Electrodes implanted in the brain have great potential, with applications in neurodegenerative disease, brain-computer interfaces, and more. However, the presence of electrodes in brain tissue causes a response known as gliosis, in which a scar forms around the electrode, reducing its effectiveness and access to neurons. To date, most gliosis studies have been done in live animals, with significant variation in results and many confounding variables. I hope to develop a non-animal lab assay for studying gliosis, using a combination of human stem cell derived “mini-brains” and a microfabricated array of functional electrodes. Such an assay would reduce the many confounding variables that exist in live animals, and would allow for a more direct comparisons of different electrode properties, allowing for insights into better implantable electrodes.