IMPRINTED NANOPARTICLE MATRICES ON AU SURFACES FOR THE ENHANCED AND SELECTIVE DETECTION OF ANALYTES

A versatile method to electropolymerize thioaniline-modified Au nanoparticles (NPs) on thioaniline-functionalized electrodes to yield imprinted bis-aniline Au NPs matrices was developed. By the design of appropriate donor-acceptor interactions or electrostatic interactions between molecular analogs to the analyte molecules, imprinted matrices for the ultrasensitive detection of TNT, RDX, PETN and nitroglycerin were developed. By the co-modification of the thioaniline-functionalized Au NPs with recognition ligands, such as mercaptophenylboronic acid or cysteine, covalent or electrostatic binding of the analytes to the NPs led, after electropolymerization of the NPs and washing-off of the linked imprinted molecules, to aggregated Au NPs matrices. These surfaces were applied for the selective and chiroselective detection of saccharides, the selective analysis of amino acids and peptides, and the selective detection of alkali-earth metal ions. Volammetric or surface plasmon resonance (SPR) analyses were used to follow the binding of the analytes to the recognition sites.

In addition, imprinted bis-aniline-bridged Au NP matrices that included imprinted sites for N,N’-dimethyl-4,4’-bipyridine or N,N’-dimethyl-4,4’-dipyridine ethylene electron acceptor substrates were prepared. The selective binding of the substrates to the matrices was demonstrated, and the electrochemically controlled wettability of the surfaces, upon binding the substrates to the imprinted sites, was achieved.

A further method to yield imprinted nanoparticle matrices has involved the electropolymerization of mercaptoaniline-functionalized Fe₃O₄ magnetic NPs. The magnetic attraction of the nanoparticles in the presence of electron acceptor substrates, e.g., N,N’-dimethyl-4,4’-bipyridinium, to a thioaniline-modified electrode, led, after electropolymerization of the aniline units, to imprinted Fe₃O₄ NP matrices for the electron acceptor substrates.