engleski

Functionalization of a NiTi Surface with Phosphonic Acid Self-Assembled Monolayers

Occlusive coronary artery disease (CAD) is reported to be the single largest cause of death in developed countries, such as Canada and United States. The disease is characterized mostly by the formation of a plaque, resulting in considerable narrowing and hardening of the vessels. Stenting following percutaneous transluminal balloon angioplasty has proved to be the less invasive treatment for CAD. Nitinol, a roughly equiatomic alloy of nickeltitanium, has been used extensively in biomedical devices, particularly in cardiovascular stents, due to its outstanding mechanical characteristics, such as the ability to remember its original shape. However, all current bare-metal stents, including Nitinol, offer low biocompatibility. This results in occurrence of in-stent restenosis in up to ca. 30% patients, and the need for further medical treatment. Therefore, various stent-surface modification approaches have been employed in order to minimize in-stent restenosis, but none of them have proven to give long-term satisfactory benefits. Furthermore, one the major concerns of using Nitinol in cardiovascular stents is the release of nickel ions to the body, which has proved to be carcinogenic and allergic. Thus, the aim of this work was to develop a new method for the Nitionol (stent) surface functionalization, with the ultimate goal decreasing the in-stent restenosis rate. We functionalized a Nitinol surface with a phosphonic acid self-assembled monolayer (SAM) which not only acts as a surface corrosion inhibitor that minimizes the nickel ions release to the human body, but also potentially enable us to further functionalize the surface with a (bio)molecule of choice, such as proteins and drugs.

Nitinol; phosphonic acid; self-assembled monolayers; implant material

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