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3D-printed NIR-responsive shape memory polyurethane/magnesium scaffolds with tight-contact for robust bone
Yuanchi Zhang1, Cairong Li1, Wei Zhang1
1Centre for Translational Medicine Research & Development, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
Bioactive Materials
|April 13, 2022
Summary
A novel 3D printed scaffold using shape memory polyurethane and magnesium offers tight bone contact and enhanced regeneration. This near-infrared-responsive material improves graft integration and repair efficacy for bone defects.
Area of Science:
- Biomaterials Engineering
- Regenerative Medicine
- Orthopedic Surgery
Background:
- Bone defects cause significant disability due to poor graft integration and low osteogenic activity.
- Existing self-expanding scaffolds have limitations in transition temperature and bioactivity, hindering clinical use.
- Improved bone scaffolds are needed to enhance graft contact and promote bone regeneration.
Purpose of the Study:
- To develop a near-infrared-responsive, tight-contacting scaffold for enhanced bone regeneration.
- To investigate the synergistic effects of shape memory polyurethane (SMPU) and magnesium (Mg) in a 3D printed scaffold.
- To evaluate the scaffold's mechanical properties, shape memory behavior, and osteopromotive potential.
Main Methods:
- Fabrication of a composite scaffold using low temperature rapid prototyping (LT-RP) 3D printing with SMPU and varying Mg content.
- Assessment of scaffold structure, mechanical properties, and photothermal effects under near-infrared (NIR) irradiation.
- Evaluation of shape memory performance (fixity and recovery ratios) and load-bearing capacity.
- Analysis of tight-contacting ability using push-out tests and finite element analysis (FEA).
- In vitro and in vivo studies to demonstrate osteopromotive function and bone regeneration efficacy.
Main Results:
- The 3D printed SMPU/Mg scaffold exhibited a homogeneous porous structure, improved mechanical properties, and stable photothermal effects.
- The scaffold demonstrated excellent shape memory behavior with high shape fixity (93.6%) and recovery (95.4%) ratios at 4 wt% Mg.
- Compressed scaffolds could lift over 1700 times their weight under NIR light, confirming strong shape recovery.
- Push-out tests and FEA confirmed significantly enhanced tight-contacting ability compared to scaffolds without shape memory effects.
- In vitro and in vivo studies confirmed the scaffold's osteopromotive function and potential for robust bone regeneration.
Conclusions:
- The developed NIR-responsive, tight-contacting SMPU/Mg scaffold shows significant potential for improving bone defect repair.
- The combination of SMPU's shape memory properties and Mg's photothermal and bioactive effects offers a promising strategy for bone regeneration.
- This 3D printed scaffold represents a clinically viable approach to address limitations in current bone graft technologies.
