Small Science最新文献

Current clinical interventions lack effective strategies to arrest temporomandibular joint osteoarthritis (TMJOA) progression. Emerging evidence highlights the therapeutic potential of microRNAs (miRNAs) in osteoarthritis (OA) management, though critical challenges persist regarding delivery efficiency, including unsatisfactory cellular uptake, immunogenicity, and structural instability of miRNA-based therapeutics. Considering the powerful editability of tetrahedral framework nucleic acids (tFNAs) for gene delivery, a novel nanoscale gene delivery system using tetrahedral framework nucleic acids functionalized with miR-143-3p (tFNAs-143) is engineered. Through comprehensive in vivo modeling of TMJOA destabilization and in vitro simulation of IL-1β-induced inflammatory microenvironments, the therapeutic efficacy and molecular mechanisms underlying OA pathophysiology of tFNAs-143 are systematically investigated. The results demonstrate that tFNAs-143 exhibits excellent cellular internalization in chondrocytes and effectively mitigates TMJOA progression by impeding ferritinophagy-mediated ferroptosis. This study advances miRNA delivery technology for TMJOA therapy, deepens the insights into TMJOA pathogenesis, and proposes a promising nanotherapeutic strategy for developing targeted TMJOA therapies.

Understanding how multidomain proteins fold, avoid misfolding, and maintain functional regulation represents a critical problem in structural biology, with broad relevance for biotechnology. In this study, the tandem PDZ1-PDZ2 domains of the scaffold protein X11, a system of particular interest due to its previously reported asymmetric folding and unfolding behavior as well as its propensity to form transient misfolded intermediates, are investigated. Through extensive mutational work and in-depth kinetic folding analysis, the folding behavior of this multidomain construct is dissected, and a comparative analysis with its isolated PDZ domains is also performed. The results reveal that folding and unfolding proceed through distinct pathways with PDZ2 folding rapidly and independently, while PDZ1 folds more slowly and only upon engagement of an autoinhibitory regulatory tail. Despite these differences, the folding mechanisms of each domain are conserved when studied in isolation, with deviations largely confined to functionally relevant and frustrated regions. The results also allow to depict the structural features of a misfolded intermediate that competes with productive folding and is stabilized by non-native interdomain contacts. Strikingly, this misfolded trap retains elements of the PDZ2 folding nucleus, an unexpected finding that allows us to draw broader conclusions about how transient misfolding can arise even from native-like structural motifs. We discuss these results in light of prior studies on multidomain proteins.

Surface reconstruction by formation of inert phases in Ni-rich cathodes is widely viewed as a degradation mechanism for batteries. Herein, this seemingly undesirable phase is leveraged to stabilize Ni-rich cathodes. Density functional theory reveals a reduction in Ni 3d-O 2p hybridization in NiO compared to LiNiO₂ (LNO), suggesting its potential as a protective layer. Guided by theory, variable temperature X-ray diffraction is used to identify optimal conditions for introducing oxygen vacancies on the surface of LiNi_0.8Mn_0.1Co_0.1O₂ (NMC811) particles, which triggers a phase transformation from layered to rock-salt NiO on the surface, creating a core-shell structure as evidenced by X-ray photoelectron spectroscopy and scanning transmission electron microscopy (STEM). Electrochemical methods such as constant-current long-term cycling, cyclic voltammetry, and electrochemical impedance spectroscopy reveal improved capacity, higher Li⁺ diffusivity, and lower resistance during cycling. X-ray absorption spectroscopy confirms that the bulk-averaged oxidation state remains unchanged after modification, and STEM imaging confirm reduced structural heterogeneity. By reframing surface NiO as a controllable design principle, a materials-intrinsic, scalable route to extend the durability of Ni-rich cathodes is offered.

Conjugated ladder polymers are a unique class of macromolecules, characterized by their rigid and thermally stable structures. This work presents the synthesis and characterization of a pyrene-based azacationic ladder polymer (polymer A). Spectroscopic analysis points to the generation of radical cationic units during photoreduction, while cationic species are retained in the polymer backbone, thereby enabling in situ n-type doping. Unconventional anti-Kasha emission, with a maximum at 490 nm, appears to originate from these radical species in solution. In toluene, the lower dipole moment of the solvent leads to dual emission: anti-Kasha emission from radical cations and an S₁ → S₀ transition from polycationic units at 780 nm. This interpretation is supported by density functional theory/time-dependent density-functional theory calculations, which indicates that the large energy gap between the D₃ and D₂ states of the radical cationic units may inhibit internal conversion, allowing anti-Kasha behavior. Despite their potential reactivity, the cationic and radical cationic species remain stable in solution in the dark for over 110 h. To the authors' best knowledge, polymer A is the only ladder-type conjugated polymer reported to exhibit anti-Kasha emission together with light-induced n-type doping behavior.

Optical neural networks (ONNs) with extremely low latency, low power consumption, and high parallelism, provide an advantageous computational paradigm to address the rapid development of artificial intelligence. Conventional ONNs focus on handling limited information dimensions such as optical amplitude and phase, which are confined to simple small-size image classification, raising demand for significant reconfigurability on the perception of inherent high-dimensional light information. Herein, magneto-optoelectronic devices with polarization sensitivity are theoretically proposed to construct the ONN with high-performance multidimensional recognition, which is composed of 2D magnetic half-metal FeCl₂ and 2H-WSe₂. Polarization sensitivity with photogalvanic effect originates from the space-inversion symmetrical breaking of 2H-WSe₂, yielding the multidimensional perception under zero power consumption. The switchable magnetic configuration of two FeCl₂ contacts with unique half-metal band structures nonvolatilely modulates the amplitude and polarity of photoresponse across the wavelength from ultraviolet to near-infrared. By leveraging multidimensional light encoding, the proposed ONN architecture conducts negative value and nonlinear computations in polarization domain through highly reconfigurable magneto-optoelectronic mechanisms, which achieves up to 93.5% accuracy across complex tasks including 3D object classification, time-series recognition, etc. This work illuminates the potential of magneto-electronics, which extends the applications of ONNs in the real world.

Metallic nanoshells heat efficiently on excitation of the localized surface plasmon resonance (LSPR). Whilst investigating the photothermal properties of citrate-stabilized hollow gold nanoshells (HGNs) synthesized using a sacrificial silver nanoparticle (AgNPs), the LSPR undergoes a distinct blueshift (70 ± 20 nm (0.20 ± 0.06 eV)) when photothermally irradiated. Notably, when functionalized with a Raman reporter, the surface-enhanced Raman scattering (SERS) signal unexpectedly and dramatically increases 8 ± 2-fold upon plasmonic heating, despite the LSPR shifting away from the excitation wavelength. This unprecedented enhancement of the SERS signal is absent in samples lacking citrate or prepared using a cobalt nanoparticle template, underscoring the importance of citrate, heat, and AgNPs in eliciting these effects. It is hypothesized that aqueous silver ions near the surface of the HGNs react with the citrate and form a complex that is both light and temperature sensitive. The formation of silver deposits, observed by electron microscopy, alters the core-to-shell thickness ratio, resulting in a blueshift in the LSPR, and change the scattering to absorption properties, enabling an improved SERS performance. This new optical phenomenon has now been understood and will be of significant interest to future studies in harnessing the properties of HGNs.

Actinide nanoparticles (NPs) are widely recognized for their role as a potentially highly mobile form of radioactive contaminants in the environment. In recent years, research has increasingly focused on elucidating their formation mechanisms, atomic structure, and physicochemical properties. The application of synchrotron radiation techniques is central to the detailed characterization of their atomic structure and oxidation state. This review retraces the evolution of actinide NPs research and highlights recent achievements enabled by high-energy-resolution fluorescence-detected X-ray absorption near edge structure, used in correlation with complementary synchrotron-based methods.

Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage degradation. Abnormal mechanical loading exacerbates intracellular ROS accumulation and glutathione (GSH) depletion. While N-acetylcysteine (NAC) has potent antioxidant properties, its therapeutic potential in OA is limited by rapid degradation and poor intraarticular retention. In this study, chondrocyte-targeted, chondroitin sulfate (CS)-modified PLGA nanoparticles (CS-NAC-NPs) is developed for sustained and localized delivery of NAC. These nanoparticles exhibit excellent physical and chemical properties, biocompatibility, and chondrocyte targeting capabilities. In vitro, CS-NAC-NPs attenuated mechanical stress-induced ROS accumulation, preserved mitochondrial integrity, restored GSH levels, and suppressed ferroptosis, as evidenced by increased GPX4 expression and improved chondrocyte viability. In a murine model of OA, intraarticular injection of CS-NAC-NPs significantly reduced cartilage degradation and osteophyte formation, improved histological scores, and maintained extracellular matrix homeostasis more effectively than free NAC or nontargeted NAC-NPs. Notably, the therapeutic effect is abolished in GPX4-deficient mice, confirming that CS-NAC-NPs act via GPX4-mediated ferroptosis inhibition. Furthermore, in vivo tracking demonstrated excellent joint retention and no off-target toxicity, underscoring their translational safety. This study introduces a novel nanotherapeutic platform that couples biomechanical targeting with redox-responsive delivery to modulate ferroptosis, offering a promising disease-modifying approach for OA treatment.

The operando study investigates propane dehydrogenation (PDH) using a liquid gallium-platinum catalyst based on the supported catalytically active liquid metal solutions (SCALMS) concept. The focus is on monitoring and analyzing the active phase during reaction using near-ambient pressure X-ray photoelectron spectroscopy (NAPXPS) combined with gas phase analysis. This approach proves practical in tracking surface changes and chemical states during catalytic reactions, providing real-time insights into the catalyst behavior. PDH, an industrially significant reaction, is investigated using a GaPt SCALMS with 1 at.% Pt content. The findings reveal that metallic liquid GaPt SCALMS exhibit high activity, while the presence of oxygen in the feed stream significantly lowers the activity of the catalyst. While current liquid metal catalysts often experience an activation period, a pathway to achieving stable conversion rates right after the start is demonstrated. This stability lays a foundation for developing next-generation catalysts with improved performance. The investigation also highlights the critical influence of oxidic Ga on catalytic activity, offering valuable guidance for optimizing catalyst design. Overall, the findings underscore the practical importance of NAPXPS in advancing the understanding of surface properties in catalytic systems.

Aqueous zinc-ion batteries (AZIBs) have garnered increasing attention as promising candidates for large-scale energy storage applications, owing to their safety, cost-effectiveness, and high theoretical capacity. However, challenges such as dendrite formation, side reactions, and cathode dissolution continue to hinder their widespread adoption. As a critical component in direct contact with both the electrodes and electrolyte, the separator plays a significant role in determining the cycle life of the cell. This review provides a comprehensive review of recent strategies for separator modification, focusing on key approaches such as surface functionalization, regulation of porous structure, and the design of composite matrices. The review highlights the mechanisms by which these modifications influence ion transport, interface stability, and dendrite suppression. Additionally, it explores separator engineering technologies with promising practical applications, bridging the gap between fundamental research and real-world implementation. It is suggested that separator engineering is not only a crucial pathway for enhancing battery performance but also an essential factor for transitioning AZIBs from laboratory-scale research to industrial-scale applications. By analyzing the structure-property relationships of separator materials, this work aims to guide the rational design of next-generation high-performance separators and contribute to the practical deployment of zinc-based energy storage technologies.