Viscoelastic Silk Fibroin Hydrogels with Tunable Strength

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Hydrogels are synthetic extracellular matrices (ECMs) for biomedical uses.
• Natural ECMs are viscoelastic, unlike typical elastic synthetic hydrogels.
• ECM-protein hydrogels are viscoelastic but often lack mechanical strength.

Purpose of the Study:

• To fabricate biocompatible viscoelastic hydrogels with excellent mechanical performance.
• To investigate the gelation mechanism and tunable properties of these hydrogels.
• To assess their suitability for cell encapsulation and tissue engineering.

Main Methods:

• Fabrication of hydrogels via an all-aqueous process at body or room temperature.
• Characterization of mechanical properties, including compressive modulus (2 kPa to 1.2 MPa).
• Investigation of the gelation mechanism involving silk fibroin, hydrophobic interactions, and hydrogen bonding.

Main Results:

• Developed viscoelastic hydrogels with obvious stress relaxation and tunable properties.
• Achieved controllable compressive modulus, mimicking native tissue properties.
• Identified silk fibroin crystals as cross-linking sites and noncrystalline nanofibers for viscoelasticity.
• Demonstrated high chondrocyte survival rate (95% ± 1%) after encapsulation.

Conclusions:

• Silk fibroin-based hydrogels exhibit synergistic gelation mechanisms, creating stable, viscoelastic networks.
• The all-aqueous process is suitable for cell and biomolecule encapsulation.
• These hydrogels offer tunable mechanics and biocompatibility for tissue engineering and regenerative medicine.