Abstract
Creating a functional intestine model remains challenging owing to the complex topography of the intestinal crypt/villus structure. Here, an inverse molding biofabrication technique is presented to address this challenge. A sacrificial hydrogel mold (SHM) with negative crypt/villus features is first fabricated using digital light processing (DLP) 3D printing of poly(ethylene glycol)-norbornene-tyramine (PEGNB-T) thiol-norbornene hydrogels. Next, decellularized small intestine submucosa-norbornene (dSIS-NB) solution is cast and photopolymerized over the SHM, also via efficient thiol-norbornene photoclick reaction using PEG-tetrathiol as the crosslinker. The hydrogel construct is placed in a buffer solution to induce autonomous and rapid dissolution of the SHM, creating dSIS-NB hydrogels with the positive crypt/villus structure. Intestinal epithelial cells seeded on the dSIS-NB crypt/villus matrices form a confluent monolayer within 3 days and display correct intestinal polarity. Through transepithelial electrical resistance (TEER) measurements and macromolecular transport studies, the new inverse-molded dSIS-NB crypt/villus model further demonstrates the selective and drug-responsive barrier functions. Finally, the unique biofabrication technique is leveraged to create an intestinal disease model carrying regions of both healthy crypts-villi structure and flattened epithelium with hindered macromolecular transport.