Electrochemistry/Photoelectrochemistry-Based Immunosensing and Aptasensing of Carcinoembryonic Antigen

Abstract

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.

Keywords: CEA; aptasensor; electrochemistry; immunosensor; photoelectrochemistry.

Figure 1

Overview of electrochemistry- and photoelectrochemistry-based immunosensing and aptasensing of CEA.

Figure 2

Schematic illustration of the preparation process for PtNPs@rGO@PS NSs and the fabrication of the electrochemical label-free immunosensor. Reprinted with permission from ref. [24]. Copyright 2020 American Chemical Society.

Figure 3

(A) The preparation procedures of Au@Pt DNs/NG/Cu²⁺-Ab₂. (B) The fabrication process of the sandwich-type electrochemical immunosensor. Reprinted with permission from ref. [41]. Copyright 2018 Elsevier.

Figure 4

The preparation process of Au@Pd NDs/Fe²⁺-CS/PPy NTs and the schemata of the fabrication process of the working electrode for label-free immunosensors. Reprinted with permission from ref. [47]. Copyright 2018 Elsevier.

Figure 5

Scheme diagram of the DNA-gated MOF-based electrochemical biosensing platform of CEA. (A) Assembly procedure of MB@DNA/MOFs. (B) Target-triggered nicking endonuclease cleavage process. (C) Signal molecule release from MB@DNA/MOFs on the electrode. Reprinted with permission from ref. [74]. Copyright 2020 American Chemical Society.

Figure 6

Fabrication and detection mechanism of the PEC immunosensor. Reprinted with permission from ref. [94]. Copyright 2021 American Chemical Society.

Figure 7

Illustration of the PEC immunoassay for the detection of CEA. Reprinted with permission from ref. [103]. Copyright 2020 American Chemical Society.

Figure 8

Construction of the designed photoelectrochemical immunosensor for CEA monitoring based on the quenching of HCR-modulated Cu²⁺ sources toward TiO₂-sensitized DS-ZnCdS HNs. Reprinted with permission from ref. [105]. Copyright 2021 Elsevier.

Figure 9

Analytical principle of the salt bridge-connected electrochromic PEC immunosensor with DMM readout: (A) The sensing cell; (B) The electrochromic cell. Reprinted with permission from ref. [109]. Copyright 2020 Elsevier.

Figure 10

Schematic diagram of this proposed PEC biosensor for CEA determination. (A) Enzyme-free target cycling amplification strategy for generating S1; (B) Fabrication of the PEC “signal-off-on” biosensor based on ZnSe QDs/Au NPs and 3D DNA nanospheres. Reprinted with permission from ref. [124]. Copyright 2020 Elsevier.

Figure 11

Schematic illustration of the proposed PEC biosensor for CEA determination. Reprinted with permission from ref. [127]. Copyright 2021 Elsevier.

Figure 12

Construction of the up-conversion-mediated ratiometric PEC aptasensor for CEA detection. Reprinted with permission from ref. [129]. Copyright 2019 American Chemical Society.