Sandwich-Type Electrochemiluminescence Immunosensor Based on CDs@dSiO2 Nanoparticles as Nanoprobe and Co-Reactant

In general, co-reactants are essential in highly efficient electrochemiluminescence (ECL) systems. Traditional co-reactants are usually toxic, so it is necessary to develop new environmentally friendly co-reactants. In this work, carbon dots (CDs) were assembled with dendritic silica nanospheres (CDs@dSiO(2) NPs) to form a co-reactant of Ru(bpy)(3)(2+). Subsequently, a sandwich immunosensor for detecting human chorionic gonadotropin (HCG) was constructed based on CDs@dSiO(2) NPs as co-reactants, the nanoprobe loaded with the secondary antibody, and Ru(bpy)(3)(2+) as a luminophore. In addition, compared to directly as a signal probe, the luminophore Ru (bpy)(3)(2+) as a part of the electrolyte solution is simpler in this work. The immunosensor has an extremely low limit of detection of 0.00019 mIU/mL. This work describes the synthesis of low-toxic, efficient, and environmentally friendly CDs, which have become ideal co-reactants of Ru(bpy)(3)(2+), and proposes an ECL immunosensor with excellent stability and selectivity, which has great potential in clinical applications.

Automated summary

In this work, CDs assembled with dendritic silica nanospheres were developed as environmentally friendly co-reactants for Ru(bpy)(3)(2+). A sandwich immunoassay using CDs@dSiO(2) NPs as co-reactants, a nanoprobe loaded with the secondary antibody, and Ru(bpy)(3)(2+) as a luminophore was constructed for the detection of human chorionic gonadotropin (HCG). The immunosensor exhibited an extremely low limit of detection and excellent stability and selectivity, making it highly promising for clinical applications.