Overview of sterilization methods for UHMWPE through surface analysis

Abstract

The sterilization process is essential for the use of biomaterials in the human body in order to avoid contamination. However, the effect of such required pretreatment on the surface must be also evaluated since some modifications may cause a shortened lifespan of this material or changes in properties of interest. Moreover, improvements in sterilization techniques may even enhance properties while the surface is cleaned. The thorough understanding of the effect that the sterilization processes have on the surface of ultra-high molecular weight polyethylene (UHMWPE), widely used biomaterial in orthopedic joint prosthesis, is, therefore, a key study since some modifications during traditional sterilization could be a major problem for patients who have undergone arthroplasty surgery. This work brings a comprehensive study on sterilization techniques already available and extensively used (hydrogen peroxide plasma, ethylene oxide, steam autoclave) and a comparison with results obtained for recently developed cold plasma-based sterilization technique. The effects of the processes have been extensively compiled by data obtained for thermal analysis, nanoscale wear and friction, physicochemical, topographical, wettability, and in vitro cytotoxicity experiments. An overall outlook on the set of samples points out to cold plasma oxidation (CPO) being an adequate and potential candidate for improving wear resistance, while maintaining thermal stability and a restrained adhesion of L929 cells, provoked by its hydrophilicity and larger surface area.