4D-Printed PLA/PEG/Mg Gyroid Metamaterial Scaffolds: Mechanistically Tunable Degradation and Body-Safe Shape...

Area of Science:

• Biomaterials Engineering
• Regenerative Medicine
• Polymer Science

Background:

• Smart bone scaffolds need safe actuation, controlled degradation, and mechanical support.
• Current scaffolds often lack integrated control over these critical features.

Purpose of the Study:

• To develop 4D-printed gyroid scaffolds with coupled shape recovery and tunable degradation.
• To investigate the effect of magnesium incorporation on scaffold properties and performance.

Main Methods:

• Fused deposition modeling of polylactic acid (PLA) scaffolds plasticized with polyethylene glycol (PEG) and incorporating magnesium (Mg) particles.
• Thermal, viscoelastic, shape-memory, and degradation analyses over 12 weeks.
• In vitro cytocompatibility assessments.

Main Results:

• Reduced glass transition temperature (Tg) to ~44°C enabled body-safe actuation.
• Optimal PLA/10PEG/2.5Mg scaffolds showed 90.4% shape recovery in ~71s.
• Synergistic degradation mechanisms (PEG leaching, Mg corrosion) led to significant weight loss and mechanical retention, with improved cytocompatibility due to Mg.

Conclusions:

• A mechanistic framework for co-designing degradation and shape recovery in 4D-printed scaffolds was established.
• PLA/PEG/Mg gyroid scaffolds offer tunable degradation, shape-memory properties, and enhanced biocompatibility for bone tissue engineering.
• This approach provides a promising strategy for developing advanced, functional bone regeneration therapies.