Cryo-OrbiSIMS for 3D molecular imaging of a bacterial biofilm in its native state

Zhang, Junting, Brown, James, Scurr, David J., Bullen, Anwen, MacLellan-Gibson, Kirsty, Williams, Paul, Alexander, Morgan R., Hardie, Kim R., Gilmore, Ian S. and Rakowska, Paulina D. (2020) Cryo-OrbiSIMS for 3D molecular imaging of a bacterial biofilm in its native state. Analytical Chemistry, 92 (13), 9008-9015. (doi:10.1021/acs.analchem.0c01125).

Abstract

Secondary ion mass spectrometry (SIMS) is gaining popularity for molecular imaging in the life sciences because it is label-free and allows imaging in two and three dimensions. The recent introduction of the OrbiSIMS has significantly improved the utility for biological imaging through combining subcellular spatial resolution with high-performance Orbitrap mass spectrometry. SIMS instruments operate in high-vacuum, and samples are typically analyzed in a freeze-dried state. Consequently, the molecular and structural information may not be well-preserved. We report a method for molecular imaging of biological materials, preserved in a native state, by using an OrbiSIMS instrument equipped with cryogenic sample handling and a high-pressure freezing protocol compatible with mass spectrometry. The performance is demonstrated by imaging a challenging sample (>90% water) of a mature Pseudomonas aeruginosa biofilm in its native state. The 3D distribution of quorum sensing signaling molecules, nucleobases, and bacterial membrane molecules is revealed with high spatial-resolution and high mass-resolution. We discover that analysis in the frozen-hydrated state yields a 10 »000-fold increase in signal intensity for polar molecules such as amino acids, which has important implications for SIMS imaging of metabolites and pharmaceuticals.

This record has no associated files available for download.

Contributors

Author: Paulina D. Rakowska

Download statistics