A three-dimensional porous network graphene aerogel (GAs) with large specific area and excellent conductivity was loaded with β-cyclodextrin polymer (Pβ-CD) to serve as a support for immobilization of antibodies. A highly sensitive immunosensor for the cancer marker carbohydrate antigen 15-3 (CA15-3) was designed based on the use of Pβ-CD/GAs. The large specific area of GAs warrants high loading with antibodies, and their excellent electrical conductivity warrants strong electrical signals. Based on the synergistic effect of GAs and Pβ-CD, an immunoassay was designed that is making use of hexacyanoferrate as an electrochemical probe and having a pleasantly low working potential of 0.2 V (vs. SCE). Response is linear in the 0.1 mU mL-1 to 100 U mL-1 activity range, and the lower detection limit is 0.03 mU mL-1 (at S/N = 3). The immunoassay is stable, selective and reproducible. It was applied to the analysis of spiked samples, and results were satisfactory. Graphical abstract Schematic of an electrochemical immunoassay for the carbohydrate antigen 15-3. It is based on the use of β-cyclodextrin polymer and a graphene aerogel.
Keywords: Biomarker; Biosensor; Breast cancer; Carbohydrate antigen 15–3; Host-guest immobilization; Human serum; Immunoassay; Three-dimensional structure; β-Cyclodextrin polymer.