Speaker: Natalie Mueller
Advisors: Dr. Jeffrey Capadona and Dr. Allison Hess-Dunning
Title: Mechanically-adaptive, antioxidant-eluting neural probes to mitigate intracortical microelectrode failure
Abstract: Intracortical microelectrodes are used in brain-computer interface systems to restore function in spinal cord injury, limb loss, and neurodegenerative disorders. Unfortunately, they often fail within months after implantation, leading to overall diminished therapeutic efficacy through reduced recording performance and increased stimulation thresholds. We have developed a mechanically-adaptive, resveratrol-loaded neural probe with the hypothesis that these probes will exhibit improved intracortical microelectrode recording performance and reduced neuroinflammatory response compared to traditional silicon probes. This device utilizes local resveratrol delivery and a mechanically-adaptive, polymer-based nanocomposite material to target the oxidative stress and mechanical mismatch failure pathways. Previous work indicated that the neural probe showed improved neuron density and decreased microglia activation compared to traditional silicon probes. However, microfabrication limitations have inhibited the addition of recording electrodes on the substrate, therefore recording performance has not been evaluated. In this work, we have developed a unique material processing and microfabrication method to integrate functional recording electrodes on the neural probe. Resveratrol release profiles from the polymer show a fast initial release followed by slow continuous release over a chronic time point. Additionally, the neural probes were packaged for interfacing with electronics for neural recording and electrodes were characterized with electrochemical impedance spectroscopy (EIS). The mechanically-adaptive, resveratrol-eluting (MARE) neural probe was implanted in an in vivo animal model to compare the neuroinflammatory response and recording performance to traditional silicon and unloaded nanocomposite probes. Initial recording data showed that MARE probes had a higher percentage of active channels and units per channel at 3 and 4 weeks compared to controls. Analysis of in vivo EIS data and the neuroinflammatory response using Nanostring bulk analysis is ongoing. Future work includes a 16-week study to evaluate the MARE probe’s recording performance and neuroinflammatory response at a chronic timepoint.