Simple "Signal‐Off" Electrochemical Aptasensor Based on Aptamer‐Cu3(PO4)2 Hybrid Nanoflowers/Graphene Oxide for Carcinoembryonic Antigen Detection.

A signal‐off aptasensor was described based on well‐designed aptamer‐Cu3(PO4)2 hybrid nanoflowers&graphene oxide composites (aptamer‐Cu3(PO4)2HNF&GO) as an effective sensing platform and molybdophosphate precipitation as the signaling element. The aptamer, as the biorecognition unit grafted on aptamer‐Cu3(PO4)2HNF&GO by the specificity of streptavidin and biotin, captured the carcinoembryonic antigen (CEA) through specific interaction. The molybdophosphate precipitation were formed by the reaction of the aptamer‐Cu3(PO4)2HNF&GO with molybdate (MoO42−). However, the CEA‐aptamer bioconjugate layer films not only hinder electron transfer on the sensing interface, but also impede the formation of molybdophosphate precipitation, resulting that the current signal significantly decreased. So, a simple aptasensor for CEA was constructed with high sensitivity and signal‐off model. Under optimal experimental conditions using square wave voltammetry (SWV), the response peak currents decreases linearly with the logarithm of CEA concentrations in the range from 10 fg mL−1 to 500 ng mL−1. Also, the feasibility of its applications has also been demonstrated in the analysis of clinical serum samples. [ABSTRACT FROM AUTHOR]