Microfluidic in vitro brain endothelial monolayer model to evaluate cell-penetrating peptides

Blood vessels in central nervous system act as a great hurdle for drug delivery to the human brain. They only allow passage of water, some gases, lipid molecules, glucose and amino acid by selective transporter while restricting most of solutes and pathogens to protect brain. A lot of studies have tried to overcome this hurdle by discovering and optimizing brain deliverable drugs however the platforms used for preclinical stage are still limited. In this study, we constructed an in vitro 3-dimensional model for brain endothelial monolayer using hydrogel incorporated microfluidic device that provides an 3D extracellular matrix scaffold. We confirmed the stable endothelial barrier by staining a tight junction marker, VE-Cadherin, and strong block ability by comparing permeability with normal endothelial cells. Also, we succeed in verifying the strong permeability of angiopep-2 using our device that is known as a brain permeable peptide by utilizing receptor-mediated transcytosis. We propose our microfluidic device as an in vitro platform for evaluating various brain drugs or drug carrier candidates.