Yanping He1, Richard Bright2, Krasimir Vasilev3, Peter Zilm4
1 Adelaide Dental School, University of Adelaide, Adelaide SA 5000, Australia, yanping.he@adelaide.edu.au, 2 College of Medicine and Public Health, Flinders University, Bedford Park SA 5042, Australia, richard.bright@flinders.edu.au, 3 College of Medicine and Public Health, Flinders University, Bedford Park SA 5042, Australia, krasimir.vasilev@flinders.edu.au, 4 Adelaide Dental School, University of Adelaide, Adelaide SA 5000, Australia, peter.zilm@adelaide.edu.au
Abstract:
Dental caries is a non-communicable disease, mediated by a multispecies biofilm that consists of high levels of acidogenic bacteria which ferment sugar to acid and cause teeth demineralization. Current treatment practice remains insufficient in addressing 1) rapid clearance of therapeutic agents from the oral environment 2) destroying bacteria that contribute to the healthy oral microbiome. In addition, increasing concerns over antibiotic resistance calls for innovative alternatives. In this study, we developed a pH responsive delivery system for polycationic silver nanoparticles. Branched-PEI capped silver nanoparticles were encapsulated in a tannic acid − Fe (III) complex-modified poly(D,L-lactic-co-glycolic acid) (PLGA) particle (Fe(III)-TA/PLGA@BPEI-AgNPs) to enhance binding to the plaque biofilm and demonstrate “intelligence” by releasing BPEI-AgNPs under acidic conditions that promote dental caries. The constructed Fe(III)-TA/PLGA@BPEI-AgNPs (intelligent particles − IPs) exhibited significant binding to an axenic S. mutans biofilm grown on hydroxyapatite. Ag+ ions were released faster from the IPs at cariogenic pH compared to pH 7.4. The antibiofilm results indicated that IPs can significantly reduce S. mutans biofilm volume and viability under acidic conditions. Cytotoxicity on differentiated Caco-2 cells and human gingival fibroblasts indicated that IPs were not cytotoxic. These findings demonstrate great potential of IPs in the treatment of dental caries.