LB膜诱导下草酸钙晶体的生物矿化研究

草酸钙（CaC２O４）结石是生物体内异常矿化形成的产物，是泌尿系结石的主要组成部分犤１犦。它形成于泌尿系统中尿路表皮细胞上犤２犦。磷脂的Langmuir－Blodgett（LB）膜是生物细胞膜的简化模拟体系犤３犦。用磷脂LB膜作为模板来研究CaC２O４晶体的形成过程，比在水溶液中更能接近CaC２O４结石在生物体内细胞膜表面形成的真实情况，将有助于对尿路结石的形成及防治的研究犤４犦。尿大分子硫酸软骨素A（C４S）存在于尿液中，但不存在于CaC２O４结石中。在结石病人尿液中C４S的含量明显低于正常人尿液中的含量，因此推测其在体内…     

酒石酸镁对水合草酸钙晶体生长的调控作用

本文在凝胶模拟体系中研究了Mgtart对草酸钙生长、 聚集和晶型、 晶相等的影响, 以期阐明Mgtart防治泌尿系结石形成的可能机理, 为临床医学提供参考.     

Morphogenetic control of calcite crystal growth in sulfonic acid based hydrogels

In this paper the mineralization of CaCO(3) in various hydrogel matrices is presented. Sulfonic acid based hydrogels were prepared by introduction of sulfonate-containing monomers into a polyacrylamide network. The sulfonate content of polyacrylamide-co-vinylsulfonate and polyacrylamide-co-allylsulfonate decreases during elution of the copolymers in demineralized water, indicating insufficient linking of the sulfonate-bearing monomers within the hydrogel. In contrast to this, acrylamidomethylpropanesulfonate (AMPS) effectively copolymerizes with acrylamide (AAm) monomers. To study the influence of spatial arrangement of ionic functional groups within hydrogel networks on the mineralization of CaCO(3), AMPS copolymers with different degrees of AMPS cross-linking were synthesized. For the mineralization experiments the copolymers were placed into a double-diffusion arrangement. Calcite as the thermodynamically stable modification of CaCO(3) was obtained with a particular morphology. The pseudocubic habitus resembles aggregates obtained by mineralization in pure polyacrylamide. However, closer examination of the aggregates by scanning electron microscopy (SEM) shows that the crystal growth in the AMPS copolymers is different from that observed in polyacrylamide. Whereas the morphology of the calcite aggregates could be fine-tuned by using copolymers with different sulfonate content, the spatial distribution of the ionic functional groups alters the course of crystallization. Calcium ions are locally accumulated due to the heterogeneous distribution of functional sulfonate groups within the copolymer network. Thereby the nucleation of calcite is triggered, resulting in enhanced mineralization.     

壳聚糖-氨基酸体系中碳酸钙模拟生物矿化的研究

本文选取壳聚糖与氨基酸作为碳酸钙模拟生物矿化的有机基质,研究并比较了侧链带不同电荷的氨基酸对碳酸钙生物矿化的调制作用,发现侧链带负电荷的酸性氨基酸能改变壳聚糖体系中原有的晶种模板,使能量比较高的球霰石型碳酸钙得以生成,而单纯的壳聚糖体系中只能得到方解石型碳酸钙;在形貌上则改变了球霰石型碳酸钙原有的球状堆积,出现了两头小、中间大椭球状的特殊形貌。     

Assembled structures of nanocrystals in polymer/calcium carbonate thin-film composites formed by the cooperation of chitosan and poly(aspartate)

Assembled structures of calcium carbonate (CaCO₃) nanocrystals have been examined for polymer/CaCO₃ thin-film composites synthesized through a self-organization process inspired by biomineralization. For the crystallization of CaCO₃, a thin-film matrix of chitosan has been used as a polymeric substrate. When the matrix is immersed into a supersaturated aqueous solution of CaCO₃ containing 1.4 × 10⁻³ wt % poly(aspartate) (PAsp), thin-film crystals of CaCO₃ are formed spontaneously. Three kinds of disklike films have been observed under a polarizing optical microscope. Electron diffraction analyses of each film have revealed that one is aragonite, displaying radial orientation of the c axes, and the others are vaterite, exhibiting different orientations. Detailed observation by scanning electron microscopy has clarified that these films are assemblies of crystalline particles 10–20 nm in size. The thin-film composites have been obtained over a PAsp concentration range of 4.4 × 10⁻⁴ to 1.0 × 10⁻² wt %. Vaterite formation becomes dominant when the concentration of PAsp is increased. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5153–5160, 2006     

Effects of temperature and sodium carboxylate additives on mineralization of calcium oxalate in silica gel systems

Urolithiasis remains a major medical problem in China, especially in Guangdong Province in the southest of China[1]. A survey in Shenzhen city, the most southern city in China, showed the incidence of renal calculus was 4.87%, being 6.12% in the males and 4.07% in the females[2]. The prevalence of renal calculus has been more as the age advances and in the male population and so was in the less-educated population. The recurrence rate is more than 80%, with a moderate improvement by conventi…