Emerging Applications for Nano-Engineered Surfaces In Medical Devices

Through engineering of nanostructured surfaces and microstructural design, Integran Technologies, Inc. has recently developed several nanometal alloy and composite surface technology platforms for structural and functional engineering applications within the medical sector.

Nanocrystalline materials (grain size < 100 nm) provide a unique combination of hardness with ductility that cannot be obtained in conventional polycrystalline materials. Integran's nanomaterials exhibit such properties as increased strength, hardness, wear resistance, lubricity, electrical resistivity and resistance to localized corrosion, with no changes to density, thermal expansion, modulus or saturation magnetization. Electrodeposition is the simplest and most cost-effective method of producing nanometals and alloys in the form of coatings, foams, free-standing foil, plates, mesh or tubes, and does not require the use of potentially harmful nanoparticulates. In addition, Integran's nanometals can be applied to engineered polymers, composites and other metals to create unique hybrid parts with added process flexibility and functionality (i.e., complex shapes, custom or tailored geometries, stiffness matching, etc.). This enables the use of extremely lightweight and/or affordable materials for structural biomedical applications.

Microstructural design through Grain Boundary Engineering (GBE) is a patent- and trademark-protected thermo-mechanical processing technology applicable to a broad range of metals and alloys, including biocompatible alloys such as 316L stainless steel. Integran's GBE process has been shown to increase the frequency of special grain boundaries (i.e, having Σ value < 29) in excess of 60%. This results in improved resistance to stress corrosion cracking, creep and solute/impurity segregation.

An overview of nanocrystalline and GBE materials and their enabling structure/property relationships is presented, with particular emphasis on processes and properties as they pertain to biomedical device design. For these examples the importance of application- and property-specific microstructural design and optimization is underscored.