Imprinting of specific molecular recognition sites in inorganic and organic thin layer membranes associated with ion-sensitive field-effect transistors

Abstract

Molecular recognition sites were imprinted in inorganic TiO 2 films, and acrylamide–acrylamidephenylboronic acid copolymer membranes, associated with ion-sensitive field-effect transistors, ISFETs, that act as transduction devices for the association of the substrates to the imprinted membranes. Molecular structures of carboxylic acids, e.g. 4-chlorophenoxyacetic acid ( 1 ), 2,4-dichlorophenoxyacetic acid ( 2 ), fumaric acid ( 3 ), and maleic acid ( 4 ), are imprinted in TiO 2 films. The imprinted sites reveal high specificity, and substrates, structurally-related to the imprinted compounds are fully differentiated by the imprinted membranes. The specificity of the imprinted sites originates from the complementary structural fitting and ligation of the guest carboxylic acid residues to the Ti(IV)–OH sites in the host carboxylic acids to the imprinted cavities. An acrylamide–acrylamidephenylboronic acid copolymer acts as a functional polymer for the imprinting of nucleotides, e.g. adenosine 5′-monophosphate, AMP, ( 7 ), guanosine 5′-monophosphate, GMP, ( 8 ), or cytosine 5′-monophosphate, CMP, ( 9 ). The specificity of the imprinted nucleotide sites originates from the cooperative binding interactions between the nucleotides and the boronic acid ligand and acrylamide H-bonds. The detection regions and sensitivities for sensing of the different substrates by the functional polymers are determined.