One major challenge in developing therapeutic neural implants is chronic gliosis that occurs at the implant/tissue interface. This is the brain’s scarring response, and it prevents accurate recording and precision stimulation of neural activity over long time periods. Here, we propose to address this challenge in two ways. First, we will develop micron-sized, ultraflexible and wirelessly powered microdevices that can be delivered into the brain via syringe injection so as to disturb the brain as little as possible when deployed. In addition to producing less scarring, these injectable devices will be fabricated with photovoltaic polymers, turning brain-penetrating near-infrared light into electrical impulses for deep-brain neural stimulation. Second, we will develop precise tools to measure the brain’s scar response to any implant. By characterizing the cellular and molecular changes induced in the brain by the devices we will not only more precisely measure the response, but also identify which pharmacologic manipulations might prevent scarring from any device. We believe our proposed research has the potential of generating transformative results for both neuroscience research and neurological applications, not only expanding the toolbox of neuromodulation techniques, but also offering strategies to manipulate key intracellular pathways to prevent gliosis in therapeutic neural implants.