中文摘要：

利用层层自组装技术将带有相反电荷的肝素和Ⅳ型胶原交替组装到材料表面,研究了组装前后及不同组装层数对内皮祖细胞的影响。Ti通过碱活化处理后,表面带上羟基,与多聚赖氨酸中的羧基结合,使材料形成带正电荷的氨基表面,接着将带有异种电荷的肝素和Ⅳ型胶原交替滴加到材料表面形成多层自组装层。通过傅立叶红外掠射检测各步处理后材料表面基团的变化,通过甲苯胺蓝定量表征材料表面肝素组装量,通过原子力显微镜观察组装前后材料表面形貌变化,通过水接触角的测定跟踪组装过程中材料表面亲疏水性能变化。结果显示肝素和Ⅳ型胶原成功地组装到材料表面,修饰后的表面较钛表面内皮祖细胞的粘附数量多,随着组装层数的增加,细胞在材料表面粘附数量也逐渐增加,且其生长与增殖逐步加快。

英文摘要：

Negatively charged heparin and positively charged type Ⅳ collagen were assembled onto titanium sur- face by a layer-by-layer （LBL） self-assembly technique. Based on this approach, this work mainly investigated the effect of modified surface and assembled layer numbers on the behavior of endothelial progenitor cells （EPCs）. Titanium was firstly activated by NaOH solution to generate a negatively charged hydroxyl-rich sur- face for subsequently poly-L lysine （PLL） electrostatically binding and thereby formed positively charged amino group modified surface. Then the negatively charged heparin and the positively charged type Ⅳ collagen were alternately assembled onto the PLL coated titanium surface to form the functional multilayer via intermolecular electrostatically interaction. The change of the surface chemical composition after each step was detected by Fourier transforca infrared spectroscopy. The total amount of assembled heparin was determined by toluidine blue assay. The surface topography and hydrophilic/hydrophobic property of the functional muhilayer sample was investigated by atomic force microscopy and water contact angle measurement, respectively. The experi- ment results showed that heparin and type IV collagen were successfully assembled onto material surface. In compared with the controlled titanium surface, the biofunctional multilayer surface significantly improved endo- thelial progenitor cells （EPCs） adhesion. Meanwhile, with increasing of the assembled layer numbers, the bio- logical behaviors of the endothelial progenitor cells were obviously improved, such as better adhesion, more ac- celerating growth and proliferation. It was due to the amount of Ⅳ collagen increasing.