Aggregation-Induced\nEnhanced Electrochemiluminescence\nResonance Energy Transfer Biosensor for Ultrasensitive Detection of\n Carcinoembryonic Antigen Based on Donor–Acceptor Organic Nanoparticles

Aggregation-induced electrochemiluminescence (AIECL)\ncombines the\nmerits of aggregation-induced emission (AIE) and electrochemiluminescence\n(ECL), which has become a research hot spot in recent years. Therefore,\nwe synthesized a novel AIE compound (<i>Z</i>)-3-(4-(2-butyl-1,3-dioxo-2,3-dihydro-1<i>H</i>-benzo[de]isoquinolin-6-yl)phenyl)-2-(4-(1,2,2-triphenylvinyl)phenyl)acrylonitrile\n(TPENI) with a donor-acceptor (D-A) structure, that is, a simple peripheral\nmodification of 4-(2-butyl-1,3-dioxo-2,3-dihydro-1<i>H</i>-benzo[de]isoquinolin-6-yl) benzaldehyde (NI-CHO) with AIE-active\ntetraphenylethylene (TPE) to achieve the transition of NI-CHO from\naggregation-caused quenching (ACQ) to an AIE molecule. When TPENI\nwas in the aggregated state, the luminescence intensity was significantly\nenhanced due to the TPE structural unit restricting the free rotation\nof the intramolecular benzene ring, as well as the π-π\nstacking interactions of the molecules, which was conducive to the\npreparation of TPENI NPs as ECL materials. Satisfactorily, we found\nthat the ECL intensity of TPENI NPs was increased by about 4.8-fold\ncompared with that of the molecules dispersed in organic solution,\nand the stability reached about 1000 s. Based on the excellent ECL\nproperties of TPENI NPs, an “on-off-on” ECL biosensor\nwith a wider detection range (1 fg/mL to 100 ng/mL) and a lower detection\nlimit of 0.20 fg/mL (S/N = 3) was proposed for sensitive analysis\nof a carcinoembryonic antigen (CEA). Overall, this work provided a\nnew approach to the realization of AIECL and laid the foundation for\nthe application of naphthalimide derivatives in ECL.