Dual suppression amplification based on resonance energy transfer and enzymatic biocatalytic precipitation for IgG electrochemiluminescence ultrasensitive assay

Due to the necessity of ultrasensitive bioassays in life science, electrochemiluminescence (ECL) methodologies coupled with amplification strategies has drawn great attention recently. Herein, a versatile and robust dual suppression-based signal amplification strategy was proposed for IgG specifically ultrasensitive detection. A sandwich ECL sensor was constructed by employing Ru(bpy)32+ adsorbed on silica microspheres (Ru@SiO2) as luminophor. Fe3O4 nanoparticles (Fe3O4 NPs) were introduced on sensing platform through an antigen-antibody affinity, which played double roles. As an acceptor of resonance energy transfer (RET), Fe3O4 NPs remarkably quenched the ECL signal of Ru@SiO2. Meanwhile, Fe3O4 NPs, as a typical peroxidase-mimicking enzyme, catalyzed H2O2 to produce insoluble product based on enzymatic biocatalytic precipitation (BCP). As such, an efficient dual suppressive ECL platform has been achieved by the integration of ECL-RET and BCP techniques, which has been applied to ultrasensitively detect IgG with a linear range and limit of detection of 10 fg/mL to 1 μg/mL and 4.9 fg/mL, respectively. The new integrated system with RET and BCP may provide a potential promising in the development of highly efficient ECL systems for clinical diagnosis.