Water as a Structural Marker in Gelatin Hydrogels with Different Cross-Linking Nature

Area of Science:

• Materials Science
• Polymer Chemistry
• Biophysics

Background:

• Gelatin hydrogels are widely used biomaterials.
• Understanding water's role in hydrogel structure is crucial for applications.
• Cross-linking modifies hydrogel properties and water interactions.

Purpose of the Study:

• To investigate the molecular properties and dynamics of water within cross-linked gelatin hydrogels.
• To correlate water behavior with the structural reinforcement of the polymer network.
• To assess the impact of chemical cross-linking on gelatin's molecular mobility and water structure.

Main Methods:

• Fourier Transform Infrared (FTIR) spectroscopy to analyze molecular structure.
• Nuclear Magnetic Resonance (NMR) relaxation to probe water dynamics.
• Diffusivity measurements to quantify water movement.
• Broadband dielectric spectroscopy to study water's dynamic properties.

Main Results:

• All methods indicated reinforcement of the gelatin hydrogel network structure.
• An increase in the amount of bound (hydrate) water was observed.
• FTIR revealed enhanced stability of collagen-like triple helices due to restricted protein mobility.
• Water properties showed significant changes attributed to protein chain strengthening, remaining stable up to 30-40 °C.

Conclusions:

• Chemical cross-linking significantly reinforces gelatin hydrogel structure and alters water binding.
• Restricted protein mobility due to cross-linking is a key factor influencing water's molecular environment.
• The observed water structural modifications are stable within a physiologically relevant temperature range.