Swelling and biocompatibility of sodium alginate/poly(γ‐glutamic acid) hydrogels

Sodium alginate (Alg) hydrogel films were crosslinked with either calcium poly(γ‐glutamate) (Ca‐PGA) or CaCl₂. The hydrophilicity of the resulting hydrogel films was evaluated through swelling tests, water retention capacity tests, and water vapor permeation tests. The swelling ratio, water retention capacity, and the water vapor transmission rate (WVTR) of Alg/Ca‐PGA were higher than those of Ca‐Alg. The swelling ratio of Alg/Ca‐PGA was 651 and 190% at pH 7.4 and pH 1.2, respectively. The tensile strength of Alg/Ca‐PGA hydrogel was lower than that of Ca‐Alg. The results of hemocompatibility test showed that Alg/Ca‐PGA caused shorter activated partial thromboplastin time (APTT) than Ca‐Alg. Both Ca‐Alg and Alg/Ca‐PGA exhibited almost no adsorption of human serum albumin (HSA), whereas the adsorption of human plasma fibrinogen (HPF) of Ca‐Alg was 10 times of that of Alg/Ca‐PGA. In addition, Alg/Ca‐PGA exhibited platelet adhesion higher than Ca‐Alg. Furthermore, both Alg/Ca‐PGA and Ca‐Alg exhibited no cytotoxicity. Copyright © 2009 John Wiley & Sons, Ltd.