Autonomous biohybrid fish made from human stem cells, see it swim here

A new paper on the curious fish has been published in the journal Science.

Researchers from Harvard University and Emory University have developed a fully autonomous biohybrid fish using cardiac muscle cells derived from human stem cells. The cells can recreate the muscular contractions of a beating heart, allowing the fish to swim and bringing scientists closer to developing artificial cardiac muscle pumps to treat heart disease.

"Our ultimate goal is to build an artificial heart to replace a malformed heart in a child. Most of the work in building heart tissue or hearts, including some work we have done, is focused on replicating the anatomical features or replicating the simple beating of the heart in the engineered tissues," said Kit Parker, the Tarr Family Professor of Bioengineering and Applied Physics at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and senior author of the paper.

"But here, we are drawing design inspiration from the biophysics of the heart, which is harder to do. Now, rather than using heart imaging as a blueprint, we are identifying the key biophysical principles that make the heart work, using them as design criteria, and replicating them in a system, a living, swimming fish, where it is much easier to see if we are successful," Parker continued.

The fish's tail fin has two layers of muscle cells, one for each side. When one side's muscle layer contracts, the other stretches, which triggers a mechanosensitive protein channel to open, leading to a contraction. Consequently, the initial side is stretched, and a closed-loop system is created that propels the fish for more than a hundred days.

"Because of the two internal pacing mechanisms, our fish can live longer, move faster and swim more efficiently than previous work. This new research provides a model to investigate mechano-electrical signaling as a therapeutic target of heart rhythm management and for understanding pathophysiology in sinoatrial node dysfunctions and cardiac arrhythmia," said Sung-Jin Park, a former postdoctoral fellow in the Disease Biophysics Group at SEAS and co-first author of the study.

You can read more from the study here.