Recent developments in organ-on-a-chip technology for cardiovascular disease research

Cardiovascular diseases are a group of heart and blood vessel disorders which remain a leading cause of morbidity and mortality worldwide. Currently, cardiovascular disease research commonly depends on in vivo rodent models and in vitro human cell culture models. Despite their widespread use in cardiovascular disease research, there are some long-standing limitations: animal models often fail to faithfully mimic human response, while traditional cell models ignore the in vivo microenvironment, intercellular communications, and tissue-tissue interactions. The convergence of microfabrication and tissue engineering has given rise to organ-on-a-chip technologies. The organ-on-a-chip is a microdevice containing microfluidic chips, cells, and extracellular matrix to reproduce the physiological processes of a certain part of the human body, and is nowadays considered a promising bridge between in vivo models and in vitro 2D or 3D cell culture models. Considering the difficulty in obtaining human vessel and heart samples, the development of vessel-on-a-chip and heart-on-a-chip systems can guide cardiovascular disease research in the future. In this review, we elaborate methods and materials to fabricate organ-on-a-chip systems and summarize the construction of vessel and heart chips. The construction of vessels-on-a-chip must consider the cyclic mechanical stretch and fluid shear stress, while hemodynamic forces and cardiomyocyte maturation are key factors in building hearts-on-a-chip. We also introduce the application of organs-on-a-chip in cardiovascular disease study.