The Preparation And Biological Evaluation Of Lactoferrin Composite Coating On Ti Implant

Titanium(Ti)and its alloys have been extensively applied in the bone joint replacement and dental fields on account of their excellent biocompatibility,high mechanical strength and corrosion resistance property.Nevertheless,studies have shown that the insufficient integration with the surrounding bone tissue and bacterial infections after surgeries were two major factors leading to the ultimate failure of the titanium implants.Therefore,taking a series of measures to modify titanium substrate surface to improve their bioactivities has been become a hot topic in the field of biomedical materials.Lactoferrin(LF),due to its excellent properties of broad-spectrum antibacterial property,promoting osteoblasts and inhibiting osteoclasts growth,was considered to be one of the most promising natural proteins in medical and biomaterial fields.In the present study,a polydopamine-assisted hydroxyapatite composites with lactoferrin coatings(PDA-HA-LF)were processed by a biomimetic approach and LBL technique,aimed to improving the integration of implants as well as inhibiting early bacterial infection.Firstly,dopamine converted to polydopamine on the surface of pure titanium by self-polymerization in alkaline conditions.Secondly,the treated samples were immersed in simulated body fluid for 7 days to form hydroxyapatite,which was fixed on the titanium surface by polydopamine.Finally,lactoferrin and carboxymethyl cellulose were alternately deposited as the outer layer of titanium substrate via spin-coating.The surface modification was tested and analyzed through field emission scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS)and water contact angle,respectively.The results indicated hybrid multilayers film has been successfully constructed.In vitro cell experiments including MTT,ALP,ECM mineralization,RT-PCR and TRAP strongly indicated that the the prepared composite multilayer(PDA-HA-LF)implants could efficiently regulate the biological behaviors of osteoblasts and osteoclasts.Additionally,the CLSM and MTT assay of bacteria shown that the adhesion and viabilities of both Staphylococcus aureus and Escherichia coli on modified Ti substrates were inhibited significantly at 6 and 12 h and it demonstrated PDA-HA-LF possessed a short-term antibacterial effect.Modified by biocomposite coating could improve the integration of Ti implants as well as inhibit bacteria adhesion,which had great significance to solve a series ofproblems in clinical application.This study will provide an effective method for the surface modification of titanium base materials and promote its further application in the field of bone joint replacement and tissue repair.