The Fabrication And Immunomodulatory Osteogenic Effect Of Zinc-Modified Porous Polyetheretherketone Surface

Polytheretherketone(PEEK)is thought to be one of the most promising orthopedic implants due to its excellent mechanical properties.However,poor biocompatibility and osteointegration hinder its widely clinical application.Some studies have reported that a surface porous coating obtained by sulfonation on PEEK can improved the biocompatibility,but the osteointegration of PEEK was not enhanced significantly.Herein,we incorporated zinc,an osteogenic and immunomodulatory element,on the surface of surface porous PEEK through magnetron sputtering to improve the osteointegration of PEEK,and further investigated the immunomodulatory effect of zinc.Zinc-incorporated surface porous PEEK(Zn-SPEEK)was successfully prepared through sulfonation and magnetron sputtering.Scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS)were used to determine the surface morphology and element distribution of Zn-SPEEK.Atom force microscopy and X-ray photoelectron spectroscopy were employed to detect the 3D morphology and element valence of Zn-SPEEK.Then the cell biocompatibility was evaluated by SEM,cell viability test and flow cytometer.Regarding the immunomodulatory effect of Zn-SPEEK,we first examine the gene expression profile of macrophage cultured on samples using RNA-seq.Immunofluorescence,flow cytometer and ELISA were used to determine the subtype of macrophages and its cytokines.To acquire the immunomodulatory osteogenic effect of Zn-SPEEK,we performed alkaline phosphatase(ALP)and alizarin red staining,immunofluorescence and RT-PCR tests.Finally,the in vivo air pouch model and bone defect repair model were built to validate the immunomodulatory and osteogenic activity of Zn-SPEEK.Our results indicated that Zn-SPEEK showed good biocompatibility and can modulate macrophage polarizing to M2 phenotype,secreting osteogenic cytokines to generate a microenvironment favoring osteogenesis both in vitro and vivo.Therefore,we concluded that zinc-incorporated surface porous PEEK(Zn-SPEEK)can be prepared through sulfonation and magnetron sputtering.The favorable biocompatibility and immunomodulatory osteogenic effect of Zn-SPEEK pave the way for its further application as orthopedic implants.