Molecular analysis based on surface plasmon spectroscopy for different nature thin films.

• Main Authors: Kostyukevych, S. O., Khrystosenko, R. V., Kostyukevych, K. V., Koptyukh, A. A., Surovtseva, O. R., Kryuchyn, A. A.
• Format: Article
• Language: Ukrainian
• Published: Інститут проблем реєстрації інформації НАН України 2019
• Subjects: surface plasmon resonance; thin films; chalcogenide vitreous semiconductor; poly-aniline; fibrinogen; monoclonal antibodies; поверхневий плазмонний резонанс; тонкі плівки; халькогенідний склоподібний напівпровідник; поліанілін; фібриноген; моно-клональні антитіла
• Online Access: http://drsp.ipri.kiev.ua/article/view/178531

Photodoping process in the thin film structures metal/chalcogenide vitreous semiconductor (AgAs2S3), electro-polymerization mechanism of the polyaniline (PANI) films and formation mechanism of the fibrinogen (FB) molecular films on gold film surfaces were investigated by means of the surface plasmon resonance (SPR) technique based on prism excitation and mechanical scanning of incidence light angle in aggregate with atomic force microscopy (Nanoscope IIIa Dimension 3000).Optical parameters (refractive index, extinction coefficient, thickness) for multilayer systems AgAs2S3 and Au-PANI were determined from the SPR resonance curve analysis based on Fresnel formulas with mathematical formalism Jones scattering matrix as well as special fitting procedure for the experimental and calculated curves with use of the objective function minimization method. For mathematical description of process in the composite material Bruggeman relation was applied. Established is the formation of Ag2S thin intermediate layer (about 0,7–1 nm) during the fabrication of Ag-As2S3 structure which remain invariable their thickness and optical constant under the ultraviolet radiation influence. Suggested is the model of formation of electro-polymerized poly-aniline films — sensitive elements for gas sensors in which the fracture of the main substance is decreased with the thickness growth, which can be explained by the alternating process of fastening free ends of polymer chains together with increasing their length.Features of the FB molecular films formation, at the different concentration (9,3–300 mg/ml) of the protein in phosphate buffer (mm 7,4), were studied based on SPR kinetic curve, when the adsorption of three proteins, FB, its DD- and E-fragments and subsequent their adlayers interactions with monoclonal antibodies against different epitops in native molecules, that were going on the gold film surfaces. Displayed is the formation of the continuous film at the 73 Mg/ml concentration in buffer is visualized, during irreversible adsorption the alteration of the FB molecule structure in the sphere of its D-fragment take place, and the local self-assembling process leads to formation of the special molecular arrangement in biofilm, consist of three overlap FB molecules, where approximately 50 M of total adsorbed molecules which retain their biofunctional properties.