Non-enzymatic electrochemical sensor to detect γ-aminobutyric acid with ligand-based on graphene oxide modi fied gold electrode

In this study, the simple and sensitive enzymeless electrochemical gamma-aminobutyric acid (GABA) neurotransmitter sensor was developed based on the graphene oxide modified Au electrode with the ligand. A mixture of orthophthalaldehyde (OPA) and an alkylthiol reagent is used as a ligand to interact with GABA, which became an electro-chemical active compound. The sensor consisted of a graphene oxide modified Au electrode. The effect of pH variation on the electrochemical signal of GABA was investigated; a good electrochemical response was observed in neutraland slightly alkalinemedium, i.e. the value of the pH for the physiological-like media. The proposed sensor detected the wide range concentration of GABA from 250 nmol L-1 to 100 mu mol L-1 with a detection limit of 98 nmol L-1. And the sensor could detect a mixture of GABA and Glutamate, and GABA in complex solutions including human serum and urine, which indicated the capability of the sensor to detect GABA in complicated matrixes. The proposed sensor system can be applied to detect neurotransmitters in the brain and be used in the field of diagnosis and treatment of neurological disorders.