John C. Gonzalez Amoretti, Nilka M. Rivera Serrano, Miraida Pagan Castillo, Luis F. Lopez and Lisandro Cunci
Dopamine (DA) neurotransmitter have an important role in cognition, motivation and reward in the neurological system. A lot of behavioral disorders are caused by the alteration in DA transmissions causing neurological disorders, such as Parkinson’s. Pesticides and heavy metals are environmental neurotoxins that target dopaminergic systems, acting on single or multiple aspects of DA neurotransmission that alter behavior. Electrochemical Impedance Spectroscopy (EIS) is an electrochemistry technique characterized by applying a potential with an amplitude of 10 mV and measuring the current at different frequencies (1Hz to 1MHz), allowing the detection of dopamine. The electrodes surface holds great significance to this method. Carbon Fiber Microelectrodes (CFMEs) meet the requirements of having a less intrusive size and provides faster measurements in EIS. This electrochemical method can bring forward a possible resolution to the detection of neurological disorders. To show a proof of concept, four potentials were chosen from 0.0 to 0.8 V vs Ag|AgCl to detect dopamine. The CFMEs were prepared by aspirating a carbon fiber of 7 µm into glass capillaries. Electrochemical analysis was carried out in presence of dopamine solutions at different concentrations (1–500 nM) that were later added to the electrochemical cell. Our results show that the capacitance of the microelectrodes surface decreased due to the dopamine concentration. The results confirm dopamine capacity to be detected at very low concentrations and frequencies up to 50KHz, when using CFMEs. This opens the door for faster measurements of neurotransmitters in real time with the potential of oversampling and increased sensitivity.