Researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences have developed a technique that allows them to 3D print a heart ventricle, that can then go on to beat rhythmically. The technology could allow researchers to create heart models to test new cardiac drugs and may even pave the way for fully implantable cardiac components. The method involves using rotary spinning to create small fibers that are then infused into a printable hydrogel ink. When 3D printed, this ink retains its printed structure, and cardiomyocytes within it align along the direction of the included fibers. When stimulated using electricity, the structure beats along the orientation of the fibers, giving the researchers plenty of control over its behavior. The technique could unlock more advanced cardiac models for drug testing, and could also permit personalized medicine for cardiac patients.
Bioengineering offers huge potential in replacing diseased tissues, but a nice side benefit as we progress towards being able to accurately recapitulate such tissues in the lab is the creation of advanced in vitro models for drug testing and personalized medicine. Cardiac patients are poised to benefit from such advances with this latest technology, which uses fiber-infused gel (FIG) ink as the medium for 3D printing of cardiac components.
“People have been trying to replicate organ structures and functions to test drug safety and efficacy as a way of predicting what might happen in the clinical setting,” said Suji Choi, a researcher involved in the study. “This concept is broadly applicable – we can use our fiber-spinning technique to reliably produce fibers in the lengths and shapes we want.”
The approach first involves using rotary spinning to create thin gelatin fibers, which is somewhat akin to the way that cotton candy is created. A postdoctoral researcher involved in the project called Luke MacQueen had the idea that infusing such fibers into a printable hydrogel ink could help it to maintain its shape after printing.
“When Luke developed this concept, the vision was to broaden the range of spatial scales that could be printed with 3D printers by dropping the bottom out of the lower limits, taking it down to the nanometer scale,” said Kit Parker, a researcher involved in the study. “The advantage of producing the fibers with rotary jet spinning rather than electrospinning is that we can use proteins that would otherwise be degraded by the electrical fields in electrospinning.”
Once printed, cardiomyocytes within the gel align along the fibers and will beat in that orientation once stimulated using electricity.
Study in journal Nature Materials: Fibre-infused gel scaffolds guide cardiomyocyte alignment in 3D-printed ventricles