In his quest to better understand the human heart and heart disease, bioengineer Kit Parker from the Wyss Institute at Harvard University looked to the ocean. Since hearts move blood through bodies, and the majority of marine life utilizes muscular pumps and other anatomical structures that move water, perhaps the study of these creatures could provide new insight for cardiovascular medicine. While observing stingrays at the New England Aquarium he saw a connection and was inspired to create something on the cutting edge of science – a biologically-enhanced robot.
Parker’s team at the Wyss Institute started by creating a simple ribbed structure. Because it is flexible and bio-friendly, gold proved to be the perfect material. The ribbed “skeleton” was then coated with a thin layer of flexible polymer – creating a fin-like structure similar to a stingray’s. Over this polymer, the researchers carefully layered rat-derived cardiomyocytes (cardiac muscle cells) that were genetically modified to respond to light instead of the usual electrical signals from the nervous system.
When stimulated by pulses of light, the cardiomyocytes contract and push the polymer fins downwards. When the muscles relax, the curvature of the gold ribs in the opposite direction provides the counterforce to flex the fins upward. Turning is accomplished by stimulating one side of the body more strongly than the other, while speed can be adjusted by using different frequencies of light. The cardiomyocytes are living cells, so the artificial ray swims in a nutrient-rich solution to keep functioning. However, since the ray has no nervous, digestive, circulatory, perceptive or reproductive systems, the presence of these cells are the only thing that makes the ray related to living organisms.
Although this “bio-bot” doesn’t have useful real-world applications, it’s a successful proof-of-concept that could pave the way for new types of medical devices and more sophisticated biologically-enhanced machines.
Image attribution: Sung-Jin Park et al., 2016/Science