Small Methods最新文献

Confined carbyne, an sp¹-hybridized linear carbon chain inside a carbon nanotube, is a novel material with remarkable properties and potential applications. Among its currently successful synthesis methods, high temperature high vacuum annealing is prevalent. Further optimization could be achieved by tuning the synthesis pathway. Here, a systematic analysis of key synthesis parameters including precursor filling, annealing step sequences, and temperature conditions during high temperature vacuum processing is performed. A novel yield determination model that overcomes previous limitations related to the irregular resonance Raman behavior of carbyne is applied to evaluate bulk yield and realized growth potential. With this refined model, it is possible to make a quantitative assessment of bulk yield optimization potential in multi-step annealing processes. These results provide crucial insights into the fundamental formation mechanisms of confined carbyne, advancing our understanding of this promising hybrid nanomaterial system. It is therefore possible to establish improved protocols for maximizing confined carbyne yields through precise control of synthesis conditions.

Efficient microwave absorbers are needed to address the electromagnetic pollution caused by the proliferation of new radio technologies and equipment. Excellent microwave absorption performance can be achieved by controlling the dielectric constant. Heteroatom-doped bimetallic materials are promising electromagnetic wave absorption (EMA) materials due to their tunable structures and low cost. In particular, the presence of anionic sites significantly affects their dielectric constant and electrical conductivity. Herein, a 1D carbon nanofiber material is prepared by encapsulating FeCo nanoparticles in a fiber cavity by electrostatic spinning. Subsequently, tellurization, vulcanization, and selenization processes are carried out. FeTe₂/ CoTe₂@C exhibits stronger conductivity and dielectric loss due to the lower electronegativity of Te. The clever configuration of FeTe₂, CoTe₂, and C heterostructures obtained by Te doping generates multi-heterogeneous interfaces that facilitate charge migration and enhance interfacial polarization, obtaining excellent EMA performance. FeTe₂/CoTe₂@C exhibits an optimum minimum reflection loss (RL_min) of -51.1 dB with a matching thickness of 2.0 mm, and the effective absorption bandwidth (EAB) reaches 4.2 GHz. Radar cross-section (RCS) calculations show the great potential of FeTe₂/CoTe₂@C for practical military stealth technology. This study offers novel guidance for improving the EMA properties of transition metal matrix composites via anionic coordination modulation.

Graphene nanoribbons (GNRs) hold significant potential for applications in semiconductor electronics. Compared to precursor design, the lateral fusion of polymers offers a versatile and flexible approach to producing GNRs with desirable properties. Developing effective methods to enhance lateral fusion is therefore highly desirable. In this study, the beneficial effects of atomic hydrogen (AH) are reported in promoting the lateral fusion of polyparaphenylene (PPP) chains into GNRs on Au(111). When PPP chains are treated with AH at 570 K, the threshold temperature for GNR formation by lateral fusion is reduced to 590 K, a substantial decrease from the 650 K required for the formation of GNR by postannealing without AH. The promoting effect of AH is attributed to the superhydrogenation of PPP chains at 570 K, which 1) locally disrupts π-aromaticity, and 2) facilitates closer proximity of PPP chains. Both effects aid in the dehydrogenative C-C coupling of PPP chains. Scanning tunneling microscopy (STM) and synchrotron radiation photoemission spectroscopy (SRPES) are used to identify reaction products and monitor reaction pathways. The demonstrated role of AH in this study may be extended to other systems involving the lateral fusion of polycyclic aromatic hydrocarbon (PAH)-based polymers.

Pt nanoparticles dispersed on carbon supports (Pt/C) are the benchmark oxygen reduction reaction (ORR) catalysts in proton exchange membrane fuel cells (PEMFCs). However, their widespread application is hindered by severe stability degradation under high potentials and acidic environments, primarily due to carbon support corrosion. To address this challenge, a multiscale template-assisted method is proposed, combined with ethylene glycol reduction, to fabricate Pt nanoparticles supported onto multiscale porous conductive antimony tin oxides (Pt/PT-SSO). Both theoretical and experimental approaches have shown that the strong interaction between Pt and support markedly accelerates electron transfer and optimizes the adsorption strength of key intermediates on the Pt surface. Furthermore, the unique multiscale porous structure of support not only provides an ideal platform for the uniform dispersion of Pt nanoparticles but also greatly enhances confinement effect, effectively preventing Pt aggregation. As a result, the Pt/PT-SSO exhibits superior ORR activity and durability compared to commercial Pt/C catalysts. Specifically, its mass activity at 0.9 V (vs RHE) reaches 0.617 A mgPt⁻¹, which is twice that of Pt/C, while maintaining outstanding stability over 50 h. Notably, PEMFCs utilizing Pt/PT-SSO achieve a high power density of 1.173 W cm⁻² and retain 94.9% after 30,000 cycles of accelerated durability testing.

Exosomes, small extracellular vesicles with lipid bilayer membranes, play a crucial role in cellular communication and can transfer diverse biological cargo, including proteins, lipids, and nucleic acids, from donor to recipient cells. Exosomes possess diverse immunological properties, such as antigen delivery and immune activation, along with excellent drug delivery capabilities, making them promising candidates for vaccine development. For different diseases, exosome-based vaccines can be designed as therapeutic or prophylactic vaccines by leveraging cellular immunity or humoral immunity. With the emergence of precision medicine, exosome-based personalized vaccines demonstrate exceptional therapeutic potential. This review systematically introduces the sources, biogenesis mechanisms, and components of exosomes and describes their regulatory roles in the immune system. Subsequently, the preparation, administration, and personalized therapy of exosome-based vaccines are discussed. Finally, the applications and clinical trials of exosome-based vaccines in the fields of anti-infection and anti-tumor therapies are particularly highlighted, with an analysis of the potential challenges in future vaccine development.

In the absence of treatment, detection of pathogenic RNA viruses and quarantine of infected individuals are critical for controlling the infection spread. Conventional antibody-based methods often lack the required accuracy and sensitivity, due to the need for a substantial amount of viral antigens. Similarly, traditional reverse transcription real-time polymerase chain reaction methods face challenges in providing timely results due to their multiple thermal nucleic acid amplification steps. To overcome these limitations, a new method based on imaging of virus-specific DNA markers is developed. This approach employs specially designed single-stranded circular DNA probes that capture virus-derived RNA fragments generated by RNase digestion of the viral genome. These fragments serve as primers for a subsequent single-step DNA filling reaction, producing double-stranded virus-specific marker molecules. These individual markers are recognized through fluorescence imaging following linearization by enzyme cleavage and subsequent fluorescence staining. This method can detect viruses at a genome equivalent level of 14 within 40 min. In addition, the molecule-level imaging-based method effectively detects human immunodeficiency virus-1 in clinical samples. This diagnostic approach does not require sophisticated thermal controls nor extensive nucleic acid amplifications, allowing for accurate, sensitive, and rapid detection without the need for large equipment, offering substantial potential for point-of-care applications.

Radioactive iodineisotopes (¹²⁹I and ¹³¹I), generated duringnuclear fission, persist in gaseous and aqueous phases due to their volatilityand bioaccumulation, posing severe health risks. Multiphase iodine removalremains challenging due to the low efficiency of conventional materials, especially in aqueous media where high polarity hinders effective adsorption. Herein, a novel bidentate precursor, 4, 4'-(((2, 3, 5, 6-tetramethyl-1, 4-phenylene)bis(methylene))bis(azanediyl))dibenzoicacid (PMBADH₂), was strategically designed having two -NH linkages to enhance interactions withiodine in the phases. Using PMBADH₂, Two new isostructural metal-organic frameworks(MOFs), {[Zn₂(PMBADH₂)₄(DMF)₂]·4DMF}_n (SVNIT-1) and {[Cd₂(PMBADH₂)₄(DMF)₂]·4DMF}_n (SVNIT-2), were synthesized. The MOFs werealso prepared on a gram scale to enhance practical applicability. Comprehensive characterization of both MOFs was performed using SCXRD, PXRD, FTIR, XPS, BET, and TGA. Both MOFs exhibited outstanding iodine uptake across vapor, organic, and aqueous phases. SVNIT-1 achieved capacities of 6.5 g g^-1 (vapor), 2.8 g g^-1 (organic), and 2.5 g g^-1 (aqueous, including seawater), while SVNIT-2 showed comparable values of 6.1, 2.6, and 2.4 g g^-1, respectively. Extensive studies on desorption, recyclability, and stability confirmed the robustness and reusability of thesematerials. Mechanistic studies using FTIR, PXRD, Raman, UV-DRS, XPS, and ESR highlighted the pivotal role of NH linkages in promoting iodine adsorption via strong hostguest interactions.

Comprehensive visualization of tissue architecture in large organs such as the brain is crucial for understanding functional relationships across key tissue regions. However, the large size of whole organs makes it challenging to image their entirety with subcellular resolution, often requiring prolonged imaging sessions, volume reconstruction, and compromises in spatial coverage. Here, Scalable Hydrogel-embedded Rapid Imaging of tissue NetworK (SHRINK) is reported to address this challenge through active tissue shrinkage and clearing. Utilizing the identified hydrogel network to preserve the spatial pattern of proteins in situ and remove the uncrosslinked biomolecules to create space, it is shown that SHRINK isotropically drives the reduction of sample sizes down to 16% of their original volume while maintaining high cellular and tissue-level integrity in a reversible manner. The size reduction and the corresponding 3D concentrating of the biomolecules render a more than sixfold enhancement for throughput and signal respectively, which addresses a key bottleneck for the stimulated Raman scattering (SRS) microscopy, ideal for 3D, label-free and super-multiplex tissue mapping. It is further demonstrated that SHRINK-SRS achieves organ-scale mapping of brain, intestine, heart, and kidney tissues. SHRINK offers a powerful approach to overcome traditional imaging barriers, enabling rapid and detailed visualization of large organs.

The blade-coating method has become an important technology that can be expanded to manufacture perovskite solar photovoltaics. However, the inherent conflict between rapid solvent removal and crystallization control in ambient blade-coating process fundamentally constrains the production throughput and film quality of perovskite solar modules. Here, a ternary solvent system (DMF/NMP/2-methoxyethanol) with hierarchical volatility gradients is developed, synergistically integrated with vacuum-flash evaporation to decouple nucleation and crystal growth kinetics. Specifically, 2-methoxyethanol (2-ME) enables vacuum flash-induced supersaturation for templated nucleation, while NMP facilitates strain-relaxed grain coalescence, and DMF ensures optimal ink rheology. This approach yields pinhole-free films with enlarged grains under ambient conditions (T = ≈30 ± 5 °C, RH = 30 ± 10%). The blade-coated n-i-p perovskite solar cells (active area: 0.08 cm²) achieve a power conversion efficiency (PCE) of 23.24%, and 5 × 5 cm² mini-modules (12 cm² active area) reach 22.12%, with merely 4.8% efficiency loss upon 150 times area upscaling. The devices exhibit improved stability, retaining 90% of their initial PCE after 800 h of maximum power point tracking (MPPT) at 25 °C. The approach establishes a unified solution that addresses crystallization precision, ambient compatibility, and industrial manufacturability in perovskite photovoltaics.

2D transition-metal dichalcogenides (TMDCs) have attracted attention as promising materials for next-generation devices owing to their versatile electronic and optical properties. The phase variety of TMDCs provides strategic opportunities for performance enhancement. Herein, a novel method is proposed to synthesize wafer-scale 1T phase MoS₂ and, simultaneously, induce a phase transition via a plasma-assisted metal-sulfidation process and spontaneous internal strain. With thicker MoS₂ layers, the strong internal strain during synthesis suppresses the undesirable phase transition from the metastable 1T phase to the 2H phase, ensuring stabilization of the 1T phase. Furthermore, as-synthesized 1T-MoS₂ shows remarkable electrical properties owing to the narrow bandgap (0.4 eV) of its semi-metallic state. As a result, the 1T-phase MoS₂ floating gate (1T-FG) flash memory demonstrates a wider memory window, a higher on/off ratio, and improved stability compared to the 2H-phase MoS₂ floating gate (2H-FG) flash memory. A 5 × 5 array structure is constructed to validate large-scale integration. Notably, under light irradiation, a single 1T-FG memory enables carrier trapping in the floating gate, even in the off state. This study introduces a facile phase control strategy and provides insights into advanced nonvolatile memory and optoelectronic synaptic functionalities.