@article{wilson_panda_schmidt_sombers_2017, title={Selective and Mechanically Robust Sensors for Electrochemical Measurements of Real-Time Hydrogen Peroxide Dynamics in Vivo}, volume={90}, ISSN={0003-2700 1520-6882}, url={http://dx.doi.org/10.1021/acs.analchem.7b03770}, DOI={10.1021/acs.analchem.7b03770}, abstractNote={Hydrogen peroxide (H2O2) is an endogenous molecule that plays several important roles in brain function: it is generated in cellular respiration, serves as a modulator of dopaminergic signaling, and its presence can indicate the upstream production of more aggressive reactive oxygen species (ROS). H2O2 has been implicated in several neurodegenerative diseases, including Parkinson's disease (PD), creating a critical need to identify mechanisms by which H2O2 modulates cellular processes in general and how it affects the dopaminergic nigrostriatal pathway, in particular. Furthermore, there is broad interest in selective electrochemical quantification of H2O2, because it is often enzymatically generated at biosensors as a reporter for the presence of nonelectroactive target molecules. H2O2 fluctuations can be monitored in real time using fast-scan cyclic voltammetry (FSCV) coupled with carbon-fiber microelectrodes. However, selective identification is a critical issue when working in the presence of other molecules that generate similar voltammograms, such as adenosine and histamine. We have addressed this problem by fabricating a robust, H2O2-selective electrode. 1,3-Phenylenediamine (mPD) was electrodeposited on a carbon-fiber microelectrode to create a size-exclusion membrane, rendering the electrode sensitive to H2O2 fluctuations and pH shifts but not to other commonly studied neurochemicals. The electrodes are described and characterized herein. The data demonstrate that this technology can be used to ensure the selective detection of H2O2, enabling confident characterization of the role this molecule plays in normal physiological function as well as in the progression of PD and other neuropathies involving oxidative stress.}, number={1}, journal={Analytical Chemistry}, publisher={American Chemical Society (ACS)}, author={Wilson, Leslie R. and Panda, Sambit and Schmidt, Andreas C. and Sombers, Leslie A.}, year={2017}, month={Dec}, pages={888–895} }
 @article{qi_thomas_white_smith_lee_wilson_sombers_2016, title={Unmasking the Effects of L-DOPA on Rapid Dopamine Signaling with an Improved Approach for Nafion Coating Carbon-Fiber Microelectrodes}, volume={88}, ISSN={["1520-6882"]}, DOI={10.1021/acs.analchem.6b01871}, abstractNote={L-DOPA has been the gold standard for symptomatic treatment of Parkinson's disease. However, its efficacy wanes over time as motor complications develop. Very little is known about how L-DOPA therapy affects the dynamics of fluctuating dopamine concentrations in the striatum on a rapid time scale (seconds). Electrochemical studies investigating the effects of L-DOPA treatment on electrically evoked dopamine release have reported conflicting results with significant variability. We hypothesize that the uncertainty in the electrochemical data is largely due to electrode fouling caused by polymerization of L-DOPA and endogenous catecholamines on the electrode surface. Thus, we have systematically optimized the procedure for fabricating cylindrical, Nafion-coated, carbon-fiber microelectrodes. This has enabled rapid and reliable detection of L-DOPA's effects on striatal dopamine signaling in intact rat brain using fast-scan cyclic voltammetry. An acute dose of 5 mg/kg L-DOPA had no significant effect on dopamine dynamics, demonstrating the highly efficient regulatory mechanisms at work in the intact brain. In contrast, administration of 200 mg/kg L-DOPA significantly increased the amplitude of evoked dopamine release by ∼200%. Overall, this work describes a reliable tool that allows a better measure of L-DOPA augmented dopamine release in vivo, measured using fast-scan cyclic voltammetry. It provides a methodology that improves the stability and performance of the carbon-fiber microelectrode when studying the molecular mechanisms underlying L-DOPA therapy and also promises to benefit a wide variety of studies because Nafion is so commonly used in electroanalytical chemistry.}, number={16}, journal={ANALYTICAL CHEMISTRY}, author={Qi, Lingjiao and Thomas, Elina and White, Stephanie H. and Smith, Samantha K. and Lee, Christie A. and Wilson, Leslie R. and Sombers, Leslie A.}, year={2016}, month={Aug}, pages={8129–8136} }