Enhanced electrochemiluminescence immunosensor using MIL-53(Fe) as co-reaction promoter of Ru(bpy)32+/PEI system for the detection of carcinoembryonic antigen

At present, tumor markers are becoming an increasingly important factor in the diagnosis and treatment of cancer. In this study, an attractive sandwich-type electrochemiluminescence sensor was established for the monitoring of embryonic antigen (CEA)，on account of the Ru(bpy)32+/PEI luminescence system and the faclitation of PEI by MIL-53 (Fe) metal–organic frameworks. In order to achieve the effect of reducing the leakage of ruthenium bipyridyl (Ru(bpy)32+) and stabilizing the luminescence in the system, a new type of ceria material (m-CeO2) with large specific surface area and suitable pore size mesoporous structure was used to load Ru(bpy)32+. Interestingly, the face-centered depressed octahedral MIL-53(Fe) was synthesized in this experiment and used to support Polyethyleneimine (PEI), which also promoted the formation of PEI●. More importantly, MIL-53(Fe) can be used as a new co-reaction promoter for PEI to effectively improve the ratio of Ru(bpy)32+/PEI ，due to the large number of Fe-O clusters and the fast recombination of electron and hole pairs. As a result, the sensitive ECL immunosensor for detecting CEA prepared by sandwich immunoreaction can not only reduce the cumbersome operation of adding co-reaction reagents to the bottom solution, but also greatly improve the convenience of operation and the accuracy of detection. The as-prepared ECL biosensor demonstrated in this paper illustrates extremely selective and sensitive determination of CEA from 10-5 ng/mL to 10 ng/mL and the detection limit of 4.04 fg/mL, which is a great contribution to the prevention and treatment of cancer.