A nanocomposite containing Prussian Blue, platinum nanoparticles and polyaniline for multi-amplification of the signal of voltammetric immunosensors: highly sensitive detection of carcinoma antigen 125

• Published in: Mikrochimica acta (1966) 2017-11, Vol.184 (11), p.4269-4277
• Main Authors: Zheng, Yun, Wang, Huiqiang, Ma, Zhanfang
• Format: Article
• Language: English
• Subjects: Amplification; Analytical Chemistry; Antigens; Biomarkers; Cancer; Carcinoma; Catalysis; Catalytic activity; Characterization and Evaluation of Materials; Chemiluminescence; Chemistry; Chemistry and Materials Science; Electric properties; Electrical conductivity; Electrical measurement; Electrical resistivity; Glassy carbon; Gold; Hydrogels; Hydrogen peroxide; Immunoassay; Immunosensors; Iron compounds; Microengineering; Nanochemistry; Nanocomposites; Nanoparticles; Nanotechnology; Original Paper; Ovarian cancer; Platinum; Polyanilines; Signal to noise ratio; Voltammetry
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-017-2470-2

The authors describe a method for signal amplification of label-free voltammetric immunosensors. A glassy carbon electrode (GCE) was modified with Prussian Blue-platinum nanoparticles (PB-PtNPs) as a redox-active species that gives a strong amperometric signal at 0.18 V (vs. Ag/AgCl). Benefitting from the excellent electrical conductivity and the strong catalytic activity to H 2 O 2 , the modified GCE gives a strongly enhanced signal. The PB-PtNPs were incorporated into a polyaniline (PANI) hydrogel to further enhance the signal. The signal response of the PB-PtNP-PANI/GCE is larger by a factor of 7.6 than that of PB-PtNP/GCE. In order to further improve electrical conductivity and immobilize antibody, gold nanoparticles (AuNPs) were deposited on the surface of the PB-PtNP-PANI hydrogel. The AuNP-PB-PtNP-PANI hydrogel nanocomposite on the GCE was used in an immunosensor for the model analyte carcinoma antigen 125 (CA125), a biomarker for epithelial ovarian cancer, by immobilizing the respective antibody on the modified GCE. A linear response found for the 0.01 to 5000 U mL −1 CA125 concentration range, with a detection limit of 4.4 mU mL −1 (at an S/N ratio of 3). The electrochemical sensitivity is as high as 119.76 μA·(U/mL) −1 ·cm −2 . The detection of CA125 in human serum showed satisfactory accuracy compared to a commercial chemiluminescent microparticle immunoassay (CMIA). Graphical abstract Schematic of a nanocomposites consisting of gold nanoparticles, Prussian Blue, platinum nanoparticles and polyaniline hydrogel as a signal multi-amplification sensing substrate for the ultrasensitive immuno detection of carcinoma antigen 125 (CA125).