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Laser-induced multiphoton fluorescence of hemoglobin
1Laboratory of Laser Spectroscopy, Anhui Institute of Optics and Fine Mechanics, Academia Sinica, China.
Journal of Photochemistry and Photobiology. B, Biology
|March 1, 1988
Summary
This study demonstrates two-photon excitation fluorescence in hemoglobin (Hb) using an Nd:YAG laser. Researchers observed red fluorescence originating from the heme group and potential emission from tryptophan groups.
Area of Science:
- Biophysics
- Laser Spectroscopy
- Photochemistry
Background:
- Hemoglobin (Hb) is crucial for oxygen transport.
- Understanding Hb's photophysical properties is vital for various applications.
- Two-photon excitation offers unique advantages for biological sample analysis.
Purpose of the Study:
- To investigate the two-photon excitation fluorescence of hemoglobin (Hb) and hematoporphyrin derivative.
- To analyze the spectral characteristics of Hb fluorescence under laser irradiation.
- To determine the origin of fluorescence emission in Hb.
Main Methods:
- Irradiation of Hb and other samples using 1064 nm nanosecond pulses from an Nd:YAG laser.
- Measurement of fluorescence emission spectra in the red spectral region.
- Two-photon excitation spectroscopy.
Main Results:
- Observed two red fluorescence bands in Hb at room temperature, attributed to two-photon absorption.
- Measured fluorescence emission spectra for Hb and hematoporphyrin derivative.
- Noted a red shift in wavelength and a mirror image in fluorescence intensity with two-photon excitation.
- Identified the heme group as the origin of Hb fluorescence.
- Detected fluorescence emission at 392 nm, possibly from tryptophan groups in Hb.
Conclusions:
- The fluorescence of hemoglobin primarily originates from its heme group.
- Two-photon excitation spectroscopy reveals distinct fluorescence properties of Hb.
- Further investigation into Hb fluorescence may involve its tryptophan residues.