Engineered Tough Silk Hydrogels through Assembling β-Sheet Rich Nanofibers Based on a Solvent Replacement Strategy

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Polymer Chemistry

Background:

• Silk nanofiber hydrogels show promise for tissue regeneration and drug delivery.
• Their application is limited by suboptimal mechanical properties.
• Developing robust silk-based biomaterials is crucial for biomedical advancements.

Purpose of the Study:

• To develop a novel method for fabricating high-performance silk nanofiber hydrogels.
• To enhance the mechanical properties and stability of silk hydrogels.
• To explore the potential of these hydrogels in stem cell applications.

Main Methods:

• Utilized formic acid to facilitate silk nanofiber assembly by shielding charge repulsion.
• Replaced formic acid with water to induce hydrogel solidification and network formation.
• Characterized the mechanical properties (modulus, stress, toughness) and stability of the resulting hydrogels.

Main Results:

• Fabricated tough silk nanofiber hydrogels with a modulus of 5.88 ± 0.82 MPa and toughness of 0.85 ± 0.03 MJ m⁻³.
• Achieved superior mechanical performance compared to hydrogels from complex cross-linking methods.
• Demonstrated good stability and anti-swelling properties due to dense network and high β-sheet content.
• Showcased tunable mechanical properties by adjusting silk nanofiber concentration for stem cell differentiation.

Conclusions:

• The developed method effectively produces high-performance silk nanofiber hydrogels with enhanced mechanical and bioactive properties.
• Understanding silk nanofiber assembly is key to advancing traditional fabrication for superior biomaterials.
• These hydrogels hold significant potential for biomedical and engineering applications, including regenerative medicine.