| Objective:In this study,the surface of polytheretherketone(PEEK)was modified by low temperature plasma treatment of argon and oxygen mixture and combined with polydopamine(PDA)coating.With the assistance of PDA,silver ions were reduced to Ag nanoparticles(Ag NPs)and deposited on the surface of modified PEEK.The biocompatibility and antimicrobial properties of PEEK modified by nano-silver coating were estimated in vitro.Methods:(1)PEEK was treated with a mixture of 30% oxygen and 70% argon plasma for 25 min to construct the nano topological morphology on the surface.(2)The surfaces of PEEK modified by plasma were coated with polydopamine.Then the specimens reacted with different concentrations of silver ammonia solution using the reductivity of PDA to prepare the nano-silver coating on the surface.(3)The microstructure of the material was observed by scanning electron microscope(SEM).The water contact angle of each sample was measured by contact angle tester.The element changes of each specimen were detected by X-ray photoelectron spectroscopy(XPS).(4)Using PEEK as the control group,mouse fibroblasts(L929)were co-cultured with extracts of samples and the cytotoxicity was detected by CCK-8 reagent.L929 cells were co-cultured with the samples and the adhesion of cells on the surface of the samples was observed by DAPI staining.(5)The samples of each group were co-cultured with Staphylococcus aureus and Escherichia coli.The bacterial on the surface of materials was detected by SEM and plate colony counting method,and the antibacterial properties were evaluated.Results:(1)After oxygen and argon plasma treatment,depressions of different sizes were detected by SEM on the surface of PEEK.The plasma modified PEEK surface was uniformly coated with PDA.The uniform distribution of Ag NPs can be observed on the surface of the coated group samples.The water contact angle of treated samples significantly decreased after plasma modification.The water contact angle decreased after PDA coating.The contact angle of samples coated with nano-silver was less than the PEEK group.XPS test results showed that C and O elements could be detected on the untreated surface of PEEK.And C and O elements could be detected on the surface of the specimen modified by plasma.The surface modified by PDA coating could detect C,O and N elements.The surface modified by nano-silver coating could detected C,O,N and Ag element. (2)CCK-8 cytotoxicity test results showed that the cell proliferation rate of each group was more than 90%,indicating that the nano-silver modified materials did not have cytotoxicity.The results of DAPI staining showed that the number of cells adhered to the surface of the specimen modified by nano-silver coating was less than that of PEEK groups.(3)The bacterial experimental results showed that the nano-silver coating could inhibit the adhesion of Staphylococcus aureus and Escherichia coli on the surface of PEEK.It was proved that PEEK modified with nano silver coating has good antibacterial properties.Conclusions:(1)The surface of PEEK was treated by a mixture of oxygen and argon gas plasma and combined with a polydopamine coating.Under the action of PDA,the nano-silver coated surface of modified PEEK was successfully constructed.(2)PEEK coated with Ag NPs did not have cytotoxicity and exhibited good antibacterial properties against Staphylococcus aureus and Escherichia coli. |
