Despite their efficient antimicrobial activity, the cytotoxicity of antimicrobial implants, including AMP-based implants, remains a concern. The enriched antimicrobial agents on the surface reduced the biocompatibility, angiogenic activity and osteogenic activity of the implant, further delayed sufficient osseointegration and increased the risk of in vivo infection. To balance the antimicrobial and osseointegration associated activities, versatile antimicrobial implants with easily adjustable bioactivities are highly desirable. However, most of the current implants require external stimuli, including electricity, light and temperature, which are difficult to be conducted in vivo. Therefore, the “statically-versatile” implant with nonessential external stimuli would greatly facilitate the in vivo applications. In recent years, fusion peptides (FPs) with different bioactive se-quences have attracted much attention as they can exhibit versatile biological behaviors simultaneously, which can efficiently tackle the challenge of simple immobilization of the peptide mixtures with limited immobilization sites and uncontrollable space or orientation of peptides. Particularly, the FP on the implant surface can equivalently increase the grafting density of the specific peptides by occupying less reaction sites, demonstrating that FPs would be greatly advantageous for the development of a statically-versatile implant. However, to the best of our knowledge, the desired FP-engineered titanium implant that can fulfill the clinical requirements of antimicrobial activity and all of the abovementioned osseointegration-associated activities (biocompatibility, angiogenic activity and osteogenic activity) has never been reported.
Considering the osseointegration-associated activities, vascular endothelial growth factor (VEGF) mimetic peptides become potential candidates for the sequence of FP. VEGF is an important growth factor in modulating angiogenesis. It can greatly improve the migration and proliferation of endothelial cells and promote vascularization. As the high immunogenicity and low stability of VEGF, many VEGF-mimetic peptides were developed, such as QK with 15 amino acids to mimic the helix region 17–25 of VEGF. It can bind VEGF receptor, and further induce the improvement of angiogenesis. But it has been seldom proved that QK has osteogenic activity as VEGF. In the present study, we developed a “statically-versatile” titanium implant through immobilizing a designed FP containing HHC36 (AMP) sequence and QK sequence on implant surface.
Recently, Professor Wang Yingjun from South China University of Technology reported the preparation of a “statically-versatile” titanium implant, which is coating with fusion peptides(FPs), it has antibacterial, osteogenic and angiogenic activities. The coating can increase the antibacterial properties of the implant and reduce postoperative infections。Also, it has good angiogenesis and osteogenic properties, which can speed up the osseointegration efficiency of implants, and is of great significance for clinically to reduce the incidence of biological material infections.