The incorporation of antibody to Listeria into polypyrrole films during electropolymerisation and the covalent attachment of these antibodies to the conducting polymer backbone after polymerisation have been investigated. While the former approach provides a simple and convenient means of immobilisation, enzyme-linked immunosorbent assay tests have shown that covalent attachment produces a more bioactive surface and greatly improved reproducibility. (C) 2002 Elsevier Science B.V. All rights reserved.