In vitro and in silico investigation of anti-biofilm activity of Citrus macroptera fruit extract mediated silver nanoparticles

Abstract

Bacteria produce biofilm not only to infect the host and spread into a new substratum but also protect themselves against conventional antibiotics. Green silver nanoparticles (AgNPs), having exceptional antimicrobial activity, have developed as an alternative to conventional synthetic medications to treat numerous issues concerning bacterial infections mainly caused by biofilm development. In the present study, we have therefore described the green synthesis of Citrus macroptera (CM) fruit extract stabilized silver nanoparticles (CM-AgNPs) and explored their potential antibiofilm activity. The particles have been conventionally characterized. Moreover, protein-corona and antibiofilm activity are evident from numerous studies including DLS and AFM (e.g. reduction of the roughness of biofilm >90%). CM-AgNPs shows surface plasmon resonance (SPR) peak at 434 nm. They are spherical (16 nm), crystalline (FCC) and anionic (zeta potential (ζ) −27.5 mV) in nature. Raman spectral data suggests that the phytochemicals in the juice extract are chemically adsorbed onto the surface of AgNPs. CM-AgNPs effectively inhibit the growth of biofilm, formed by Bacillus subtilis and Pseudomonas aeruginosa. Molecular docking studies indicate strong binding interactions of CM-AgNPs with biofilm-forming proteins of B. subtilis and P. aeruginosa and the formation of the protein corona. Thus, the experimental findings and theoretical supports make the whole study informative regarding bacterial biofilm and suggest that the CM-AgNPs could be potential alternative therapeutics against infections involving biofilms.