3D Bioprinting of Complex Cellular Alignment through Pre-aligned Anisotropic Microtissues

The gastroesophageal junction, where the esophagus empties into the stomach, is a unique structure in the body that presents a challenge to current tissue engineering processes. In addition to the common requirements of vascularization, innervation, and precise positioning of multiple types of cells, the muscular structure itself is highly complex in its alignment of smooth muscle bundles. Although much progress has been made in engineering the alignment of muscle cells in single directions, reconstituting structures of the complexity found in the gastroesophageal junction has not been demonstrated. This work provides a review of the gastroesophageal junction from the tissue-engineering perspective and presents a novel 3D bioprinting technique that could one day address this muscle alignment issue.