Recent progress in mass spectrometry based molecular imaging

Imaging mass spectrometry is a rapidly developing research field, especially in the fields of life sciences and medicine. Various types of small and macromolecules in biological tissues can be scanned by imaging mass spectrometry technology. These biomolecules are closely related to the physiological and pathological states of organisms. Therefore, imaging mass spectrometry is a vital supplement to the method of optical morphological imaging. There are three techniques of imaging mass spectrometry: matrix assisted laser desorption ionization (MALDI) mass spectrometry imaging, secondary ion mass spectrometry (SIMS) imaging, and desorption electrospray ionization (DESI) mass spectrometry imaging. This review illustrated the principles and techniques of these three techniques and their applications in scientific and clinical research. The characteristics of these three types of mass spectrometry imaging can be summarized as follows: the spatial resolutions are separately 100, 10, and 0.1–1 μm; the working environments are atmospheric pressure, vacuum or low pressure, and vacuum; the analytes are small molecules, peptides or proteins or nucleic acid, small molecule or inorganic element; the application fields are environment, biomedicine, and material science.