A dual mode immunosensing platform constructed on CdIn2S4 near-infrared electrochemiluminescence emitter and AuNPs@g-C3N4 for zearalenone sensing

Abstract

In this study, a near-infrared (NIR) electrochemiluminescence (ECL) emitter CdIn2S4 was synthesized by a convenient hydrothermal strategy. The ECL properties of the obtained CdIn2S4 were examined in the presence of potassium persulfate coreactant at an excitation potential of − 1.25 V. The low trigger voltage of CdIn2S4 may be ascribed to its lower bandgap. This lower excitation potential could effectively reduce the side-effects induced by high voltages, while maintaining the biological activity of antibodides and antigens. The ECL features of CdIn2S4 were also investigated, demonstrating that CdIn2S4 exhibited excellent NIR characteristics, and surface state transitions led to the ECL emission. Importantly, CdIn2S4 was introduced into ECL and electrochemical impedance spectroscopy (EIS) to establish a dual-mode immunosensing interface. Meanwhile, AuNPs@g-C3N4 with excellent properties were used to promote electron transmission and increase the immobilization amount of zearalenone (ZEA) antibodies in the dual-mode sensing system. The developed immunosensing strategy displayed superior sensing performance in ZEA analysis. The detection limits of ZEA were 30 fg mL−1 (ECL model) and 10 fg mL−1 (EIS model), respectively. The desirable recovery results of ZEA in corn samples prove the application potential of the NIR emitter CdIn2S4 in developing a dual-mode immunosensing system for early real-time use.