Highly Efficient Dopamine Sensing with a Carbon Nanotube-Encapsulated Metal Chalcogenide Nanostructure

Carbon nanotube-encapsulated nickel selenide composite nanostructures were used as nonenzymatic electrochemical sensors for dopamine detection. These composite nanostructures were synthesized through a simple, one-step, and environmentally friendly chemical vapor deposition method, wherein the CNTs were formed in situ from pyrolysis of a carbon-rich metallo-organic precursor. The composition and morphology of these hybrid NiSe2-filled carbon nanostructures were confirmed by powder X-ray diffraction, Raman, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy images. Electrochemical tests demonstrated that the as-synthesized hybrid nanostructures exhibited outstanding electrocatalytic performance toward dopamine oxidation, with a high sensitivity of 19.62 mu A mu M-1 cm(-2), low detection limit, broad linear range of 5 nM-640 mu M, and high selectivity. The synergistic effects of enhanced electrochemical activity of nickel selenide along with the enhanced conductivity of carbon nanotubes led to the high electrocatalytic efficiency for these nanostructured composites. The high sensitivity and selectivity of this nanostructured composite could be exploited to develop simple, selective, and sensitive electrochemical sensors to detect and quantify dopamine in human tear samples with high reliability. This nanotube-encapsulated sensor, hence, paves the way for discoveries in the development of dopamine sensors with low cost and high stability, which can be used for noninvasive dopamine detection in peripheral bodily fluids.