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. An engineered protein-based material that can be used to replace damaged tissue in humans has been created by scientists in Singapore and China. The cells in our body are supported by a three-dimensional extracellular matrix. Creating artificial tissue that can replace this matrix when it is damaged or diseased requires biomaterials that have uniform porosity, thin walls and mechanical durability. Now, Nam-Joon Cho from Nanyang Technological University in Singapore and co-workers have created a gelatin hydrogel that supports cells while allowing them to maintain their vital functionality. This three-dimensional scaffold has uniform pore interconnectivity, structural stability and tailorable degradation properties. The team created it by using a colloidal templating microfabrication technique and a material called gelatin methacryloyl. The biomaterial provided cells with attachment sites as well as improved cell function over previous two-dimensional approaches. We demonstrate the fabrication of three-dimensional, highly ordered protein-based hydrogel platforms for tissue engineering applications. The combination of colloidal templating microfabrication strategies and highly substituted, photocrosslinkable gelatin methacryloyl (GelMA) protein allowed us to fabricate inverted colloidal crystal (ICC) scaffolds with uniform pore interconnectivity, high structural stability and tailorable degradation properties. The resulting scaffolds provided cell attachment sites and promoted intercellular interaction among hepatocytes, which resulted in improved cell function compared to a flat, two-dimensional system. The results demonstrate the potential of GelMA ICC scaffolds to become an effective tissue engineering platform for drug screening and regenerative medicine applications.