Synthesis of physically crosslinked PVA/Chitosan loaded silver nanoparticles hydrogels with tunable mechanical properties and antibacterial effects.

Limitation of antibacterial activity, low water vapour, oxygen permeation and mechanical strength are the disadvantages of existing wound dressings. The present research is focused on synthesis of Polyvinyl alcohol (PVA) and Chitosan (CH) hydrogels using freeze thaw process. The formation of AgNPs and PVA/CH hydrogels was confirmed by UV spectroscopy, particle size, morphology, spectral analysis, swelling studies, and in-vitro drug release studies. The particle size of AgNPs was found to be in the range of 20-35 nm with an intense peak at 430 nm. The results of spectral peaks showed that PVA/CH blend maintains characteristics peak of -OH and -NH in the spectrum with higher intensity. The morphology and tensile strength of hydrogels showed a wrinkled surface with an increase in force and extension values from 0.49 to 11.15 N and 45 to 129 mm, respectively. A controlled release of 84.3% (28 h) of Ocimum sanctum extract was noticed from hydrogel discs which scavenges 69.2% of free radicals as compared to raw extract 82.5% (16 h) which scavenges 63.1% of free radicals, respectively. The results of zone of inhibition (ZOI) against gram +ve and gram -ve bacteria was found to be 9.3 mm and 6.3 mm, respectively.