title: Key Structural Elements of Unsymmetrical Cyanine Dyes for Highly Sensitive Fluorescence Turn-On DNA Probes.
abstract: Unsymmetrical cyanine dyes, such as thiazole orange, are useful for the detection of nucleic acids with fluorescence because they dramatically enhance the fluorescence upon binding to nucleic acids. Herein, we synthesized a series of unsymmetrical cyanine dyes and evaluated their fluorescence properties. A systematic structure-property relationship study has revealed that the dialkylamino group at the 2-position of quinoline in a series of unsymmetrical cyanine dyes plays a critical role in the fluorescence enhancement. Four newly designed unsymmetrical cyanine dyes showed negligible intrinsic fluorescence in the free state and strong fluorescence upon binding to double-stranded DNA (dsDNA) with a quantum yield of 0.53 to 0.90, which is 2 to 3 times higher than previous unsymmetrical cyanine dyes. A detailed analysis of the fluorescence lifetime revealed that the dialkylamino group at the 2-position of quinoline suppressed nonradiative decay in favor of increased fluorescence quantum yield. Moreover, these newly developed dyes were able to stain the nucleus specifically in fixed HeLa cells examined by using a confocal laser-scanning microscope.
authors.affiliation: Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan.
authors.forename: Kakishi
authors.initials: K
authors.lastname: Uno
authors.affiliation: Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan.
authors.forename: Taeko
authors.initials: T
authors.lastname: Sasaki
authors.affiliation: Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, 464-8601, Japan.
authors.forename: Nagisa
authors.initials: N
authors.lastname: Sugimoto
authors.affiliation: Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan.
authors.forename: Hideto
authors.initials: H
authors.lastname: Ito
authors.affiliation: Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan.|JST-ERATO, Itami Molecular Nanocarbon Project, Nagoya University, Chikusa, Nagoya, 464-8602, Japan.
authors.forename: Taishi
authors.initials: T
authors.lastname: Nishihara
authors.affiliation: Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan.|Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, 464-8601, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Hagihara
authors.affiliation: Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan.|Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, 464-8601, Japan.|JST-ERATO, Higashiyama Live-Holonics Project, Nagoya University, Chikusa, Nagoya, 464-8602, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Higashiyama
authors.affiliation: Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan.
authors.forename: Narie
authors.initials: N
authors.lastname: Sasaki
authors.affiliation: Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, 464-8601, Japan.
authors.forename: Yoshikatsu
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan.|Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, 464-8601, Japan.|JST-ERATO, Itami Molecular Nanocarbon Project, Nagoya University, Chikusa, Nagoya, 464-8602, Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Itami
mesh_terms: D002232:Carbocyanines / Q000737:chemistry*; D015342:DNA Probes / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D057230:Limit of Detection; D018613:Microscopy, Confocal; D015394:Molecular Structure; D019047:Phantoms, Imaging; D011804:Quinolines / Q000737:chemistry
chemical_list: D002232:Carbocyanines; D015342:DNA Probes; D005456:Fluorescent Dyes; D011804:Quinolines; C037219:quinoline
keywords: DNA recognition; cell imaging; cyanines; dyes/pigments; fluorescence; structure-activity relationships