Preparation conditions and swelling equilibria of biodegradable hydrogels prepared from microbial poly(gamma-glutamic acid) and poly(epsilon-lysine)

Biodegradable hydrogels prepared by gamma-irradiation from microbial poly(amino acid)s are reviewed. pH-sensitive hydrogels were prepared by means of gamma-irradiation of poly(gamma-glutamic acid) (PGA) produced by Bacillus subtilis IF03335 and poly(epsilon-lysine) (PL) produced by Streptomyces albulus in aqueous solutions. The preparation conditions, swelling equilibria, hydrolytic degradation, and enzymatic degradation of these hydrogels were studied. A hydrogel with a wide variety of swelling behaviors has been produced by gamma-irradiation from a mixture solution of PGA and FL.