Visible Light Photoinitiation of Cell Adhesive Gelatin Methacryloyl Hydrogels for Stereolithography 3D Bioprinting

We present the first cell attachable and visible light crosslinkable hydrogels based on gelatin methacryloyl (GelMA) with eosin Y (EY) photoinitiation for stereolithography 3D bioprinting. In order to develop visible a light crosslinkable hydrogel, we systematically studied five combinations of the GelMA and EY photoinitiator with various concentrations. Their mechanical properties, microstructures, and cell viability and confluency after encapsulation were investigated rigorously to elucidate the effects of the EY and GelMA macromer concentration on the characteristics of the hydrogel. Experimental results show that the compressive Young’s Modulus and pore size are positively affected by the concentration of EY, while the mass swelling ratio and cell viability are negatively affected. Increasing the concentration of GelMA helps to improve the compressive Young’s Modulus and cell attachment. We further employed the developed visible light-based stereolithography bioprinting system to print the patterned cell-laden hydrogels to demonstrate the bioprinting applications of the developed hydrogel. We observed good cell proliferation and the formation of a 3D cellular network inside the printed pattern at day 5, which proves the great feasibility of using EY-GelMA as the bioinks for biofabrication and tissue engineering.