Selective Adsorption of Molecules by Imprinted Titania Nanohybrid Thin Films with Anchored Cyclodextrin Host Molecules

Abstract

A novel combination of cyclodextrin hosts and imprinting effects in TiO₂ gel ultrathin layers prepared by the gas-phase surface sol-gel process was demonstrated. For bisphenol A (BPA) imprinting in TiO₂ films, a complex of β-CD/BPA (from 1:1 to 3:1) and Ti(O-ⁿBu)₄ were alternately deposited on a quartz crystal microbalance (QCM) electrode, and then the BPA template was removed by washing with ethanol. The film formation and sensing ability of the TiO₂/(β-CD/BPA) films were confirmed by QCM frequency measurements. The imprinted TiO₂/(β-CD/BPA, 2:1) film showed about 7 times higher selectivity than the non-imprinted TiO₂/β-CD film, showing a sensitivity lower than 50 ppb to BPA. The present approach has potential for the detection of a variety of organic compounds in liquids and gases.