Electrochemical sensor for the detection of eosinophil cationic protein as a marker of allergic rhinitis based on colloidal quantum dots

The electrochemical sensor fused with the principle of immunoassay can recognize the specific binding reaction of antigen and antibody, and transduce it directly into an electrical signal, realizing the rapid detection of relevant disease markers in the liquid sample. In this study, an electrochemical sensor for detecting eosinophil cationic protein (ECP), a marker of allergic rhinitis, was constructed based on a chemically modified electrode , and the surface of the carbon electrode was modified with semiconductor colloidal quantum dots (CQDs). Owing to the remarkable surface effect, size effect and unique quantum effect of CQDs, which can improve the enrichment of biomolecules and signal transduction on the surface of the carbon electrode, the lead sulfide (PbS) CQDs have good adhesion to the carbon electrode. On the basis of the ECP antibody coating and sealing treatment on the surface of the CQDs modified working electrode , the differential pulse voltammetry (DPV) was combined to significantly reduce the background current for electrochemical performance test, and then the quantitative detection of ECP antigen of different concentrations can be achieved. The detection time of the electrochemical sensor for ECP antigen was about 30 seconds, and the detection limit was 0.508 pg mL −1 . The electrochemical sensor has the characteristics of high sensitivity, convenience and non-invasiveness, showing the potential for early screening of diseases such as allergic rhinitis.