Micro-CT dilatometry measures of molecular collagen hydration using bovine extensor tendon

Area of Science:

• Biophysics
• Materials Science
• Biochemistry

Background:

• Macromolecular hydration is crucial for protein function but complex to study.
• Factors like temperature, pH, and ionic composition influence hydration.
• Understanding protein-solvent interactions is key to deciphering biological processes.

Purpose of the Study:

• Introduce micro-computed tomography (micro-CT) dilatometry as a novel method for studying macromolecular hydration.
• Validate bovine tendon as a model system to investigate protein-solvent interactions.
• Explore the relationship between macroscopic tendon properties and molecular hydration levels.

Main Methods:

• Utilized micro-CT to measure changes in tendon length, diameter, and volume during dehydration.
• Employed gravimetric analysis to determine tendon mass as a function of hydration (h).
• Applied the stoichiometric hydration model (SHM) to relate macroscopic measurements to molecular hydration.

Main Results:

• Observed asymmetric changes in length, diameter, and density consistent with SHM predictions.
• Demonstrated significant changes in hydration at critical levels (h = 0.0653, 0.262, 0.724 g/g).
• Confirmed elevated hydration density (20-50% higher than bulk water) around collagen molecules.

Conclusions:

• Tendon dilatometry, with amplification factors of 10^6-10^8, effectively models protein shape changes in response to solvent.
• This approach provides direct insights into protein hydration and functional responses under physiological conditions.
• Bovine tendon serves as a valuable model for studying the intricate relationship between proteins and their solvent environment.