JOSKA Luděk VŠCHT v Praze

Spoluautoři FOJT Jaroslav, MORAVEC Hynek

DLC (Diamond-Like Carbon) is general designation of broad group of layers based on metastable amorphous carbon. One area of their application is medicine. DLC layers are in principle bioinert, alloying, in this case by zirconium, could change this behaviour to bioactive. Layers prepared on Ti grade 5 ELI at CTU Prague contained 7,4 %at. Zr in the form of oxides, based on Xray photoelectron spectroscopy (XPS) results. Electrochemical measurements were done in several forms of physiological saline solution (PS). Measurement technique was electrochemical impedance spectroscopy (EIS). Precipitation of Ca-P compounds from simulated body fluid (SBF) and surface colonization by MG63 human osteosarcoma cells were tested as well. Corrosion behaviour of DLC-Zr was in physiological saline solution fully changed by alloying. It was more close to zirconium than to carbon. Systems were corrosion resistant even though the pH was decreased to 4,2 value as a model of inflammation. Layers were slightly unstable in PS containing fluorides (model of prophylactic solution). Alloying by zirconium lead to slight change of layers behaviour to bioactive - increase of EIS modullus and decrease of phase during the SBF exposure in comparison with exposures in PS indicated surface Ca-P layer creation. This conclusion was confirmed by XPS. DLC-Zr layers are stable under common conditions expectable in human body. The use in dentistry is questionable, it regards further study. Alloyed DLC layers supported to some extent precipitation of Ca-P compounds from SBF solution, increase of colonization by MG63 cells was in the frame of experimental error.