AVS 53rd International Symposium
    Biomaterial Interfaces Tuesday Sessions
       Session BI-TuP

Paper BI-TuP10
Optical Waveguide Spectroscopy of DNA Molecules Adsorbed on an Amino-Terminated Surface

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Biomaterial Interfaces Poster Session
Presenter: H. Mori, Nagoya University, Japan
Authors: H. Mori, Nagoya University, Japan
M.A. Bratescu, Nagoya University, Japan
N. Saito, Nagoya University, Japan
O. Takai, Nagoya University, Japan
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Deoxyribonucleic acid (DNA) chip has recently emerged as a powerful tool for genetic research. The optical properties of DNA have received considerable attention in the past few years, motivated by the detection of the adsorption processes in a DNA chip. Our work is focused on the adsorption processes study of the DNA molecule, on an amino-terminated self assembling monolayer (SAM) surface. The investigation method is the absorption of the evanescent light by the DNA molecules lying on the surface, in a depth of hundred nanometers. DNA absorption of the evanescent light was performed by using a slab optical waveguide (SOWG), made from quartz, in the UV region, around 260 nm. The average number of total reflections on SOWG surfaces, controlled by the incident light angle was established in order to obtain a maximum absorbance signal. A comparative analysis of the DNA molecules adsorption was investigated on SOWG surface covered with an amino-terminated SAM and on the clean quartz surface of SOWG. The amino-terminated SAM was obtained by dipping the freshly clean SOWG into 1 wt % solution of (3-aminopropyl) trimethoxysilane in toluene for 3 hours at 60°C. Different DNA molecules are investigated: Oligo-DNA (5@super '@-AAAAAAAA-3@super '@), Oligo-DNA (5@super '@-AAATAAAA-3@super '@), Oligo-DNA (5@super '@-TTTTTTTT-3@super '@) and Oligo-DNA (5@super '@-carboxydecyl-TTTTTTTT-3@super '@). The concentration of DNA solution in distilled water was in the range from 25 @micro@M to 200 @micro@M. The time dependence of the absorption spectra shows an increased DNA UV absorbance on SOWG surface covered with amino-terminated SAM as compared with clean SOWG surface.