| Author(s) | Bolger FB, McHugh SB, Bennett R, Li J, Ishiwari K, Francois J, Conway MW, Gilmour G, Bannerman DM, Fillenz M, Tricklebank M, Lowry JP. |
| Tissue O(2) can be monitored using a variety of electrochemical techniques and electrodes. In-vitro and in-vivo characterisation studies for O(2) reduction at carbon paste electrodes (CPEs) using constant potential amperometry (CPA) are presented. Cyclic voltammetry indicated that an applied potential of -650 mV is required for O(2) reduction at CPEs. High sensitivity (-1.49 ± 0.01 nA/μM), low detection limit (ca. 0.1 μM) and good linear response characteristics (R(2) > 0.99) were observed in calibration experiments performed at this potential. There was also no effect of pH, temperature, and ion changes, and no dependence upon flow/fluid convection (stirring). Several compounds (e.g. dopamine and its metabolites) present in brain extracellular fluid were tested at physiological concentrations and shown not to interfere with the CPA O(2) signal. In vivo experiments confirmed a sub-second response time observed in vitro and demonstrated long-term stability extending over twelve weeks, with minimal O(2) consumption (ca. 1 nmol/h). These results indicate that CPEs operating amperometrically at a constant potential of -650 mV (vs. SCE) can be used reliably to continuously monitor brain extracellular tissue O(2). |
