Development of Real-Time Transendothelial Electrical Resistance Monitoring for an In Vitro Blood-Brain Barrier System

Three-dimensional (3D) cell cultures and organs-on-a-chip have been developed to construct microenvironments that resemble the environment within the human body and to provide a platform that enables clear observation and accurate assessments of cell behavior. However, direct observation of transendothelial electrical resistance (TEER) has been challenging. To improve the efficiency in monitoring the cell development in organs-on-a-chip, in this study, we designed and integrated commercially available TEER measurement electrodes into an in vitro blood-brain barrier (BBB)-on-chip system to quantify TEER variation. Moreover, a flowing culture medium was added to the monolayered cells to simulate the promotion of continuous shear stress on cerebrovascular cells. Compared with static 3D cell culture, the proposed BBB-on-chip integrated with electrodes could measure TEER in a real-time manner over a long period. It also allowed cell growth angle measurement, providing instant reports of cell growth information online. Overall, the results demonstrated that the developed system can aid in the quantification of the continuous cell-pattern variations for future studies in drug testing.