Macrophage adhesion on gelatin-based interpenetrating networks grafted with PEGylated RGD

Human blood-derived macrophage adhesion on interpenetrating networks (IPNs) composed of PEGylated RGD-modified gelatin and poly(ethylene glycol) diacrylate was studied. The interaction between biomaterial immobilized with biofunctional peptides such as RGD and macrophages is central in the design of tissue-engineering scaffolds. PEGylated RGD-modified gelatin was synthesized via several steps involving PEG derivations and characterized by high-performance liquid chromatography, mass spectroscopy, gel permeation chromatography, and the trinitrobenzenesulfonic acid method. IPNs containing modified or unmodified gelatin were cultured with human macrophages and monitored at 2, 24, 96, and 168 h. At each time point, IPNs containing gelatin modified with PEGylated RGD showed a comparable adherent macrophage density as tissue culture polystyrene and a significantly higher cell density than other IPN formulations containing unmodified gelatin or gelatin modified with PEGylated triglycine. Although surface-immobilized RGD can serve to mediate the adhesion of different cell types on the biomaterial surface, the interaction of RGD with immune/inflammatory cells such as macrophages should also be considered when assessing the potential host response of tissue-engineering scaffolds.