Preparation of ROS‐Responsive Exosome Coating of Nitinol Material for Making the Neurointerventional Stent

Abstract

Nitinol (NiTi) alloy is an ideal material for preparing neurointerventional stents due to its excellent mechanical properties and biocompatibility. However, NiTi stents without surface‐specific functionalization cause a high rate of stent thrombosis and in‐stent restenosis after implantation. In ischemic stroke, exosomes have a role in regulating nervous system development, regeneration, vascular remodeling, and neuroinflammation. In this work, the effect of exosome coating on the biocompatibility of NiTi alloy is evaluated. NiTi alloy is successively immersed in relevant solution (sodium alginate, 3‐aminophenylboronic acid, distearoylphosphatidylethanolamine, and exosomes) to form ROS‐responsive exosome coated surfaces. In vitro experiments (platelets, endothelial cells, smooth muscle cells, and macrophages) and in vivo subcutaneous implantation experiments are performed to test coatings for biocompatibility. The results show that the modified NiTi alloy surface has high hydrophilicity, which has the functions of inhibiting platelet aggregation, promoting endothelialization, inhibiting smooth muscle cell migration, anti‐inflammatory, and good tissue biocompatibility. This study develops exosome neurointerventional stent coating as a bioactive drug via reactive oxygen species accumulation in lesions, thus targeting drug release, inhibiting intimal hyperplasia, and reducing inflammation and thrombosis.

Selective Tumor Inhibition Effect of Drug-Free Layered Double Hydroxide-Based Films via Responding to Acidic Microenvironment

“…Due to good biocompatibility, stable mechanical properties, and unique shape memory effect, nickel–titanium alloys are extensively used in the manufacture of luminal self-expanding stents. − For specific applications such as gallbladder cancer, bile duct cancer, and liver cancer combined with portal vein thrombosis, self-expanding stents need to have excellent mechanical properties to keep the lumen open to ensure blood and digestive fluid flow. − On the other hand, they should also have good antibacterial and antitumor properties to avoid malignant obstruction caused by tumor invasion and bacterial colonization. − At present, the existing bare-metal nickel–titanium alloy stents cannot meet both of these requirements. Therefore, it is scientifically important to develop new nickel–titanium alloy stents with anticancer and antibacterial functions based on bare-metal stents.…”