Shape Memory Effect of Four-Dimensional Printed Polylactic Acid-Based Scaffold with Nature-Inspired Structure

Area of Science:

• Biomaterials Engineering
• Additive Manufacturing
• Materials Science

Background:

• Four-dimensional (4D) printing, an advancement of 3D printing, enables materials to change shape in response to stimuli.
• Biomedical scaffolds require advanced materials with specific mechanical and shape-memory properties for tissue regeneration.
• Polylactic acid (PLA) and its composites are widely investigated for biomedical applications due to their biocompatibility.

Purpose of the Study:

• To investigate the feasibility of 4D printing PLA-based composite scaffolds incorporating nature-inspired architectures.
• To evaluate the impact of Calcium Phosphate (CaP) addition on the thermomechanical and shape memory properties of these scaffolds.
• To assess the potential of these 4D printed scaffolds for bone-repair applications.

Main Methods:

• Fabrication of PLA/CaP composite scaffolds using 4D printing with honeycomb, giant water lily, spiderweb, and nautilus shell architectures.
• Incorporation of 1, 3, and 5 wt.% CaP into PLA.
• Thermomechanical testing and shape memory characteristic evaluation under controlled thermal conditions.

Main Results:

• PLA and PLA/CaP composite materials exhibited favorable thermal stability and hydrophilic characteristics.
• The honeycomb architecture demonstrated the most promising shape memory and mechanical behavior.
• Calcium Phosphate addition enhanced mechanical strength and shape memory but negatively impacted surface integrity.

Conclusions:

• 4D printed PLA/CaP composite scaffolds, particularly with honeycomb architecture, show potential for bone-repair applications.
• Optimizing CaP content and structure design is crucial for balancing mechanical enhancement and surface integrity.
• This research contributes to the development of advanced, self-fitting biomedical scaffolds with high shape recovery.