title: Near-field optical imaging of abasic sites on a single DNA molecule.
abstract: Scanning near-field optical microscopy (SNOM) imaging was performed to allow for the direct visualization of damaged sites on individual DNA molecules to a scale of a few tens of nanometers. Fluorescence in situ hybridization on extended DNA molecules was modified to detect a single abasic site. Abasic sites were specifically labelled with a biotinlylated aldehyde-reactive probe and fluorochrome-conjugated streptavidin. By optimizing the performance of the SNOM technique, we could obtain high contrast near-field optical images that enabled high-resolution near-field fluorescence imaging using optical fiber probes with small aperture sizes. High-resolution near-field fluorescence imaging demonstrated that two abasic sites within a distance of 120 nm are clearly obtainable, something which is not possible using conventional fluorescence in situ hybridization combined with far-field fluorescence microscopy.
authors.affiliation: ISIR-Sanken, Osaka University, 8-1 Mohogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: JongMin
authors.initials: J
authors.lastname: Kim
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Muramatsu
authors.forename: HeaYeon
authors.initials: H
authors.lastname: Lee
authors.forename: Tomoji
authors.initials: T
authors.lastname: Kawai
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D001665:Binding Sites; D019921:Biotinylation; D004247:DNA / Q000032:analysis* / Q000737:chemistry*; D004249:DNA Damage; D005336:Fiber Optic Technology; D005456:Fluorescent Dyes; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods*; D015335:Molecular Probes / Q000737:chemistry; D055100:Optical Fibers; D019809:Streptavidin / Q000737:chemistry
chemical_list: D000447:Aldehydes; D005456:Fluorescent Dyes; D015335:Molecular Probes; D004247:DNA; D019809:Streptavidin