Phytic acid-based copper() ion-selective electrode on graphene oxide for potentiometric immunoassay of breast cancer antigen 15-3

• Published in: New journal of chemistry 2019-07, Vol.43 (28), p.11171-11177
• Main Authors: Zheng, Min, Cao, Yong-Jin, Cai, Wei-Hua, Shi, Xi, Wang, Mou-Feng, Deng, Yu-Jie
• Format: Article
• Language: English
• Subjects: Antibodies; Antigens; Biomarkers; Breast cancer; Carbohydrates; Copper compounds; Copper oxides; Electric potential; Electrodes; Gold; Graphene; Immunoassay; Immunosensors; Nanoparticles; Phytic acid
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c9nj01834d

A potentiometric immunoassay based on a copper( ii ) ion-selective electrode (Cu-ISE) was designed for the quantitative determination of carbohydrate antigen 15-3 (CA 15-3; a tumor marker associated with breast cancer). To construct such a Cu-ISE-based assay system, a sandwiched immunoreaction was carried out on a capture antibody-coated microplate by using a cupric oxide (CuO) nanoparticle-labeled detection antibody, whereas the Cu-ISE was prepared on a gold-disk electrode by using phytic acid-functionalized graphene oxide nanosheets as the transducer. Followed by forming the immunocomplexes, the dissolved Cu 2+ ions from CuO nanoparticles by acids were specifically chelated with immobilized phytic acid on the electrode because of the highly efficient complexing ability, thereby resulting in a change of the electrode potential. Under optimum conditions, the Cu-ISE-based potentiometric immunosensor yielded a near Nernstian slope (12.01 ± 0.66 mV dec −1 ) for the detection of CA 15-3 within a dynamic linear range of 0.01-100 U mL −1 with a low detection limit of 5.3 mU mL −1 . Moreover, the Cu-ISE-based immunoassay showed good reproducibility, high specificity and long-time stability. Furthermore, it was applied for the determination of CA 15-3 in human serum specimens, providing well-matched results in comparison with the referenced CA 15-3 ELISA kit. Importantly, the Cu-ISE-based immunoassay provides a promising alternative for simple and reliable screening of disease-related biomarkers. A potentiometric immunoassay based on a copper( ii ) ion-selective electrode (Cu-ISE) was designed for the quantitative determination of carbohydrate antigen 15-3 (CA 15-3; a tumor marker associated with breast cancer).