Microscale 3-D hydrogel scaffold for biomimetic gastrointestinal (GI) tract model

Here we describe a simple and efficient method for fabricating natural and synthetic hydrogels into 3-D geometries with high aspect ratio and curvature. Fabricating soft hydrogels into such shapes using conventional techniques has been extremely difficult. Combination of laser ablation and sacrificial molding technique using calcium alginate minimizes the stress associated with separating the mold from the hydrogel structure, and therefore allows fabrication of complex structures without damaging them. As a demonstration of this technique, we have fabricated a microscale collagen structure mimicking the actual density and size of human intestinal villi. Colon carcinoma cell line, Caco-2 cells, was seeded onto the structure and cultured for 3 weeks until the whole structure was covered, forming finger-like structures mimicking the intestinal villi covered with epithelial cells. This method will enable construction of in vitro tissue models with physiologically realistic geometries at microscale resolutions.