Novel silver-loaded semi-interpenetrating polymer network gel films with antibacterial activity

Novel semi-interpenetrating polymer networks (SIPNs) based on segmented polyurethane-urea and poly(N-isopropylacrylamide-co-acrylic acid-co- butylmethacrylate) (poly(NIPAM-co-AA-BMA)) were synthesized for the fabrication of silver nanoparticles (AgNPs) in the SIPN system that could be useful for wound dressing applications. The obtained SIPN films, after neutralization, showed high swelling in aqueous environments and good mechanical properties in both dry and hydrated states. Analysis of the dried SIPN films by differential scanning calorimetry and dynamic viscoelastic measurements revealed the presence of crosslinked copolymers as well as homopolymers in the SIPN system. The neutralized swollen SIPN film, coordinated with the silver ions (Ag⁺) that were incorporated into it. AgNPs were subsequently formed by the reduction of Ag⁺. The formation of AgNPs was characterized by UV-visible spectroscopy, atomic force microscopy, wide-angle X-ray diffraction, and thermogravimetric analysis (TGA). Bactericidal activity tests revealed a distinct zone of microbial inhibition within and around the silver-doped SIPN films.