Research On The Antibacterial Activity Of Drug-loaded Modified PMMA Resin Base Surface

Objective:To prepare KSL liposome loaded with antibacterial peptide and PMMA resin base modified with cefotaxime sodium,and study the cytotoxicity and antibacterial properties of functionalized base surface.Methods:KSL liposomes loaded with antibacterial peptides and cefotaxime sodium were covalently modified on the surface of PMMA resin base with polydopamine as medium.X-ray photoelectron spectroscopy,scanning electron microscopy and static contact angle were used to evaluate the elemental composition,surface morphology,hydrophilicity and hydrophobicity of the functionalized surface;MTT assay was used to detect the effect of functionalized surface on the proliferation of mouse fibroblasts L929.The antimicrobial activity of the functionalized surfaces against Candida albicans and Streptococcus mutans was evaluated by film close-sticking method,microbial activity test kit and bacterial live/dead staining method.Results:(1)Material characterization of drug-loaded modified PMMA resin baseThe composition of surface chemical elements of PMMA modified by different drug loading was analyzed by XPS.The main elements of PMMA were C and O,the content of C decreased and the content of N increased after PMMA modified by PDA,because dopamine contained amino-NH2,and the content of S on the surface of PMMA modified by cephalosporin increased obviously,which indicated that cefotaxime sodium was successfully grafted.The content of P on the surface of PMMA modified by liposome increased obviously,which indicated that the modification of liposome was successful;From SEM images,the surface of PMMA modified by PDA was rougher than that of PMMA without any modification,which proved that PDA was successfully modified.The surface of PDA-PMMA is the roughest after being grafted with Cephalosporin and liposome at the same time;The results of static contact angle showed that the surface of PMMA modified by the drug had a significant effect on the surface hydrophilicity(p<0.05).Material characterization confirmed that KSL liposome loaded with antibacterial peptide and cefotaxime sodium were successfully modified on the surface of PMMA resin base.(2)Research on the cytotoxicity of drug-loaded modified PMMA resin base Surface.The results of MTT assay showed that the functional drug-loaded surface had no significant effect on the proliferation of L929 cells(P>0.05);By calculating the RGR value of L929 cells,the RGR of each group was ≥94%,The results of cytotoxicity test showed that the corresponding cytotoxicity level of PMMA modified by different drugs were all 0-1,and the biosafety was qualified,which indicated that PMMA modified by drugs did not affect cell proliferation,and the surface of modified materials had good cell compatibility.(3)Research on the Antibacterial Activity of Drug-loaded Modified PMMA Resin Base Surface.The experimental results of film close-sticking method showed that the functionalized surface-modified KSL liposomes and the PMMA resin base of cefotaxime sodium had obvious antifungal effects on the Candida albicans;The results of microbial kit showed that the functionalized surface-modified antimicrobial peptide KSL liposomes and the PMMA resin base of cefotaxime sodium had significant bacteriostatic effect on Streptococcus mutans(p<0.05);The antibacterial activity of KSL liposome and PMMA resin base of cefotaxime sodium against Streptococcus mutans and Candida albicans were confirmed by fluorescence staining.Conclusion:The antibacterial activity of PMMA resin base surface can be enhanced by KSL liposome and cefotaxime sodium.Functional modified PMMA has a great prospect of clinical application in stomatology.