A chemical bonding process developed by a multi-disciplinary team at the University of Alberta and Canada's National Institute for Nanotechnology could enhance functions of stainless steel and enable its use in implanted biomedical devices.
Embedded biomedical devices including cardiac stents are implanted in more than 2 million people annually. Stainless steel is strong, stable and can maintain its shape long after implantation. But if it is implanted in an artery, it can cause blood clotting, or cause allergy to metal ions such as nickel ions.
The University of Alberta CIHR Team is developing Glyconanotechnology for use in transplantation and will create artificial nanomaterials that can change the body's immune response prior to an organ transplant. This will allow for organ transplants across various blood groups. In order to address the complex needs and issues, the team drew on surface science chemistry and engineering, carbohydrate chemistry, and immunology and medicine.
Carbohydrate (sugar) molecules had to be bound to the stainless steel surface to induce the needed interaction with the immune system. Its characteristic makes it difficult to add new functions to stainless steel, especially with the monitored coverage essential for biomedical implants. The Edmonton-based team discovered that surface coating of the steel with a thin layer of glass silica using the Atomic Layer Deposition (ALD) technique could address the non-reactivity of steel. The silica offers a chemical handle, through which the clinically prepared carbohydrate molecules could be bound. The team showed that the carbohydrate molecules coated the steel in the correct orientation to interact with the immune system.
Source: http://www.nint.ca