1. Direct suction by microprobes. The concept of the microprobe was initially proposed by Masujima in 1999 , leading to the first SCMS experiment in 2008 using live single-cell video mass spectrometry (Video-MS) . In these early experiments, cells were monitored using a video microscope, and a gold-coated capillary nano-electrospray ionization (nanoESI) emitter (tip size is about 1-2 μm) was employed as a micropipette to extract cell contents . The same nanoESI emitter was then used for ionization in MS analysis. This technique has been applied to study plant cells, quantify analytes in live SCMS, and integrate with fluorescence imaging, laser microscopy, and microdroplet array systems . Vertes et al. integrated the capillary microsampling system with ion mobility MS to identify metabolites in single human hepatocytes . Additionally, this system has been applied to analyze neurons of the mollusk Lymnaea stagnalis . When combined with fluorescence microscopy, specific subcellular components (e.g., cytoplasm and nucleus) can be selected for analysis. The pressure probes facilitated direct sample injection using an internal electrode capillary , reduced the need for extensive sample preparation. High voltage ionization capabilities enabled these probes to operate efficiently under ambient conditions. Other direct-suction methods, including nanopipettes , micropipettes , and Tprobes , have also been adapted for ambient single-cell analysis.