Fabrication of multilayer films containing horseradish peroxidase and polycation-bearing Os complex by means of electrostatic layer-by-layer adsorption and its application as a hydrogen peroxide sensor

Layer-by-layer (LBL) assembled multilayer films were obtained on the surface of quartz slides and gold electrode by alternating deposition of negatively charged horseradish peroxidase (HRP) and quaternized poly(4-vinylpyridine) complexed of (Os(bpy)(2)Cl)(+/2+) (PVP-Os). The assembly process was monitored by UV-VIS spectroscopy. The electrochemical behavior of the enzyme electrode showed that multilayer films containing the enzyme and the redox polymer were highly stable. Mediator PVP-Os in the multilayer films as electron shuttle was able to transfer electrons successfully between the active center of the immobilized HRP and the electrode surface. The enzyme electrode of multilayer films was sensitive for the electrocatalytic reduction of hydrogen peroxide and can be used as amperometric sensors for hydrogen peroxide. (C) 2000 Elsevier Science B.V. All rights reserved.