Figure 4

Fourier-transform infrared microspectroscopic patterns of mineral deposits. A) Cells exposed to modified DMEM with 10 % rabbit serum for 2 hrs. B) Cells exposed to the media without rabbit serum. After a 2-hr exposure to the media with or without the serum, cells were washed twice with TBS, twice with water, scraped off from the dishes, and finely suspended with Pasteur pipets. The initial Ca × P ion product in culture media was 9.37 mM². Five-μl aliquots containing 1 μg proteins were then spotted onto BaF₂ windows for infrared analysis. The infrared spectra were obtained by scanning the deposit over a 0.6–0.8 cm path. The graphs show the intensity of protein amide at wavenumber 1650 and a minute peak of mineral P appearance at wavenumbers 1050–1080 from the control with serum exposure whereas the P peak was much more prominent in the serum-depletion experiments. A Shimadzu Fourier-transform infrared microspectroscopy model AIM8400/8800 was used for the analysis.