Green synthesis of TA@AgNPs and their use as antimicrobial agents in PVA/Collagen biofilms for potential wound dressing applications

In this research, tannic acid-decorated silver nanoparticles (TA@AgNPs) were prepared in situ in aqueous media. Tannic acid (TA) was used as a green reducing and stabilizing agent for AgNPs. The prepared TA@AgNPs were characterized by different techniques, including FTIR, XRD, and TEM. The prepared TA@AgNPs were incorporated into polyvinyl alcohol (PVA)/collagen (CO) biofilms plasticized with glycerol to be used for wound dressing applications. The PVA/CO biofilms were prepared by mixing their aqueous solutions at a weight percentage of PVA/CO (4:1) using the casting method. The physicomechanical properties and swelling behavior of the prepared PVA/CO biofilms containing TA@AgNPs at different concentrations were also measured. The antimicrobial activity of PVA/CO biofilms containing TA@AgNPs was assessed using the agar method against different gram-positive ( Staphylococcus Aureus and Bacillus Subtilis ), gram-negative ( Escherichia Coli ) bacteria, and fungi ( Candida Albicans and Aspergillus Niger ). A control sample free of TA@AgNPs was used for comparison. The obtained results demonstrated PVA/CO biofilms with adequate tensile properties and fast swelling behavior in aqueous buffer media (PBS, pH = 7.4), which is a basic requirement for wound dressing application. Surprisingly, the PVA/collagen biofilm (blank) showed antibacterial activity against all gram-positive bacteria investigated and Candida Albicans fungus. In addition, all PVA/collagen biofilms containing TA@AgNPs showed significant and more effective antibacterial activity against all bacteria investigated (gram-positive and gram-negative) and Candida albicans fungus as compared with the blank biofilm.