Supramolecular Amperometric Immunosensor for Detection of Human Chorionic Gonadotropin

Abstract

10.1002/elan.201400103Human 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-ßhCG 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