Supramolecular Amperometric Immunosensor for Detection of Human Chorionic Gonadotropin

Human chorionic gonadotropin (hCG) is a hormone produced in high concentrations through the placental trophoblasts and is used for the detection of pregnancy and certain diseases. Here we explored a supramolecular strategy for the potentially substrateless amperometric detection of hCG. A carboxymethylcellulose (CMC) carrier was synthesised and trifunctionalised with anti‐βhCG antibody, horse radish peroxidase (HRP) and ferrocene (Fc) moieties. The ferrocene was used to house the functionalised CMC within the cavities of electrode surface immobilised cyclodextrin, via host‐guest interactions. hCG was detected via a sandwich format, forming an immunocomplex between the surface immobilised antibody and a glucose oxidase/lactate oxidase labelled secondary antibody. Following formation of the immunocomplex, lactate/glucose, which would typically be present in serum/urine samples, was added and the hydrogen peroxide formed detected at the electrode surface via the HRP‐Fc enzyme‐mediator couple. The work reported demonstrates a potential supramolecular platform for the detection of targets in blood/urine samples using endogenous substrates.