Ultrasensitive Determination of Microcystin-Leucine-Arginine (MCLR) by an Electrochemiluminescence (ECL) Immunosensor with Graphene Nanosheets as a Scaffold for Cadmium-Selenide Quantum Dots (QDs)

Abstract

In order to satisfy the needs for the trace microcystins in water, a novel electrochemiluminescence (ECL) immunosensor was developed based on a dual signal amplification strategy. A MoS₂-Au hybrid nanocomposite served as the matrix to add a large number of active-sites, and graphene nanosheets were employed as the scaffold to capture cadmium-selenide quantum dots (CdSe QDs). Transmission electron microscopy (TEM), scanning electron microscopy (SEM), ultraviolet-visible absorption spectroscopy and photoluminescence spectroscopy were used to characterize these materials. The fabrication of the immunosensor was performed by electrochemical impedance spectroscopy (EIS). Under the optimum conditions, a strong ECL signal was obtained from immunosensor that was approximately 7-fold higher than from an immunosensor with a pure CdSe QDs probe. The ECL immunosensor possesses a wide linear response to microcystins-LR (MCLR) from 0.005 to 100 µg/L with a low detection limit of 0.0032 µg/L. Moreover, the immunosensor exhibited good selectivity, stability, and reproducibility for MCLR.

Keywords:

• Cadmium-selenide quantum dots
• electrochemiluminescence (ECL) immunosensor
• glassy carbon electrode (GCE)
• graphene nanosheets
• microcystin-leucine-arginine

Acknowledgments

The authors acknowledge financial support from the National Key Research and Development Project (NO.2016YFC0700604), the Bud Plan of BJAST (NO.BGS201910), and the High-Level Innovation Team Plan of BJAST (NO.HIT202001).

Additional information

Funding

The authors acknowledge financial support from the National Key Research and Development Project (NO.2016YFC0700604), the Bud Plan of BJAST (NO.BGS201910), and the High-Level Innovation Team Plan of BJAST (NO.HIT202001).