ABSTRACT
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.