Small Science最新文献

Infected diabetic foot ulcer (DFU) endangers patients through complex complications, which seriously increase the risk of amputation, prolongation of disability time and mortality, as well as bring a heavy burden to the medical system. This review focuses on the emerging biomedical engineering therapy of DFU and deeply analyzes the multiple pathogenic factors driving these intractable DFU wounds, including impaired angiogenesis, inflammatory disorder, microbial biofilm formation, and impaired immune response. It also synthesizes current clinical treatments and elaborates on their limitations that underscore the need for innovative solutions. The core of the review delves into recent breakthroughs in responsive antimicrobial biomaterials, emphasizing their stimuli-triggered mechanisms that enable targeted drug release, enhanced bacterial eradication, and tissue regeneration promotion. Furthermore, it explores future trajectories for multifunctional biomaterials, envisioning integrated systems that combine antimicrobial, anti-inflammatory, and pro-healing properties to address the complex pathophysiology of infected DFU. By bridging current clinical challenges with biomaterial innovations, it can provide actionable insights for developing patient-centric therapeutic strategies in biomedical engineering.

A photomagnet, Co₈[W(CN)₈]₅Cl·(pyrazine)₁₁·21H₂O, exhibiting Class II mixed valency due to homometallic intervalence charge transfer (IVCT) between Co^II and Co^III centers, is synthesized. The compound features a 3D cyanido-bridged CoW coordination network composed of two crystallographically independent Co sites (Co1 and Co2) and one W site. Rectangular tubular structures formed by Co1-W bridges are further crosslinked by the Co2 sites. Defects in the [W(CN)₈] sites enable the formation of pyrazine bridges between the Co1 sites. Upon cooling, the compound undergoes a two-step thermal phase transition, attributed to heterometallic charge-transfer-induced spin transitions between high- and low-spin electronic states. The first-step charge transfer (CT) phase transition leads to the formation of homometallic [Co^II-pyrazine-Co^III] bridges, producing a near-infrared IVCT band at 2300 nm. Photoirradiation at 785 nm at 3 K induces a transition to a photoinduced (PI1) phase. The PI1 phase also shows a homometallic IVCT band due to the emergence of the [Co^II-pyrazine-Co^III] state. Subsequent photoirradiation at 532 nm to the PI1 phase induces a transition to the paramagnetic photoinduced (PI2) phase. This study demonstrates the modulation of electronic states in a phase transition material and a photomagnet, enabled by homo- and heterometallic CT processes.

Tin perovskite solar cells (Sn-PSCs) have emerged as excellent candidates for nontoxic narrow bandgap PSCs. Nevertheless, the technology remains limited by both stability and suboptimal energetic alignment with conventional charge transport layers. Compositional tuning is central to high-performance Sn-PSCs, replacing substoichiometric iodide ions with bromide. However, incorporating SnBr₂ as the bromide source introduces SnBr₄ impurities, underscoring the need to understand the consequences of SnBr₄ on both performance and degradation chemistry. Presently, the absence of such understanding has engendered a reliance on organobromide salts, neglecting a critical opportunity to enhance stability via the reduction of unstable SnI₂. Herein, the influence of SnBr₄ impurities on the structural, optoelectronic, and electronic properties of Sn-perovskites is investigated. Removal of SnBr₄ impurities from SnBr₂ results in drastically improved morphology, a 40% lower trap density and enhanced device performance of 150%. Furthermore, both the fundamental chemistry and degradation pathways in SnI₄ and SnBr₄ are compared, demonstrating the latter does not decompose to the molecular halogen-a key weakness of iodine-based Sn-PSCs. The present findings offer critical chemical and electronic insights into the presence of SnBr₄, the importance of its removal and the opportunities afforded by using SnBr₂ to minimize unstable SnI₂ in Br-rich Sn-perovskite phases.

With the growing prevalence of global microplastic and nanoplastic pollution, the accumulation of nanoplastics in the human body has increased, heightening the risk of noncommunicable diseases including cancer, cardiovascular disease, and amyotrophic lateral sclerosis. However, the development of fluorescent probes for detecting nanoplastics remains challenging due to the lack of reactive sites on nanoplastics for conventional design of responsive probes. In this work, a novel strategy for the sensitive detection of nanoplastics by probing the viscous nanoenvironment surrounding them is presented. This study synthesizes a cationic fluorescent probe, Purification by silica gel column chromatography (CH₂Cl₂/MeOH) provided (E)-2-(2-(4-(dimethylamino)nanphthalen-1-yl)vinyl)-1,3,3-trimethyl-3H-indol-1-ium (named HCY due to its structural similarity to hemicyanine dyes) as a tawny solid (HCY), via a simple one-step reaction. HCY demonstrates high sensitivity to nanoplastics, achieving an 8.5-fold fluorescence enhancement in the presence of carboxylated polystyrene nanoplastics, with a detection limit of 0.153 μg mL^-1. Moreover, HCY exhibits excellent biocompatibility, enabling the monitoring of nanoplastics level in living cells and visualization of nanoplastics distribution in zebrafish. This work offers a new design strategy for responsive fluorescent probes and provides a promising avenue for detecting environmental pollutants.

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.

Iron-oxide nanoflowers (NFs) are one of the most efficient nanoheaters for magnetic hyperthermia therapy. However, the physics underlying the dynamic response of realistic nanoparticles, containing disorder, beyond the single-domain limit remains poorly understood. Using large-scale micromagnetic simulations, the magnetization of biocompatible iron-oxide NFs (d = 10-400 nm) has been mapped, connecting their microstructure to their macroscopic magnetic response. Above the single-domain regime (d > 50 nm), the magnetization folds into a vortex state, within which the coercivity reaches a secondary maximum, not present for nondisordered nanoparticles. The dynamics of the vortex shows two distinct reversal modes: 1) a core-dominated one, with an increasing coercivity with d; 2) a flux-closure-domains dominated reversal mode, with a decreasing coercivity-size dependence. The coercivity maximum is located at the transition between both reversal modes and results from the combination of grain anisotropy and grain-boundary pinning. The results provide the first description of spin textures in iron oxide NFs beyond the macrospin framework, revealing how particles with identical static magnetization exhibit fundamentally distinct dynamics, which result in different macroscopic behavior. By adjusting the grain size, the coercivity "sweet spot" can be tailored, offering a practical route to next-generation, high-efficiency nanoheaters.

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.