材料科学最新文献

Chronic diabetic wounds are one of the most challenging clinical problems because of poor angiogenesis, prolonged inflammation, and retarded tissue repair. Conventional wound dressing does not provide localised and continuous treatment, frequently resulting in unsuccessful therapeutic outcomes. Microneedle (MN) based delivery is envisioned as an ideal approach to transdermal interface with the wound microenvironment to deliver bioactive agents. Because of its minimally invasive nature, ease of use, and ability to bypass the stratum corneum, microneedles as a delivery medium have inherent advantages of site-specific, controllable, and painless drug administration. This review summarises recent progress in the development of MN-based systems for diabetic wound healing and emphasises their potential for delivering growth factors, anti-inflammatory agents, and gene therapies. The addition of smart materials, including stimulus-responsive and bioelectronic microneedles, makes them more efficacious as a therapeutic system. We also address current barriers, regulatory challenges, and prospects for clinical translation of MN-based wound care for diabetes.

Origami, the art of paper folding, can transform sheets into three-dimensional (3D) configurations and reshape deployed structures into folded forms, inspiring the design of deployable and multifunctional structures. Graphene oxide (GO) flakes can be assembled into papers that are promising substrates to fabricate actuators because of their light weight, high surface area for integration of functional components, and responsiveness to stimuli. In this work, we develop macroscopic deployable GO origamis with anisotropic mechanical properties, structural bistability, and humidity-responsive deformations. To produce strong yet flexible GO papers, we propose a high-throughput fabrication method by drop-casting GO suspensions on a wet cellulose substrate. The cellulose allows retaining water within the GO flakes during evaporation, enhancing the flexibility and toughness of the resulting GO paper. We fabricate GO Miura-ori and Kresling origamis that unfold in humid environments and fold upon water evaporation, thanks to the hygroscopic expansion of GO combined with the 3D origami design. This enables the creation of programmable, multifunctional structures that serve as actuators in a two-digit humidity signaling device. The deployable GO origamis, powered by origami engineering and the humidity responsiveness of graphene materials, offer new opportunities for the design of next-generation graphene metamaterials and responsive soft robots.

Hydrogen sulfide (H₂S), a gaseous signaling molecule with multiple cardioprotective effects, has attracted considerable attention for treating myocardial infarction (MI), a leading global cause of death. However, its ultrashort half-life (seconds to minutes) and the extended recovery required for myocardial repair pose substantial challenges to therapeutic efficiency, emphasizing the urgent need for month-level controlled H₂S delivery strategies, an endeavor still unresolved. Inspired by natural trisulfide H₂S donors, we introduce a novel disulfide/trisulfide cross-linked network derived from natural lipoic acid (LA) and its trisulfide derivative LATS, engineered as a drug-carrier homologated cardiac patch (Fe@LA/LATS) for MI therapy. Fe@LA/LATS adheres firmly to wet cardiac tissue, providing a stable mechanical support while undergoing thiol-responsive depolymerization to release LA and H₂S. In situ-released LA scavenges reactive oxygen species (ROS) and attenuates the inflammatory response around the infarcted myocardium. Concurrently, H₂S significantly stimulates cardiomyocyte proliferation and angiogenesis, further accelerating myocardial regeneration and functional recovery. Impressively, Fe@LA/LATS containing 5% LATS ensures a controlled release of H₂S at therapeutically effective levels for 1 month, with a seamless release process until complete degradation. This new strategy dramatically enhances the overall therapeutic efficiency, exhibiting promising potential for further applications.

Photoswitching among several states is essential for the development of photoresponsive materials showing multiple functions. Here, we developed multistate photochromism under a single light source with constant wavelength and intensity, based on the new concept of temporal separation of photoreactions.

This study investigates the structural and microstructural characteristics of magnetite (Fe₃O₄) and cobalt ferrite (CoFe₂O₄) nanoparticles synthesized via the sol-gel auto-combustion method using ferric nitrate and cobalt nitrate as metal precursors. X-ray diffraction (XRD) analysis confirmed the formation of single-phase crystalline nanoparticles with a cubic inverse spinel structure. Transmission electron microscopy further validated the nanocrystalline nature and morphological uniformity of the particles. To gain deeper insight into the crystallite size and lattice strain, multiple XRD-based analytical approaches Williamson-Hall, size-strain plot, and Halder-Wagner methods were employed. The novelty of this work lies in the first systematic side-by-side comparison of Fe₃O₄and CoFe₂O₄nanoparticles synthesized under identical conditions and evaluated using four complementary XRD models, ensuring cross-validated accuracy. The comparative evaluation of these models revealed slight discrepancies in size estimations, attributed to their varied assumptions regarding strain and instrumental broadening. Notably, CoFe₂O₄nanoparticles exhibited marginally larger crystallite sizes and higher lattice strain compared to Fe₃O₄, imply compositional influence on structural properties. The combined application of these analytical techniques enabled accurate estimation of crystallite size, microstrain, and energy density, providing insights into the mechanical stability and potential functional behavior of the synthesized nanoparticles.