A three-dimensional graphene-based ratiometric signal amplification aptasensor for MUC1 detection.

A three-dimensional graphene-based ratiometric signal amplification aptasensor for highly sensitive and selective detection of mucin1 (MUC1) by electrochemical method has been developed. Au-reduced graphene oxide (Au-RGO) composite, which was synthesized through hydrothermal reaction and freeze-drying treatment, was used as substrate for fabricating the sensor interface on glassy carbon electrode (GCE). The application of Au-RGO is beneficial for improving electrochemical performance and immobilizing aptamer. Ferrocene labeled aptamer (Fc-Apt), grafting on Au-RGO composite, worked for specific recognition of MUC1 and as internal reference to improve the detection accuracy. Au nanoparticle modified with methyl blue labeled aptamer (MB-Apt@Au) was adopted to combine with MUC1 that captured on the electrode surface to amplify the electrical signal. Under optimal experimental conditions, this sensor was applied to detect a series concentration of MUC1 solution by alternating current voltammetry method. The aptasensor shows satisfactory detection results with a wide linear range of 1 pM to 1 µM, a low detection limit of 0.25 pM and good specificity. The good performance of the prepared electrochemical aptasensor implies that this method has potential for MUC1 detection, and it would be promising for early screening and diagnosis of cancer diseases. The proposed method also lays an important foundation for preparing ratiometric signal amplification aptasensor for other biomarkers detection.