Simpler, cheaper method for DNA sequence recognition is of a greater scientific and economic interest. In this paper, we develop a novel colorimetric detection method for recognition of specific DNA. The detection method bases on the strong distance-dependent optical properties of gold nanoparticles (Au-nps) and the DNA sequences' electrostatic interactions with the Au-nps. As a result of the single-stranded DNA (ssDNA) displaying far higher affinities than double-stranded DNA (dsDNA) to negatively charged Au-nps, when the concentration of salt is added, Au-nps in ssDNA keep stable because of the absorption of large amount of ssDNA, the mixture's color is red. But Au-nps in dsDNA aggregate immediately, and the mixture's color turns out to be blue. Therefore, we can judge whether the hybridization occurs by the mixture's color or absorption spectrums. Au-nps aggregation in this detection mode is not induced by hybridization of target DNA which cross-links the nanoparticles but by salt, then the color transition is rapid and clearly visible. This method is simple, cheap, and we can detect about 2Opmol specific DNA sequences.

Date Published: 27 October 2006
PDF: 6 pages
Proc. SPIE 6047, Fourth International Conference on Photonics and Imaging in Biology and Medicine, 60473X (27 October 2006);

Published in SPIE Proceedings Vol. 6047:
Fourth International Conference on Photonics and Imaging in Biology and Medicine
Kexin Xu; Qingming Luo; Da Xing; Alexander V. Priezzhev; Valery V. Tuchin, Editor(s)