Electrochemical methods are becoming a very useful technique nowadays used to detect biomolecules. Known appliances are the detection and characterization of neurotransmitters, such as dopamine which is responsible for the feeling of pleasure, satisfaction and our motor functions. The deficiency of this molecule can cause disorders such as Parkinson's, schizophrenia and addiction. With these electrochemical techniques, it is possible to detect dopamine in terms of milliseconds to know how much dopamine is released in the brain of an organism in real time, especially with Fast Scan Cyclic Voltammetry. This can measure molecules that does redox reactions, but there is another technique that it can measure at potentials where does not occur the redox reaction and it is called Electrochemical Impedance Spectroscopy (EIS). Our objective is to use EIS for the detection of dopamine at different concentrations using potentials where dopamine does not do this reactions. We prepared artificial cerebrospinal fluid as a buffer solution at a pH of 7.4 and different dopamine solutions between 1 nM and 1000 nM. We use a carbon fiber microelectrode (CFME) with a diameter of 7 µm inserted on a capillary of 1.0 mm × 0.5 mm using a vacuum. Then using a puller at 65% of heat we cut the capillary and it seals the fiber with the capillary leaving the tip exposed between 50 µm to 100 µm. Once the solutions and the electrode are prepared, we begin the characterization of dopamine using the technique of EIS at potentials between 0.0V to 0.8V vs a reference electrode of Ag/AgCl and with a counter electrode of Ag. Using the technique of EIS, it was possible to see the adsorption of dopamine in the surface of a carbon fiber microelectrode at lower frequencies. With the data obtained this has confirmed that we can measure the adsorption of dopamine to the surface of the microelectrode at low concentrations. These results will render useful in later studies where we'll measure the release of neurotransmitters in vivo with a model organism.

Detection and characterization of dopamine dynamically using electrochemical impedance spectroscopy

256th National Meeting (2018)

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