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.