A novel electrochemical immunosensor was developed for the simultaneous detection of alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA) using Cu2O–graphene oxide–β-cyclodextrin (Cu2O–GO–CD) and β-cyclodextrin–graphene oxide–ferrocenecarboxylic acid (GO–CD–Fc–COOH) as the distinguishable signal probe, and graphene oxide–gold nanoparticles (GO–AuNPs) as the sensor platform. GO–CD displayed excellent solubility in water and rich capture capability to Fc–COOH and the secondary antibody. The proposed immunosensor exhibited an excellent electrochemical performance. The linear ranges were from 0.001 ng mL−1 to 80 ng mL−1 for AFP and CEA with a detection limit of 0.0002 ng mL−1 for AFP and 0.0001 ng mL−1 for CEA. With the merits of acceptable stability, high sensitivity, a wide linear range and a low detection limit, the proposed immunosensor showed great potential for the simultaneous detection of multi-analytes in clinical diagnosis.

A novel electrochemical immunosensor was developed for carcinoembryonic antigens (CEA) based on gold nanoparticle load carbon nanotubes (CNTs–AuNPs) as an immunosensor platform and porous CuO nanowire supported ferrocene (pCuOw@Fc) as signal amplification labels. The pCuOw were prepared by a simple decomposition of the Cu(OH)2 precursor. The products were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The electrochemical performance of the resulting immunosensor was investigated by cyclic voltammetry (CV), and the electrochemical immunosensor showed enhanced electrochemical performance toward the detection of CEA with a range from 0.005 ng mL−1 to 80 ng mL−1 and a detection limit of 0.0008 ng mL−1 (S/N = 3). The proposed immunosensor was successfully used in determining the CEA in real samples and holds great potential for the sensitive electrochemical biosensing of other analytes.

•Immunosensor based on Fe3O4@SiO2 was prepared.•Amino-functionalized Fe3O4@SiO2 was loading a large amount of Fc-COOH.•Fe3O4@SiO2–Fc–Ab2/HRP was as signal label could achieve signal amplification.•The HRP on the probe could accelerate the decomposition of H2O2.•The immunosensor exhibited a low detection limit of 0.0002 ng/mL for CEA.A sandwich-type electrochemical immunosensor was developed for sensitive detection of carcinoembryonic antigen (CEA) by using ferroferric oxide@silica–amino groups (Fe3O4@SiO2–NH2) as carriers and gold nanoparticles–graphene oxide (GO–AuNPs) as platform. The Fe3O4@SiO2–NH2 surface was used as linked reagents for co-immobilization of ferrocenecarboxylic acid (Fc-COOH) and secondary anti-CEA (Ab2) to prepare the signal probe, and it also could hasten the decomposition of hydrogen peroxide (H2O2) to amplify signals. Differential pulse voltammetry (DPV) was successfully used to quantify CEA. Under the optimized conditions, the designed immunosensor shows an excellent analytical performance wide dynamic response range of CEA concentration from 0.001 ng mL−1 to 80 ng mL−1 with a relatively low detection limit of 0.0002 ng mL−1 (S/N=3), and high specificity and good reproducibility. The proposed immunosensor was successfully used to determine CEA in spiked human serum samples.

In this article, a novel electrochemical immunosensor was proposed based on ferrocenecarboxylic acids (Fc-COOH) connected to the branched structure of an electrode surface for the detection of carcinoembryonic antigen (CEA). The electrode was first modified with multi-walled carbon nanotubes–chitosan (MWCNT–CS) complexes, and the MWCNT–CS coating contains active secondary reaction functional entities that could form covalent bonds with molecules containing carboxyl or aldehyde groups. A large number of Fc-COOH groups were connected to the branched structure of the electrode surface, and then the electrode was further modified with polydopamine (PDA) and gold nanoparticles (AuNPs), which not only provided a favorable microenvironment and increased the loading capacity of the biomolecules to maintain the activity of the immobilized biomolecules, but also enhanced the conductivity and charge-transport properties of the modified electrode. Under optimal conditions, the immunosensor showed a low limit of detection (0.002 ng mL−1) and a wide linear range (0.01–80 ng mL−1). With the merits of acceptable stability, high sensitivity, the wide linear range and the low detection limit, the new immunosensors show great potential in the field of analytical applications.

A novel electrochemical immunosensor was developed for the simultaneous detection of alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA) using Cu2O–graphene oxide–β-cyclodextrin (Cu2O–GO–CD) and β-cyclodextrin–graphene oxide–ferrocenecarboxylic acid (GO–CD–Fc–COOH) as the distinguishable signal probe, and graphene oxide–gold nanoparticles (GO–AuNPs) as the sensor platform. GO–CD displayed excellent solubility in water and rich capture capability to Fc–COOH and the secondary antibody. The proposed immunosensor exhibited an excellent electrochemical performance. The linear ranges were from 0.001 ng mL−1 to 80 ng mL−1 for AFP and CEA with a detection limit of 0.0002 ng mL−1 for AFP and 0.0001 ng mL−1 for CEA. With the merits of acceptable stability, high sensitivity, a wide linear range and a low detection limit, the proposed immunosensor showed great potential for the simultaneous detection of multi-analytes in clinical diagnosis.

In this article, a novel electrochemical immunosensor was proposed based on ferrocenecarboxylic acids (Fc-COOH) connected to the branched structure of an electrode surface for the detection of carcinoembryonic antigen (CEA). The electrode was first modified with multi-walled carbon nanotubes–chitosan (MWCNT–CS) complexes, and the MWCNT–CS coating contains active secondary reaction functional entities that could form covalent bonds with molecules containing carboxyl or aldehyde groups. A large number of Fc-COOH groups were connected to the branched structure of the electrode surface, and then the electrode was further modified with polydopamine (PDA) and gold nanoparticles (AuNPs), which not only provided a favorable microenvironment and increased the loading capacity of the biomolecules to maintain the activity of the immobilized biomolecules, but also enhanced the conductivity and charge-transport properties of the modified electrode. Under optimal conditions, the immunosensor showed a low limit of detection (0.002 ng mL−1) and a wide linear range (0.01–80 ng mL−1). With the merits of acceptable stability, high sensitivity, the wide linear range and the low detection limit, the new immunosensors show great potential in the field of analytical applications.