Breathing-in/breathing-out approach to preparing nanosilver-loaded hydrogels: Highly efficient antibacterial nanocomposites

The key objective of developing novel materials for hygienic living conditions is to lower the risk of transmitting diseases and biofouling. To this end, a number of silver-hydrogel nanocomposite systems are under development. In this study, we attempted a unique strategy to prepare silver-nanoparticle-loaded poly(acrylamide-co-N-vinyl-2-pyrolidone) hydrogel composites. To load nanosilver particles into such a nonionic hydrogel, a novel breathing-in/breathing-out (BI-BO) approach was employed. As the number of BI-BO cycles increased, the amount of the silver nanoparticles loaded into these hydrogels also increased. This behavior was obvious and was confirmed by ultraviolet-visible spectroscopy and thermal analysis. Furthermore, the hydrogel-silver-nanoparticle composites were confirmed with Fourier transform infrared spectroscopy and transmission electron microscopy studies. Antibacterial studies of these hydrogel-silver nanocomposites showed excellent results against Escherichia coli. The antibacterial activity increased with the number of BI-BO cycles, and samples that underwent three BI-BO cycles showed optimal bactericidal activity. The degree of crosslinking and the silver content had a great influence on the antibacterial efficacy.