Biocompatible Magnetic Poly(carbonate urethane) Microspheres for Potential Applications in Aneurysm Embolization

Poor durability and lack of neointima formation of microcoils used in transcatheter arterial embolization of aneurysms can increase the risk of recanalization, which may necessitate additional clinical operations. In this study, biostable poly(carbonate urethane) (PCU) and superparamagnetic iron oxide (Fe3O4) particles were used to fabricate the embolic microspheres. Mass loss and surface morphology changes during degradation were evaluated to confirm the biostability. A comprehensive biocompatibility assessment of the composites and the influence of different contents of Fe3O4 (10, 15, and 20 wt %) on vascular smooth muscle cells (VSMCs) are investigated. The results of the CCK-8 assay, the flow cytometry test, and scanning electron microscopy (SEM) showed that the composites could promote the cell proliferation and adhesion of VSMCs in vitro, especially 10% Fe/PCU and 15% Fe/PCU. The composites showed lower hemolysis ratios and exhibited a longer clotting time, revealing better hemocompatibility than the pure PCU. In addition, from the results of the Western blot, significant differences were found in the expression of the neointima-related factors secreted by VSMCs, such as Ang II, between the cells cultured in the control group and the PCU-based polymers (15% Fe/PCU the highest). The overall results indicated that 15% Fe/PCU with biocompatibility holds the best potential in promoting the formation of neointima to reduce the chances of recanalization and enhance the occlusion rates.