Interpenetrating polymer networks (IPN), either semi-IPN (s-IPN) or full IPN, based on a natural polymer tannic acid (TA) and synthetic poly(acrylamide) (p(AAm)) were prepared by incorporation of TA during p(AAm) hydrogel film preparation with and without crosslinking of TA simultaneously. The synthesis of p(AAm/TA) s-IPN and IPN hydrogels with different amounts of TA were prepared by concurrent use of redox polymerization and epoxy crosslinking. The p(AAm)-based hydrogels were completely degraded at 37.5 degrees C within 9 and 2 days at pHs 7.4 and 9, respectively. Biocompatibility of p(AAm), s-IPN, and IPN were tested with WST assay and double staining, they had 75% cell viability up to almost 20 mu g mL(-1) concentration against L929 fibroblast cell. Antioxidant properties of IPN and s-IPN hydrogels were investigated with a:: and ABTS(-) methods. Antimicrobial properties of TA-containing s-IPN, and IPN hydrogels were determined against three common bacterial strains, Escherichia coli ATCC 8739, Staphylococcus aureus ATCC 6538, and Bacillus subtilis ATCC 6633, and it was found that p(AAm/TA)-based s-IPN and IPN hydrogels are effective antimicrobial and antioxidant materials. Moreover, almost up to day-long linear TA release profiles were obtained from IPN and s-IPN hydrogels in phosphate buffer solution at pH 7.4 at 37.5 degrees C. (C) 2015 Wiley Periodicals, Inc.