Examples of 2D BBB microfluidic models: (a) modular polydimethylsiloxane (PDMS) device to recreate the NVU by co-culture of neuroglial and endothelial cells, (b) pumpless microdevice that provides in vivo-like BBB properties for drug permeability screening, (c) multi-layered system composed of a triple culture of co-immortalized mouse brain endothelial cells (bEnd.3), mouse astrocytes (C8D1A) and pericytes, (d) microfluidic device that mimics the cerebral vasculature and is a reliable permeability assay system. Reprinted and adapted with permission from: (a) Achyuta et al. [52], (b) Wang et al. [53], (c) Wang et al. [55]. Copyright (2016) American Chemical Society, (d) Yeon et al. [56].