Simple method for the fabrication of 1-hydroxypyrene-imprinted TiO2 gel nanofilms

In this study, 1-hydroxypyrene (1-OHP)-imprinted TiO2 gel films were prepared by spin coating. Incorporation of the template molecules and their removal were confirmed by UV–vis absorption spectra measurements. Guest selectivity of the 1-OHP-imprinted TiO2 film was estimated to be 1.6, 1.9, and 1.4 against benzoic acid (BA), 1-naphthol (1-NA), and 4-(phenylazo)benzoic acid (4-PABA)-imprinted TiO2 film, respectively. The 1-OHP-imprinted films demonstrated greater binding to 1-OHP than the reference imprinted films. Similar results were obtained with the BA, 1-NA, and 4-PABA-imprinted films, and their guest selectivity against the reference imprinted films amounted to 1.2–3.1 times greater. This result suggests that the binding cavity of the imprinted TiO2 gel matrices discriminates between molecular size, shape, and functional groups. Although much improvement is still needed, this imprinting process is a simple, useful, and less time-consuming way to prepare discriminative receptor cavities.