A thorough analysis of the surface chemistry of silica nanowires has been performed by X-ray photoelectron spectroscopy to investigate unexpected surface changes. Examination of the Si 2p, O 1s, and C 1s core level states before and after exposure of the nanowires to various liquid media showed that silica nanowires are capable of much higher surface hydroxyl concentrations than planar native oxides. It is further demonstrated that the nanowire surface hydroxyl concentration corresponds to the pH of the aqueous media to which the nanowires are exposed. Spectral feature changes due to water exposure similar to those observed for fibronectin binding suggests that fibronectin binding is competitively inhibited by slow changes in surface chemistry resulting from water exposure. (C) 2011 Elsevier B. V. All rights reserved.