Commercialization of Enzyme Modified Carbon-Fiber Electrodes Paired with Voltammetry for Simultaneous Real-Time Monitoring of Electroactive and Non-Electroactive Species at Discrete Brain Locations

ABSTRACT Commercially available, real-time molecular monitoring technologies are designed to selectively measure only one molecule at a time at a given recording site. This is a problem because chemical signals in the brain do not work in isolation; rather, neurotransmission involves many chemical species simultaneously working to modulate neural circuits. Quantitative analysis of these neurochemical signals is a critical first step when developing therapeutic strategies to treat neurological/psychological disorders, but little is known about how specific neurochemicals fluctuate relative to one another. The Sombers Lab has established the feasibility of using fast- scan cyclic voltammetry (FSCV) and carbon-fiber microelectrodes for the real-time detection of dopamine fluctuations while simultaneously detecting non-electroactive species, such as glucose and lactate, at the same recording site. The microbiosensors have higher spatial and temporal resolution than currently available technologies, minimal analyte consumption, and they can be easily integrated into existing protocols. During Phase I, a 7-um probe was developed and commercialized that can simultaneously measure dopamine and glucose in real time, at single micron-scale recording sites in vivo. A software suite and FSCV tutorials were developed. In Phase II, we will develop and commercialize 7-um dopamine/lactate, dopamine/glutamate, and serotonin/glucose sensors. We will develop additional tutorials to simplify access to this important technology, and we will continue to develop software and electronics. Overall, this project is innovative, because it departs from the status quo by utilizing the redox activity inherent to enzymatically generated H2O2 to identify targeted non-electroactive species, even in the presence of electroactive molecules that are typically excluded as interferents. It is significant, because it combines two state-of-the-art and well-characterized technologies for neurochemical monitoring in a clever, straightforward, and unprecedented manner. Ultimately, this project will provide the community with a sensor suite that can be used to study the interplay of a range of critical analytes in complex physiological processes ranging from basic endocrine function to motivation. It promises to have a transformative effect on neuroscience by allowing researchers interested in diverse aspects of brain function to better understand how these specific neurochemicals co-fluctuate in discrete brain locations.