Identification of water compartment in bone using ATR-FTIR spectroscopy

Area of Science:

• Biomaterials Science
• Spectroscopy
• Skeletal Biology

Background:

• Bone's mechanical integrity relies on matrix-bound water.
• Attenuated Total Reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy detects bone composition and water.
• Quantifying bone hydration using ATR-FTIR has not been previously established.

Purpose of the Study:

• To identify and validate the water compartment in human bone using ATR-FTIR spectroscopy.
• To establish a method for quantifying bone hydration status.
• To assess the utility of ATR-FTIR for evaluating bone quality.

Main Methods:

• Human bone tissue subjected to dehydration, hydrogen/deuterium (H/D) exchange, and glycation experiments.
• Analysis of changes in the OH region of ATR-FTIR spectra.
• Correlation of spectral peak intensities with weight loss and glycation.

Main Results:

• Four sub-peaks in the OH region were identified, decreasing with dehydration.
• A sub-peak at ~3200 cm⁻¹ disappeared with H/D exchange, confirming its relation to water.
• This ~3200 cm⁻¹ sub-peak intensity strongly correlated with bone weight loss (R² = 0.92) and was reduced in glycated samples.

Conclusions:

• ATR-FTIR spectroscopy can quantify bone hydration status.
• The ~3200 cm⁻¹ spectral peak serves as an indicator of water bound to the bone matrix after short air drying.
• This method offers a rapid and simple approach for assessing bone quality ex vivo.