Detection of Dopamine Based on Tyrosinase-Fe3O4 Nanoparticles-chitosan Nanocomposite Biosensor

Abstract

A tyrosinase biosensor based on Fe3O4-chitosan nanocomposite has been developed for the amperometric detection of dopamine by the biocatalytically liberated dopaquinone at −0.25V vs. saturated calomel electrode. The obtained bio-nanoparticles, which were attached to the surface of a glassy carbon electrode (GCE), showed excellent electrochemical characteristics and at the same time acted as mediator to transfer electrons between the enzyme and the electrode. Under optimal conditions, the biosensor showed broad linear response of 2.0×10−8 to 7.5×10−5 mol L−1 , with the low detection limit of 6.0×10−9 mol L−1 and the high sensitivity of 46 μA/mM for the determination of dopamine in the presence of ascorbic acid. Such tyrosinase biosensor exhibits great promise for rapid, simple and cost-effective analysis of dopamine in the samples. This immobilization approach effectively improved the stability of the electron transfer mediator and is promising for construction of biosensor and bioelectronic devices.