Development of Thiol–Ene Reaction-Based HA Hydrogel with Sustained Release of EGF for Enhanced Skin Wound Healing

This study develops a novel drug delivery system using a hyaluronic acid (HA) hydrogel for controlled release of epidermal growth factor (EGF) to enhance skin wound healing. Conventional hydrogel-based methods suffer from a burst release and limited drug delivery times. To address this, we employ bioconjugation to introduce an acrylate group to EGF, enabling chemical bonding to the HA hydrogel matrix through thiol-ene cross-linking. This approach results in sustained-release delivery of EGF based on the degradation rate of the HA matrix, overcoming diffusion-based limitations. We confirm the introduction of the acrylate group using matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry. We evaluated the hydrogel morphology and rheological properties following binding of acrylate-conjugated EGF to the HA matrix. Assessment of the EGF release profile demonstrates delayed release compared to unconjugated EGF. We evaluate the impact on cells through cell proliferation and scratch assays, indicating the system's efficacy. In a rat wound healing model, the sustained release of EGF from the hydrogel system promotes appropriate tissue healing and restores it to a normal state. These findings suggest that this practical drug delivery system, involving the modification of growth factors or drugs to chemically bind healing factors to hydrogels, can achieve long-lasting effects.