Synthesis of Au@ZIF-8 Nanocomposites for Enhanced Electrochemical Detection of Dopamine

Abstract

Dopamine (DA) is a well-known neurotransmitter, which is an organic chemical of the catecholamine and phenethylamine families, playing important roles in in the brain and body. However, a deficiency of DA in the human body could lead to neurological disorders. In contrast, a high level of DA could cause an increased risk of depression. Therefore, the significance of DA in the clinical diagnostic perspectives has drawn great awareness for the development of sensitive and reliable techniques for their detection. In our recent study, gold nanoparticles and zeolitic imidazolate framework-8 nanocomposites (Au@ZIF-8) were synthesized through a simple hydrothermal method and used as an enzyme-free sensor for the detection of DA. To gain insight into the structure and morphology of Au@ZIF-8 nanocomposites, various characterizations were used, i.e. scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopic (TEM), scanning transmission electron microscope-energy X-ray diffraction spectroscopy (STEM-EDX). Then, Au@ZIF-8 nanocomposites modified glass carbon electrodes (Au@ZIF-8/GCEs) were examined in 0.1 M phosphate-buffered saline (PBS) with different concentrations of DA. Au@ZIF-8/GCE possessed an excellent electrochemical catalytic performance to DA which are derived from electrochemical test, having been reported to own wider linear range from 0.01-50 μM, lower detection limit of 0.01 μM (S/N = 3) and higher sensitivity of 6.452 μA mM-1 cm-2. The proposed Au@ZIF-8/GCE exhibits better sensitivity than ZIF-8/GCE that we previously reported, it also shows good selectivity and long-term stability after 1000-cycle CV test. Such selectivity and comparable performance can be attributed the synergetic electrochemical performance between Au NPs and ZIF-8, and fast charge transfer ability between the electrochemical sites and the electrode. Therefore, Au@ZIF-8/GCE presents promising performance as a potential non-enzymatic dopamine sensor. Figure 1