A ruthenium-containing polyoxometalate Rb(8)K(2)[{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)]center dot 25H(2)P (RuSiW(10)) with two redox-active centers of Ru and W was assembled on quartz, and ITO by the layer-by-layer self-assembly method. The regular assembled process was monitored by collecting UV-vis spectra of film after each bilayer recycle. The electrochemical properties were studied by cyclic voltammetry and hydrodynamic amperometry. The composite film showed electrocatalytic activity towards reduction of NO(2)(-) attributing to SiW(10) units, and oxidation of ascorbic acid, benzyl alcohol, and dimethyl sulfoxide (DMSO) arised from the Ru(4)O(6) core. It may provide a novel material as bifunctional electrocatalyst for oxidation and reduction reactions, and amperometric sensor for the detection of NO(2)(-) and ascorbic acid. (C) 2010 Elsevier B.V. All rights reserved.