We demonstrate the capabilities of a highly parallel, active pixel detector for large-area, mass spectrometric imaging of biological tissue sections. A bare Timepix assembly (512x512 pixels) is combined with chevron microchannel plates on an ion microscope matrix-assisted laser desorption time-of-flight mass spectrometer (MALDI TOF-MS). The detector assembly registers position- and time-resolved images of multiple m/z species in every measurement frame. We prove the applicability of the detection system to bio-molecular mass spectrometry imaging on biologically relevant samples by mass-resolved images from Timepix measurements of a peptide-grid benchmark sample and mouse testis tissue slices. Mass-spectral and localization information of analytes at physiological concentrations are measured in MALDI-TOF-MS imaging experiments. We show a high spatial resolution (pixel size down to 740x740 nm2 on the sample surface) and a spatial resolving power of 6 {\mu}m with a microscope mode laser field of view of 100-335 {\mu}m. Automated, large-area imaging is demonstrated and the Timepix' potential for fast, large-area image acquisition is highlighted.
@article{arxiv.1305.5437,
title = {Biological Tissue Imaging with a Position and Time Sensitive Pixelated Detector},
author = {Julia H. Jungmann and Donald F. Smith and Luke MacAleese and Ivo Klinkert and Jan Visser and Ron M. A. Heeren},
journal= {arXiv preprint arXiv:1305.5437},
year = {2013}
}