Novel engineering efforts by a California Institute of Technology (Caltech) and Harvard University research team have yielded a tissue-engineered artificial jellyfish, dubbed Medusoid, that provides insight into the design of bioinspired pumps. The development represents a step forward in tissue engineering and could contribute to the eventual creation of a pacemaker featuring biological elements.
"A big goal of our study was to advance tissue engineering," says Janna Nawroth, a doctoral student in biology at Caltech and lead author of the study. "In many ways, it is still a very qualitative art, with people trying to copy a tissue or organ just based on what they think is important or what they see as the major components—without necessarily understanding if those components are relevant to the desired function or without analyzing first how different materials could be used."
Close-up of engineered cardiac muscle used to power the tissue-engineered jellyfish. The image shows the junction connecting the radial muscle in the engineered jellyfish lappet to the circular muscle of the main body. Photo Credit: Janna Nawroth (Caltech)
The researchers opted to focus on the jellyfish as a biological system subject because the manner in which it employs a muscle to move through the water resembles, on some level, the function of muscular pumps, such as the heart. Employing silicone as the base for the body, the team then printed a protein pattern onto the membrane that resembled the muscle architecture of actual jellyfish and provided a guide for growth of harvested heart muscle tissue from rats. Upon completion of the biological system, the team placed the synthetic jellyfish in an electrically conducting container and shocked it into 'swimming' via synchronized contractions akin to those of real jellyfish.
In light of this success of synthetic biology, the researchers believe that their approach could someday influence the reverse engineering of muscular organs in humans and the development of engineered systems using biological materials. In fact, the team hopes to next design a self-contained system capable of sensing and actuating based on its signals. Eventually, it also aims to explore the use of the systems as the foundation for a pacemaker equipped with biological elements.
"As engineers, we are very comfortable with building things out of steel, copper, concrete," says Kevin Kit Parker, Tarr Family Professor of Bioengineering and Applied Physics at Harvard and a coauthor of the study. "I think of cells as another kind of building substrate, but we need rigorous quantitative design specs to move tissue engineering from arts and crafts to a reproducible type of engineering. The jellyfish provides a design algorithm for reverse engineering an organ's function and developing quantitative design and performance specifications. We can complete the full exercise of the engineer's design process: design, build, and test."