Potential-Resolved Multicolor Electrochemiluminescence for Multiplex Immunoassay in a Single Sample

Electrochemiluminescence (ECL) is a highly successful technique used in commercial immunoassays for clinical diagnosis. Developing an ECL-based multiplex immunoassay, with the potential to enable high-throughput detection of multiple biomarkers simultaneously, remains a current research interest yet is limited by a narrow choice of ECL luminophores. Herein we report the synthesis, photophysics, electrochemistry, and ECL of several new ruthenium(II) and iridium(III) complexes, three of which are eventually used as signal reporters for multiplex immunoassay. The ECL behaviors of individual luminophores and their mixtures were investigated in multiple modes, including light intensity, spectrum, and image measurements. The spectral peak separation between Ru(bpy)2(dvbpy)2+ (bpy = 2,2′-bipyridine, dvbpy = 4,4′-bis(4-vinylphenyl)-2,2′-bipyridine), and Ir(dFCF3ppy)2(dtbbpy)+ (dFCF3ppy = 3,5-difluoro-2-[5-(trifluoromethyl)-2-pyridinyl]phenyl, dtbbpy = 4,4′-bis(tert-butyl)-2,2′-bipyridine) was up to 145 nm, thus p...