Time-resolved ICP-MS analysis of mineral element contents and distribution patterns in single cells

Novel single cell techniques are attracting growing interest for clinical applications, because they can elucidate the cellular diversity and heterogeneity instead of the average masked by bulk measurements. Herein, time-resolved ICP-MS for the determination of essential mineral elements in single cells has been developed and is used to analyze the contents and distribution patterns of Fe, Cu, Zn, Mn, P and S in two types of cancer cells (HeLa and A549) and one type of normal cells (16HBE). The results show that there are obvious differences in contents and distribution patterns of the elements among the three types of cells. The mass of Fe, Zn, Cu, Mn, P, and S in individual HeLa cells is significantly higher and span a broader range of values than in the single 16HBE and A549 cells. The contents of Fe, Zn, and Cu follow log-normal distributions, and Mn, P, and S follow Poisson distributions with high λ values in single HeLa cells, indicating a large cell-to-cell variance. Comparatively, the contents of Cu, Zn, P, and S in 16HBE cells show the narrowest distribution range among the three tested cells, demonstrating the homogenous distribution of the elements in the cells. The method of single cell ICP-MS (SC-ICP-MS) provides potential applications for the monitoring of the variation of mineral elements at a single cell level.