Competitive electrochemical aptasensor based on a cDNA-ferrocene/MXene probe for detection of breast cancer marker Mucin1.

A competitive electrochemical aptasensor based on a cDNA-ferrocene/MXene probe is used to detect the breast cancer marker Mucin1 (MUC1). MXene (Ti3C2) nanosheets with excellent electrical conductivity and large specific surface area are selected as carriers for aptamer probes. The ferrocene-labeled complementary DNA (cDNA-Fc) is first bound on the surface of MXene to form a cDNA-Fc/MXene probe. Then, the MUC1 aptamer is fixed to the electrode by Au-S bonds. The sensing electrode is named Apt/Au/GCE. After the probe is complementary to the aptamer, a cDNA-Fc/MXene/Apt/Au/GCE aptasensor is fabricated. When the aptasensor is used for detection of MUC1, a competitive process happens between the cDNA-ferrocene/MXene probe and MUC1, which makes cDNA-Fc/MXene probe detach from the sensing electrode, resulting in a decrease in electrical signal. The difference in the corresponding peak current before and after the competition can be used to indicate the quantitative change in bound MUC1. The proposed competitive electrochemical aptasensor gives a wide linear range of 1.0 pM-10 μM and a low detection limit of 0.33 pM (S/N = 3), which is promising for clinical diagnosis.