[MALDI imaging mass spectrometry for direct tissue analysis].

Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry is a new method for investigating the distribution of proteins and small molecules within biological systems through the in situ analysis of tissue sections using MALDI-TOF (time-of-flight) mass spectometry. The power of this technology lies in its capability to reliably combine protein data with specific cellular regions within the tissue. For the molecular image analysis, tissue samples are measured in a raster-like process in the mass spectrometer and for each spot a mass spectrum is obtained from molecules within the irradiated area. Software tools generate a mass spectrometry image or molecular weight-specific map of the sample at any desired molecular weight value and the presence and location of proteins and peptides are visualized in the tissue.There are three main fields of application, comprising molecular histology, screening for new biomarkers, and detection of drugs and their metabolites directly in the tissue.