In vitro efficacy of green synthesized ZnO nanoparticles against biofilm and virulence of Serratia marcescens

Abstract

Zinc oxide reduced into nanosized exhibits antibacterial activity due to the interaction of ZnO with the cell surface and inside of the bacteria making them adaptive candidate for antibacterial activity. ZnO nanoparticles (ZnO NPs) synthesized using plant extract and their biomolecules makes them a safer, non-toxic and bactericidal solution against pathogenic bacteria. Till date, only few research articles are published on analysing the antibiofilm and anti-virulence activity of ZnO NPs synthesized using Ruellia tuberosa extract. Based on these literature survey, the present study was focused on synthesizing ZnO NPs using Ruellia tuberosa and efficacy to inhibit biofilm formation and virulence factor of Serratia marcescens. ZnO NPs at the concentration of 100 μg/mL showed highest antibacterial activity by reducing S. marcescens growth upto 4-fold (0.25 OD600nm) in comparison to untreated bacteria (1.8 OD600nm). ZnO NPs also showed 50% of inhibition of biofilm formation 25 μg/mL concentration. Microscopic analysis revealed the phenotypical change in the biofilm matrix formation after treating with >25 μg/mL of ZnO NPs. Prodigiosin, a quorum sensing regulated factor of S. marcescens was also inhibited >70% at 100 μg/mL concentration of ZnO NPs. Therefore, the present study shows the efficacy of green fabricated ZnO NPs to inhibit the growth, biofilm, and virulence factor of S. marcescens.