AVS 51st International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI2-WeM

Paper BI2-WeM4
Detection of DNA Hybridization by Infrared Absorption Spectroscopy

Wednesday, November 17, 2004, 9:20 am, Room 213C

Session: Oligo Nucleotide - Surface Interactions
Presenter: K. Miyamoto, Tohoku University, Japan
Authors: K. Miyamoto, Tohoku University, Japan
Y. Kimura, Tohoku University, Japan
H. Ishii, Tohoku University, Japan
M. Niwano, Tohoku University, Japan
Correspondent: Click to Email
We have previously proposed a new, label-free method of in-situ (in-vitro) determining the chemical bonding conformation of DNA in aqueous solution, by infrared absorption spectroscopy in the multiple internal reflection geometry (MIR-IRAS). In our method, a Si prism, through which infrared lights penetrate, internally reflecting a number of times, serves as an electrochemical electrode. By applying a positive or negative potential to the electrode (prism), we can manipulate negatively-charged DNA molecules in aqueous solutions. In this study, we have selected the chemical system of complementary DNA as an appropriate template for testing the possible application of our method to biosensors for detecting DNA hybridization. We first collect IRAS spectra for complementary single-stranded (ss) DNAs that are comprised of 30 bases, and then analyze the hybridization by observing the spectral changes in the IRAS spectra caused by mixture of the two complementary DNAs in D@sub 2@O solution. We observed significant spectral changes in the frequency region of 1600-1750 cm@super -1@, where the bases of DNA have specific vibration modes (C=O stretching and -NH@sub 2@ scissoring modes) that are quite sensitive to base-paring. On the other hand, no significant spectral changes were observed for mixture of non-complementary DNAs. This confirms that the observed spectral changes were specifically induced by DNA hybridization. Our method would be capable of detecting and classifying other biomolecules such as proteins and peptides.