A Study Of Constructing Novel Chimeric Peptides To Prevent Peri-implantitis

Objective:Bacteria adhesion and biofilm formation are the primary causes of implant associated infection,which is difficult to eliminate and may induces failures in dental implants.Additionally,the oral implant penetrates through the bone tissue,soft tissue and oral environment,and the good cuff closure at the implant-soft tissue interface is a prerequisite for the protection of the underneath osseointegration of implant-bone tissue interface.When the biological barrier of the soft tissue is destroyed,the bacteria and the inflammatory factors would invade along the implant-soft tissue interface to destroy the osseointegration of the implant,which eventually leads to the failure of implant repair.The chimeric peptides with both binding and antimicrobial motifs may provide a promising alternative to inhibit the biofilm formation on titanium surfaces.In this study,chimeric peptides with antimicorbial capacity or fuction of reinforcing biological sealing around implant were constructed,which may provide new ideas to prevent peri-implant mucositis and peri-implantitis.Methods:Antimicorbial chimeric peptides were designed by connecting antimicrobial motif（JH8194:KRLFRRWQWRMKKY）with binding motif（minTBP-1:RKLPDA）directly or via flexible/rigid Linkers to modify Ti surfaces.We evaluated the binding behavior of peptides by using quartz crystal microbalance（QCM）and Atomic Force Microscope（AFM）techniques and XPS,and investigated the effect of modification of titanium surfaces with these peptides on the bioactivity of P.gingivalis,S.gordonii and S.sanguis.Moreover,we designed novel chimeric peptides to modify Ti surfaces by connecting LNA3G3P with minTBP-1.Then,the connections formed by a rigid Linker with anα-helix structure（EAAAK）₄ and a representative flexible GS Linker（GGGGS）₄ were compared.A series of in vivo and in vitro experiments were conducted to verify the effect of chimierc peptides on reinforcing biological sealing around implant.Finally,the effects of different Linkers on the optimal design of chimeric peptide were investigated by in silicon methods.Results:Compared to the chimeric peptides without Linkers,the Linker inserted peptides significantly increased the adsorption of the chimieric peptide on titanium surfaces（p<0.05）.The concentration-dependent adsorption accords with a single Langmuir model,while the time-dependent adsorption is in line with a two-domain Langmuir model.Also,the chimeric peptide with the rigid Linker exhibited a more effective antimicrobial ability than the one with the flexible Linker.This could be ascribed to that the Linker and minTBP-1 can separate the functional domains and reduce their interference to the maximum extent.The novel chimeric peptides was successfully designed and tested.One end in each of them specifically adsorbed onto Ti surfaces to firmly bind to Ti implants;the other end interacted with OEC surface receptors to activate the integrin signaling pathway and initiate HD assembly,thereby enhancing epithelial sealing around implants.Conclutions:Consequently,the performance of chimeric peptides with specific titanium-binding motif and functional motif can be optimized by a proper selection of Linkers.This rational design of chimeric peptide provides a promising alternative to inhibit the biofilm formation on titanium surfaces with the potential to prevent peri-implantitis and peri-implant mucositis.Through a series of in vitro and in vivo experiments,we verified the chimeric peptide’s effect on promoting soft tissue closure and explored its mechanism of action.This study summarized the chimeric peptide design rules in order to provide experimental evidence for the prevention of peri-implant mucositis and peri-implantitis in clinical practice and for improving the long-term success rate after implantation.