Figure S2. Summary of 46Ca/40Ca ratios from HEK293 cultured in 46Ca-enriched media for varying experimental times.
(A) Isotopically enriched calcium carbonate (5% 46CaCO3) was added to the culture media of five coverslips of HEK293 cells in Ca-free DMEM. One coverslip was cultured in ordinary DMEM, as a control. These samples were then embedded and measured with NanoSIMS using the radio-frequency RF source (O− primary ions). (B) NanoSIMS images of 40Ca and 46Ca/40Ca from all experimental treatments. (C) Comparison of 46Ca/40Ca ratios of cells cultured in labeled medium for various time points. As the isotopically enriched carbonate only contains 5% 46Ca, the maximum isotope enrichment achievable is 50‰. There is no statistically significant difference between the 46Ca/40Ca ratios of control cells (N = 46) and cells cultured in labeled media for 1 h (N = 35, P = 1.000). A statistically significant difference in 46Ca/40Ca ratios exists between cells cultured for 1 h and cells cultured for 6 h (N = 76, P < 0.001). Cells cultured for 6 h again have a statistically lower 46Ca/40Ca ratio than cells cultured for 1 d (N = 90, P < 0.001). There is no statistically significant difference between the mean 46Ca/40Ca ratio of cells cultured for 1 d and cells cultured for 3 d (N = 51, P = 0.492).
Source data are available for this figure.
