Abstract
Drug delivery across the BBB represents a significant clinical challenge. In vitro models are widely used for prediction of permeability and toxicity of compounds. These are typically achieved via culture of brain endothelial cells on permeable membrane inserts. However, such models are limited in physiological relevance due to their 2D nature, lack of extracellular matrix, presence of an artificial membrane, and absence of perfusion. Microfluidic models are becoming increasingly adopted. The OrganoPlate is a microfluidic platform enabling perfused, 3D co-culture of up to 96 tissues in a membrane free manner. It allows growth of tubular endothelial structures and is based on a 384-well plate. To create a BBB model, brain endothelial cells are seeded against a collagen-I extracellular matrix. Under perfusion, endothelia form confluent tubule structures, accessible from both apical and basolateral sides. It comprises a perfused 3D microvessel of hBMECs, with option to include cell types such as astrocytes and pericytes. It shows expression of phenotypic and junctional proteins, transporters, and receptors. Using fluorescent assays, we demonstrate low permeability of primary hBMECs to sodium fluorescein, as well as functional P-glycoprotein and GLUT1 activity. Barrier and transport readouts are performed directly in-plate without the need for sampling. Time-dependent barrier disruption by toxic compounds is measured in 40 cultures in parallel with OrganoTEER. This BBB model serves as a versatile model for high-throughput applications including toxicity and transport studies.
