Muscle-Inspired Self-Growing Anisotropic Hydrogels with Mechanical Training-Promoting Mechanical Properties

Area of Science:

• Materials Science
• Biomaterials Engineering
• Polymer Chemistry

Background:

• Muscles are highly anisotropic, force-bearing tissues.
• Muscle formation involves nutrient absorption and mechanical training for matrix toughening.
• Cyclic disassembly-reconstruction of muscle fibers is crucial for strong anisotropic structures.

Purpose of the Study:

• To develop a mechanical training-associated growing strategy for preparing tough anisotropic hydrogels.
• To mimic the muscle's self-assembly process for material fabrication.
• To enhance the mechanical properties and adaptability of hydrogels.

Main Methods:

• Utilized polyvinyl alcohol (PVA)/tannic acid (TA) hydrogels.
• Incorporated poly(ethylene glycol) diacrylate (PEGDA) by disassembling aligned nanofibrillar structures.
• Applied mechanical training to induce PVA crystallization and restore aligned fibrillar structures.

Main Results:

• Achieved a ≈2 times expansion in hydrogel size.
• Significantly enhanced mechanical properties: Young's modulus (2.4 to 2.85 MPa), ultimate tensile strength (8.2 to 14.1 MPa), and toughness (335 to 465 MJ m⁻³).
• Demonstrated high energy dissipation efficiency (≈90%).

Conclusions:

• The developed strategy successfully prepares tough and adaptable anisotropic hydrogels.
• The process effectively enhances material size and mechanical performance.
• Potential applications include impact-protective materials and surgical sutures.