Fabrication of glucose-sensitive TiO₂ ultrathin films by molecular imprinting and selective detection of monosaccharides

In this study, we extended the molecular imprinting capability of TiO₂ gel to the monosaccharide family. Composite nanofilms were prepared from d-glucose and titanium n-butoxide, Ti(O-ⁿBu)₄, on a QCM electrode by the surface sol-gel process. After the d-glucose template was removed, the binding behavior of the template and other monosaccharides (d-mannose, d-galactose and d-fructose) was examined by QCM measurement The d-glucose imprinted TiO₂ gel film provided sensitively mass increases for monosaccharides. The largest binding was achieved with d-glucose, showing a maximal binding ratio of 2.3 (λ = M_imp/M_non-imp, mol/mol) between the imprinted and non-imprinted films. The other six-membered monosaccharide guests gave 44-68% binding efficiencies of that of d-glucose. It is concluded that the imprinted TiO₂ gel film could efficiently discriminate the structure of monosaccharide isomers.