Figure 4.

Left: X-ray fluorescence microscopy measurements acquired at 15 nm pixel size (expressed in areal mass (g/cm²)) in a single mineral nucleus formation reporting from top to bottom, the Ca, Zn composition, and Zn/Ca ratio. Right: results of the Zn/Ca ratio in bMSCs exposed to the differentiation cocktail at 10 vs 4 days. To calculate the ratio, the moles of Ca and Zn of the analyzed mineral nuclei were calculated multiplying the respective XRF maps (expressed in areal mass (g/cm²)) for the pixel area and normalizing for respective atomic weight.