Abstract

Multiphoton excitation was used to investigate properties of the fluorescent DNA base analogs, 2-aminopurine (2AP) and 6-methylisoxanthopterin (6MI). 2-aminopurine, a fluorescent analog of adenine, was excited by three-photon absorption. Fluorescence correlation measurements were attempted to evaluate the feasibility of using three-photon excitation of 2AP for DNA-protein interaction studies. However, high excitation power and long integration times needed to acquire high signal-to-noise fluorescence correlation curves render three-photon excitation FCS of 2AP not very useful for studying DNA base dynamics. The fluorescence properties of 6-methylisoxanthopterin, a guanine analog, were investigated using two-photon excitation. The two-photon absorption cross-section of 6MI was estimated to be about 2.5 x 10(-50) cm(4)s (2.5 GM units) at 700 nm. The two-photon excitation spectrum was measured in the spectral region from 700 to 780 nm; in this region the shape of the two-photon excitation spectrum is very similar to the shape of single-photon excitation spectrum in the near-UV spectral region. Two-photon excitation of 6MI is suitable for fluorescence correlation measurements. Such measurements can be used to study DNA base dynamics and DNA-protein interactions over a broad range of time scales.

Original languageEnglish (US)
Pages (from-to)44004
Number of pages1
JournalJournal of Biomedical Optics
Volume11
Issue number4
DOIs
StatePublished - Jul 2006

Fingerprint

Photons
DNA
deoxyribonucleic acid
analogs
2-Aminopurine
photons
excitation
Fluorescence
fluorescence
proteins
Proteins
guanines
adenines
Guanine
Adenine
absorption cross sections
Noise
interactions
6-methylisoxanthopterin
curves

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology
  • Clinical Biochemistry
  • Atomic and Molecular Physics, and Optics

Cite this

Multiphoton excitation of fluorescent DNA base analogs. / Katilius, Evaldas; Woodbury, Neal.

In: Journal of Biomedical Optics, Vol. 11, No. 4, 07.2006, p. 44004.

Research output: Contribution to journalArticle

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