Cell interaction with protein-loaded interpenetrating networks containing modified gelatin and poly(ethylene glycol) diacrylate

The effects of modification to an interpenetrating network (IPN) system composed of gelatin and poly(ethylene glycol) diacrylate were characterized by protein release kinetics, fibroblast adhesion, and in vivo host response. The maximum cumulative percent of parvalbumin released from various IPN formulations ranged from 17.6±3.2% to 56.9±35.4% over 2–96 h. Despite modifying gelatin with ethylenediaminetetraacetic dianhydride and/or monomethoxy poly(ethylene glycol) monoacetate ester or increasing the gelatin content, the largest amount of parvalbumin released occurred within 24 h, prior to material bulk degradation. Over the time period evaluated, little (i.e. <1%) of the basic fibroblast growth factor (bFGF) loaded into the IPNs evaluated was released, independent of modifications made to the IPN formulation. Fibroblast adhesion to IPNs with or without loaded bFGF was quantified. The adherent fibroblast density on the IPNs was significantly lower than that of TCPS controls at all times independent of the IPN formulation tested and bFGF loading. Select IPN formulations elicited a comparable level of acute and chronic inflammatory response in vivo when compared with the gelatin and poly(ethylene glycol) diacrylate starting materials. IPNs provide a minimal cell-active surface that could be employed as delivery matrices and for further bioconjugation to mediate specific cellular response.