Carbon nanotube-based transducers for immunoassays

The attachment of mouse immunoglobulin G (IgG) and anti-mouse IgG antibodies onto carbon nanotubes (CNTs), using either non-covalent or covalent means was investigated. The resultant CNTs were characterised using a variety of techniques including enzyme-linked and fluorescence-linked immunoassays, UV–visible-NIR and Raman spectroscopy, transmission electron microscopy and cyclic voltammetry. TEM images of the adsorbed antibody on the CNTs show that the covalent modification approach was successful, whereas the non-covalent approach resulted in no electrochemically detectable labelled antibody. Direct electrical communication between CNTs covalently linked to peroxidase-labelled antibodies was observed during cyclic voltammetry, which suggests applications in developing carbon-nanotube-based immunosensors.