Microfluidic endothelium-on-a-chip development, from in vivo to in vitro experimental models.

In the last years, animal testing in medical research has been a controversial topic because of various reasons, such as ethical considerations and species differences. Therefore, more attention has been given to develop new technologies that can replace animal experiments and create in vitro models. Organ-on-a-chip (OOC) technology is a new and advanced technology based on microfluidic devices that can mimic the structure and function of entire organs and tissues as in vitro models. OOC models are miniature tissues and organs that assign characteristics for three-dimensional (3D) cell culture representation that resemble the original organs, together with their specific microenvironment microfluidic systems and specific biophysical processes, in order to mimic the normal physiological conditions and functionalities of the organs. Existing OOC models, such as liver, pancreas, heart, skin, brain, kidney, vessels, have been developed and designed for a specific function study. This review focuses on the main knowledge concerning OOC research and especially vascular endothelium-on-a-chip (EOC) model, developed in order to offer specific tools for studying vascular functions in physiological and pathological conditions. The field of OOC devices is still at the beginning, but in the future, this technology may have important roles in developing novel therapeutic approaches, offering new therapeutic molecules and providing the first step towards personalized medicine.