The application of the inexpensive and synthetically simple electrocatalyst CuFe-MoC@NG in immunosensors

Dual-mode immunosensor based on Cu-doped Mo2C 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 Mo₂C co-catalyst as an enhancer. Especially, Cu-doped Mo₂C presents a strong different pulse voltammetry (DPV) signal for the electron transfer between Cu²⁺ and Cu⁺, without the addition of K₃[Fe(CN₆)] and other electron transfer mediators, but also shows high electrocatalytic activity towards H₂O₂ 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, Ti₃C₂ Mxenes can be effective in promoting electron transfer and loading a large number of AuNPs. In the meantime, AuNPs can also immobilize CEA-Ab₁ through Au-N bonds. Based on a Cu-Mo₂C-Au dual-signal indicator, Ti₃C₂ Mxene-Au as the matrix, the immunsosensor was developed to achieve dual-signal detection of CEA. Satisfactory detection ranges (1 fg.mL^-1 to 40 ng.mL^-1) were obtained with limits of detection of 0.33 fg.ml^-1 (DPV) and 1.67 fg.ml^-1 (CA), respectively. Therefore, the prepared electrochemical immunosensor has good application prospects for the detection of CEA.

Electrochemistry/Photoelectrochemistry-Based Immunosensing and Aptasensing of Carcinoembryonic Antigen

Recently, electrochemistry- and photoelectrochemistry-based biosensors have been regarded as powerful tools for trace monitoring of carcinoembryonic antigen (CEA) due to the fact of their intrinsic advantages (e.g., high sensitivity, excellent selectivity, small background, and low cost), which play an important role in early cancer screening and diagnosis and benefit people's increasing demands for medical and health services. Thus, this mini-review will introduce the current trends in electrochemical and photoelectrochemical biosensors for CEA assay and classify them into two main categories according to the interactions between target and biorecognition elements: immunosensors and aptasensors. Some recent illustrative examples are summarized for interested readers, accompanied by simple descriptions of the related signaling strategies, advanced materials, and detection modes. Finally, the development prospects and challenges of future electrochemical and photoelectrochemical biosensors are considered.