Novel immunosensor based on electrochemiluminescence inner filter effect and static quenching between fibrillary Ag-MOGs and SiO2@PANI@AuNPs for enabling the sensitive detection of neuron-specific enolase

Abstract

Metal-organic gels (MOGs) are unique supramolecular gels that are convenient to synthesize. In this work, a cathodic electrochemiluminescence (ECL) system based on Ag-MOGs as a luminophore and K₂S₂O₈ as a co-reactor was developed. The ECL spectrum of the Ag-MOGs overlapped significantly with the strong UV-Vis spectrum of the SiO₂@PANI@AuNPs, which effectively quenched the ECL luminescence of the Ag-MOGs. Relying on the inner filter effect between Ag-MOGs and SiO₂@PANI@AuNPs, a novel ECL-IFE immunosensor was developed for the detection of neuron-specific enolase (NSE). Under optimal conditions, the ECL signal of the immunosensor displayed excellent linearity over the NSE concentration range of 10 fg/mL-100 ng/mL. The limit of detection (LOD) was 2.6 fg/mL (S/N = 3) with a correlation coefficient R² of 0.9975. The ECL immunosensor also exhibited excellent stability and reproducibility for the detection of NSE. The results reported provide a feasible concept for the development analytical methods for the detection of other clinically relevant biomarkers.

Keywords: Electrochemiluminescence; Inner filter effect sensor; Metal-organic gel; Neuron-specific enolase.