Accurately modeling the blood-brain barrier (BBB) in vitro remains a major challenge in the study of neurodegenerative diseases. Traditional static Transwell systems fail to replicate key physiological features of the BBB, including fluid shear stress, multicellular architecture, and barrier integrity. These drawbacks lead to poor translation into in vivo BBB studies.
Our researchers have developed a polydimethylsiloxane (PDMS)-based microfluidic blood-brain barrier model featuring top and bottom microchannels coated with fibronectin and separated by a 10 µm-thick, 0.4 µm-pore membrane. Human umbilical vein endothelial cells are seeded above and primary astrocytes and/or pericytes below, all exposed to controlled flow to impose physiologically relevant shear stress, encouraging tight junction formation. Integrated Ag/AgCl electrodes measure TEER using impedance spectroscopy, while concurrent permeability assays with 3, 10, and 70 kDa fluorescent dextrans quantify size-selective transport. Results indicated higher TEER values and selective permeability reflecting in vivo BBB, surpassing Transwell models, and that increasing impedance and restricted tracer diffusion correlate with expression of tight junction proteins ZO-1 and occludin, validating robust barrier formation. This platform uniquely combines co-culture underflow with real-time, high-resolution electrical monitoring, multiplexed permeability, and protein assays to accurately model in vivo BBB function.
Model of a BBB includes a mask used to generate an insert including a plurality of devices (section A), a close-up view of an individual device (section B), insert combined system (section C), initial fluid configuration (section D), and fluid configuration after a period (section E).