Sandwich-Type Electrochemiluminescence Immunosensor Based on CDs@dSiO(2) 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.