Transparent epidural devices that facilitate the concurrent use of electrophysiology
and neuroimaging are arising tools for neuroscience. Testing the biocompatibility
and evoked immune response of novel implantable devices is essential to lay down the
fundamentals of their extensive application. Here we present an immunohistochemical
evaluation of a Parylene HT/indium-tin oxide (ITO) based electrocorticography (ECoG)
device, and provide long-term biocompatibility data at three chronic implantation
lengths. We implanted Parylene HT/ITO ECoG devices epidurally in 5 mice and evaluated
the evoked astroglial response, neuronal density and cortical thickness. We found
increased astroglial response in the superficial cortical layers of all mice compared
to contralateral unimplanted controls. This difference was largest at the first time
point and decreased over time. Neuronal density was lower on the implanted side only
at the last time point, while cortical thickness was smaller in the first and second
time points, but not at the last. In this study, we present data that confirms the
feasibility and chronic use of Parylene HT/ITO ECoG devices.
