Asymmetric Hard Domain-Induced Robust Resilient Biocompatible Self-Healable Waterborne Polyurethane for Biomedical...

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Developing eco-friendly and biocompatible waterborne polyurethanes (WPUs) with superior mechanical properties and self-healing capabilities presents significant challenges due to conflicting property requirements.
• Existing WPUs often struggle to balance mechanical strength, shape recovery, and self-healing efficiency, limiting their application in demanding fields like biomedical engineering.

Purpose of the Study:

• To develop a transparent, self-healable WPU elastomer with enhanced mechanical toughness, fracture energy, and shape recoverability using a facile synthesis method.
• To evaluate the hemocompatibility and in vitro biocompatibility of the synthesized WPU elastomer for potential biomedical applications.
• To investigate the melt re-processability and biodegradation characteristics of the novel WPU material.

Main Methods:

• Molecular engineering of WPUs by incorporating high-density hindered urea-based hydrogen bonds and an asymmetric alicyclic architecture (isophorone diisocyanate-isophorone diamine).
• Utilizing glycerol ester of citric acid as a bio-based internal emulsifier within the hard domains.
• Assessing mechanical properties (strength, toughness, fracture energy, strain), transparency, self-healing efficiency, and shape recovery.
• Conducting hemocompatibility tests (platelet adhesion, LDH activity, erythrocyte lysis) and in vitro biocompatibility assays (live/dead, Alamar blue) with human dermal fibroblasts.
• Evaluating melt re-processability and microbe-assisted biodegradation.

Main Results:

• Achieved a transparent WPU elastomer (80.57-91.48% transparency) with high self-healing efficiency (67-76%) and excellent mechanical properties, including a strain of 3297-6356%.
• Reported the highest mechanical toughness (436.1 MJ m^-3) and ultrahigh fracture energy (126.54 kJ m^-2) for a WPU elastomer, alongside good shape recovery (95% in 40 s).
• Demonstrated excellent hemocompatibility and in vitro biocompatibility, with melt re-processability and microbe-assisted biodegradation.

Conclusions:

• The developed WPU elastomer, engineered with specific chemical structures and a bio-based emulsifier, overcomes the property conflicts in traditional WPUs.
• The material exhibits a unique combination of transparency, self-healing, superior mechanical performance, biocompatibility, and eco-friendly characteristics (re-processability, biodegradability).
• These findings suggest the synthesized WPU elastomer holds significant potential as a smart biomaterial and coating for advanced biomedical devices.