Phd in INNOVATIVE TECHNOLOGIES IN DISEASES OF
SKELETON, SKIN AND ORO-CRANIOFACIAL DISTRICT

Thesis title: POTERE ANTIMICROBICO DI UNA FORMULAZIONE A BASE DI PROPOLI, POLLINE E NANOPARTICELLE DI OSSIDO DI ZINCO

In a clinical context increasingly challenged by antibiotic resistance, interest in alternative strategies is growing. In this study, an innovative formulation combining propolis, pollen, and zinc oxide nanoparticles (ZnO NPs) was developed and evaluated for its antimicrobial activity, antibiofilm efficacy, and biocompatibility. The incorporation of ZnO NPs into the matrix was confirmed by scanning electron microscopy, and antimicrobial activity was assessed against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. The formulation significantly inhibited S. aureus and P. aeruginosa, reducing viability by up to 85% and biofilm formation by 50% and 40%, respectively. In C. albicans, PrPoZnO reduced growth by 90%, inhibited biofilm formation by 60%, and suppressed the yeast-to-hyphae transition, a key virulence factor. Biocompatibility assays on several cell lines revealed no cytotoxic effects even at the highest concentrations, supporting its potential for biomedical use. Mechanistically, PrPoZnO modulated oxidative stress responses, lowering ROS levels in bacteria while inducing ROS generation in C. albicans, suggesting that ZnO NPs play a key role in causing mechanical damage to microorganisms. Overall, these findings indicate that the formulation represents a natural and biocompatible antimicrobial candidate, with potential applications in pediatric endodontics—for example, as an intracanal medicament in the treatment of primary teeth or as a component of temporary filling materials with prolonged antimicrobial activity. The results warrant further preclinical and clinical investigation.