Electrochemical transducers based on surfactant bilayers for the direct detection of affinity interactions

The simple methods for the preparing of direct affinity sensors are proposed. The proposed method consists of the immobilizations of either oligonucleotide or antibodies as recognizing elements onto the surfactant bilayer. For DNA-sensor we propose to immobilize oligonucleotide by spontaneous infiltration of hydrocarbon chain bound to oligonucleotide pentadecathymidylate (dT(15)) into the hydrophobic region of surfactant bilayer. The adsorption of antibodies on bilayer surface has resulted in immunosensor development. The direct detection of affinity interactions in both cases has been investigated by impedance spectroscopy. At both studies the significant changes in impedance spectra have observed. The dynamics of response manifestation have been followed the specific DNA-coupling causing the decrease of real part of impedance, whereas the antibody-antigen interaction caused the increase of real part. The obtained results are promising for the development of impedimetric affinity sensors for clinical or environmental applications. (C) 2002 Elsevier Science B.V. All rights reserved.