A chemiluminescence aptasensor for sensitive detection of carcinoembryonic antigen based on dual aptamer-conjugates biorecognition

A dual aptamer-conjugates biorecognition chemiluminescence aptasensor was established for detecting carcinoembryonic antigen (CEA). Method for replacing part of the iron source of MIL-88B (Fe) by hemin, a metalloporphyrinic iron-based metal-organic framework, called as hemin@MIL-88B (Fe), was prepared. Then, hemin@MIL-88B (Fe)/CEA aptamer1 (hemin@MIL-88B (Fe)-apt1) as the large signaling strategy and Luminol-CEA aptamer2 (L-apt2) which can generate the chemiluminescent signal were prepared. The ssDNA was immobilized on the surface of Fe3O4@SiO2 magnetic material, and hemin@MIL-88B (Fe)-apt1 was adsorbed on the Fe3O4@SiO2 by the complementary pairing of the partial bases between ssDNA and CEA apt1. L-apt2 was adsorbed on the matrix material magnetic carbon nanotubes (MCNTs) by the electrostatic adsorption. With CEA as target, hemin@MIL-88B (Fe)-apt1, L-apt2 and CEA formed by sandwiched-like ternary complexes. Introduction of dual aptamer conjugates could effectively solved the CEA detection problem of false positives. The positively charged hemin@MIL-88B (Fe) easily accumulates near the hydroperoxide anion (HO2-) through electrostatic adsorption, thereby catalyzing the luminol transient chemiluminescence system. Under the optimal conditions, a detection range of this strategy was 0.01-100 ng/mL and a detection limit was 1.5 x 10(-3) ng/mL. This chemiluminescent aptasensor is expected to detect other proteins with ultra-sensitivity in clinical diagnosis.