Medical 3D printer for inside the human body

Researchers have long been developing 3D bioprinting technology to print cells in structures that can be implanted in the body. Now, bioengineer Tao Xu and colleagues at Tsinghua University in Beijing have built a tiny 3D printing robot mounted on an endoscope that's inserted into the body where it squirts out cell-laden gels. Thus far, they've only tested the device on a plastic model of a human stomach but hope the device can eventually be used to patch gastric ulcers among other applications. From Scientific American:

The resulting micro robot is just 30 millimeters wide—less than half the width of a credit card—and can fold to a length of 43 millimeters. Once inside a patient's body, it unfolds to become 59 millimeters long and can start bioprinting. "The team has constructed clever mechanisms that make the system compact when entering the body yet unfurl to provide a large working area once past the tight constrictions at entry," says David Hoelzle, a mechanical engineer at the Ohio State University, who did not take part in the study[…]

Future research could bring the micro robot down to 12 millimeters wide and equip it with cameras and other sensors to help it perform more complex operations, Xu adds. 

More in their technical paper: "Preliminary engineering for in situ in vivo bioprinting: a novel micro bioprinting platform for in situ in vivo bioprinting at a gastric wound site" (Biofabrication)