Preparation and evaluation of visible-light cured glycol chitosan hydrogel dressing containing dual growth factors for accelerated wound healing

The visible light-cured glycol chitosan (GC) hydrogel systems for the sustained release of growth factors (GFs) were prepared, and their efficacies in wound healing acceleration were investigated. Vascular endothelial growth factor (VEGF) and platelet-derived growth factor-BB (PDGF-BB) were selected as the dual GFs and commercially available Duoderm^® was used as control. In order to increase intermolecular chain mobility, methoxy (polyethylene glycol) acetic acid (MPEG-COOH) was conjugated to GC through condensation reaction resulting in MPEG grafted GC (MPEG-g-GC). As a crosslinker, glycidyl methacrylate was covalently conjugated to the amine group of MPEG-g-GC (MPEG/GM-g-GC), and crosslinking of MPEG/GM-g-GC chains were made by visible light irradiation (MPEG-g-GC hydrogels). To enhance wound healing efficacy, specific amounts of GFs was incorporated into the crosslinking solutions at this photo-curing stage (VEGF/MPEG-g-GC, PDGF/MPEG-g-GC and VEGF/PDGF/MPEG-g-GC). The grafting of MPEG plasticized the samples yielding low viscoelastic properties, ranging from 56 Pa to 58 Pa. In vitro release test showed that GFs were rapidly released within 24 h, and released in a sustained manner thereafter. In vivo studies showed that the GF-loaded samples further enhanced wound healing compared to control. Particularly, VEGF/PDGF/MPEG-g-GC, dual GFs releasing hydrogel, showed outstanding granulation effects among samples.