Biogenic synthesis of Zinc oxide nanostructures from Nigella sativa seed: Prospective role as food packaging material inhibiting broad-spectrum quorum sensing and biofilm

Abstract

Bacterial spoilage of food products is regulated by density dependent communication system called quorum sensing (QS). QS control biofilm formation in numerous food pathogens and Biofilms formed on food surfaces act as carriers of bacterial contamination leading to spoilage of food and health hazards. Agents inhibiting or interfering with bacterial QS and biofilm are gaining importance as a novel class of next-generation food preservatives/packaging material. In the present study, Zinc nanostructures were synthesised using Nigella sativa seed extract (NS-ZnNPs). Synthesized nanostructures were characterized hexagonal wurtzite structure of size ~24 nm by UV-visible, XRD, FTIR and TEM. NS-ZnNPs demonstrated broad-spectrum QS inhibition in C. violaceum and P. aeruginosa biosensor strains. Synthesized nanostructures inhibited QS regulated functions of C. violaceum CVO26 (violacein) and elastase, protease, pyocyanin and alginate production in PAO1 significantly. NS-ZnNPs at sub-inhibitory concentrations inhibited the biofilm formation of four-food pathogens viz. C. violaceum 12472, PAO1, L. monocytogenes, E. coli. Moreover, NS-ZnNPs was found effective in inhibiting pre-formed mature biofilms of the four pathogens. Therefore, the broad-spectrum inhibition of QS and biofilm by biogenic Zinc oxide nanoparticles and it is envisaged that these nontoxic bioactive nanostructures can be used as food packaging material and/or as food preservative.

Biofabrication of Zinc Oxide Nanoparticle fromOchradenus baccatusLeaves: Broad-Spectrum Antibiofilm Activity, Protein Binding Studies, andIn VivoToxicity and Stress Studies

“…The sub-MICs of OB-ZnNPs exhibited concentration-dependent inhibitory activity and all tested concentrations of OB-ZnNPs led to a statistically significant ( ≤ 0.05) reduction in violacein production of C. violaceum compared to that of the untreated control. Our findings on violacein inhibition are in accordance with reports with silver nanowires [45] and zinc oxide nanostructures synthesized from the seed extract of Nigella sativa [24].…”

“…From Figure 2(d), oxygen, carbon, and sulphur were found to be 13.47, 23.37, and 1.16%, respectively. Nanoparticles with similar morphology from Aloe barbadensis [22] and Nigella sativa [24] have been reported. Figure 2(e) at 30000x and 100000x magnification, respectively.…”

“…Our results are agreement with previously published report of Kalishwaralal et al [50], wherein biologically synthesized Ag nanoparticle (NPs) showed an antibiofilm activity against P. aeruginosa and S. epidermis. In an another study, Al-Shabib et al [24] demonstrated broad-spectrum biofilm inhibition in P. aeruginosa PAO1, E. coli 25922, L. monocytogenes, and C. violaceum 12472 after treatment with sublethal doses of zinc nanostructures synthesized from the seed extract of Nigella sativa.…”

“…After microwave processing, the solution was cooled to room temperature. The resulting precipitate was separated by centrifugation, then washed with deionized water and absolute ethanol several times, and dried in an oven at 80 ∘ C for 24 h. Finally, the product was calcined at 800 ∘ C for 2 h [24].…”

“…ZnO nanoparticles (ZnONPs) from plants have been synthesized using green chemistry approaches by several workers [22][23][24].…”