TY - JOUR
T1 - Improved electrochemical detection of biogenic amines in Aplysia using base-hydrolyzed cellulose-coated carbon fiber microelectrodes
AU - Marinesco, Stéphane
AU - Carew, Thomas J.
N1 - Funding Information:
This work was supported by NIH grant RO1 MH 14-1083 to TJC.
PY - 2002/5/30
Y1 - 2002/5/30
N2 - A major challenge with electrochemical techniques in vivo, using carbon-fiber microelectrodes, is to achieve sufficient sensitivity to detect the low concentrations of transmitters released by neurons. In particular, when an electrode is inserted into living tissue, its sensitivity is usually substantially decreased as a result of the degradation of the carbon surface by proteins. Here, we show that this decrease can be significantly attenuated by coating the electrode with cellulose acetate. The cellulose film offers a steric barrier that prevents macromolecules from diffusing to the carbon surface and its porosity can be progressively increased by controlled hydrolysis. We compared different cellulose-coated electrodes, either non-hydrolysed or hydrolyzed, in 0.08 N KOH for 10-30 min. We found that dopamine and serotonin detection was blocked by non-hydrolysed cellulose films, but that hydrolysis restored optimal detection similar to uncoated electrodes. Moreover, cellulose films (hydrolyzed for 20 min) significantly diminished electrode degradation in vivo and allowed reliable detection of fast concentration changes with <0.5 s delay, compared to uncoated electrodes. Finally, the sensitivity to endogenous 5-HT release in Aplysia central nervous system was more than doubled with these electrodes. We conclude that the optimal hydrolysis time of cellulose-coated electrodes is ≈20 min with our protocol and carbon fiber electrodes prepared with this method offer improved sensitivity for the detection of biogenic amines.
AB - A major challenge with electrochemical techniques in vivo, using carbon-fiber microelectrodes, is to achieve sufficient sensitivity to detect the low concentrations of transmitters released by neurons. In particular, when an electrode is inserted into living tissue, its sensitivity is usually substantially decreased as a result of the degradation of the carbon surface by proteins. Here, we show that this decrease can be significantly attenuated by coating the electrode with cellulose acetate. The cellulose film offers a steric barrier that prevents macromolecules from diffusing to the carbon surface and its porosity can be progressively increased by controlled hydrolysis. We compared different cellulose-coated electrodes, either non-hydrolysed or hydrolyzed, in 0.08 N KOH for 10-30 min. We found that dopamine and serotonin detection was blocked by non-hydrolysed cellulose films, but that hydrolysis restored optimal detection similar to uncoated electrodes. Moreover, cellulose films (hydrolyzed for 20 min) significantly diminished electrode degradation in vivo and allowed reliable detection of fast concentration changes with <0.5 s delay, compared to uncoated electrodes. Finally, the sensitivity to endogenous 5-HT release in Aplysia central nervous system was more than doubled with these electrodes. We conclude that the optimal hydrolysis time of cellulose-coated electrodes is ≈20 min with our protocol and carbon fiber electrodes prepared with this method offer improved sensitivity for the detection of biogenic amines.
KW - Chronoamperometry
KW - Dopamine
KW - Electrode fouling
KW - Nafion
KW - Serotonin
KW - Voltammetry
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U2 - 10.1016/S0165-0270(02)00093-6
DO - 10.1016/S0165-0270(02)00093-6
M3 - Article
C2 - 12084568
AN - SCOPUS:0037198355
SN - 0165-0270
VL - 117
SP - 87
EP - 97
JO - Journal of Neuroscience Methods
JF - Journal of Neuroscience Methods
IS - 1
ER -