The Synergistic Effect of Ferrocene and Cu2O to Construct a Sandwich-Type Multi-Signal Amplification Ultra-Sensitive Immunosensor for Carcinoembryonic Antigen Detection

We reported the first use of "coral-like" nanostructure synthesized from MoS2 @ Cu2O/Fc composites with good biocompatibility, large surface areas, and high specificity to create a new ultrasensitive electrochemical immunosensor. We demonstrate its efficacy via quantitative detection of the carcinogenic fetal antigen (CEA) using labeled antibody (Ab2). Owing to the synergistic effect of MoS2, Fc, and Cu2O and the excellent electrocatalytic activity of the nanocomposite, our immunosensor could reduce hydrogen peroxide, expand CEA detection signal, and effectively reduce the loss of Cu2O in acidic environments, dramatically improving the signal. Monitoring the electrocatalytic processes of our immunoprobe (wide dynamic range [0.001 ngml−1-80 ng ml−1] and detection limit as low as 0.03 pg ml−1 [S/N = 3]) with square wave voltammetry (SWV) resulted in the development of an efficient signal amplification mechanism. Our nanostructures could load a large amount of redox-mediated ferrocenecarboxylic acid and Ab2, thus providing a higher electrochemical signal response and sensitivity. Specific detection could be implemented during the test, creating the possibility to exhibit acceptable reproducibility, selectivity, and stability. These results suggest that our immunoprobe provides an effective clinical approach for monitoring tumor markers and demonstrate the potential application of composites for immunosensor manufacturing.