Neurotransmitter Assay for In Vivo Nerve Signal Detection Using Bismuth Immobilized on a Carbon Nanotube Paste Electrode

Background: Voltammetric analysis of the neurotransmitter epinephrine (EP) was performed using bismuth immobilized on a carbon nanotube paste electrode (BCE), whose properties were compared with those of a carbon nanotube paste electrode (CE). BCE was found to be more efficient in detecting EP. Methods: The analytical parameters used were 0.3 V square-wave (SW) stripping voltammetric amplitude, 400 Hz frequency, −0.8 V initial potential, and 0.015 V increment potential. The optimized conditions were applied to an assay of a carp’s front fin. Results: A BCE was inserted into a carp’s front fin muscle, and a stimulus was given every 50 s. This circuit is easy to use and does not require much analytical preparation time. Conclusions: The working electrode is miniscule, and its detection limit is very low. The in vivo muscle’s chronoamperometric nerve currents were analyzed. These results have potential for applications in medical diagnostics, pharmaceuticals, interface controllers, and other fields.