Invited Paper BN+AS-WeA7
Biological Applications of Lipid Imaging with Cluster-TOF-SIMS and MALDI-TOF

Wednesday, October 31, 2012, 4:00 pm, Room 23

Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) using keV energy metal cluster beams as primary ions is now recognized as a powerful method for in situ chemical, biological and medical applications [1,2]. It opens a new field of surface imaging, particularly for biological tissue sections. Compared to the more established MALDI (Matrix Assisted Laser Desorption Ionisation) imaging approach, TOF-SIMS imaging provides the incomparable advantages of a routine micrometre scale resolution and of an easy sample preparation which does not require matrix coating of the surface. However TOF-SIMS suffers from some limitations, such as the narrow mass range, the lack of structural analysis of the species by tandem mass spectrometry, and the fact that mainly lipids are preferentially released from the biological samples.

This lecture intends to show the wealth of powerful information that can be obtained from the chemical analysis of biological surfaces, with several examples chosen among various applications such as the localization of xenobiotics, natural substances, lipid markers from genetic diseases and non-alcoholic fatty liver disease. The strengths and weaknesses of lipid imaging using TOF-SIMS and MALDI-TOF will also be compared, showing the complementarity between the two methods.

Tissue imaging using TOF-SIMS can also be associated with histology for medical diagnosis in order to correlate structural features with ion images. The possibility to use the same tissue section for both histology and mass spectrometry imaging has been tested. It is a major advantage in terms of sample preparation and precision on the histological structure localization, provided that none of the two methods disturbs the performances of the other [3].

Massive cluster ion sources of argon have recently been used for SIMS experiments [4]. These ion beams interact with surfaces with incomparable physical properties, and thus hold the promise for new opportunities such as organic depth profiling or large increases of sensitivity. Recent results will be presented showing the possibility of depth profiling in organic samples, but also the enhancement of the sensitivity, using both massive clusters and bismuth for dual beam depth profiling.

[1] F. Benabdellah, A. Seyer, L. Quinton, D. Touboul, A. Brunelle, O. Laprévote, Anal Bioanal Chem 396 (2010) 151-162

[2] D. Touboul, O. Laprévote, A. Brunelle, Curr Opin Chem Biol 15 (2011) 725-732

[3] C. Bich, S. Vianello, V. Guérineau, D. Touboul, S. De La Porte, A. Brunelle, Surf Interface Anal in press DOI:10.1002/sia.4846

[4] H. Gnaser, K. Ichiki, J. Matsuo, Rapid Commun Mass Spectrom 26 (2012) 1-8