The Construction Of Hard Tissue Implants Based On Antimicrobial Peptide And Its Antimicrobial Activity

Due to its excellent mechanical property,biocompatibility and corrosion resistance ability,titanium has been widely used in clinical implant materials.However,it exists bacterial infection problems in application.Bacterial infection does not only bring a heavy financial burden to the patients,but also endangers patients' health,causes disabilities and even death.Combining antimicrobial agents to construct antimicrobial implant surfaces is an effective way to prevent such bacterial infections.Nowadays,the most common antimicrobial agents are metal ions and antibiotics.However,the pathway of metal ions is not clear and might be accumulated in body.Antibiotics have the risk to produce drug-resistant bacteria.Therefore,it is a hot spot to combine new antimicrobial agents to build antimicrobial titanium implants.With excellent antimicrobial property,biodegradability in vivo and hard to produce drug-resistant bacteria,antimicrobial peptides have been concerned widespread by researchers.In this study,after using a variety of methods to study the antimicrobial mechanism,different innovative ways were used to construct antimicrobial peptide coating by combing antimicrobial peptide from the interface of implant and bone tissue.The mainly results and contents were as follow:(1)An antimicrobial fluorescent probe with aggregation-induced emission property was synthesized to research the interaction between peptides and bacteria in situ,and researched the site of action,efficiency and action of antimicrobial peptide via its unique fluorescence property.Meanwhile,in order to further study the antimicrobial property of selected antimicrobial peptide,SEM,AFM and TEM were chosed to study the effect of peptide on the morphology change of bacterial surface before and after add of peptide.(2)The anodic oxidation was used to fabricate nanotube structure in situ on the titanium surface.Co-loading method was chosen to load antimicrobial peptide and RGD peptide into the nanotube to construct multifunctional sustained-release system.The nanotubes exhibited excellent antimicrobial peoperty and biocompatibility when the molar ratio of AMP to RGD was 1:2.The implants had long-term antimicrobial activity,and with continue antimicrobial 4 times,they still had more than 70%antimicrobial ability.(3)The anchor-peptide was introduced to construct self-assemble antimicrobial peptide to form stable antimicrobial coating.Moreover,OEG molecule chain was introduced to maintain its antimicrobial activity.The antimicrobial titanium implants had excellent antimicrobial property and stability in vitro and in vivo.Moreover,the designed peptide could not only be assembled onto titanium,but also onto other materials.(4)After the successful research of click reaction onto silicon substrate,this method was also used to form antimicrobial layer onto titanium surface via this method.In addition,RGD peptide with promoting cell adhesion ability was selected to co-graft,and regulate the ratio between different peptides to prepare the materials with different antimicrobial property and biocompatibility.When the ratio of AMP to RGD in the reaction system was 1:4,the constructed material showed excellent antimicrobial property and biocompatibility.The above work provides a theoretical basis and method to research the antimicrobial mechanism of new antimicrobial peptide,offers new thoughts and methods to solve the clinical infection caused by surgical implantation.Moreover,it also presents new theoretical basis for reducing bacterial infection.