Hardystonite bioceramic-endowed multifunctions of polylactic acid-based composites favourable for developing...

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedic Implants

Background:

• Polylactic acid (PLA) is biocompatible and biodegradable but has suboptimal mechanical properties for internal fixation.
• Implant-associated infections remain a significant challenge in regenerative medicine.
• Developing multifunctional implants with anti-infection capabilities is crucial.

Purpose of the Study:

• To develop multifunctional polylactic acid (PLA)-based composites incorporating hardystonite (HAR) powders for internal fixation.
• To enhance the mechanical properties, biodegradability, and anti-infection capabilities of PLA implants.
• To evaluate the efficacy of these composites in preventing implant-associated infections.

Main Methods:

• PLA-based composites were fabricated using low-temperature calcining and melt-blending with hardystonite (HAR) powders, with and without sodium (Na) doping.
• Mechanical properties (tensile strength, flexural strength, Young's modulus) were assessed.
• In vitro biodegradation, osteogenic stem cell viability, and antibacterial efficacy against Staphylococcus aureus and Escherichia coli were evaluated.
• A muscle-embedding model was used for preliminary histological observation of methicillin-resistant Staphylococcus aureus-loaded implants.

Main Results:

• Addition of HAR or Na-HAR powders to PLA enhanced Young's/elastic modulus, particularly with 12% Na-HAR.
• Inorganic powder addition accelerated in vitro biodegradation and improved osteogenic stem cell viability.
• Antibacterial efficacy against Staphylococcus aureus and Escherichia coli exceeded 90%.
• Histological observations confirmed infection prevention, reduced inflammation, and stimulated angiogenesis in a soft tissue model.

Conclusions:

• PLA/HAR composites offer improved mechanical properties and biodegradability compared to pure PLA.
• These composites demonstrate significant antibacterial efficacy and promote a favorable microenvironment for tissue regeneration.
• The developed PLA/HAR materials show multifunctional potential for clinical applications, especially in treating bone-injury infections.