溶胶凝胶法制备含有生物活性成分的PLGA组织工程支架材料

采用溶胶凝胶法制备了具有生物活性的SiO2/聚乙醇酸-乳酸共聚物（PLGA）组织工程支架材料。该方法选用廉价的硅溶胶作为硅源制备二氧化硅凝胶,简单易行,大大降低了成本。用模拟体液（SBF）溶液对含有SiO2的PLGA支架材料进行体外模拟浸泡实验。从电子探针照片上可以看到制得的含有SiO2的PLGA多孔支架材料有着良好的...     

Reduced Graphene Oxide‐GelMA Hybrid Hydrogels as Scaffolds for Cardiac Tissue Engineering

Biomaterials currently used in cardiac tissue engineering have certain limitations, such as lack of electrical conductivity and appropriate mechanical properties, which are two parameters playing a key role in regulating cardiac cell behavior. Here, the myocardial tissue constructs are engineered based on reduced graphene oxide (rGO)‐incorporated gelatin methacryloyl (GelMA) hybrid hydrogels. The incorporation of rGO into the GelMA matrix significantly enhances the electrical conductivity and mechanical properties of the material. Moreover, cells cultured on composite rGO‐GelMA scaffolds exhibit better biological activities such as cell viability, proliferation, and maturation compared to ones cultured on GelMA hydrogels. Cardiomyocytes show stronger contractility and faster spontaneous beating rate on rGO‐GelMA hydrogel sheets compared to those on pristine GelMA hydrogels, as well as GO‐GelMA hydrogel sheets with similar mechanical property and particle concentration. Our strategy of integrating rGO within a biocompatible hydrogel is expected to be broadly applicable for future biomaterial designs to improve tissue engineering outcomes. The engineered cardiac tissue constructs using rGO incorporated hybrid hydrogels can potentially provide high‐fidelity tissue models for drug studies and the investigations of cardiac tissue development and/or disease processes in vitro.     

丝素蛋白支架的制备及其在组织工程中的应用

作为一种天然的纤维蛋白,蚕丝具有良好的力学性能、生物相容性和可降解性,这使其在生物医学方面的应用不断拓展。多孔支架能够为细胞的粘附和增殖提供有利的微环境,在重塑和修复组织的过程中起着至关重要的作用。本文综述了丝素蛋白支架的多种制备方法,如静电纺丝法、冷冻干燥法、沥除法和发泡法等,阐述了丝素蛋白支架的表面改性方法,总结了丝素蛋白支架在组织工程中的应用。     

Solvent‐Free Synthesis of Uniform MOF Shell‐Derived Carbon Confined SnO2/Co Nanocubes for Highly Reversible Lithium Storage

Tin dioxide (SnO₂) has attracted much attention in lithium‐ion batteries (LIBs) due to its abundant source, low cost, and high theoretical capacity. However, the large volume variation, irreversible conversion reaction limit its further practical application in next‐generation LIBs. Here, a novel solvent‐free approach to construct uniform metal–organic framework (MOF) shell‐derived carbon confined SnO₂/Co (SnO₂/Co@C) nanocubes via a two‐step heat treatment is developed. In particular, MOF‐coated CoSnO₃ hollow nanocubes are for the first time synthesized as the intermediate product by an extremely simple thermal solid‐phase reaction, which is further developed as a general strategy to successfully obtain other uniform MOF‐coated metal oxides. The as‐synthesized SnO₂/Co@C nanocubes, when tested as LIB anodes, exhibit a highly reversible discharge capacity of 800 mAh g^?1 after 100 cycles at 200 mA g^?1 and excellent cycling stability with a retained capacity of 400 mAh g^?1 after 1800 cycles at 5 A g^?1. The experimental analyses demonstrate that these excellent performances are mainly ascribed to the delicate structure and a synergistic effect between Co and SnO₂. This facile synthetic approach will greatly contribute to the development of functional metal oxide‐based and MOF‐assisted nanostructures in many frontier applications.     

Bioglass® Coatings on Biodegradable Poly(3‐hydroxybutyrate) (P3HB) Meshes for Tissue Engineering Scaffolds

Osteoconduction and non‐toxic bioresorbability can be achieved by combining Bioglass® particles and Poly (3‐hydroxybutyrate) (P3HB) fibre meshes in novel composites for tissue engineering scaffolds. Bioglass® coatings readily induce hydroxyapatite (HA) formation on fibre surfaces in vitro, while biodegradable P3HB yields non toxic degradation products. In the present investigation, P3HB meshes were used, which were generated by means of an embroidery technology on the basis of yarns with 12 and 24 filaments with diameters of ～ 30 μm. Bioglass® particles of average particle size < 5 μm were used to produce coatings on P3HB meshes by slurry dipping. By varying the concentration of Bioglass® particles in aqueous slurry, coating thickness and homogeneity could be controlled. Optimally coated meshes were incubated in simulated body fluid (SBF) for 3, 7, 14, and 21 days to detect formation of HA, as a qualitative assessment of bioactivity. Scanning electron microscopy (SEM) observations coupled with X‐ray diffraction analyses revealed the presence of HA crystals on mesh surfaces following 3 days of incubation in SBF. The amount of HA crystals was shown to increase with incubation time in SBF. Minimal polymer degradation was seen after 21 days in SBF, suggesting a suitable time frame for tissue replacement. The novel Bioglass® /P3HB composite meshes developed here are potential materials for bone tissue engineering scaffold applications.     

Glass,Ceramic, Polymeric,and Composite Scaffolds with Multiscale Porosity for Bone Tissue Engineering

Porosity affects performance of scaffolds for bone tissue engineering both in vitro and in vivo. Macropores (i.e., pores with a diameter >100 μm) are essential for cellular infiltration; micropores (i.e., pores with a diameter of 1–10 μm) promote cell adhesion and facilitate nutrient absorption. Scaffolds containing both macropores and micropores exploit the advantages of both pore sizes and have excellent osteogenic properties. Nanopores (i.e., pores with a diameter of 1–50 nm) can be included as well, to improve cell–material interactions by further enhancing the surface area of the scaffold. This article reviews fabrication techniques and properties of scaffolds with multiscale porosity, focusing on glass, ceramic, polymeric, and composite scaffolds. After discussing the structure of bone and how it inspired scaffolds for bone tissue engineering, pore nomenclature is introduced. Then, the techniques used to induce multiscale porosity, the nature of the pores created, and the effects of scaffold porosity on mechanical properties and biological activity of the scaffolds are discussed. The review concludes by providing an outlook for this field, including advancements that are made possible by computational modeling and artificial intelligence.     

纳米纤维组织工程支架及其纳米效应研究进展

综述了纳米纤维组织工程支架的最新研究进展,评述了其制备技术、特点及其存在的纳米效应.指出天然细胞外基质为三维纳米纤维结构,其纤维连续,直径为纳米级,包含比例确定的纳米与微米空间,且与细胞存在纳米水平的相互作用;然而,目前的人工纤维支架,其纤维直径多为微米或数百纳米,或者缺乏纳米空间.采用生物纳米技术获得的细菌纤维素纳米纤维,其直径小于10 nm,自身呈三维网状结构,富含纳米空间,是构建新一代纳米组织工程支架的理想材料.     

ACF/PLGA骨组织工程复合支架的制备及其性能

本文利用溶剂灌制/粒子沥滤的方法将具有较强吸附性能的活性碳纤维（activated carbon fiber,ACF）掺杂于聚乳酸-羟基乙酸共聚物（poly（lactic-co-glycolic acid）,PLGA）制备了一种新型ACF/PLGA骨组织工程复合支架。论文对比研究了纯PLGA支架以及两种ACF/PLGA支架（ACF含量为2.75%,8.26%）的结构和性能。SEM研究发现三者都具有较高的孔隙度,分别为73.5340%、75.1214%和79.8216%,且孔隙度随着ACF含量的增加逐渐增大;压汞法测得三者的孔径分布基本在50~250μm之间;研究其亲水性发现,其表面接触角随AC     

Solvent‐Free Self‐Assembly to the Synthesis of Nitrogen‐Doped Ordered Mesoporous Polymers for Highly Selective Capture and Conversion of CO2

A solvent‐free induced self‐assembly technology for the synthesis of nitrogen‐doped ordered mesoporous polymers (N‐OMPs) is developed, which is realized by mixing polymer precursors with block copolymer templates, curing at 140–180 °C, and calcination to remove the templates. This synthetic strategy represents a significant advancement in the preparation of functional porous polymers through a fast and scalable yet environmentally friendly route, since no solvents or catalysts are used. The synthesized N‐OMPs and their derived catalysts are found to exhibit competitive CO₂ capacities (0.67–0.91 mmol g^?1 at 25 °C and 0.15 bar), extraordinary CO₂/N₂ selectivities (98–205 at 25 °C), and excellent activities for catalyzing conversion of CO₂ into cyclic carbonate (conversion >95% at 100 °C and 1.2 MPa for 1.5 h). The solvent‐free technology developed in this work can also be extended to the synthesis of N‐OMP/SiO₂ nanocomposites, mesoporous SiO₂, crystalline mesoporous TiO₂, and TiPO, demonstrating its wide applicability in porous material synthesis.     

Anisotropic Materials for Skeletal‐Muscle‐Tissue Engineering

Repair of damaged skeletal‐muscle tissue is limited by the regenerative capacity of the native tissue. Current clinical approaches are not optimal for the treatment of large volumetric skeletal‐muscle loss. As an alternative, tissue engineering represents a promising approach for the functional restoration of damaged muscle tissue. A typical tissue‐engineering process involves the design and fabrication of a scaffold that closely mimics the native skeletal‐muscle extracellular matrix (ECM), allowing organization of cells into a physiologically relevant 3D architecture. In particular, anisotropic materials that mimic the morphology of the native skeletal‐muscle ECM, can be fabricated using various biocompatible materials to guide cell alignment, elongation, proliferation, and differentiation into myotubes. Here, an overview of fundamental concepts associated with muscle‐tissue engineering and the current status of muscle‐tissue‐engineering approaches is provided. Recent advances in the development of anisotropic scaffolds with micro‐ or nanoscale features are reviewed, and how scaffold topographical, mechanical, and biochemical cues correlate to observed cellular function and phenotype development is examined. Finally, some recent developments in both the design and utility of anisotropic materials in skeletal‐muscle‐tissue engineering are highlighted, along with their potential impact on future research and clinical applications.     

Electronic and Structural Engineering of Carbon‐Based Metal‐Free Electrocatalysts for Water Splitting

Since first being reported as possible electrocatalysts to substitute platinum for the oxygen reduction reaction (ORR), carbon‐based metal‐free nanomaterials have been considered a class of promising low‐cost materials for clean and sustainable energy‐conversion reactions. However, beyond the ORR, the development of carbon‐based catalysts for other electrocatalytic reactions is still limited. More importantly, the intrinsic activity of most carbon‐based metal‐free catalysts is inadequate compared to their metal‐based counterparts. To address this challenge, more design strategies are needed in order to improve the overall performance of carbon‐based materials. Herein, using water splitting as an example, some state‐of‐the‐art strategies in promoting carbon‐based nanomaterials are summarized, including graphene, carbon nanotubes, and graphitic‐carbon nitride, as highly active electrocatalysts for hydrogen evolution and oxygen evolution reactions. It is shown that by rationally tuning the electronic and/or physical structure of the carbon nanomaterials, adsorption of reaction intermediates is optimized, consequently improving the apparent electrocatalytic performance. These strategies may facilitate the development in this area and lead to the discovery of advanced carbon‐based nanomaterials for various applications in energy‐conversion processes.     

骨组织工程PLGA/TCP复合材料的性能研究

骨组织工程的支架要求有与人骨在功能梯度上相一致的材料结构、几何结构和生理功能。PLGA／TCP复合材料具有适用于骨组织工程支架的综合性能。以快速成形技术低温沉积工艺的成形效果来评价材料的成形性能，以体外降解试验来评价材料的降解性能，以国家标准的方法来评价材料的细胞毒性，对PLGA和TCP不同配比下的性能进行了研究，发现TCP含量的增加有利于降低材料的细胞毒性，加快了材料的降解，但同时降低了材料的成形性能。从骨组织工程的临床应用来看，低的细胞毒性是需要首先得到保证的，成形性能则通过其他方式来改善。     

Buoyancy‐Driven Gradients for Biomaterial Fabrication and Tissue Engineering

The controlled fabrication of gradient materials is becoming increasingly important as the next generation of tissue engineering seeks to produce inhomogeneous constructs with physiological complexity. Current strategies for fabricating gradient materials can require highly specialized materials or equipment and cannot be generally applied to the wide range of systems used for tissue engineering. Here, the fundamental physical principle of buoyancy is exploited as a generalized approach for generating materials bearing well‐defined compositional, mechanical, or biochemical gradients. Gradient formation is demonstrated across a range of different materials (e.g., polymers and hydrogels) and cargos (e.g., liposomes, nanoparticles, extracellular vesicles, macromolecules, and small molecules). As well as providing versatility, this buoyancy‐driven gradient approach also offers speed (<1 min) and simplicity (a single injection) using standard laboratory apparatus. Moreover, this technique is readily applied to a major target in complex tissue engineering: the osteochondral interface. A bone morphogenetic protein 2 gradient, presented across a gelatin methacryloyl hydrogel laden with human mesenchymal stem cells, is used to locally stimulate osteogenesis and mineralization in order to produce integrated osteochondral tissue constructs. The versatility and accessibility of this fabrication platform should ensure widespread applicability and provide opportunities to generate other gradient materials or interfacial tissues.