A NEW DESIGN OF CARBON-FIBER MICROELECTRODE FOR IN-VIVO VOLTAMMETRY USING FUSED-SILICA

Voltammetric probes were constructed from stainless steel and fused si lica tubing sheathing carbon fibers. Electrochemical tests were carrie d out to compare these electrodes with commercially available glass-se ared IVEC-5 electrodes. Electrodes of both types displayed a similar d eclining baseline and calculated coefficients of stabilization (tangen t of baseline during a stable period). There were no significant diffe rences in sensitivity between the two designs of electrodes to norepin ephrine (NE) and dopamine (DA). All tested electrodes showed linear cu rrent responses to increasing concentrations of NE and DA. Fused silic a (FS type) electrodes are suitable for electrochemical measurements ( in vivo voltammetry) and display characteristics similar to those of c ommercially available IVEC-5 glass-sealed carbon fiber microelectrodes . Manufacture of FS type electrodes in a biochemical laboratory is eas y and does not require any special equipment (such as a micropipette p uller) or glass-handling skills. An additional fused silica tube can b e glued to the electrode for microinjections. The electrodes are very robust, easy to handle and can be mounted on the arms of standard ster eotaxic instruments. The electrodes can be made long enough to reach t he deepest parts of brain of large animals. (C) 1997 Elsevier Science B.V.