Electrochemical evaluation of magnetic reduced graphene oxide nanosheet-modified glassy carbon electrode on dopamine electrochemical sensor for Parkinson's diagnostic application

Background: Dopamine is an important catecholamine neurotransmitter that plays a critical function as a chemical messenger that aids in the signal transmission in the brain and other important places. Dopamine is known to play an important role in several neurological diseases such as schizophrenia and Parkinson's disease in which a key factor in the development of Parkinson's disease is abnormally lower levels of dopamine compared to normal levels. However, these methods are expensive, requires manual labor and resources, and demands large number of reagents and chemicals. Therefore, it is essential to develop dopamine detection methods that are less costly, more stable, and easier to perform. Objective: To develop a magnetic reduced graphene oxide (MRGO) nanosheet-modified glassy carbon electrode (GCE) for the electrochemical detection of dopamine. Methods: Magnetic reduced graphene oxide (MRGO) nanosheet were prepared by the in situ coprecipitation of Fe3+ and Fe2+ in the GO solution. To prepare the MRGO nanosheet ink, 38 mg of MRGO nanosheet was mixed with 2mg of acetylene black and 80 mu L of Nafion solution (5%). The mixture was then mixed with 210 mu L of deionized water and 210 mu L of 2-propanol and subjected to ultrasonication for 120 min using a sonicator to obtain a homogenous MRGO nanosheet ink. Furthermore, 3 mu L of MRGO ink was dripped onto the surface of the GCE. Results: MRGO consists of graphene layered tethered with the spherical Fe3O4. The oxygen-based functional groups on the surface of MRGO could act as chemically active sites for the attachment of dopamine. The MRGO nanosheet has been proven to be an effective GCE modifier with a remarkable electroactive surface area of approximately 0.0104 cm(2), demonstrating stable and sensitive electrochemical performance towards dopamine. Conclusions: The MRGO nanosheets-modified GCE presented a great potential as an electrocatalyst for dopamine detection, especially in the presence of interfering compounds like uric acid. By effectively discriminating dopamine and uric acid, MRGO nanosheets-modified GCE have demonstrated a sensitive, stable, and specific electrochemical performance. This remarkable result underlines the immense potential of MRGO nanosheets-modified GCE for real-world applications, particularly in the medical field, where the ability to detect dopamine precisely and accurately is critical.