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Interfacial Molecular-level Structures of Polymers and Biomacromolecules Revealed via Sum Frequency Generation Vibrational Spectroscopy
Published on: August 13, 2019
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Third-harmonic generation susceptibility spectroscopy in free fatty acids
Yu-Cheng Chen1, Hsun-Chia Hsu2, Chien-Ming Lee3
1National Taiwan University, Molecular Imaging Center, Taipei 10617, Taiwan.
Journal of Biomedical Optics
|September 26, 2015
Summary
This study explores third-harmonic generation (THG) microscopy for lipid imaging. Researchers found a new wavelength range for enhanced, label-free lipid detection in biological tissues.
Area of Science:
- Biomedical Optics
- Molecular Imaging
- Biophysics
Background:
- Lipid-correlated diseases like atherosclerosis are significant research areas.
- Third-harmonic generation (THG) microscopy is a promising technique for in vivo lipid detection.
- THG microscopy utilizes specific laser wavelengths to visualize lipids in biological samples.
Purpose of the Study:
- To investigate the THG excitation spectroscopy of oleic acid and linoleic acid.
- To identify optimal wavelengths for enhanced THG imaging of lipids.
- To explore new possibilities for label-free lipid imaging in biological tissues.
Main Methods:
- Performed THG excitation spectroscopy on pure oleic acid and linoleic acid samples.
- Measured THG third-order susceptibility (χ(3)) spectra across a wavelength range of 1090 to 1330 nm.
- Analyzed the relationship between THG spectra and resonant absorption wavelengths.
Main Results:
- Observed distinct THG χ(3) spectra for different pure fatty acids.
- Found that peak THG susceptibility did not perfectly align with resonant absorption wavelengths (1190-1210 nm).
- Identified a potential new spectral window (1240-1290 nm) for improved THG lipid imaging.
Conclusions:
- THG microscopy offers label-free lipid visualization capabilities.
- Wavelength selection is crucial for optimizing THG imaging sensitivity and avoiding absorption.
- The 1240-1290 nm window presents significant opportunities for advanced lipid imaging in biological research.
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