A surface-eroding poly(1,3-trimethylene carbonate) coating for fully biodegradable magnesium-based stent...

Area of Science:

• Biomaterials Science
• Cardiovascular Engineering
• Surface Chemistry

Background:

• Magnesium (Mg)-based alloys are promising biodegradable materials for cardiovascular stents.
• Key challenges include controlling corrosion and ensuring biocompatibility for safe in-vivo performance.

Purpose of the Study:

• To investigate the dynamic degradation, corrosion resistance, hemocompatibility, and histocompatibility of a poly(1,3-trimethylene carbonate) (PTMC) coating on Mg alloy.
• To evaluate PTMC as a surface-eroding coating for biodegradable cardiovascular implants.

Main Methods:

• Electrochemical corrosion tests were performed on bare, PTMC-coated, and poly(ε-caprolactone) (PCL)-coated Mg alloys.
• In vitro static and dynamic blood compatibility tests assessed platelet adhesion/activation and erythrocyte hemolysis.
• In vivo subcutaneous implantation in rats for 16 weeks evaluated coating degradation and surface morphology.
• Long-term in vivo assessment (52 weeks) analyzed Mg alloy degradation and corrosion product formation.

Main Results:

• PTMC coating significantly reduced corrosion current density compared to bare and PCL-coated Mg alloys.
• In vitro tests showed reduced platelet adhesion/activation and erythrocyte hemolysis on PTMC-coated surfaces.
• PTMC exhibited homogeneous surface erosion over 16 weeks in vivo, maintaining ~55% thickness.
• Mg alloy with PTMC coating showed reduced degradation and fewer corrosion products after 52 weeks, with no excessive inflammation or gas accumulation.

Conclusions:

• PTMC coating provides effective corrosion protection and excellent hemocompatibility for Mg-based cardiovascular stent materials.
• The surface-eroding behavior and neutral degradation products of PTMC contribute to its superior performance.
• PTMC is a highly promising candidate for surface-eroding coatings on biodegradable Mg-based implants.