What ingredients would you need to recreate the organ that enables you to digest your salad? According to Prof. John March, biological and environmental engineering, a 3-D printer would suffice. Together with researchers from his lab, March used 3-D printing technology to create a microscopic artificial small intestine. Unlike previous attempts, the Cornell device recreates the natural contraction and relaxation of muscles — peristalsis — in the small intestine. Without this fundamental feature, researchers have been unable to completely understand the biology that underlies the working of the organ.