Curcumin-ZnO nanocomposite mediated inhibition of Pseudomonas aeruginosabiofilm and its mechanism of action

Multidrug-resistance and strong biofilm formation potential of P. aeruginosamakes it a severe risk to public health and nanoparticles/nanocomposites find potential applicability to address this crisis. Curcumin is a potential anti-biofilm/antibacterial molecule that is limited due to large sized particle, reduced water solubility and decreased bioavailability. In this study, curcumin-ZnO nanocomposite was synthesized and its anti-biofilm efficacy as well as mechanism of action against P. aeruginosabiofilm was investigated. Here, using the FTIR peaks, the novel structure of curcumin-ZnO nanocomposites was established and using that as ligand the potential anti-biofilm drug targets were identified followed by superoxide anion, lipid peroxidation, cell viability and TEM analysis to reveal its mechanism of anti-biofilm action. Here, curcumin-ZnO nanocomposites at 300 μg/mL dosage having suitable particle size (110.51 nm), improved zeta potential (−22.3 mV), reduced hydrodynamic size (253.2 nm) were more efficiently able to penetrate through biofilm matrix and bind to P. aeruginosa'scell membrane through the OprM-MexAB receptor and inhibit its growth and biofilm (efficacy = 49.36% compared to control) than ZnO nanoparticle (42.38% compared to control). Curcumin-ZnO nanocomposites could efficiently inhibit P. aeruginosabiofilm by mechanisms involving increased superoxide anion generation by 48.94% possibly due to catalase and rubredoxin-rubredoxin reductase inhibition that mediated increased bacterial membrane lipid peroxidation by 183.75% thus causing severe disintegration of cell membrane and increased cell death by 25.18% compared to control. Curcumin-ZnO nanocomposites can thus be considered as a capable anti-biofilm drug candidate against P. aeruginosainfections.