Perovskite nanostructure based electrochemical biosensor for selective determination of dopamine

Abstract

Dopamine (DA), present in the central nervous system is a well-known catecholamine neurotransmitter. Abnormal DA concentration results in some major disorders such as Parkinson s, Schizophrenia and Alzheimer which remains critical for the early diagnosis and prevention of these disorders. In this research, we present FeTiO3 perovskite nanostructure based biosensor for the efficient electrochemical detection of DA. The FeTiO3 nanostructure was synthesized through a facile hydrothermal route and dropcasted on the surface of Glassy Carbon Electrode (GCE). Electrochemical experiments such as cyclic voltammetry and differential pulse voltammetry were carried out to investigate the electrochemical behaviour of the fabricated biosensor. The sensor showed a low detection limit of 1.3nM for DA and a detection limit of 30nM was observed for Uric Acid (UA), the common interfering component of DA. Two linear ranges were observed for DA and UA ranging from 1 and#956;M to 90 and#956;M; 110 and#956;M to 350 and#956;M and 1 and#956;M to 150 and#956;M and 200 and#956;M to 500 and#956;M respectively. Further, the electrochemistry of DA on FeTiO3/GCE surface was studied briefly by calculation of electrochemical kinetic parameters from hydrodynamic voltammetry and impedance spectroscopy. The mechanistic pathway for DA oxidation was also proposed for FeTiO3/GCE. In order to improve the performance of perovskite sensor in terms of sensitivity and selectivity, the FeTiO3 nanostructures were coated with a polymer polydopamine (PDA). PDA-FeTiO3/GCE sensor showed superior electrocatalytic activity for DA oxidation compared to FeTiO3/GCE and the detection limit for DA was 0.3 and#956;M. Perovskite FeTiO3 based sensor was thus used as an electroactive probe for the selective and simultaneous determination of DA and UA. The practical applicability of the sensor for DA detection was demonstrated in biological samples such as serum and urine with satisfactory results. newline