Green silver nanobioarchitectures with amplified antioxidant and antimicrobial properties

Abstract

Cornelian silver-based architectures were achieved from liposomes, silver nanoparticles (AgNPs) and single-walled carbon nanotubes (SWCNTs) by a “green” bottom-up strategy. Liposomes were prepared by a thin film hydration method and labelled with a natural porphyrin extracted from spinach leaves, cholorophyll a (Chla). Due to its strong visible absorption and fluorescence emission, this phytopigment was used as a spectral sensor to monitor any possible changes occurring in lipid membranes caused by the action of various agents. An aqueous extract from Cornus mas L. fruits was used for AgNP phytosynthesis. Addition of appropriate amounts of phytonanosilver particles and SWCNTs to biomimetic membranes resulted in biohybrid material with good physical stability (ZP = −34 mV) and high antioxidant activity (AA = 97.8%). Moreover, they have been shown to be a strong biocide having diameters of inhibition zones of 18.3 mm, 23.8 mm and 21.6 mm against Escherichia coli ATCC 8738, Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212, respectively. Chla rapidly sensed the modifications that occurred in artificial lipid bilayers as a result of interactions with silver nanoparticles and carbon nanotube surfaces indicating the biohybrid formation, and these results were supported by AFM analysis. The bioconstructed hybrid material consisting of biomimetic membranes, phyto-nanosilver and SWCNTs could be applied as an antimicrobial and antioxidant coating.