Coating HA And Grafting BFP On PEEK With Promoted Bioantivity

Objective:Due to its excellent compatibility,corrosion resistance property and appropriate mechanical strength,polyether-ether-ketone(PEEK)has become a promising biomaterial candidate to replace conventional metallic implants made of titanium(Ti)and its alloys which is applied for bone defect repair resulting from tumors,trauma,cancer,disease or congenital deformity.However,the bioinert nature of PEEK,which is not sufficient to achieve successful osseointegration in the human body hampers its clinical applications.In this study,we have tried to coat Hydroxyapatite(HA)through technique of Polydopamine-assisted hydroxyapatite formation(pHAF)and immobilize synthetical peptide(BFP)by the assistance of polydopamine on the surface of 3D printed PEEK,and explored the influence on bioantivity of double modified PEEK.Methods:Soaked 3D printed PEEK(named as PEEK)in polydopamine(PDA)solution(pH = 8.5)for 24 hours,took them out and named as PDA-PEEK.Then transferred PDA-PEEK into 1.5 simulated body fluid(SBF)for 7 days.PDA-PEEK was coated with HA and named as HA-PEEK.HA-PEEK was soaked in PDA solution for 24 hours and named as PDA/ HA-PEEK.PDA/ HA-PEEK was transferred into BFP polypeptide solution to complete grafting BFP and named as HA-BFP-PEEK.Samples were divided into five groups: PEEK,PDA-PEEK,HA-PEEK,PDA/HA-PEEK and HA-BFP-PEEK.Water contact angles of each group were measured to determine the hydrophilicity.The surface microstructure was observed under scanning electron microscope(SEM).The composition of surface chemical elements from each group was analyzed by X-ray electron spectroscopy(XPS).The samples were co-cultured with osteoblast-like cells MG63.Cell adhension and proliferation was detected by CCK-8;alkaline phosphatase(ALP)activity and alizarin red staining was carried out to assess osteogenic activity.Results:1.PEEK had the largest contact angle(P<0.05).After modification,contact angle of each group had decreased variously,and HA-BFP-PEEK’s was the smallest(P<0.05).A large number of spherical aggregates were observed on the surface of sample coated with HA under SEM,liked flowers with typical HA structure.EDS analysis showed that the aggregate was composed of Ca and P elements.In the XPS test,PEEK group was detected strong C and O absorption peaks,while PDA-PEEK group presented obvious N absorption peaks.In addition to the C,O and N elements,significant Ca and P absorption peaks were observed on the surface of HA-PEEK,PDA/HA-PEEK and HA-BFP-PEEK.The HA-BFP-PEEK group surface had the highest N absorption peak.2.Compared with pure PEEK,groups with modification had significantly enhanced cell adhesion,proliferation,ALP activity and calcium nodules formation(P<0.05).Furthermore,HA-BFP-PEEK was significantly better than the other groups(P<0.05).The bioactivity of PEEK after double modification had been obviously improved.Conclusion:1.This study successfully coated HA and grafted BFP on the surface of 3D printed PEEK,achieved the goal of double modification for PEEK.The whole process of our method is simple immersion,and can meet the modification requirements of 3D printed materials.This method has the advantages of low cost,low technical requirements and good repeatability,and is expected to provide a new surface modification strategy for PEEK.2.The double-modified PEEK has good biocompatibility,its surface changes from biological inertness to biological activity,and the osteogenesis is accelerated.HA and BFP may have a synergistic effect,jointly promoted the osteogenesis of MG 63,which would facilitate the formation of osseointegration,and provided a new theoretical basis for the better application of PEEK in clinical practice.