Nitinol-based nanotubular coatings for the modulation of human vascular cell function

Area of Science:

• Biomaterials Science
• Surface Engineering
• Medical Device Technology

Background:

• Nitinol (Nickel-Titanium alloy) is widely used in medical implants due to its superelasticity.
• Current Nitinol implants face challenges like restenosis and limited biocompatibility.
• Surface modification is crucial for enhancing the performance of Nitinol-based devices.

Purpose of the Study:

• To synthesize and characterize an upright nanotubular coating on Nitinol.
• To evaluate the coating's effect on endothelial cell behavior for improved re-endothelialization.
• To assess the coating's impact on smooth muscle cell proliferation and inflammation for reduced neointimal hyperplasia.

Main Methods:

• Anodization technique used to create upright nanotubular structures on Nitinol.
• Surface elemental composition and nickel ion release rates were characterized.
• In vitro studies using primary human aortic endothelial cells (HAECs) and human aortic smooth muscle cells (HASMCs) were performed.

Main Results:

• The nanotubular coating successfully formed discrete, exposed nanotubes on Nitinol.
• Enhanced cell spreading and migration of HAECs were observed on the nanotubular surface.
• Reduced proliferation and collagen I/MMP-2 expression in HASMCs were noted, indicating reduced neointimal hyperplasia.
• No significant increase in ICAM-1 expression (inflammation marker) was observed in HASMCs compared to controls.

Conclusions:

• The developed nanotubular coating improves Nitinol biocompatibility by promoting endothelialization and reducing smooth muscle cell response.
• This surface modification strategy shows potential for reducing restenosis rates in Nitinol stents.
• The coating offers a generalized approach for enhancing various Nitinol-based medical devices.