Multiplexed aptasensor for simultaneous detection of carcinoembryonic antigen and mucin-1 based on metal ion electrochemical labels and Ru(NH3)63+ electronic wires

•Signal labels and amplification are realized using metal ion and metal complex ion.•Several different metal ion species allow the simultaneous detection of several targets.•Large numbers of labelling metal ions enable sensitive detection down to 3.33 fM.

In this paper, a dual-target electrochemical aptasensor has been developed for simultaneous detection of carcinoembryonic antigen and mucin-1 based on metal ion electrochemical labels and Ru(NH3)63+ electronic wires. When targets are present, the interaction between targets and their respective aptamers leads to the dissociation of double-strand DNA because the targets have higher affinity to its aptamer than the complementary strand. And the qualitative and quantitative analyses of the two targets are realized by the differential pulse voltammetry (DPV) peaks generated by metal ion electrochemical labels. For the effective loading of a large number of metal ions, Au/bovine serum albumin (Au/BSA) nanospheres are employed as carriers to develop Au/BSA-metal ions. After Ru(NH3)63+ complexes are embedded into double-strand DNA to form the electronic wires, the electrical conductivity and the electron transfer of the detection system are greatly improved. The detection limit of the proposed assay was calculated as 3.33 fM ranging from 0.01 pM to 100 nM. Therefore, this novel sensing assay provides a new and sensitive platform for detecting several targets simultaneously in biochemical research and clinical diagnosis.