载锌功能化多壁碳纳米管/壳聚糖复合支架的制备与性能评价

摘要

背景:单纯使用壳聚糖作为骨组织工程支架时机械性能较差,在骨缺损区不能有效承重,因此,许多学者尝试开发多壁碳纳米管/壳聚糖骨组织工程支架.目的:构建载锌功能化多壁碳纳米管/壳聚糖复合支架,测试其力学性能、抗菌活性与细胞相容性.方法:①采用“混酸法”制备功能化多壁碳纳米管;将壳聚糖、功能化多壁碳纳米管溶液(功能化多壁碳纳米管质量分数0.5％)与不同浓度的ZnSO4·7H2O(锌质量分数分别0.2％、1％、2％)混合,制备载锌功能化多壁碳纳米管/壳聚糖复合支架,检测纯壳聚糖支架及载锌功能化多壁碳纳米管/壳聚糖复合支架的表面硬度及拉伸强度;②采用抑菌圈实验检测纯壳聚糖支架及载锌功能化多壁碳纳米管/壳聚糖复合支架对金黄色葡萄球菌或大肠杆菌的抑制作用;③采用载锌功能化多壁碳纳米管/壳聚糖复合支架浸提液培养小鼠成骨细胞MC3T3-EI,培养1,2,3d后,采用MTT法检测细胞增殖,计算细胞相对增殖率,评价细胞毒性.结果与结论:①3组载锌功能化多壁碳纳米管/壳聚糖复合支架的表面硬度、拉伸强度均高于纯壳聚糖支架(P＜0.05),3组载锌功能化多壁碳纳米管/壳聚糖复合支架间的表面硬度、拉伸强度比较差异无显著性意义;②3组载锌功能化多壁碳纳米管/壳聚糖复合支架对金黄色葡萄球菌和大肠杆菌的抗菌性能均高于纯壳聚糖支架(P＜0.05),且抗菌性能随着复合支架中锌质量分数的增加而增强;③含锌质量分数0.2％、1％的载锌功能化多壁碳纳米管/壳聚糖复合支架无细胞毒性;④结果表明,含锌质量分数1％的载锌功能化多壁碳纳米管/壳聚糖复合支架具有良好的力学性能、抗菌活性及细胞相容性.%BACKGROUND:A pure chitosan (CS) scaffold has poor mechanical properties,and cannot play a load-bearing role in the bone defect region.Therefore,many scholars attempt to develop multi-walled carbon nanotube (MWCNT)/chitosan (MWCNT/CS) bone tissue scaffolds.OBJECTIVE:To develop the functionalized MWCNT/CS composite scaffolds carrying zinc (f-MWCNT/CS-Zn) and to test its mechanical properties,antibacterial activity and biocompatibility.METHODS:(1) F-MWCNT composite scaffolds were prepared by the acid mixture method,and f-MWCNT/CS-Zn composite scaffolds were prepared through mixing CS,f-MWCNT (0.5％) with different concentrations of ZnSO4·7H2O (the concentrations of Zn in the composite scaffolds were 0.2％,1％,2％,respectively).The surface hardness and tensile strength of the pure CS scaffold and the f-MWCNT/CS-Zn composite scaffolds were measured.(2) The inhibitory effect on Staphylococcus aureus or Escherichia coii of the pure CS scaffold and f-MWCNT/CS-Zn scaffolds was tested by inhibition zone test.(3) The osteoblasts MC3T3-El were cultured with the leaching solution of f-MWCNT/CS-Zn composite scaffolds.The cell proliferation was detected by MTT assay at 1,2,3 days after culture,then the relative proliferation rate was calculated and the cytotoxicity was evaluated.RESULTS AND CONCLUSION:(1) The surface hardness and tensile strength of the f-MWCNT/CS-Zn composite scaffolds were higher than those of the pure CS scaffold (P ＜ 0.05),and there was no significant difference in the surface hardness and tensile strength between the different zinc-containing composite scaffolds.(2) The antibacterial properties of the three f-MWCNT/CS-Zn composite scaffolds against Staphylococcus aureus and Escherichia coii were higher than those of the pure CS scaffold (P ＜ 0.05),and the antibacterial activity was enhanced with the increase of zinc mass fraction.(3) The f-MWCNT/CS-0.2％Zn and f-MWCNT/CS-1％Zn composite scaffolds had no cytotoxicity.To conclude,the f-MWCNT/CS-1％Zn composite scaffold has good mechanical properties,antibacterial activity and biocompatibility.