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

Abstract 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 µL 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.