In The Wizard of Oz, the Tin Man famously sang, “If I only had a heart . . . “ Although the Tin Man had to be satisfied with a heart-shaped clock, researchers reporting in ACS’ Nano Letters have now created a miniature cyborg heart that produces electrical signals like the human version. But instead of implanting the organoid into a robot, the researchers plan to use it to study heart development, diseases and therapeutics.
To better understand complex organs like the heart and brain, scientists would like to implant sensors that could continuously monitor cellular activities throughout the entire 3D structure of an organ over a long period of time. However, implanting or injecting such devices directly into a living organ could destroy intricate cellular networks, and the sensors wouldn’t penetrate into all regions. Therefore, Jia Liu at the School of Engineering and Applied Sciences at Harvard and his colleagues wanted to incorporate nanoelectronics into human tissue to produce a miniature cyborg heart, outside of the human body.
The researchers made the cyborg heart by placing a soft, stretchable mesh of nanoelectronics over a sheet of stem cells growing in a dish. The cells grew around and through the mesh, covering it completely. By adding certain substances, the team triggered the stem cells to fold into a 3D shape, about the size of a pencil eraser, and transform into cardiac tissue that beat just like a real heart. The researchers used the embedded nanoelectronics to take electrophysiological recordings during the formation of the organoid, which could shed light on how the human heart develops. Further work on cyborg organoids could provide a “paradigm-shifting platform” to study organs of all types in health and disease, as well as to develop and test new therapeutics, the researchers say.
The authors acknowledge funding from the Harvard Dean’s Competitive Fund for Promising Scholarship and the facility at the Harvard University Center for Nanoscale Systems supported by the National Science Foundation.