Colloidal templating of highly ordered gelatin methacryloyl-based hydrogel platforms for three-dimensional tissue analogues

Three-dimensional, protein-based hydrogel scaffolds that successfully mimic in vivo extracellular matrix microenvironments are desirable for tissue engineering and regenerative medicine applications, and can provide highly capable in vitro tissue analogues. However, the fabrication of protein-based scaffolds with uniform porosity, thin walls and durable mechanical properties remains a challenging prospect that might be overcome by integrating advances in microfabrication and protein functionalization. Towards this goal, herein, we report the successful fabrication of a highly ordered, gelatin-based inverted colloidal crystal (ICC) hydrogel platform that is robust and supports high levels of cell function. In particular, the utilization of colloidal templating microfabrication strategies together with highly substituted, photocrosslinkable gelatin methacryloyl (GelMA) allowed us to fabricate protein-based three-dimensional scaffolds with uniform pore interconnectivity, structural stability and tailorable degradation properties. The resulting GelMA ICC scaffolds provided cell attachment sites and promoted intercellular interaction of hepatocytes, which resulted in improved cell function compared to a flat 2D system. The results demonstrate the potential of GelMA ICC scaffolds to become an effective tissue engineering platform for drug screening and regenerative medicine.