Evaluation of Trans-Epithelial Electrical Resistance of Proximal Tubule Tissue by Inclusion and Removal of Extracellular Calcium Ion

We developed a bi-channel microfluidic device integrated with four electrodes to measure trans-epithelial electrical resistance (TEER). Time course of TEER was monitored when the extracellular Ca
²⁺
was removed from and replenished to the top or bottom channels. We demonstrated that the cell junctions of human renal proximal tubule epithelial cells (RPTECs) responded differently to the presence or absence of extracellular Ca
²⁺
at the apical and basal sides. These results indicate the possibility of detecting cell polarity in real time and low invasion by using TEER measurements.