Antimicrobial efficacy of polyurethane foams impregnated with amba turmeric mediated silver nanoparticles

The state-of-art studies on polyurethane foams (PUF) focuses on evaluating its structure, qualities, and applications lacking it antimicrobial capability. In this study the pristine and pretreated PUF of varying densities were impregnated with green synthesized silver nanoparticles (AgNPs) using Amba turmeric (AT) to broaden the application spectra of PUF with antimicrobial capability. The pretreated PUFs were ineffective against Escherichia coli (E. coli) used as a model pathogen for evaluating the antimicrobial efficiency. On the other hand, high-density pristine foams (HDF) demonstrated bactericidal activity with 1.2 log reduction after 30 min treatment. NPs coated pristine foams showed antimicrobial efficacy in the order of high-density > medium-density > low-density. Scanning electron microscopy (SEM) revealed the bactericidal impact of coated HDF on lysed bacterial cells with pits in the cell membrane. Energy-Dispersive Spectroscopy (EDS) analyses of live and dead bacterial cells also demonstrated elemental changes (absence of P, Cl, and Ca and drop in C) induced by the nanoparticle treatment. Bio-interface process study revealed that the affinity of positively charged NPs for E. coli was observed via confocal laser scanning microscopy (CLSM). Remarkably, in cell concentrates containing MDF and LDF with limited antibacterial efficacy, live bacterial aggregates were observed next to the NP-bacterial interface. NP-mediated clustering of E. coli can be correlated with quorum sensing, rendering MDF and LDF ineffective against bacteria. The proposed NP coated pristine high-density foam can be effectively utilized in industries where aseptic environment is required. [Display omitted] •Green synthesized AgNPs via Amba turmeric was probed on different density PUFs.•E coli was found susceptible against AgNPs coated on high density pristine foam.•NPs-bacterial interface had live bacterial aggregates and low concentration of NPs in LDF and MDF allowed NP tolerance in bacteria•The NPs coated HDF (pristine) can be utilized in medical facilities for sterile environment.