Synthesis of alginate based silver nanocomposite hydrogels for biomedical applications

Sodium alginate and poly(acrylamide-co-N-vinylcaprolactam-co- acrylamidoglycolic acid) based dual responsive semi-IPN hydrogels (SA-PAVA) were successfully synthesized by free radical redox polymerization. N, N′-Methylene-bis-acrylamide was used as a crosslinker and 5-fluorouracil, an anti-cancer drug, was loaded onto these semi-IPN hydrogels via equilibrium swelling method. The hydrogels were also used as templates for the production of silver nanoparticles by using NaBH₄ as reducing agent. In order to understand the polymer-drug interactions, pristine, as well as drug loaded, SA-PAVA hydrogels were characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry. The formation of silver nanoparticles was confirmed by UV-visible spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The swelling behavior of the hydrogel was investigated in distilled water under various pH and temperature conditions. In vitro release of 5-fluorouracil from these SA-PAVA hydrogels was carried out in gastro-intestinal fluids different temperatures. The SA-PAVA hydrogel/silver nanocomposites showed excellent anti-bacterial activity towards Escherichia coli and Bacilli.