Direct analysis of in vitro grown microorganisms and mammalian cells by ambient mass spectrometry
Abstract
Mass spectrometry (MS) is a firmly established method for in vitro cell studies with numerous applications documented in the literature. Considerable sample pretreatment is normally required for MS cell analysis assisted by classic ionization techniques including electrospray ionization (ESI), electron-impact ionization (EI), matrix-assisted laser desorption/ionization (MALDI), chemical ionization (CI), etc. The speed and throughput of mass spectrometric analysis have been dramatically improved with the emergence of ambient sampling methods, requiring little-to-no sample preparation for virtually any type of biological samples. Direct chemical sampling makes MS analysis simpler, faster and less invasive to living objects. To date, considerable experimental evidence has been accumulated that strongly indicates the broad applicability of ambient mass spectrometry (AMS) in different areas of cell research. Particular areas include early detection and rapid classification of pathogenic bacteria, authentication of cancer cell lines, drug/therapy development, biomarker discovery, clinical diagnosis, as well as the mechanistic studies of cellular metabolism and cell–host interactions. In this review, we summarize recent AMS studies on in vitro grown cells of microorganisms and mammals and systematically describe current analytical strategies, technologies and achieved results. The perspective of ambient mass spectrometry for this particular field is also discussed.