Small Science最新文献

Single-atom catalysts (SACs) have rapidly progressed from early proof-of-concept studies to high-performance sensing platforms. Their atomically dispersed active sites and tunable coordination environments, offer superior catalytic activity and selectivity compared with conventional nanocatalysts. Recent advances in support engineering, spanning carbon nanomaterials, metal oxides, and metal organic frameworks have enabled precise control over SAC composition, electronic structure, and stability under complex operating conditions. This review summarizes the current state of SAC research from three complementary perspectives. First, it compare top-down and bottom-up synthesis strategies, emphasizing scalable approaches that preserve single-atom dispersion. Second, it outlines the characterization techniques, highlighting how advanced spectroscopy, microscopy, and theoretical calculations are integrated to correlate coordination environments with catalytic performance. Third, it discusses emerging sensing applications including biosensing, environmental monitoring, gas and electrochemiluminescence detection, and photoelectrochemical analysis where SAC-based materials achieve record-low detection limits. Despite significant advancements, key challenges remain: (i) preventing atom aggregation under harsh electrochemical conditions, (ii) integrating SACs into miniaturized devices, and (iii) establishing standardized metrics that bridge theoretical predictions and practical performance. This review concludes that addressing these issues will advance SACs toward real-time sensing, with multi-atom cooperative sites and AI-assisted catalyst design as promising strategies to unlock their full potential in next-generation analytical platforms.

Vertically aligned nanocomposite (VAN) thin films have attracted extensive research interests in recent years owing to their unique structure anisotropy and broad integration compatibility with versatile material systems, which open enormous possibilities in the applications of electronic and photonic devices. In this article, to further expand the materials selection in oxide-metal alloys VAN structure, self-assembled BaTiO₃ (BTO): (Au-Co-Pd) and BTO: (Au-Pd) nanocomposite films are integrated using a simplified oxide-metal strips deposition method via pulsed laser deposition (PLD). Microstructural characterization results confirm the epitaxial film quality and vertically grown Au-Co-Pd and Au-Pd alloyed nanopillars in both nanocomposite films, where the elemental segregation of Au, Co, and Pd is primarily due to the differences in their surface energies. Both experimental and simulated optical data show the highly tailorable optical properties of the hybrid films such as localized surface plasmon resonance and hyperbolic dispersion wavelength shifts in the visible to near-infrared wavelength region. The successful integration of multiple metal elements via the one-step oxide-metal strips method in PLD demonstrates the wide feasibility of integrating diverse materials systems into VAN structure toward multifunctional property coupling for electronic, photonic, and energy devices applications.

The incorporation of graphene-based materials into hydrogels enhances their mechanical, electroconductive, and antimicrobial properties, offering significant potential for biomedical applications. However, 3D printing graphene-containing inks may present challenges because of their unsuitable shape retention or the fact that the concentration of the graphene component can hinder photocrosslinking. This study explores embedded 3D printing to process a chemically crosslinkable poly(ethylene glycol) ink with a high (4% w/v) graphene oxide concentration (PEG/GO). Given the PEG/GO ink's insufficient shape retention and slow crosslinking, various support baths are screened, with the microparticulate bath of the crystal self-healing embedding bioprinting (CLADDING) method proving most effective. The interstitial solution of the CLADDING bath influences the mechanical properties of printed PEG/GO constructs. Multilayered PEG/GO cylindrical constructs with <500 μm filament width and up to 4.5 mm height (30 layers) are fabricated, presenting better tensile properties when printed within CLADDING in calcium chloride (vs. baths in crosslinking initiators). The surface of PEG/GO constructs is anti-adhesive toward human foreskin fibroblasts, and their extracts are cytocompatible. Hence, embedded 3D printing emerges as an innovative strategy to surpass limitations of shaping graphene-containing hydrogels into complex geometries, broadening the biomanufacturing possibilities for diverse biomedical applications requiring kPa-range mechanical properties.

This study investigates the synergistic interaction of CuO and SnO₂ in a heterostructure catalyst (CuO@SnO₂) for the conversion of C1 carbon dioxide (CO₂) reduction products to C2 products and its application in high-performance aqueous Zn-CO₂ batteries. This synergistic combination enhances the Faradaic efficiency (FE) for ethanol production from 12.5% to 41.8%, shifting the selectivity from C1 to C2 products. The flow-type aqueous Zn-CO₂ battery exhibits an ultrahigh power density of 6.5 mW cm^-2, demonstrates a high discharge voltage of 0.9 V, and maintains stable operation over 140 cycles, underscoring the catalyst's exceptional reversibility and durability. During battery discharge, the system achieves a FE of 36.86% for ethanol production. These results highlight the pivotal role of the CuO@SnO₂ synergy in optimizing CO₂ conversion efficiency while generating electrical energy. The findings advance the development of dual-function energy storage systems that integrate renewable electricity generation with sustainable CO₂ utilization, paving the way for industrial-scale applications.

Two-dimensional boron offers unique advantages in bone tissue engineering, unlocking capabilities that conventional additives struggle to achieve. Herein, the 2D morphology and intrinsic bioactivity of boron nanoplatelets are leveraged, to be incorporated into collagen-based scaffolds and simultaneously achieve osteogenic, mechanically reinforcing, and antimicrobial effects, with a shift toward neurogenic, angiogenic, and anti-inflammatory signaling. Boron nanoplatelets, synthesized from nonlayered precursors using liquid-phase exfoliation, are combined with collagen to form boron-collagen scaffolds (BColl). Boron significantly reinforces the collagen matrix, beneficial for mechanoresponsive bone cells. Osteoblasts and mesenchymal stem cells exhibit healthy morphology and proliferation on BColl films and scaffolds, with extended culture leading to increased alkaline phosphatase release and significantly increased calcium deposition, indicating enhanced osteogenesis. E. coli viability decreases significantly on BColl films, demonstrating their potential to limit postimplantation infections. Finally, angiogenic, neurogenic, and anti-inflammatory signaling, with dose-dependent upregulation of vascular endothelial growth factor-A, nerve growth factor-beta, and interleukin-10, and downregulation of interleukin-6 are observed, highlighting boron's potential to drive pro-reparative processes. Taken together, these data showcase boron's potential for next-generation bone biomaterials, by offering multifunctional benefits to clinically relevant aspects of bone regeneration such as mineralization, angiogenesis, and innervation, while improving the mechanical and antimicrobial properties of natural polymer scaffolds.

Implantable vascular devices are becoming increasingly essential in clinical practice, particularly in the management of chronic cardiovascular diseases (CVDs), such as heart failure. These devices enable continuous hemodynamic monitoring, support early interventions, and promote personalized, cost-effective care by providing real-time data that enhance patient outcomes. However, their development and clinical application face significant regulatory and biological challenges. Regulatory frameworks, such as the European Union's Medical Device Regulation, ensure safety, efficacy, and high-quality standards throughout a device's lifecycle. Despite these regulations, intravascular devices interact with vascular tissues and blood, triggering biological responses, such as inflammation and thrombosis, which may impair device functionality, reduce long-term durability, and cause severe adverse events. The bioactive surface of implanted devices initiates inflammatory responses and coagulation, leading to complications like fibrotic encapsulation and vascular injury. After device implantation, endothelial injury promotes platelet activation, thrombus formation, and leukocyte infiltration, compromising both device integration and vascular function. Therefore, the material and structural design of these devices play a crucial role in mitigating thrombotic and inflammatory reactions. This review explores the potential benefits and challenges of vascular implantable devices in the management of chronic CVDs, highlighting regulatory aspects, biological responses, and future clinical perspectives.

The development of miniaturized, remotely addressable sensing devices is crucial in a variety of fields, including healthcare, environmental monitoring, and security. This study introduces an optrode sensor comprising a multimaterial fiber composed of a phosphate glass cladding and a continuous Zn wire core, interfaced with a photoactive ZnO coating on its tip, deposited by anodization. It is shown that this optrode can promote photoelectrochemical reactions under illumination with UV light when immersed in an aqueous electrolyte. Proof-of-principle experiments demonstrate that these optrodes produce a glucose-responsive photocurrent, opening the way to biomedical applications. This optical sensor shows promise, as it would ultimately allow the decoupling of input stimuli, i.e., potential and light excitation, over a long distance. Due to its advantages in terms of integration, detection speed, and ease of use, these ZnO/Zn/phosphate optrodes hold significant potential for remote analysis and implantable sensors.

Antimicrobial susceptibility testing (AST) that is easily adaptable for point-of-care (POC) use is essential for addressing the growing threat of antibiotic resistance. Here, the solid medium droplet microarray (SM-DMA), a simple yet versatile testing platform consisting of a single microscope slide patterned with an array of 80 agar droplets (6-8  μL each), containing customizable combinations of clinically relevant antibiotics, is introduced. The test allows for easy manual sample application and features a colorimetric self-check readout. Using E. coli (DSM498) as a model organism, accurate determination of minimum inhibitory concentrations for clinically relevant antibiotics (cefotaxime, ciprofloxacin, and ampicillin), producing results consistent with EUCAST clinical breakpoints, is demonstrated. Furthermore, SM-DMA facilitates combinatorial antibiotic testing, represented by intuitive viability heatmaps. The platform is more time efficient (≈16-18 h total) compared to the conventional agar plate-based methods. Owing to the robustness, ease of use, and independence from specialized equipment, the SM-DMA can be adapted for POC applications by nontrained personnel or even by patients themselves.

Chronic inflammatory diseases of bone and soft tissue pose significant clinical challenges due to their complex pathogenesis and the limitations of conventional therapies, which often fail to address immune microenvironment dysregulation. This review explores the pivotal roles of key immune cells (including mast cells, macrophages, neutrophils, T cells, B cells, and dendritic cells) in driving inflammatory progression and tissue damage through dynamic cellular interactions and cytokine networks. It systematically analyzes the molecular and structural foundations of immunomodulatory biomaterials, such as nanoparticles, hydrogels, and scaffolds, which offer precise spatiotemporal control over immune cell phenotypes and inflammatory mediators. By integrating advances in immunology and materials science, this review highlights how surface functionalization, controlled drug release, and composite material strategies synergistically restore immune homeostasis and promote tissue regeneration. Studies across common chronic inflammatory diseases (e.g., osteoporosis, osteomyelitis, osteoarthritis, diabetic wounds, spinal cord injury, and intervertebral disc degeneration) demonstrate the therapeutic potential of biomaterial-mediated immunomodulation, such as nanoparticle-driven macrophage polarization, cytokine-loaded hydrogel-mediated immune cell balance, and scaffold-guided immune cell recruitment. Challenges in clinical translation, including material biocompatibility and multicomponent synergy, are critically addressed. This review underscores the transformative potential of immunomodulatory biomaterials as next-generation precision therapies to overcome therapeutic bottlenecks in chronic inflammatory diseases.

Graphene, a pioneering 2D carbon nanomaterial, has attracted significant attention owing to its exceptional structural, mechanical, thermal, and electrical performances. These intrinsic properties position it as a promising material platform for nanoelectromechanical systems, flexible electronics, and biomedical devices. Despite numerous existing reviews on graphene, a comprehensive assessment across graphene variants remains limited. Addressing this critical gap, this review provides an in-depth overview of the structural configurations, physical properties, and application domains of key graphene forms-including monolayer, bilayer, few-layer, and multilayer graphene, as well as functionalized derivatives. The review systematically discusses fabrication and synthesis strategies. Furthermore, it delves into state-of-the-art methodologies for mechanical characterization, highlighting experimental and computational techniques, including in situ scanning electron microscopy and transmission electron microscopy, atomic force microscopy, nanoindentation, tensile testing, Raman spectroscopy, and multiscale simulations based on molecular dynamics, density functional theory, coarse-grained modeling, and continuum mechanics. A comparative analysis of experimentally measured and computationally predicted mechanical properties is presented, elucidating existing discrepancies among methods. Collectively, this review aims to serve as a comprehensive reference for researchers at the intersection of nanomaterials, mechanics, and multifunctional material systems, offering a critical foundation for future research and the application of graphene nanostructures in next-generation technologies.