Surface-enhanced Raman Spectroscopic Studies Of DNA And BSA And Their Components

Surface-enhanced Raman Scattering(SERS) technology is widely used as an analytical tool to investigate molecular structure and interaction between molecules and metal surface resulting in strongly increased Raman signals and fluorescence quenching The use of SERS for the research of the permutation orientation and the structure between the interface and the molecules such as the DNA and BSA is meaningful for understanding the living vitality course.This paper studies the SERS of the DNA and adenine,The BSA and its amino acids(L-tyrosine,L-tryptophan) in the presence of anions.Then the adsorption spot and the structure transformation is analyzed. Through the analysis of the spectra information.The adsorption mechanisms in the presence of anions are concluded. The results are acquired below:The first part investigated the SERS of DNA and adenine in the presence of anions (Cl^-,SO₄^2-).The results indicates that with the addition of the Ag colloid, The bands assigned to adenine and C=O group of thymine have a large enhancement, and the band assigned to C=O group shifted downwards to low-wavelength. When the anions were added, all DNA's characteristic bands have enhancement on the basis of the SERS of DNA. Then we concluded that the DNA molecule can absorb on the Ag colloid particle through its adenine and C=O of thymine. At last, the SERS of adenine with anions was recorded to approve the effect mechanism of anions and the interaction spot between the DNA molecule and the Ag particle.The second part investigates the SERS and the adsorptive behavior of the BSA, L-tyrosine and L-tryptophan. No SERS signals are detected in the absence of the inorganic salts under our conditions. But the signals are substantially enhanced withthe addition of the Cl^- and SO₄^2- anions. From the characterization of the Ramanspectra, we conclude that the BSA molecule can adsorb on the Ag colloid particle through its amino acids and the carboxylate group component. The band positions of the amino acid components in the molecule of BSA are in good agreement with those of the corresponding free L-tyrosine and the L-tryptophan molecules.