富含羧基的多肽基双亲水杂化共聚物控制碳酸钙的形成  

Polypeptide-Based Doubly-Hydrophilic Hybrid Copolymers Containing Carboxyl Groups for Control of the Form of CaCO_3

作　　者：黄玉刚[1,2] 褚曰环 何明辉[2] 曾兆华[2] 杨建文[2] 

机构地区：[1]广州医科大学药学院化学教研室,广东广州510183 [2]中山大学化学与化学工程学院//聚合物复合材料及功能材料教育部重点实验室,广东广州510275

出　　处：《中山大学学报（自然科学版）》2014年第3期73-79,共7页Acta Scientiarum Naturalium Universitatis Sunyatseni

基　　金：国家自然科学基金资助项目(50773097);广州医科大学博士启动基金资助项目(L135015)

摘　　要：结合N-羧基-环内酸酐开环聚合和"巯-炔"光点击反应制备了侧链富含羧基的多肽基双亲水杂化共聚物(PEO-b-PPLG-g-MPA)。该多肽基共聚物可以模拟蛋白质指导CaCO3在水溶液中的形成。圆二色谱(CD)揭示了多肽链段在水溶液中的构象变化;扫描电子显微镜(SEM)揭示了矿化过程中CaCO3的形貌变化;X-射线衍射(XRD)确认了CaCO3的晶型。结果表明,该聚合物可以有效地控制CaCO3的形貌,此时多肽链段呈无规线团构象,而不是更为有序的α-螺旋或β-折叠构象;多肽链段的含量只有达到足够的浓度时,才能有效地控制的CaCO3晶体的生长;CaCO3的形貌则可以通过调节多肽链段的长度、溶液的pH值等因素进行调控,其可以是表面光滑的微球、表面堆满了CaCO3小颗粒的超结构微球、纳米棒或呈"花瓣状"聚集的纳米棒。XRD则证明形成的CaCO3呈稳定的方解石晶型。Polypeptide-based doubly-hydrophilic hybrid copolymers （PEO-b-PPLG-g-MPA） containing a great amount of carboxyl groups at the side-chains of polypeptide blocks were synthesized by combination of ring opening polymerization of N-carboxyanhydrides （NCAs） and thiol-yne photo-click reaction. The obtained polypeptide-based doubly-hydrophilic hybrid copolymers （DHHC） were used as protein template to direct biomineralization of CaCO3 in aqueous solution. Conformational changes of the polypeptide blocks were revealed by circular dichroism （CD） spectroscopy. Morphology of the obtained CaCO3 was investigated by scanning electron microscope （SEM）. Crystal form of the CaCO3 was confirmed by x-ray diffraction （XRD）. The results of CD analysis indicated that the polypeptide blocks could effectively con- trol the morphology of CaCO3in water when they adopted random coil conformation, rather than more or- dered a-helix or β-sheet. SEM analysis showed that the growth of the CaCO3 crystals was strongly depend-ent on the concentration of polypeptides. Furthermore, the morphology of CaCO3 was tunable by the vari- ation of length of polypeptide blocks and pH value of the aqueous solution. CaCO3 could form the micro- sphere with smooth surface, spherical superstructures with some tiny disklike particles grown on the surface and ＂flower＂ aggregated nanorod structures. XRD analysis verified that the obtained CaCO3 was calcite in a very stable form in nature.

关 键 词：羧基 多肽 双亲水杂化共聚物 碳酸钙 

分 类 号：O63[理学—高分子化学]