Employing a glutathione-s-transferase-tag and hyaluronidase to control cytokine retention and release from a hyaluronic acid hydrogel matrix

Abstract

Thiolated hyaluronic acid can be combined with poly-(ethylene glycol)-diacrylate to generate a self-polymerizing hydrogel with potential applications as an injectable depot for targeted drug delivery. There is a specific need for formulations that can incorporate and control the delivery of protein-based biologics over time. In this investigation, the incorporation and release of recombinant human granulocyte macrophage-colony stimulating factor and interleukin-4 from a commercial hyaluronic acid-based hydrogel was initially examined. The release profile was rapid; essentially complete within the first 4–24 h. However, addition of a glutathione-s-transferase-tag to these cytokines reduced their initial bolus release and extended the retention to more than three days. Hypothesizing a direct interaction of the glutathione-s-transferase-tag with poly-(ethylene glycol)-diacrylate, we observed a concentration-dependent slowing of cytokine release and prolonged retention as poly-(ethylene glycol)-diacrylate concentration was increased. Hyaluronidase was then added to promote a controlled degradation and independently modulate release rate and duration. The effects were concentration-dependent, resulting in a flexible hydrogel platform in which loading and release can be independently adjusted to meet a range of delivery needs. When injected in vivo, a localized cytokine reservoir was created and exhibited the same features as observed in vitro. These findings identify a tunable platform for the targeted local delivery and controlled release of protein-based biologics.