Preparation And Mechanical,antibacterial And Biocompatibility Of ZnO/PLA/PBAT Composites

The ideal artificial bone material can not only avoid the secondary trauma caused by autologous bone harvesting,but also provide an environment for the regeneration of bone tissue to grow and differentiate during the repair of bone defects.The ideal artificial bone material has certain antibacterial properties,which can reduce risk of bacterial infection during surgery,which is of great importance for the repair of bone defects.In this paper,the biocompatible polylactic acid(PLA)is used as the matrix of the composite material,and polyadipate/butylene terephthalate is used as the reinforcing phase of the polylactic acid.PLA/PBAT composites,the effects of nano-ZnO addition content on the mechanical properties,antibacterial properties and biocompatibility of nano-ZnO/PLA/PBAT composites were studied.Nano-ZnO was pretreated to reduce the occurrence of agglomeration during the preparation of composite materials,single-screw extruder was used to prepare wires,and characterization samples were prepared by injection molding;through SEM,mechanical property test,rotational rheometer,FTIR test,XRD test,The effects of nano-ZnO addition content on the mechanical properties,rheological properties,microscopic morphology and structural properties of the composites were studied.The results show that with the increase of nano-ZnO content,the mechanical properties of the composites first increase and then decrease.The tensile properties of nanoZnO/PLA/PBAT(2/70/30)composites are the highest at 18.6MPa,nanoZnO/PLA/PBAT composites exhibited typical linear rheological behavior under rotational rheometer test.The other groups of composite materials did not produce new absorption peaks and intensity changes,did not change the chemical structures of PLA and PBAT,and the addition of nano-ZnO did not change the crystal forms of PLA and PBAT.The effect of nano-ZnO/PLA/PBAT composites with different nano-ZnO mass fractions on the antibacterial properties of Escherichia coli was studied.With the increase of the mass fraction of nano-ZnO in the composite,the antibacterial rate of the nano-ZnO/PLA/PBAT(2/70/30)composite was the highest,reaching 93.92±0.67%;One-way ANOVA analysis showed that the antibacterial rate of Escherichia coli was significantly different between the content of nano-ZnO and the composite material(P<0.05).The contact angle and water absorption increased with the increase of nanoZnO content.gradually become hydrophobic.The degradation characteristics of the composites were studied by in vitro degradation method.Mouse myoblasts(C2C12)cells were selected as experimental cells,and nano-ZnO/PLA/PBAT with different mass fractions of nano-ZnO were studied by cell proliferation experiments and laser confocal microscopy.The biocompatibility of the composite material shows that the composite material degrades slowly in a simulated body fluid environment.When the nano-ZnO content is less than or equal to 2%,the toxicity rating of the composite material is in line with the toxicity rating of artificial bone implants.Under the laser confocal microscope,The cell morphology is complete,the cell viability is good,and it shows good biocompatibility.The nano-ZnO/PLA/PBAT composites prepared in this paper have potential application prospects in bone defect repair.