Cytocompatibility for Co-Cr-Mo alloy with a small amount of zirconium or carbon

The aim of this study is to examine the cytocompatibility of new cobalt-29 chromium-6 molybdenum alloys prepared by addition of a small amount of zirconium or carbon. Four kinds of Co-based alloy, containing 0.05 mass% of zirconium (0.05Zr-CCM), 0.08 mass% of zirconium (0.08Zr-CCM), 0.09 mass% of carbon (0.09C-CCM) and 0.18 mass% of carbon (0.18C-CCM), were prepared. The tests for cell adhesion, colony formation and cell growth were carried out according to a procedure of JIS T0301 by use of L929 cells. By addition of ziruconium to cobalt-based alloy, some cytocompatibilities were improved, in cell adhesion and colony formation in the direct contact tests. In 0.05Zr-CCM, the rates of cell adhesion and colony formation in the direct contact tests were improved in 0.05Zr-CCM but not in the other alloys. The colony formation rate in the static extract solution was improved in 0.08Zr-CCM. In the dynamic extract solution, the rate was decreased in 0.09C-CCM and increased in 0.18C-CCM. These results indicate that the cytocompatibility of Co-based alloy is changeable by addition of a small amount of zirconium or carbon.