Harvard University scientists build autonomous 'robot fish' using human heart cells

In a bid to study heart diseases like arrhythmia, Harvard researchers have developed the first fully autonomous biohybrid fish using human stem-cell-derived cardiac muscle cells. The 'robot fish', as the picture shows, has two strips of human heart cells and swims by recreating the muscle contractions of a pumping heart. According to Harvard University experts, this development has brought them one step closer to developing a more complex artificial muscular pump. 

The artificial fish is inspired by the shape and swimming motion of a zebrafish and has the human heart cells on each side of the tail fin, as seen in the picture above. The researchers explained that when on one side of the fin contract, the other stretches propelling the fish which makes it appear as if it's swimming. 

Developers explain their aim behind the biohybrid fish

Harvard professor and senior author Kit Parker of the paper published in the journal Science, said as per the university's report, "Our ultimate goal is to build an artificial heart to replace a malformed heart in a child." 

Parker told The Daily Beast that until now, most of their work has focused on replicating the simple beating of the heart in the engineered tissues. "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," he added. 

The latest development builds on the previous research from Parker’s Disease Biophysics Group which developed a jellyfish-like biohybrid pump using cardiac muscle cells from rats in 2012 and an artificial stingray in 2016. Moreover, the fish can also control the frequency and rhythm of these spontaneous contractions as the developers have engineered an autonomous pacing node, like a pacemaker. The researchers say that the biohybrid fish improves with age as they found the muscle contraction amplitude, maximum swimming speed, and muscle coordination increasing for the first month as the cardiomyocyte cells matured. 

Image: Harvard University/Michael Rosnach/Keel Yong Lee/Sung-Jin Park/Kevin Kit Parker