Controlled release of vascular endothelial growth factor from alginate hydrogels nano-coated with polyelectrolyte multilayer films

Abstract
Alginate (ALG) hydrogels incorporating vascular endothelial growth factor (VEGF) were nano-coated with polyelectrolyte multilayer (PEM) films composed of chitosan (CT) and dextran sulfate (DEX) in order to control the VEGF release from the hydrogels. When non- and nano-coated ALG hydrogels containing VEGF were incubated in phosphate-buffered saline (PBS) at 37°C for the prescribed times, the nano-coated hydrogels were stable, even after incubation for a week, whereas the non-coated hydrogels collapsed after 6 h. The release profile of VEGF from the non- and nano-coated ALG hydrogels was evaluated by an enzyme-linked immunosorbent assay (ELISA). Although all of the VEGF incorporated into the non-coated ALG hydrogels was released within 6 h by the collapse, only a few percent of the VEGF incorporated in the nano-coated hydrogels was released. Furthermore, the incorporated VEGF in the nano-coated hydrogels was released continuously, even after a month, without any initial burst release. The release percentag...