Cocktail Approach\nwith Polyserotonin Nanoparticles\nand Peptides for Treatment of Streptococcus mutans

Dental\nplaque, formed by a Streptococcus mutans biofilm, is a major contributor to cavity formation. While antimicrobial\nstrategies exist, the growing risk of antibiotic resistance necessitates\nalternative therapeutic solutions. Polyserotonin nanoparticles (PSeNPs),\nrecently recognized for their photothermal property and promising\nbiomedical applications, open up a new avenue for antimicrobial use.\nHere, we introduced a UV-initiated synthetic route for PSeNPs with\nimproved yield. Using these PSeNPs, a cocktail treatment to reduce\nthe viability of this cavity-causing bacteria was developed. This\ncocktail comprises an S. mutans-targeting\nantimicrobial peptide (GH12), an intraspecies competence-stimulating\npeptide that triggers altruistic cell death in S. mutans, and laser-activated heating of PSeNPs. The “peptide + PSeNP\n+ laser” combination effectively inhibits S.\nmutans growth in both planktonic and biofilm states.\nMoreover, the cocktail approach remains effective in reducing the\nviability of S. mutans in a more virulent\ndual-species biofilm with Candida albicans. Overall, our results reinforce the utility of a multipronged therapeutic\nstrategy to reduce cariogenic bacteria in the complex model oral biofilm.