Chapter 11 - Efficacy of green synthesized silver nanoparticles (AgNP) over crude plant extract of Allium cepa and standard antibiotic against bacterial biofilms

Abstract

Biofilms are the dense population of bacterial cells that occur when microorganisms irreversibly adhere to both biotic and abiotic objects with the help of pili and by extracellular polymeric substances (EPS). EPS provides nutrients to the developing bacterial cell and leads to pathogenicity. In fact several biofilm associated infections are caused by providing resistance to host immune responses and antibiotic treatment. Hence an alternative strategy of using plant extract and green synthesized nanoparticles has led to reassessment of ancient remedies. We intend to study the antibiofilm activity of aqueous extract of Allium cepa and green synthesized silver nanoparticles from crude extract of Allium cepa in comparison with standard antibiotic, for example, ciprofloxacin on both Gram-negative (Pesudomonas aeruginosa ATCC 1014) and Gram-positive (Staphylococcus aureus ATCC 0352) bacterial biofilms. In this study green synthesized nanoparticles showed considerable zone of inhibition in comparison to that of crude extract of Allium cepa and Ciprofloxacin. The studies showed that green synthesized silver nanoparticles (AgNPs) from Allium cepa brought about maximum inhibition to the sessile communities of S. aureus and P. aeruginosa in comparison to allicin and ciprofloxacin. The in silico studies also recealed that AgNPs were able to interact maximally with the biofilm forming protein. Thus AgNPs can be an efficient alternative to treat biofilm associated infections.