Label-Free Electrochemiluminescence Immunosensor for the Determination of Cardiac Troponin I Using a Cadmium Sulfide–Molybdenum (IV) Sulfide Nanocomposite Modified Glassy Carbon Electrode

Abstract

A label free electrochemiluminescence (ECL) immunosensor for the determination of cardiac troponin I was developed using CdS-MoS₂ composites as the electrochemiluminescence emitters. The CdS-MoS₂ composites were synthesized by a hydrothermal method and used for the construction of the electrochemiluminescence biosensing platform. For the fabrication of the immunosensor, CdS-MoS₂ composites, chitosan, cardiac troponin I antibodies, and bovine serum albumin were consecutively assembled on the glass carbon electrode. Under the optimum conditions, the label free electrochemiluminescence determination of cardiac troponin I was obtained. Due to the excellent electrochemiluminescence performance of CdS-MoS₂ composites and high specificity of the immunoreactions, the sensor shows satisfactory selectivity and high sensitivity for cardiac troponin I determination. The detection limit was 1.0 pg mL⁻¹ and the linear range was from 5.0 pg mL⁻¹ to 100.0 ng mL⁻¹. Moreover, the method was successfully used to determine cardiac troponin I in human serum samples with recoveries between 85.4 and 111.0%. This label-free immunosensor possesses many merits, including a simple sensing process, good electrochemiluminescence performance of the CdS-MoS₂ composites, and high flexibility for extending the strategy for the determination of other biomarkers.

Keywords:

• Cardiac troponin I
• CdS-MoS2 composites
• electrochemiluminescence
• glassy carbon electrode

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (Grants 21874115 and 21675136), Science and Technology Innovation Talents in Universities of Henan Province (18HASTIT003), and the Nanhu Young Scholar Supporting Program of XYNU.