Atorvastatin Eluting Coating for Magnesium-Based Stents: Control of Degradation and Endothelialization in a Microfluidic Assay and In Vivo

While absorbable magnesium (Mg) based vascular stents show promise, more progress is needed to fulfil suitable durability, fast endothelialization, anti-restenosis, and anti-inflammation. To design a multifunctional stent, the authors screen a common oral atorvastatin calcium (ATVC) loaded into a surface-eroding poly(1,3-trimethylene carbonate) (PTMC) on a Mg alloy material (AZ31 wire) to achieve well-controllable degradation rate, target drug delivery, and vascular remodeling. Moreover, to reduce cytocompatibility discrepancy between in vitro static culture and in vivo tests for Mg-based materials, a microfluidic model is developed to mimic the microenvironment of an early-stage stented vessel for the study of endothelial cell responses to Mg. The PTMC and PTMC-ATVC coatings effectively reduce degradation rate of the Mg alloy in the static immersion, electrochemical measurement, microfluidic chip, and in vivo tests. The PTMC-ATVC-coated wires perform an outstanding growth and migration of endothelial cells in the microfluidic chip at a flow rate of 10 mu L min(-1), compared with uncoated and PTMC-coated wires. In vivo rat test, the PTMC-ATVC coating positively regulate endothelial cells and smooth muscle cells, reduce intimal hyperplasia and inflammation. The target atorvastatin delivery by PTMC coating show a promising dual-function for improving the durability and early endothelialization of Mg-based stents.