Bio-inspired microstructures in collagen type I hydrogel.

This article presents a novel technique to fabricate complex type I collagen hydrogel structures, with varying depth and width defined by a single fabrication step. This technique takes advantage of reactive ion etching lag to fabricate three-dimensional (3-D) structures in silicon. Then, a polydimethylsiloxane replica was fabricated utilizing soft lithography and used as a stamp on collagen hydrogel to transfer these patterns. Endothelial cells were seeded on the hydrogel devices to measure their interaction with these more physiologically relevant cell culture surfaces. Confocal imaging was utilized to image the hydrogel devices to demonstrate the robustness of the fabrication technique, and to study the cell-extracellular matrix interaction after cell seeding. In this study, we observed that endothelial cells remodeled the sharp scallops of collagen hydrogel structures and compressed the structures with low degree of slope. Such patterning techniques will enhance the physiological relevance of existing 3-D cell culture platforms by providing a technical bridge between the high resolution yet planar techniques of standard lithography with more complex yet low resolution 3-D printing methods.