Scanning Near-field Optical/Atomic Force Microscope Imaging Dye intercalated or Labeled DNA Molecules

J.M. Kim¹, T. Ohtani¹, S. Sugiyama¹, T. Hirose², H. Muramatsu³

1) Dept. of Food Engineering, National Food Research Institute, Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
2) Plant Resources Laboratory, Japan Atomic Energy Research Institute, Takasaki 370-1292, Japan.
3) R&D Center, Seiko Instruments Inc., 563 Takatsuka-shinden, Matsudo-shi, Chiba 270-2222, Japan.

High-resolution fluorescence imaging of l-phage DNA molecules, intercalated with dye YOYO-1 or labeled with Cy3, has been performed by a SNOM/AFM based on a bent type optical fiber probe. We have already presented the optical resolution of 45 nm for the dye YOYO-1 intercalated single l-DNA molecules. As a second step, we will present various dye intercalated or labeled single DNA molecules by the change of intercalation and labeling ratios. Applied ratio is ranged from 1:1(dye:bp) to 1:10, and the resulting fluorescence signals show the change from relatively separated signal to continuous signal by the increasing the ratio. Also, we will discuss several interesting characteristics in the SNOM/AFM imaging for long stranded DNA molecules.

Acknowledgement
Authors thank to Bio-oriented Technology Research Advancement Institute for the support of research.