Towards engineering integrated cardiac organoids: beating recorded

Modeling human physiology in vitro is burgeoning as an exciting new field that requires coherent efforts encompassing multiple disciplines including engineering, biology, and medicine, among others (1). Originating from the concept of tissue engineering (2), yet with a distinct aim that is to construct models of human tissues and organs outside the body for improved biological, pharmaceutical, and environmental studies (3-6) rather than repairing them in vivo, these microphysiological systems have further undergone significant developments with the inclusion of the microfabrication and microfluidics technologies that conveniently bring in the beneficial complexity (4,7). While various microfabrication strategies allow us to engineer microscale tissue and organ units that possess shapes and architecture that mimic their in vivo counterparts (8-10), the ability to manipulate fluids at small scales leads to reproduction of the dynamic microenvironments indispensable for the functions of natural tissues and organs (1,4), both of which are otherwise not achievable using the conventional planar, static culture platforms. Of note, these individual microphysiological systems can be further linked together in such a way that the interconnected multi-unit platforms recapitulate the linkage of the various tissues and organs in their native arrangements, facilitating investigations of the intricate interactions among these different components in vitro (3-6)