Synthesis and characterization of silver nanoparticles capped Guar Gum-co-Polyacrylonitrile hybrid nanocomposite: Anti-quorum sensing and anti-biofilm potential against food-borne pathogenic bacteria.

Biofilms are implicated in roughly 80% of chronic and 65% of acute bacterial infections. Therefore, targeting QS-regulated virulence and biofilm presents a potential strategy for the development of novel antimicrobials. In this investigation, AgNPs-capped Guar Gum-co-Polyacrylonitrile hybrid (GPAG) nanocomposites were synthesized biogenically by modifying guar gum (GG) chains chemically with polyacrylonitrile (PAN) chains, resulting in a copolymer matrix with suitable capping sites preventing the aggregation of Ag NPs during the synthesis of GPAG. Chemical and structural properties of the synthesized GPAG were determined using various techniques like XRD, XPS, UV-Vis spectroscopy, SEM and TEM. Characterization studies revealed successful Ag NPs formation in the matrix of GG-co-PAN matrix and GG has been copolymerized by PAN chains with an average particle size of 16 nm. GPAG demonstrated antimicrobial potential in terms of MIC against Escherichia coli ATCC 25922, Pseudomonas aeruginosa PAO1, Chromobacterium violaceum ATCC 12472, Listeria monocytogenes ATCC 19114, and Serratia marcescens MTCC 97. The effect of GPAG on quorum-sensing (QS) revealed a significant reduction in QS-regulated production, such as production of violacein, pyoverdine, pyocyanin, rhamnolipid, elastase, and prodigiosin. Further, GPAG impaired biofilm formation (58%-77%) and reduced established biofilm (43%-53%) along with the significant reduction of EPS, CSH and exoprotease. Thus, GPAG is effective in curbing drug resistance, while also offering utility in controlling biofilm-related food spoilage and ensuring food safety.