Electrochemical studies of biofunctionalized MoS2 matrix for highly stable immobilization of antibodies and detection of lung cancer protein biomarker

Abstract

To address the issue of the lack of stable immobilization of antibodies on the biosensing matrix for repeated cycles of measurement, MoS₂ biofunctionalized with chitosan (CS) is prepared to serve as a biosensing matrix. The electrochemical performance of the CS/MoS₂ matrix towards the detection of neuron-specific enolase (NSE), a lung cancer biomarker, is also investigated. Unlike other complex matrices involving various steps of modification, the matrix studied herein involves only 2 steps of modification without the use of any label, amplifying its appeal for biosensing applications. The fabricated immunoelectrode is found to exhibit remarkable cyclic stability, with a sensitivity of 3.35 μA ng⁻¹ mL cm⁻² and a wide linear detection range of 0.1–100 ng mL⁻¹. Also, the sensor is found to be fast, specific, reproducible, regenerable up to 4 cycles, and has a shelf life of 6 weeks. The stability study of our fabricated immunoelectrode revealed that the cumulative effect of CS and MoS₂ ensures the stable immobilization of biomolecules on the immunoelectrode for 50 cyclic voltammetry (CV) cycles. The results of this study suggest that the proposed matrix will be promising in the fabrication of devices for early monitoring of protein biomarkers.