Bioactive photocrosslinkable resin solely based on refined decellularized small intestine submucosa for vat photopolymerization of in vitro tissue mimics

Three-dimensionally (3D) printed tissue mimics are unique in vitro platforms for studying human pathophysiology in a more physiologically relevant manner compared to oversimplified 2D cell cultures and complex animal models. However, their 3D printing requires an availability of materials that at the same time show a high level of biomimicry and also have a suitable viscosity profile and crosslinking kinetics for the desired printing technique. We developed a new biomimetic material for vat photopolymerization by solubilizing and functionalizing porcine small intestine submucosa (dSIS) into photocrosslinkable dSIS methacryloyl (dSIS-MA) and by subsequently formulating it into a bioactive 3D printing resin. The concentration of 1.5 wt% of dSIS-MA yielded desired viscosity and photocrosslinking kinetics, and the 3D printing of the resin resulted in fully transparent and highly swelling dSIS-MA hydrogels with a stiffness resembling native intestinal tissue. The new dSIS-MA resin was successfully 3D printed into acellular intestine-mimicking scaffolds that desirably guided the seeded human intestinal cells to grow along the 3D villi mimics. Human small intestinal organoid-derived undifferentiated primary cells grew to confluency on the dSIS-MA hydrogels and formed continuous tight junctions, thereby demonstrating the suitability of the 3D printing material for growing intestinal epithelium mimics. Furthermore, a small fraction of the human primary intestinal cells produced mucin 5AC, demonstrating early differentiation of these cells on the dSIS-MA hydrogels. The excellent cell compatibility of the dSIS-MA material combined with its high printability and biomimicry indicated that this new resin can be a great help in modelling and reproducing native tissue architectures where enhanced physiological relevancy is desired.