Advancing Microelectrode Technology
Biotechnology has improved the understanding of the central nervous system, by enabling chemical fluctuations to be linked with behavioral, cognitive, and emotional states of organisms. Electrochemical techniques are well-suited for measuring neurochemical fluctuations in living tissue, by coupling fast-scan cyclic voltammetry (FSCV) with microelectrodes. This union benefits the high spatial resolution of the small electrode size with rapid temporal resolution of the voltammetric scan, while providing superior chemical selectivity. However limitations remain. This research individually addresses several of these limitations to produce novel electroanalytical tools for monitoring dynamic molecular fluctuations in biological preparations.
- Enzyme-modified electrodes
We detect fluctuations of non-electroactive species, including glucose and acetylcholine, by quantitatively monitoring subsecond H2O2 evolution at oxidase modified carbon fiber microelectrodes using background-subtracted, fast-scan cyclic voltammetry (FSCV). These electrodes are used in intact brain tissue to monitor the dynamics of both pharmacologically-evoked and naturally-occurring molecular fluctuations with unprecedented chemical and spatial resolution.
- Nanofiber electrodes
We are working with Prof. Saad Khan of NCSU Chemical Engineering to electrospin a nanofiber matrix onto the electrode surface that is specifically tailored to enable and enhance detection of various biological species. To achieve this, enzyme is mixed with various polymer solutions and "spun" (using a high voltage) into an ultrafine fiber that is wrapped around the electrode surface, forming a mesh.
- Microelectrode arrays
Disc-shaped electrodes can be incorporated into microarrays; however, the reduced surface area of these sensors results in an insufficient sensitivity for practical in vivo applications. To enable the design of electrodes with enhanced sensitivity, we are working with Prof. Greg McCarty of NCSU/UNC Biomedical Engineering using atomic force microscopy (AFM) and Raman spectroscopy to study the surface properties of untreated and electrochemically pretreated disc microelectrodes. We have also begun multiplexing these electrodes into a novel microelectrode array to allow simultaneous voltammetric measurements at multiple sites in vivo.