Hofmeister effect in gelatin-based hydrogels with shape memory properties.

Area of Science:

• Materials Science
• Biomaterials Engineering
• Physical Chemistry

Background:

• Gelatin hydrogels are promising biomaterials, but their properties require precise control.
• The Hofmeister effect, influencing protein behavior in ionic solutions, offers a potential strategy for hydrogel fabrication.
• A detailed understanding of how Hofmeister ions modulate gelatin hydrogel properties is lacking.

Purpose of the Study:

• To investigate the detailed effects of Hofmeister ions on gelatin hydrogel properties.
• To elucidate the mechanism by which ions influence gelatin's structural and mechanical characteristics.
• To leverage the Hofmeister effect for fabricating functional gelatin-based hydrogels.

Main Methods:

• Systematic study of gelatin hydrogels in solutions containing various Hofmeister ions (kosmotropic and chaotropic).
• Characterization of hydrogel structural, thermal, viscoelastic, and mechanical properties.
• Fabrication of gelatin-poly N-methylolacrylamide (PNMA) double network hydrogels.

Main Results:

• Kosmotropic anions (citrate, sulfate, phosphate, thiosulfate) strengthened hydrogen bonds and hydrophobic interactions, increasing triple helix length and content, thus enhancing hydrogel properties.
• Chaotropic anions (iodide, thiocyanate) weakened inter-molecular interactions, attenuating hydrogel properties.
• Successfully fabricated gelatin-PNMA double network hydrogels with shape memory properties using the Hofmeister effect.

Conclusions:

• The Hofmeister effect provides a powerful tool for tuning gelatin hydrogel properties.
• Kosmotropic ions are beneficial for enhancing gelatin hydrogel performance.
• This study offers a rational design strategy for functional gelatin-based hydrogels via ion modulation.