Perylene Dianhydride and Perylene Diimide Luminophores Integrated with Gold Nanoparticles for Dual-Potential Electrochemiluminescence Ratiometric Immunosensors

In electrochemiluminescence (ECL) field, screening luminophores, especially potential-resolved luminophores with the same parent chromophore, is essential for the development of fundamental theory study and accurate assay application such as ratiometric assay in biomedical research and clinical diagnosis. In this work, we developed a luminophore, reported a pair of potential-resolved luminophores with perylene as chromophore, and fabricated a dual-potential ECL ratiometric immunosensor. Luminophore chlorine-substituted perylene dianhydride (PTCDA-Cl₄) was reported to produce strong ECL at −1.2 V with a wavelength at 630 nm. The ECL mechanism was interpreted with excited J-type PTCDA-Cl₄ dimers. PTCDA-Cl₄ and perylene diimide exhibited potential-resolved ECL features with K₂S₂O₈ as a coreactant between 0 and −1.2 V, which were used to integrate gold nanoparticles for fabricating dual-potential ECL ratiometric immunosensors to detect α-fetoprotein (AFP). The biosensor showed good linear response for AFP from 10 fg mL^–1 to 100 pg mL^–1 with a detection limit of 3.33 fg mL^–1. The biosensor also showed good application in real sample detection.