Tissue Characterization Using Synchrotron Radiation at 0.7 THz to 10.0 THz with Extended ATR Apparatus Techniques

Area of Science:

• Terahertz (THz) spectroscopy
• Far-infrared spectroscopy
• Materials characterization

Background:

• Water and water-dominated compounds exhibit unique spectral properties in the THz-far infrared range.
• Characterizing biological specimens often requires non-destructive methods with minimal sample preparation.
• Existing techniques may lack the sensitivity or real-time capabilities for certain analyses.

Purpose of the Study:

• To develop and demonstrate a novel THz-ATR spectroscopy method for characterizing water-based substances.
• To identify spectral signatures indicative of bound and bulk water.
• To explore the potential of this technique for analyzing biological specimens, including fats and oils.

Main Methods:

• Utilized an attenuated total reflection (ATR) apparatus with a partial reflection/partial transmission mode.
• Employed a diamond-crystal-equipped ATR probe for measurements at the Australian Synchrotron THz-far infrared beamline.
• Investigated spectral scans of water-based substances across the 0.7 to 10.0 THz frequency range.
• Monitored temperature-dependent changes in reflectance to identify spectral features.

Main Results:

• Observed a distinct "crossover flare" feature characteristic of water and water-dominated compounds.
• Identified a "quiet zone" in the spectra where no temperature-dependent reflectance variation occurred.
• Demonstrated that variations in these spectral features serve as signatures for bound and bulk water.
• Showed potential for identifying fats and oils in biological samples.

Conclusions:

• The novel THz-ATR method provides a non-destructive, low-preparation technique for analyzing water-based substances.
• Spectral features like "crossover flare" and "quiet zone" can differentiate water states and potentially identify other biomolecules.
• This technique offers promising avenues for real-time analysis in medical diagnostics and industrial applications.