An electrochemical aptasensor based on Ce-MOF@COF to detect carcinoembryonic antigen

In this work, a gold-supported cerium-based organic framework hybrid structure (Au@Ce-MOF@COF) and gold@molybdenum disulfide@graphene oxide (Au@MoS2@rGO) were successfully prepared, and used for constructing an electrochemical aptasensor to detect carcinoembryonic antigen (CEA). Au@MoS2@rGO has a large surface area and good electron transfer rate, so it was used as the substrate to immobilize more aptamers (Apt1). The prepared Ce-MOF@COF was also used as a substrate for the immobilization of aptamers (Apt2) and horseradish peroxidase (HRP). When CEA exists, CEA binds to Au@Ce-MOF@COF-HRP-Apt2. In the presence of H2O2, it can effectively promote the oxidation of hydroquinone (HQ) to benzoquinone (BQ), and the electrochemical reduction signal of BQ was significantly amplified. So, the highly sensitive and selective detection of CEA was achieved. The linear range of the aptasensor is 0.1 pg mL-1-100 ng mL-1, and the detection limit is 0.019 pg mL-1, which shows excellent selectivity, reproducibility and stability. Finally, the aptasensor was applied to detect CEA in serum. In the presence of H2O2, Au@Ce-MOF@COF-HRP can effectively promote the oxidation of hydroquinone (HQ) to benzoquinone (BQ), and the electrochemical reduction signal of BQ was significantly amplified.