Publication details

Authors: Wang, J.; He, Y.; Maitz, M. F.; Collins, B.; Xiong, K.; Guo, L.; Yun, Y.; Wan, G.; Huang, N. 
Title: A surface-eroding poly(1,3-trimethylene carbonate) coating for fully biodegradable magnesium-based stent applications: Toward better biofunction, biodegradation and biocompatibility 
Type: Journal Article 
Publisher: Acta Biomaterialia 
Year: 2013 
Issue: 10 
Start Page: 8678 
End Page: 8689 
DOI: 10.1016/j.actbio.2013.02.041 
Abstract: Biodegradable magnesium-based materials have a high potential for cardiovascular stent applications; however, there exist concerns on corrosion control and biocompatibility. A surface-eroding coating of poly(1,3-trimethylene carbonate) (PTMC) on magnesium (Mg) alloy was studied, and its dynamic degradation behavior, electrochemical corrosion, hemocompatibility and histocompatibility were investigated. The PTMC coating effectively protected the corrosion of the Mg alloy in the dynamic degradation test. The corrosion current density of the PTMC-coated alloy reduced by three orders and one order of magnitude compared to bare and poly(epsilon-caprolactone) (PCL)-coated Mg alloy, respectively. Static and dynamic blood tests in vitro indicated that significantly fewer platelets were adherent and activated, and fewer erythrocytes attached on the PTMC-coated surface and showed less hemolysis than on the controls. The PTMC coating after 16weeks' subcutaneous implantation in rats maintained approximately 55% of its original thickness and presented a homogeneously flat surface demonstrating surface erosion, in contrast to the PCL coated control, which exhibited non-uniform bulk erosion. The Mg alloy coated with PTMC showed less volume reduction and fewer corrosion products as compared to the controls after 52weeks in vivo. Excessive inflammation, necrosis and hydrogen gas accumulation were not observed. The homogeneous surface erosion of the PTMC coating from exterior to interior (surface-eroding behavior) and its charge neutral degradation products contribute to its excellent protective performance. It is concluded that PTMC is a promising candidate for a surface-eroding coating applied to Mg-based implants. 
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