Biosynthesis and Optimization of ZnO Nanoparticles Using Bacillus velezensis for the Control of Streptococcus mutans Biofilms

The development of novel, effective, and minimally side-effect antimicrobial agents for the control and prevention of oral biofilm formation is a major priority in dentistry. This study used the Taguchi design of experiments as a methodical technique to describe and optimize the biosynthesis of zinc oxide nanoparticles (ZnO-NPs) using Bacillus velezensis. Following synthesis, the produced nanoparticles were evaluated for their antibacterial activity against Streptococcus mutans (S. mutans), a significant oral pathogen. In this work, the effects of three factors, zinc nitrate concentration (۰.۲, ۰.۴, and ۰.۶ mg/mL), glucose concentration (۱.۵, ۳, and ۴.۵ mg/mL), and bacterial incubation time (۲۴, ۴۸, and ۷۲ h), were comprehensively examined to determine the ideal conditions for maximum nanoparticle yield and efficacy. The results revealed that the nanoparticles synthesized under experimental condition No. ۵ (containing ۰.۴ mg/mL zinc nitrate, ۳ mg/mL glucose, and a ۷۲ h incubation period) exhibited the highest antibacterial activity. These nanoparticles significantly inhibited bacterial growth, as indicated by a bacterial survival rate of ۰.۴۶ Log₁₀ CFU/mL upon exposure. The experimental findings demonstrated that ZnO-NPs synthesized under optimized conditions exhibited remarkable antibacterial activity against S. mutans. These results suggest that biosynthesized ZnO-NPs have substantial potential for clinical applications, particularly for the management and prevention of infections associated with bacterial biofilm formation in the oral cavity.

کلیدواژه ها:

Biosynthesis ، antibacterial ، Incubation time ، Zinc nitrate ، Glucose ، Zinc oxide nanoparticles