Cytocompatibility of titanium and poly(etheretherketone) surfaces after O₂ non-thermal plasma sterilization

by Christina Maillet, Florence M. Klein, Florian Le Bras, Frederic Velard, Christine Guillaume, Sophie C. Gangloff, Marie-Paule Gelle

The sterilization of medical devices is paramount to achieve an acceptable level of sterility assurance and to prevent hospital-acquired infections. However, some medical devices cannot be sterilized by usual processes such as autoclave (AC) and gamma-ray irradiation (GI). A new non-thermal plasma (NTP) process using sealed bag that preserves the sterile state of the devices could be used as an alternative sterilization method. The aim of the study was to assess the cytocompatibility of titanium and poly(etheretherketone) (PEEK) surfaces after O₂-NTP sterilization compared to GI and AC. MG-63 osteoblast-like cells were seeded on titanium (TA6V) and PEEK disks sterilized by AC, GI and O₂-NTP. The cells’ viability and proliferation, determined by WST-1 and DNA quantification respectively, were enhanced whatever the material types from 3 to 10 days. When seeded on titanium, MG-63 cells showed a higher viability and proliferation after GI and O₂-NTP treatment compared to AC treatment. When cultured on PEEK, MG-63 cells showed a higher viability after O₂-NTP treatment. No difference of proliferation was observed whatever the sterilization processes. The cell colonization of the materials’ surface was confirmed by scanning electron microscopy. Lactate dehydrogenase (LDH) assay revealed no cytotoxicity. Thus, O₂-NTP led to similar cell responses to AC and GI and could be a cost-effective alternative process to the usual sterilization methods for fragile medical devices.