Fig. 6.

FTIR spectroscopic measurements of the effects of heat and RFGD pretreatments of Ti6Al4V disks on calcium-phosphate mineral levels and the mineral:matrix ratio in MC3T3 osteoprogenitor cell cultures. Cells were incubated with cell culture media containing ascorbic acid and β glycerophosphate for 1–4 weeks. FTIR spectroscopic analyses were performed on pellets prepared from KBr combined with air-dried samples of the material that covered the disks. Relative levels of calcium-phosphate mineral (A) were measured as the area under the apatite phosphate peak (900–1,180 cm⁻¹). Data were normalized to the area under the apatite phosphate peak (900– 1,200 cm⁻¹) for untreated and uncoated disks at 1 week. The mineral to matrix ratio (B) was determined as the area under the phosphate peak (900– 1,180 cm⁻¹) divided by the area under the amide I peak (1,585–1,720 cm⁻¹). Both the levels of calcium-phosphate mineral and the mineral:matrix ratio were corrected for control (no supplementation with ascorbic acid or β glycerophosphate) values. Data represent means ±SE for 3–5 independent cultures at each time point. ^a–d Significantly greater compared to the same experimental condition measured at 1 week (P <0.05); 1 and 2 weeks (P <0.05); 1, 2, and 3 weeks (P <0.001); or 2 weeks (P <0.05), respectively, based on analysis of variance. FN, fibronectin; HEAT, heat pretreatment; RFGD, radiofrequency plasma glow discharge pretreatment.