Dual-mode immunosensor based on Cu-doped Mo 2 C nanosheets as signal labels

A method for detecting of Carcinoembryonic antigen(CEA) with improved accuracy is urgently needed. In this work, a dual-mode immunosensor for accurate detection of CEA was fabricated, which used a Cu-doped Mo C co-catalyst as an enhancer. Especially, Cu-doped Mo C presents a strong different pulse voltammetry (DPV) signal for the electron transfer between Cu and Cu , without the addition of K [Fe(CN )] and other electron transfer mediators, but also shows high electrocatalytic activity towards H O redox reactions. So that detection sensitivity of the chronoamperometry (CA) was enhanced. Furthermore, characterized by excellent conductivity, highly ordered pore distribution and great surface area, Ti C Mxenes can be effective in promoting electron transfer and loading a large number of AuNPs. In the meantime, AuNPs can also immobilize CEA-Ab through Au-N bonds. Based on a Cu-Mo C-Au dual-signal indicator, Ti C Mxene-Au as the matrix, the immunsosensor was developed to achieve dual-signal detection of CEA. Satisfactory detection ranges (1 fg.mL to 40 ng.mL ) were obtained with limits of detection of 0.33 fg.ml (DPV) and 1.67 fg.ml (CA), respectively. Therefore, the prepared electrochemical immunosensor has good application prospects for the detection of CEA.