The Research Of Osteogenic Modification With BFP-1 Peptide Via Polydobamine On Surface Of Polyetheretherketone Nano Composites

After implanted, implants will directly interact with the surrounding bone tissues through their surface. The surface properties of implants can influence the bone cell adhesion, proliferation and differentiation; lastly determine the quality of bone integration. Therefore, it’s an important factor for the success of implant operation. For improving the success rate of clinical implant, the implants should have good biocompatibility and decent mechanical properties; also need to have osteogenic activity to form good bone integration with the surrounding bone tissue. Our research group prepared of PEEK/CF/n-HA composite materials by adding bioactive HA and high strength of CF. Although its more matches on the mechanical properties of the bone tissue, can avoid stress concentration that could lead to bone resorption, implants loose etc. But the PEEK/CF/n-HA composite lack the good biocompatibility and good bone integration. Therefore, it is necessary to seek a better method for surface modification. Using protein and peptide fragments as a biological activity of biological material is currently one of the hotspot in the research of tissue engineering. Research proves that bioactive proteins and polypeptides (such as collagen and fibronectin, RGD peptides or bone morphogenetic proteins, etc.) can promote the activity of cells, adhesion, proliferation and differentiation. Proteins have some problems such as immunogenicity and easy to decompose. However, peptide fragments can synthetic more easily, no immunogenicity, and also has the function of the activity of biological macromolecules, of RGD domain structure that intercepted from proteins had been reported that has the function of promoting cell adhesion, in the research of the bone morphogenetic proteins (BMPs), Hyung Keun Kim, etc extracted a polypeptide from the mature section structure of BMP 7, named BFP1.After the detection of in vivo and in vitro, found the osteogenic activity of BFP1 is superior to BMP-7.In order to obtain a better osteogenic activity of PEEK composites, this study used the strong adhesive attraction of polydopamine to functionalize the PEEK composites surface. After the aqueous solution of dopamine oxidation polymerization-crosslinking reaction, the surface of PEEK composites form a rich in catechol groups of polydopamine composite layer. Catechol reactive ability of secondary reaction, will grafted the bone forming peptide (BFP1) to the surface of PEEK composites, which has good mechanical properties and improve the osteogenic activity of PEEK composites. This study will grafted the bone forming peptide (BFP1) to the surface of PEEK composites after dopamine coating. We analysis the functionalized PEEK composites surface by scanning electron microscopy (SEM), atomic force microscope (AFM), deionized water contact Angle and X-ray photoelectron spectroscopy (XPS). The changed surface of the chemical elements, hydrophilic, surface microtopography and chemical groups demonstrated the PEEK composites surfaces have been modified. In vitro cell experiment tested the functionalized surface of the material was more conducive to cell adhesion and proliferation, and no cytotoxicity, explained functionalized modifications to improve the biological activity of material. Through real time quantitative PCR, immunofluorescence, alkaline phosphatase activity experiments. We proved that the functionalized surface were better for the human bone marrow mesenchymal stem cell differentiation. According to the results of in vivo, the BFP1 modified surface had more bone integration with the surrounding bone tissue.These results fully illustrates the bone forming peptide (BFP1) based on polydopamine not only changed the surface properties of PEEK composites and biological activity but also maintained the osteogenesis activity of the peptides. Osteogenesis functionalized modifications improved the cell compatibility of PEEK composites and osteogenesis differentiation, and can promote the integration of implants with the bone in vivo. Functionalized biomaterial through polydopamine is a reliable, easy and safe method for material surface modification.