A photoelectroactive TiO2/DNA hybrid film was synthesized via the liquid phase deposition (LPD) process. Scanning electron microscopic (SEM) characterization showed that the compact TiO2 film was changed to a mesoporous structure when DNA was present in the deposition solution, which might be the result of TiO2 particles growing along the backbones of the double-helical structure of DNA molecules. Although UV absorption spectra and cyclic voltammograms indicated that the deposited TiO2 on the substrate surface was decreased in the presence of DNA, an enhanced photocurrent response was observed. The electrochemical impedance and cyclic voltammetric measurements using K-3[Fe(CN)(6)] as a redox probe suggested that the mesoporous film provided a relatively more efficient electron transfer interface, which could improve the photoelectron transfer rate from the semiconducting film to the electrode and reduce the recombination of photoelectrons and holes. This results in an enhanced photocurrent. Even after long-term and continuous UV irradiation, the mesoporous film exhibited a promoted photoelectrochemical response. The promoted photoelectrocatalytic degradation of methylene blue was obtained on the TiO2/DNA composite film, which is consistent with the enhanced photocurrent, and this demonstrates that DNA behaved as a useful biomaterial for the synthesis of a photoelectroactive hybrid film with improved performance. (C) 2010 Elsevier Ltd. All rights reserved.