≈5.5 W m^-1 K^-1 at 300 K) compared to the bulk material (≈9.1 W m^-1 K^-1 at 300 K), making them ideal for thermoelectric applications. The research lays the foundation for the tunable growth of IV-VI nanowire arrays and opens up possibilities for innovative thermoelectric nano-micro devices.

The actin cytoskeleton and its nanoscale organization are central to all eukaryotic cells-powering diverse cellular functions including morphology, motility, and cell division-and is dysregulated in multiple diseases. Historically studied largely with purified proteins or in isolated cells, tools to study cell type-specific roles of actin in multicellular contexts are greatly needed. DeActs are recently created, first-in-class genetic tools for perturbing actin nanostructures and dynamics in specific cell types across diverse eukaryotic model organisms. Here, ChiActs are introduced, the next generation of actin-perturbing genetic tools that can be rapidly activated in cells and optogenetically targeted to distinct subcellular locations using light. ChiActs are composed of split halves of DeAct-SpvB, whose potent actin disassembly-promoting activity is restored by chemical-induced dimerization or allosteric switching. It is shown that ChiActs function to rapidly induce actin disassembly in several model cell types and are able to perturb actin-dependent nano-assembly and cellular functions, including inhibiting lamellipodial protrusions and membrane ruffling, remodeling mitochondrial morphology, and reorganizing chromatin by locally constraining actin disassembly to specific subcellular compartments. ChiActs thus expand the toolbox of genetically-encoded tools for perturbing actin in living cells, unlocking studies of the many roles of actin nano-assembly and dynamics in complex multicellular systems.