Live single-cell molecular analysis by video-mass spectrometry.

The direct molecular analysis of a live single cell viewed under a video-microscope has been developed. The cell contents are sucked into a nano-electrospray tip, and hundreds of peaks of ionic compounds of low molecular weight are detected by nano-ESI Q-TOF mass spectrometry (MS). Cell-specific MS peaks in a single mouse-embryonic fibroblasts cell are extracted by a t-test, and one of the peaks is proceeded to MS/MS analysis for molecular identification. This method is direct and quick to identify the molecules of a cell with simultaneous observation by a video-microscope.