This method was first employed to rapidly quantify the absolute amounts of the anticancer drug in individual adherent cancer cells under ambient conditions . Pan et. al. performed the measurement of anticancer drug amounts within live cells (Figure ). In this study, both HCT-116 and HeLa cell lines were employed to investigate the intracellular uptake of irinotecan under various treatment durations and concentrations. To minimize the diffusion loss of cellular contents and internal standard (irinotecan-d10), glass chips containing microwells (diameter: 55 μm, depth: 25 μm) were used during cell incubation and treatment. Single cells in individual cells were selected for measurements. The amount of irinotecan within single cells was obtained. When comparing these single cell results with those obtained through traditional LC/MS techniques, it was found that the LC/MS approach yielded lower intracellular drug levels. This discrepancy was attributed to drug losses during the sample preparation process in LC/MS, highlighting the advantage of single-cell mass spectrometry in preserving and detecting accurate drug concentrations within cells. This method offers a more direct and precise approach to understanding drug uptake dynamics. Recent advancements have integrated the Single-probe with a cell manipulation system, enabling analysis of suspension cells and patient-isolated cells from body fluids (Figure a-c) . To extend quantitative SCMS techniques to suspended cells, the Single-probe system was coupled with an integrated cell manipulation platform (ICMP), which consists of an Eppendorf TransferMan cell micro manipulation system, a Nikon Eclipse TE300 inverted microscope, and a Tokai Hit