Sensitive Electrochemical Immunosensor Based on MXene-Nafion/Polyaniline (PANI) for the Sensitive Determination of the Novel Biomarker sST2 for Atherosclerotic Coronary Heart Disease by Differential Pulse Voltammetry (DPV)

Atherosclerotic coronary heart disease (CHD) is ischemic and a worldwide health issue. The soluble suppression of tumorigenicity 2 (sST2) is a novel biomarker for atherosclerotic coronary heart disease. This work develops an immunosensor with a nanocomposite consisting of polyaniline (PANI) and MXene-Nafion for the specific and sensitive determination of sST2. PANI was first electropolymerized on a glassy carbon electrode (GCE) to enhance electron transfer. Subsequently, MXene-Nafion dispersion was drop cast on the PANI/GCE substrate to further increase the electrical conductivity and immobilize anti-sST2 which captures sST2 for detection. The current response as a function of sST2 concentration was measured by differential pulse voltammetry (DPV). Under the optimal conditions, this immunosensor demonstrates a linear range from 1 pg mL−1 to 1 μg mL−1 and a detection limit of 0.149 pg mL−1. The device offers high sensitivity, excellent specificity, satisfactory reproducibility, good stability, and has significant potential for detecting clinical biomarkers. In addition, the immunosensor is able differentiate between serum of healthy people and CHD patients.