Heterostructured Au/MoS2-MWCNT nanoflowers: A highly efficient support for the electrochemical aptasensing of solvated mercuric ion

The solvated mercury ion (Hg2+) is considered as the most common heavy metal pollutant ion in the environment. A nano-enhanced aptasensor is established here as a very sensitive and reliable device for sensitive and selective detection of Hg2+ in water samples. Here, the gold nanoparticles-coated molybdenum disulfide-multiwalled carbon nanotubes nanocomposite (Au/MoS2-MWCNT) was synthesized and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and Raman spectroscopy. The nanocomposite was coated on the surface of a glassy carbon electrode and DNA aptamer probes were immobilized on the surface of the modified electrode. Electrochemical methods were used to investigate the importance of Au/MoS2-MWCNT as an aptasensing platform in the measurement of Hg2+. A decrease in the voltammetric current signal of redox couple after the interaction of Hg2+ with the aptamer was occurred. The variation in the current is proportional to the concentration of Hg2+. Based on the calibration curve, the very low detection limit of 0.05 nmol L-1 and a very wide linear range of 0.1 nmol L-1-1 mu mol L-1 were obtained. The reproducibility of this aptasensor was 5.1%. Moreover, the effective determination of the Hg2+ by our Au/MoS2-MWCNT-based sensor in the complex environmental water samples was realized, which displays a good application possibility.