Impedance testing of porous Si3N4 scaffolds for skeletal implant applications

Si 3 N 4 ceramics show excellent characteristics of mechanical and chemical resistance in combination with good biocompatibility, antibacterial property and radiolucency. Therefore, they are intensively studied as structural materials in skeletal implant applications. Despite their attractive properties, there are limited data in the field about in vitro studies of cellular growth on ceramic implant materials. In this study, the growth of bone cells was investigated on porous silicon nitride (Si 3 N 4 ) ceramic implant by using electrochemical impedance spectroscopy (EIS). Partial sintering was performed at 1700 °C with limited amount of sintering additive for the production of porous Si 3 N 4 scaffolds. All samples were then sterilized by using ethylene oxide followed by culturing MG-63 osteosarcoma cells on the substrates for in vitro assays. At 20 and 36 h, EIS was performed and results demonstrated that magnitude of the impedance as a result of the changes in the culture medium increased after incubation with osteosarcoma cells. The changes are attributed to the cellular uptake of charged molecules from the medium. Si 3 N 4 samples appear to show large impedance magnitude changes, especially between 100 and 1 Hz. Impedance changes were also correlated with WST-1 measurements (36 h) and DAPI results.