Effects of Metallic Concentrations Other Than Ti, Al and V on Cell Viability

Abstract

New titanium alloys containing zirconium, tin, niobium, tantalum and palladium are being developed by our group. Using metallic particles we investigated effects of Zr, Sn, Nb, Ta and Pd concentrations in Eagle's medium and a medium, added as alloying elements for the new Ti alloy, on the colony formation ratio of fibroblast V79 cells taken from the lungs of Chinese hamsters, and on the relative growth ratios of murine fibroblast L929 and murine osteoblast-like MC3T3-E 1 cells. Moreover, we investigated the effects of chromium and molybdenum concentrations on the colony formation ratio of V79 cells and on the relative growth ratios of L929 and MC3T3-E1 cells. The effects of Co, Ni, Fe and Si concentrations on the relative growth ratios of L929 and MC3T3-E cells were examined. Various sterilized metallic particles were extracted after incubation for 86.4 ks (I d) to 432 ks (5 d) under a 95%air-5%CO 2 atmosphere at 310 K (37°C). The maximum concentrations of Zr, Sn, Nb, Ta and Cr released into Eagle's medium and α medium after 0.2 μm membrane filtering were 2.1, 4.1, 0.5, 0.07 and 0.14 mass ppm, respectively. Therefore, the colony formation of the V79 cells and the relative growth ratios of L929 and MC3T3-E1 cells were nearly unity. For palladium particle extraction, the colony formation of V79 cells and the relative growth ratio of L929 cells gradually decreased from a concentration of approximately 2 mass ppm or higher and reached nearly zero at greater than 20 mass ppm. Influences of Mo, Fe, Ni and Co concentrations on the MC3T3-E1 cell viabilities were more pronounced at lower concentrations than with the L929 and V79 cells. In the case of Mo particle extraction, the relative growth ratio of MC3T3-E cells decreased from the concentration of about 10 mass ppm. For iron, nickel and cobalt particle extractions, the MC3T3-E1 cell viabilities decreased from concentrations of about 2, 1 and I mass ppm or higher, respectively, and the relative growth ratio of MC3T3-E1 cells decreased to zero at concentrations greater than 20 mass ppm. In the case of Si particle extraction, the relative growth ratio of the L929 cells was nearly unity at the high concentrations of 65 mass ppm and over. However, the relative growth ratio of MC3T3-E1 cells decreased from I mass ppm and was nearly zero at concentrations greater than 50 mass ppm.