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Careful combination of a metal compound,a ligand and an inorganic support material leads to supramolecular catalysts that mimic the structural, organizational and functional aspects of enzyme activity.After discussing essential features of metalloenzyme-catalyzed reactions and coordination chemistry in inorganic hosts, we present examples of supramolecular materials selected from our own work that eventually resulted in useful catalysts for organic transformations in the liquid phase. 相似文献
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Ca-P仿生人工骨材料的设计与制备 总被引:2,自引:0,他引:2
本文设计了用磷酸钙生物陶瓷制备仿生人工骨的工艺路线 ,从原料合成、材料成型和烧结等讨论了仿骨材料的制备方法 相似文献
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The nanometer scale topography of self‐assembling structural protein complexes in animals is believed to induce favorable cell responses. An important example of such nanostructured biological complexes is fibrillar collagen that possesses a cross‐striation structure with a periodicity of 69 nm and a peak‐to‐valley distance of 4–6 nm. Bovine collagen type I was assembled into fibrillar structures in vitro and sedimented onto solid supports. Their structural motif was transferred into a nickel replica by physical vapor deposition of a small‐grained metal layer followed by galvanic plating. The resulting inverted nickel structure was found to faithfully present most of the micrometer and nanometer scale topography of the biological original. This nickel replica was used as a die for the injection molding of a range of different thermoplastic polymers. Total injection molding cycle times were in the range of 30–45 seconds. One of the polymer materials investigated, polyethylene, displayed poor replication of the biological nanotopographical motif. However, the majority of the polymers showed very high replication fidelity as witnessed by their ability to replicate the cross‐striation features of less than 5 nm height difference. The latter group of materials includes poly(propylene), poly(methyl methacrylate), poly(L ‐lactic acid), polycaprolactone, and a copolymer of cyclic and linear olefins (COC). This work suggests that the current limiting factor for the injection molding of nanometer scale topography in thermoplastic polymers lies with the grain size of the initial metal coating of the mold rather than the polymers themselves.
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细胞色素P-450是一种生物体内催化分子氧氧化内源底物的单加氧酶,其活性片段的核心结构是金属卟啉络合物。人工合成的金属卟啉络合物可作为细胞色素P-450的有效模拟物,应用于烯烃、直链烷烃、环烷烃、芳烃、芳烃侧链、及各种杂原子等多种底物的催化氧化。人工合成的金属卟啉络合物可分为:对称型金属卟啉、非对称型金属卟啉、μ-氧代双核金属卟啉、负载型金属卟啉4大类。现以金属卟啉络合物的结构为线索,论述了结构与催化活性及稳定性的内在联系,重点介绍了近几年国内外金属卟啉仿生催化剂的氧化应用研究进展,及仿生催化氧化的工业化发展前景。 相似文献
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Farnaz Ghorbani Dejian Li Zeyuan Zhong Melika Sahranavard Zhi Qian Shuo Ni Zhenhua Zhang Ali Zamanian Baoqing Yu 《应用聚合物科学杂志》2021,138(8):49888
Although many efforts have been made to regenerate the bone lesions, existing challenges can be mitigated through the development of tissue engineering scaffolds. However, the weak control on the microstructure of constructs, limitation in preparation of patient-specific and multilayered scaffolds, restriction in the fabrication of cell-laden matrixes, and challenges in preserving the drug/growth factors' efficacy in conventional methods have led to the development of bioprinting technology for regeneration of bone defects. So in this review, conventional 3D printers are classified, then the priority of the different types of bioprinting technologies for the preparation of the cell/growth factor-laden matrixes are focused. Besides, the bio-ink compositions, including polymeric/hybrid hydrogels and cell-based bio-inks are classified according to fundamental and recent studies. Herein, different effective parameters, such as viscosity, rheological properties, cross-linking methods, biodegradation biocompatibility, are considered. Finally, different types of cells and growth factors that can encapsulate in the bio-inks to promote bone repair are discussed, and both in vitro and in vivo achievement are considered. This review provides current and future perspectives of cell-laden bioprinting technologies. The restrictions and challenges are identified, and proper strategies for the development of cell-laden matrixes and high-performance printable bio-inks are proposed. 相似文献
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Rongnian Xu Xiaoduo Zhao Shuanhong Ma Zhengfeng Ma Rui Wang Meirong Cai Feng Zhou 《应用聚合物科学杂志》2021,138(46):51374
Anisotropic hydrogels are appealing with their merits of similar biochemical and structural properties to the biological tissues. However, the mechanical properties of current anisotropic hydrogels need to be further improved. Herein, three kinds of novel anisotropic poly(2-hydroxyethyl methacrylate) (pHEMA), poly(acrylamide) (pAM), and poly(acrylamide-co-acrylic acid) (p[AM-co-AA]) sugarcane composite hydrogels were prepared successfully by filling the hydrogel monomer precursor into porous aligned sugarcane nanofibers network and then performing subsequent free radical polymerization. The hydrogel matrix and sugarcane nanofibers network were combined closely together through hydrogen bonding interaction. The anisotropic sugarcane composite hydrogels exhibit good flexibility and elastic recovery properties upon encountering mechanical crimping and twisting. In typical case, the as-prepared pHEMA sugarcane composite hydrogel can exhibit high anisotropic tensile strength of 2.37 and 0.54 MPa, while differential tear strength of 0.36 and 0.78 N/mm, along the parallel and vertical nanofibers directions. Finally, anisotropic lubrication behaviors were found and investigated systematically for those three kinds of sugarcane composite hydrogels when water was used as lubricant. Our current work proposes a simple and universal strategy for developing bioinspired anisotropic functional composite matters such as artificial skin, flexible sensor, and cartilage lubrication materials. 相似文献
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