Speaker: Julia Jungmann

Title: Molecular imaging (Active Pixel Detectors for Mass Spectrometry Imaging)

Affiliation: FOM-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands 2 Paul Scherrer Institut, 5232 Villigen PSI, Switzerland

Abstract: Mass spectrometry imaging (MSI) targets accurate compound localization and identification on complex surfaces and has seen increased use as an analytical tool for biomolecular and biomedical research [1]. In terms of dedicated instrumentation, this translates into the demand for more detail in the image dimension (spatial resolution) and in the spectral dimension (mass resolution and accuracy), preferably combined in one instrument. At the same time, large area biological tissue samples require fast acquisition schemes, instrument automation and a robust data infrastructure. Here, the opportunities and challenges that active pixel detectors have provided to the field of mass spectrometry imaging are discussed to provide the audience with an insight in the current technological advances and the potential of MSI for biomolecular and biomedical research.
In particular, this presentation outlines the analytical capabilities of microscope mode MSI, which is a high throughput and high spatial resolution molecular imaging technique. Here, ions are projected on a position-sensitive detector and the spatial resolution of the image is determined by the quality of the ion optics and segmentation of the detection system. In time-of-flight (TOF) ion microscopy, an ideal single detection system records the ion TOF and the arrival position. This avoids the selection of individual molecular masses for imaging, and hence the need for time-consuming, repetitive measurements on degrading biological samples. In-vacuum active pixel detectors enable such high sensitivity, highly parallel time- and space-resolved detection of ions from complex surfaces [2,3]. We present the implementation and application of an in-vacuum, pixelated camera for high throughput, high spatial resolution matrix-assisted laser desorption/ionization (MALDI) ion microscopy. The detection system consists of a fully-integrated, active solid state Timepix pixel detector [4] in combination with a chevron microchannel plate stack. Each pixel of the Timepix detector returns the position of impact of a particle and its TOF (10ns maximum time resolution). A typical 2x2 chip Timepix detector arrangement consists of 4 chips with 256x256 pixels of 55umx55um each. This results in 262,144 parallel detection channels, each of which can record the position of impact (x- and ycoordinate) and the arrival time of a particular ionic species at the same time. The Timepix detection system was tested for automated, large area imaging of biological tissue sections. Already now, TOF-MSI systems can benefit from several unique Timepix system capabilities. These are the combination of high signal-to-noise ratios, the multiplexed detection of events by the highly parallel detection system, the high sensitivity, the large mass range and the simultaneous detection of position- and timeinformation by a single detector system.

Julia H. Jungmann (1,2), Donald F. Smith (1,3), Andras Kiss (1), Luke MacAleese (1,4), Jan Visser (5) and Ron M.A. Heeren (1)

1) FOM-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
2) Paul Scherrer Institut, 5232 Villigen PSI, Zwisterland
3) National High Magnetic Field Laboratory, 1800 E. Paul Dirac Drive, Tallahassee, FL 32310-3706, United States of America
4) Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon 69622, Villeurbanne Cedex, France
5) Nikhef, Science Park 105, 1098 XG Amsterdam, The Netherlands

References
[1] Julia H. Jungmann and Ron M. A. Heeren, Emerging Technologies in Mass Spectrometry Imaging, Journal of Proteomics, 75, 5077-5092, 2012
[2] Julia H. Jungmann, Luke MacAleese, Jan Visser, Marc J.J. Vrakking, Ron M.A. Heeren, High Dynamic Range Bio-Molecular Ion Microscopy with the Timepix Detector, Analytical Chemistry, 83, 20, 7888-7894, 2011
[3] J. H. Jungmann, D. F. Smith, L. MacAleese, I. Klinkert, R. M. A. Heeren, Biological Tissue Imaging with a Position and Time Sensitive Pixelated Detector, Journal of the American Society for Mass Spectrometry, 23, 1679-1688, 2012
[4] http://medipix.web.cern.ch/medipix/

© 2013, EMRG

Sponsored by:
   

Centro Tecnologia e Innovazione
Tecnopolo di Ravennna
Via S.Alberto 163, 48123 Ravenna, Italia
andrea.contin@unibo.it