Almost all diseases of the brain are associated with disruption or dysfunction of the BBB, which leads to entry of blood components, immune cells, and pathogens into the brain, and ultimately causes neuroinflammation, oxidative stress, and neurotoxicity.   We use tissue engineering and stem cell technology to build physiological models of the BBB that can recapitulate multiple processes regulated by the brain microvascular endothelial cells.   We use these models for fundamental studies of disruption or dysfunction of the BBB (e.g. the role of stress, inflammation, pathogens), disease models (e.g. brain cancer), developing strategies for drug and gene delivery to the brain (e.g. transient opening of the BBB), and the development of strategies for BBB repair (e.g. in response to disease or trauma).