EFFECTS OF ALUMINUM-OXIDE FILM ON FIBROBLAST L929 AND V79 CELL VIABILITIES

The effects of Ti and Al oxide films on the relative growth ratio of m urine fibroblast L929 and the colony formation ratio of fibroblast V79 cells derived from the lung of a Chinese hamster were investigated. T itanium and aluminum particles were oxidized inside an oven at 453 K ( 180 degrees C) for 7.2 ks. These particles were suspended in Eagle's m edium and kept for 173 ks (48 h) inside an incubator under a 95%air-5% CO2 atmosphere. Eagle's medium without metallic particles was also kep t inside the incubator under similar conditions for the control. The m ediums were filtered with a 0.2 mu m membrane filter to remove metalli c particles (Eagle's medium extract). 3.0 x 10(4) L929 cells/dish and 10(2) V79 cells/dish were seeded in both the control and in the Eagle' s medium extracts. In the case of oxidized Al particle extraction, the relative growth ratio of L929 cells was 0.8 +/- 0.07 after 346 ks (4 d) of incubation. A relatively strong oxide film formed on the surface s of the Al particles, hence the relative growth ratio of the L929 cel ls markedly increased. Al and Ti plates were polished to a mirror-like finish using diamond paste and alcohol, well proliferated colonies of V79 cells were observed on the mirror-like finished Ti plate (Ra=4.8 +/- 0.2 nm), whereas no colonies existed on the mirror-like finished A l plate (Ra=38.5 +/- 8.4 nm). However, the colonies appeared when the Al plates were acid-treated with a solution of NaHCO3 and C2H4O2 (Ra=4 3.4 +/- 10.1 nm) after mirror-like finishing, and also when roughening with #240 water-proof emery paper (Ra=1548 +/- 169 nm). The colony fo rmation ratio of the V79 cells was found to depend on the surface roug hness (Ra) and strength of the Al oxide film.