Gelatin-based hydrogel functionalized with taurine moieties for in vivo skin tissue regeneration

Functionalized hydrogels stimulate the migration and morphogenesis of endothelial cells (ECs) and are useful substrates for wound healing. The present study investigates the feasibility of covalent conjugation of taurine (Tau) on a gelatin-based hydrogel. This hydrogel is expected to maintain positive charged growth factors such as basic fibroblast growth factor (bFGF) and vascular endothelial growth factors (VEGFs) near ECs within the hydrogel microenvironment. The gelatin was conjugated with hydroxyl phenol (Ph) and Tau moieties, and in following that Ph residues were crosslinked through a horseradish peroxidase-catalyzed reaction. The migration characteristics of ECs were analyzed by scratch migration assay and microparticle-based cell migration assay. Cellular morphology and amounts of angiopoietin 1 (Ang 1), bFGF, and VEGF proteins were evaluated for encapsulated cells. The potential of synthesized hydrogels in wound healing was assessed by the percentage of reduction from the original wound size and histopathological analyses of rat skin. The incorporated Tau molecules within the hydrogel remained stable through covalent bonds during incubation. During extended incubation, the gelatin-based hydrogel conjugated with Tau improved the migration distance and number of existing migrated ECs. Immobilized Tau within the gelatin-based hydrogel induced high motility of ECs, accompanied by robust cytoskeleton extension and a cell subpopulation that expressed CD44 and CD31 receptors as well as enhancement of Ang 1, bFGF, and VEGF. We found that injectable Gel-Ph-Tau effectively improves wound-healing parameters. Graphic abstract