New biofabrication approach reveals importance of heart’s helical tissue structure

Using a new type of additive manufacturing called focused rotary jet spinning (FRJS) enabled researchers to make three-dimensional helically aligned biohybrid models of human heart tissue. Not only do the findings offer new insights into how the heart’s helical structure contributes to cardiac function, they also provide proof-of-concept for a streamlined approach to fabricating tissues and organs with complex 3D geometries. The heart’s pumping action comes from cardiomyocytes – the muscle cells of the heart – which are organized as helical fibers that enwrap the ventricles. With each beat, this arrangement results in a combined contracting and twisting motion. While the importance of torsion to the heart’s pumping efficiency has long been speculated, how the heart’s helical tissue structure relates to its function has been difficult to assess. Further, structural abnormalities resulting in altered ventricle twists have been linked to heart failure. To this end, understanding and replicating the helical structure of heart tissue is crucial. Here, Huibin Chang and colleagues present FRJS, an additive manufacturing approach that uses centrifugal jet spinning to rapidly form and deposit long thin fibers into complex 3D alignments. Because fibers like these can be used to direct tissue formation, FRJS enables the recreation of tissue anatomies that would be impossible through conventional biofabrication techniques. Chang et al. fabricated heart ventricles with similar structural properties to those in natural human hearts. They were also able to biofabricate models of diseased hearts with misaligned fiber orientations. Once the scaffolds were seeded with human cardiomyocytes, the authors were able to show that helical architectures increased cardiac performance. In a related Perspective, Michael Sefton and Craig Smith put these findings into the broader context of regenerative medicine. “The heart is more than a simple pump,” they write. “Nonetheless, Chan et al. have taken a step toward making biomechanically equivalent functional structures.”