Excimer laser and lamp-based techniques applied to the nanostructuring of biomaterials

Bone-bonding implants include some of the commonest biomaterials currently used. The useful lifetimes of these materials are limited in part by the capacity of the material to support an intimate bond with the tissue in which they are implanted. A number of materials currently used have either good mechanical properties but poor biological responses, or have the ability to form suitable bonds with bone but lack the requisite strength, wear resistance, etc. In particular, polymeric materials have generally been shown to be inert with respect to bone. We report on our work on developing methods to surface treat polymers to encourage colonisation by bone, either for clinical implantation or in vitro tissue engineering applications. Polymers were treated by one of two methods; either 1) using an excimer laser to machine arrays of grooves in the surface; the periodicity of the grooves was varied from a few hundred nanometers to 10 μm; or 2) using an excimer lamp to affect the chemistry of the surface layer by breaking surface bonds and incorporating atmospheric oxygen. Surface structures of samples treated by method 1 were examined using Scanning Electron Microscopy (SEM), White Light Intereferometry and Atomic Force Microscopy (AFM) and surfaces of samples treated by method 2 were examined by using contact angle measurements which indicated a higher surface energy. The difference in cellular response to the control surfaces and modified surfaces was investigated. In conclusion, these methods provide viable means for altering polymers and may generate improved polymers for bone-bonding applications.