Low Energy Electron Beam Sterilization for Medical Technical Applications

Many new medical products cannot be sterilized by standard techniques like hot steam or exposure to sterilizing gases, as they are temperature sensitive, contain electronic parts like microchips or consist of polymeric materials. Also, the use of gamma irradiation for such applications is problematic due to long exposure time under radical atmosphere which leads to an increased degradation and therefore to a loss of functionality. Using low energy electron irradiation it is possible to sterilize medical surfaces within some seconds because of very high dose rates. Therefore, degradation processes can be prevented compared to gamma irradiation. In addition, it is possible to define the penetration depth in order to prevent electronic parts from damage. Besides sterilization of polymers and electronic components, we were able to show the usability of low energy electron beam irradiation for modification and sterilization of diverse biological materials like peptides, collagen matrices, transplantation tissues or hydrogels. The process is accepted all over the world and complies with international standards (ISO 11137). The aim of the development work at the Fraunhofer FEP is to adapt the electron beam process for new applications, but also to develop in-line-capable systems for sterilization applications in production-processes and as batch systems.