Mass Spectrometric Imaging for Biomedical Tissue Analysis

Mass spectrometry (MS) is a great scientific tool due to its capabilities to determine the mass of large biomolecular complexes, individual biomolecules, small organic molecules, and single atoms and their isotopes has been reported. It emerged as a response to the demand for spatial information about biomolecules detected by conventional mass spectrometry. The third ionization method used for MSI evolved recently in the form of desorption electrospray ionization (DESI). Mass spectrometric imaging is essentially a four step process. It involves sample preparation, desorption and ionization, mass analysis, and image registration. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a dramatic improvement of laser desorption/ionization mass spectrometry (LDI-MS). MSI provides two-dimensional distributions of multiple ions detected from biological samples. Cross-sectional views of the 3D models can be used to investigate distributions of many additional molecules detected by MSI.