@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} }
 @article{amos_roberts_qi_sombers_mccarty_2014, title={Reducing the Sampling Rate of Biochemical Measurements Using Fast-Scan Cyclic Voltammetry for In Vivo Applications}, volume={14}, ISSN={["1558-1748"]}, DOI={10.1109/jsen.2014.2321479}, abstractNote={Recent advances in science and technology have permitted the development of wireless systems that can make biochemical measurements within functioning tissue in behaving animals. However, data transfer requirements and power limitations have significantly limited the applicability of these systems. In an effort to create protocols that will reduce the density of the data to be transferred and the power consumption of wireless systems, this paper evaluates reducing the sampling rate of a proven in vivo measurement technology, fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes. Existing FSCV protocols to measure biochemical signaling in the brain were created without consideration for data density or power consumption. In this paper, the sampling rate of the FSCV protocol for detecting the neurotransmitter dopamine in functioning brain tissue was reduced from 10 to 1 Hz. In vitro experiments showed that the 1-Hz protocol did not negatively affect sensor responsivity or selectivity. The reduced sampling rate was verified in vivo by directly monitoring dopamine fluctuations in intact brain tissue. The 1-Hz sampling rate reduces the quantity of data generated by an order of magnitude compared with the existing protocol, and with duty cycling is expected to decrease power consumption by a similar value in wireless systems.}, number={9}, journal={IEEE SENSORS JOURNAL}, author={Amos, Alison N. and Roberts, James G. and Qi, Lingjiao and Sombers, Leslie A. and McCarty, Gregory S.}, year={2014}, month={Sep}, pages={2975–2980} }