Share Email Print
cover

Proceedings Paper

Fluorescence intensity and anisotropy decays of the DNA stain Hoechst 33342 resulting from one-photon and two-photon excitation
Format Member Price Non-Member Price
PDF $17.00 $21.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

We studied the steady state and time-resolved fluorescence spectral properties of the DNA stain Hoechst 33342 for one-photon (OPE) and two-photon (TPE) excitation. Hoechst 33342 was found to display a large cross-section for two-photon excitation within the fundamental wavelength range of pyridine 2 and rhodamine 6G dye lasers, 690 to 770 nm and 560 to 630 nm, respectively. The time-resolved measurements show that intensity decays are similar for one- and two-photon excitation. The anisotropy decay measurements of bis-benzimide, 2,5'-bi-1H-benzimidazole, 2'-(4- ethoxphenyl)-5-(4-methyl-1-piperazinyl) (HOECHST 33342) in ethanol revealed the same correlation times for two-photon excitation as observed for one-photon excitation. However, the zero-time anisotropies recovered from anisotropy decay measurements are 1.4-fold higher for two-photon excitation than for one-photon excitation. The anisotropy spectra of Hoechst 33342 was examined in glycerol at -20 degree(s)C, revealing limiting values close to the theoretical limits for one-photon (0.4) and two-photon (0.57) excitation. The steady-state anisotropy for one-photon excitation decreases in the shorter wavelength region (R6G dye laser, 280 to 315 nm), but the two-photon anisotropy for 560 to 630 nm excitation remains as high as in the long- wavelength region (690 to 770 nm). This result suggests that one- photon absorption is due to two electronic transitions, but only one transition contributes to the two-photon absorption over the wavelength range from 580 to 770 nm.

Paper Details

Date Published: 17 August 1994
PDF: 9 pages
Proc. SPIE 2137, Time-Resolved Laser Spectroscopy in Biochemistry IV, (17 August 1994); doi: 10.1117/12.182738
Show Author Affiliations
Ignacy Gryczynski, Univ. of Maryland/Baltimore School of Medicine (United States)
Joseph R. Lakowicz, Univ. of Maryland/Baltimore School of Medicine (United States)


Published in SPIE Proceedings Vol. 2137:
Time-Resolved Laser Spectroscopy in Biochemistry IV
Joseph R. Lakowicz, Editor(s)

© SPIE. Terms of Use
Back to Top