Phototunable Gelatin-Based Hydrogels as Cell Scaffolds for Modulating Cell Adhesion on Hydrogel Surfaces

The objective of this study was to design a light-responsive gelatin acrylate hydrogel for tunable cell-material interactions for tissue engineering applications. Hydrogels are widely used as cell scaffolds owing to their high water retention and cell encapsulation capabilities. Stereolithography techniques allow for the precise three-dimensional (3D) printing of hydrogels, creating complex tissue scaffold models. To enhance the limited tunabilities of 3D hydrogel cell scaffolds, photodegradable hydrogels that are responsive to light irradiation are known to enable controlled degradation and tunability, thereby promoting their application in tissue engineering. In this study, a photodegradable gelatin acrylate was synthesized by incorporating o-nitrobenzyl acrylate into the gelatin backbone, and the photodegradation behavior of the resulting gelatin acrylate hydrogel was evaluated using microsized patterned light irradiation to demonstrate the modulation of a limited area of the gelatin acrylate hydrogel surface. When human mesenchymal stem cells (hMSCs) were seeded on the light-irradiated hydrogel, cell spreading was enhanced by ca. 16-52%, whereas cell attachment decreased by ca. 25-40% compared with the unirradiated area of the hydrogel. These results suggested that the prepared gelatin acrylate hydrogel serves as a phototunable cell scaffold for fine-tuning biological microenvironments enabling postfabrication modulation that contributes to future regenerative medicine applications such as dynamic cell migration and vascular tissue modeling.