Study of Hydroxyapatite-coated High-strength Biodegradable Magnesium-based Alloy in Repairing Fracture Damage in Rats

Area of Science:

• Biomaterials Engineering
• Orthopedic Implants
• Tissue Regeneration

Background:

• Hydroxyapatite (HA) coating enhances metallic implant properties, including degradation rate and biological activity.
• Biodegradable magnesium (Mg) alloys are promising for orthopedic applications due to their biocompatibility and mechanical properties.
• WE43 magnesium alloy is a suitable candidate for biodegradable implants, but its surface properties require optimization.

Purpose of the Study:

• To fabricate a hydroxyapatite-coated ultrafine-grained WE43 magnesium (HA/UFG-WE43 Mg) implant for bone fracture repair.
• To evaluate the physicochemical and biological properties of the developed HA/UFG-WE43 Mg implant.
• To assess the efficacy of the HA/UFG-WE43 Mg implant in promoting tibial fracture healing in a rat model.

Main Methods:

• A hybrid fabrication approach combining parallel tubular-channel angular pressing (PTCAP) and physical vapour deposition (PVD) magnetron sputtering was utilized.
• The microstructure, phase composition, and surface characteristics of the HA/UFG-WE43 Mg samples were analyzed.
• In vitro cell adhesion, morphology, and proliferation assays using rat skeletal muscle cells were performed.
• In vivo studies assessed Mg ion concentration in blood and histological analysis of tibial fracture healing in rats.

Main Results:

• PTCAP processing resulted in ultrafine microstructures with improved uniformity in the WE43 Mg samples.
• The HA coating exhibited characteristic peaks, confirming successful deposition on the UFG-WE43 Mg implant.
• In vitro studies demonstrated good cell adhesion, morphology, and proliferation on the HA/UFG-WE43 Mg specimens.
• In vivo results indicated reduced Mg ion concentration after HA deposition and efficient biodegradation with moderate inflammatory response during tibial fracture healing.

Conclusions:

• The combination of PTCAP processing and HA surface modification successfully created a functional HA/UFG-WE43 Mg implant.
• The developed implant demonstrated efficient biodegradation and promoted tibial fracture healing with a moderate inflammatory reaction.
• This HA/UFG-WE43 Mg implant shows significant potential for orthopedic applications in bone fracture repair.