Electrical Resistance Measurements in a Blood-Brain-Barrier Microdevice

The Blood-brain-barrier (BBB) is a sophisticated microvascular barrier system laying within the brain capillary vessel, which separates circulating blood from brain tissue. This barrier is to regulates the transport of essential substances in and out of the brain, thus creating an undeniable challenge for therapeutic molecules to reach the brain disease site. To study the ability of brain therapeutics to cross the BBB, there is a need to create a more realistic in vitro BBB model that can represent the in vivo microenvironment. To meet this need, the application of microfluidic systems with brain microvascular endothelial cells have shown the capacity to recapitulate key features of the BBB in vitro. To evaluate the quality of the in vitro BBB models, trans-endothelial electrical resistance (TEER) is an important characteristic that is commonly used. To obtain TEER measurements, we are interested in using two distinct types of electrodes, Ag/AgCl wires and thin gold coated straps in a microfluidic BBB model. Ag/AgCl wire electrodes will be inserted directly into the device at the inlet and outlet locations, and as a current is passed through the membrane, the Ag/AgCl wire electrodes measure the voltage. In an alternative approach, gold coated straps will be integrated into the BBB device via a sputter coater to generate a more even conducting current across the barrier. While both methods are commonly applied and viable options for the TEER measurement, this study will compare these two methods in parallel to determine which is the suitable approach.