Two-photon excitation of ethidium bromide labeled DNA
1997; Elsevier BV; Volume: 67; Issue: 1-3 Linguagem: Inglês
10.1016/s0301-4622(97)00017-3
ISSN1873-4200
AutoresHenryk Malak, Felix N. Castellano, Ignacy Gryczynski, Joseph R. Lakowicz,
Tópico(s)Spectroscopy and Quantum Chemical Studies
ResumoWe examined the steady state and time-resolved emission of DNA stained with ethidium bromide (EB) when excited with 90 fs pulses from a mode-locked titanium sapphire laser. Over the wavelength range from 840 to 880 nm EB-DNA was found to display two-photon excitation, with a cross-section near 7 × 10−50 cm4s/photon. Frequency-domain intensity decay measurements revealed similar multi-exponential intensity decays for one- and two-photon excitation. Time-resolved anisotropy decay measurements revealed similar correlation times, but different amplitudes as has been observed previously for two- versus one-photon excitation. These results indicate that two-photon excitation of EB-DNA can be accomplished with the fundamental output of a Ti:sapphire laser without obvious heating or perturbation of the DNA.
Referência(s)