Brain-on-a-chip: Recent advances in design and techniques for microfluidic models of the brain in health and disease

Recent advances in biomaterials, microfabrication, microfluidics, and cell biology have led to the development of organ-on-a-chip devices that can reproduce key functions of various organs. Such platforms promise to provide novel insights into various physiological events, including mechanisms of disease, and evaluate the effects of external interventions, such as drug administration. The neuroscience field is expected to benefit greatly from these innovative tools. Conventional ex vivo studies of the nervous system have been limited by the inability of cell culture to adequately mimic in vivo physiology. While animal models can be used, their relevance to human physiology is uncertain and their use is laborious and associated with ethical issues. To date, organ-on-a-chip systems have been developed to model different tissue components of the brain, including brain regions with specific functions and the blood brain barrier, both in normal and pathophysiological conditions. While the field is still in its infancy, it is expected to have major impact on studies of neurophysiology, pathology and neuropharmacology in future. Here, we review advances made and limitations faced in an effort to stimulate development of the next generation of brain-on-a-chip devices.