Injectable thermoresponsive hydrogel/nanofiber hybrid scaffolds inducing human adipose-derived stem cell chemotaxis

Abstract

Hydrogels with three-dimensional networks similar to extracellular matrix (ECM) have been widely investigated as biomaterials in tissue engineering. Injectable hydrogels have been studied for less invasive treatments, and moreover, the endogenous cell recruitment capability can create synergy with these hydrogels for repairing damaged tissues. However, their low mechanical properties or difficult process has been a disadvantage for their use in load-bearing cartilage such as intervertebral disc. Therefore, high-modulus injectable hydrogels which have the potential in cell recruitment are required for fundamental and less invasive treatments. In this study, we fabricated injectable and thermoresponsive hybrid scaffolds comprising chitosan/gelatin hydrogel and polycaprolactone nanofibers, and we added platelet-derived growth factor-BB (PDGF-BB) within the hybrid scaffolds to recruit human adipose-derived stem cells (hADSCs). The modulus of the hybrid scaffolds was approximately 0.9MPa after gelation at 37℃ with structural similarity to the ECM. Also the modulus could be managed by changing the concentration of the components in the hybrid scaffolds. The release of PDGF-BB from the hybrid scaffolds induced hADSC chemotaxis under rough condition which chemoattractant was diluted by serum free cell culture medium. Our proposed hybrid scaffolds are promising candidates for less invasive tissue engineering strategies to induce endogenous hADSC recruitment.