Enhancement of surface properties of biomaterials using plasma-based technologies

Development of new biomaterials typically takes a long time due to extensive tests and lengthy approval procedures. Plasma surface modification offers an exciting alternative by modifying selective surface mechanical and biological properties of conventional biomaterials to suit particular needs. Hence, materials that possess favorable bulk properties can have their surfaces redesigned to cater to biomedical applications. Plasma surface modification is a popular method to improve the multi-functionality, tribological and mechanical properties, as well as biocompatibility of artificial biomaterials and medical devices. Here, our recent research work on plasma modification of orthopedic nickel-titanium shape memory alloys and cardiovascular materials, namely diamond-like carbon is described. The shape memory effect and super-elasticity of NiTi alloys allow for a novel surgical technique for gradual correction of spinal deformity. However, out-diffusion of toxic Ni ions into human tissues is a health concern and plasma treatment is an excellent method to impede Ni leaching while the super-elastic properties of the bulk alloy can be retained. The two important requirements for cardiovascular materials such as those used in artificial heart valves, are that they must possess adequate surface mechanical properties and blood compatibility. Our recent experiments indicate that doping diamond-like carbon with elements such as nitrogen and phosphorus can enhance the biocompatibility of the materials.