Biosynthesized selenium nanoparticles enhance antibiofilm properties of PMMA resin for dental applications.

This study investigates the development of biosynthesized selenium nanoparticles (SeNPs) and their integration into polymethyl methacrylate (PMMA) resin to create a new material with enhanced antimicrobial properties. SeNPs were successfully synthesized using Bacillus subtilis (B. subtilis) BSN313 and thoroughly characterized. Analysis confirmed spherical SeNPs (250-600 nm) with a negative zeta potential (-26.9 mV), indicating moderate colloidal stability, and FTIR spectroscopy identified bacterial proteins and polysaccharides as capping agents. The incorporation of the optimal concentration of 15 % (w/w) SeNPs significantly improved PMMA's physical attributes. Surface roughness decreased notably from 0.42 to 0.45 μm in pure PMMA to 0.12-0.16 μm in the composite. Hydrophilicity increased, with the water contact angle dropping from 88° to 72°. The composite demonstrated high thermal stability with no significant degradation up to 300 °C. Antimicrobial assays revealed strong activity against Streptococcus mutans (S. mutans), Pseudomonas aeruginosa (P. aeruginosa), and Candida albicans (C. albicans) (MICs: 100-200 μg/mL), effectively inhibiting and dispersing biofilms. PMMA discs (10 mm diameter × 2 mm thickness) containing SeNPs achieved significant reductions in biofilm biomass after 48 h-60 % for S. mutans, 54 % for C. albicans, and 53 % for P. aeruginosa. Crucially, stability studies over 90 days confirmed no detectable SeNP leaching, indicating strong nanoparticle immobilization, and consistent antimicrobial efficacy. These findings highlight SeNP-modified PMMA's potential as a durable, biocompatible material for biomedical and dental applications, offering sustained resistance to microbial adhesion and biofilm formation.