胆固醇改性壳聚糖的生物学评价及其矿化性能

发布时间：2018-07-12 10:51

本文选题：壳聚糖 + 胆固醇　；参考：《暨南大学》2012年博士论文

【摘要】：壳聚糖(CS)及其衍生物在组织修复中的应用研究报道很多，也非常系统，其中壳聚糖的生物功能化是目前国内外研究的热点。本研究以壳聚糖为基材，创新性的利用功能特异的胆固醇对其进行仿生功能化，并系统研究改性壳聚糖的生物相容性和矿化性能，为开辟一类新型的骨组织修复材料奠定了基础。本研究首先将胆固醇与卵磷脂掺入到壳聚糖和羟基磷灰石的水溶液中，经过浇铸成膜，碱液中和、陈化处理后，考察胆固醇和卵磷脂含量对羟基磷灰石微结构的影响。结果表明，卵磷脂与胆固醇的比例增加，羟基磷灰石可由球状转变为棒状，当卵磷脂/胆固醇为5:1时，体系中的羟基磷灰石形貌与尺寸与天然骨组织接近；而无胆固醇与卵磷脂作用的壳聚糖模板中主要以无定形的片状为主。此结果表明胆固醇、卵磷脂具有改变羟基磷灰石微结构的功能。本研究还借助琥珀酸酐将胆固醇接枝到壳聚糖氨基上，合成了具有不同接枝率的胆固醇-g-壳聚糖(CHCS)。研究表明，胆固醇在壳聚糖上的接枝率随着胆固醇投料量的提高略有增加，并呈非线性关系。当投料摩尔比为15:1，10:1和5:1时(壳聚糖糖环数比胆固醇分子)，接枝率(胆固醇分子数/100个壳聚糖糖环)分别为3.71，4.02与5.94。胆固醇改性壳聚糖的疏水性随着接枝率的增加而增大，壳聚糖膜接触角为72.1°，而接枝率为3.71，4.02与5.94的CHCS膜接触角依次为76.6°，81°与85.8°。白蛋白在膜材上的吸附也是随着接枝率的增加而增大，壳聚糖膜上的蛋白吸附量为0.354μg，而接枝率为3.71，4.02与5.94的CHCS膜上的蛋白吸附量依次为7.664μg，8.248μg，16.815μg。同时，，研究结果还表明改性后的壳聚糖具有促进成纤维3T3细胞黏附、增殖的效果。3T3细胞在壳聚糖及不同改性程度的胆固醇-g-壳聚糖膜上培养一天后，改性后材料上细胞的铺展明显比纯壳聚糖膜上充分，且有较多的板状伪足与丝状伪足伸出。在支架材料上培养三天后，CHCS材料上的细胞分泌较多的细胞外基质，且随着改性程度的提高，纤维状细胞外基质越明显。模拟体液仿生矿化表明，本研究研制的CHCS所沉积的钙磷盐稳定性更好。支架材料的快速矿化结果表明，24h内钙磷盐在改性后的材料上呈球状，在壳聚糖材料上呈无定形状。48h后，壳聚糖材料上所沉积的钙磷盐为颗粒状与无定形状，而低接枝率的CHCS支架上钙磷盐呈现海岛针状，高接枝率的CHCS材料上钙磷盐呈现有序化片状堆积。与成骨细胞的相互作用研究表明，改性后材料比纯壳聚糖具有更好的促进细胞黏附、增殖的效果。细胞在改性后的材料上伸出的伪足更为丰富，成骨细胞的特征形态维持得更好。细胞在改性后的材料上更容易地呈有序性黏附与增殖。特别是高接枝率的CHCS在一定时间内具有促进成骨细胞增殖和抑制分化的趋势，而7天后则是促进成骨细胞的分化。
[Abstract]:Chitosan ( CS ) and its derivatives have been widely used in tissue repair , and the biofunctionalization of chitosan is a hot spot at home and abroad .

The effects of cholesterol and lecithin on the microstructure of hydroxyapatite were investigated by the incorporation of cholesterol and lecithin into the aqueous solution of chitosan and hydroxyapatite . The results showed that the ratio of lecithin to cholesterol increased . The results showed that the ratio of lecithin to cholesterol increased , and hydroxyapatite can be converted from globular to rod . When the lecithin / cholesterol was 5 : 1 , the morphology and size of hydroxyapatite in the system were close to the natural bone tissue .
The results showed that cholesterol and lecithin had the function of changing the microstructure of hydroxyapatite .

Cholesterol - g - chitosan ( CHCS ) with different grafting ratios was synthesized by grafting cholesterol onto chitosan amino group by succinic anhydride . The results showed that the grafting rate of cholesterol on chitosan increased slightly with the increase of grafting rate . The graft rate was 3.71 , 4.02 and 5.94 . The surface contact angle of chitosan membrane was 3.71 , 4.02 and 5.94 , respectively .

The results showed that the calcium and phosphorus salts deposited on chitosan material were spherical and had no definite shape on chitosan material . The results showed that the modified material had better adhesion and proliferation than pure chitosan .
【学位授予单位】：暨南大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：R318.08

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