The 3D OrbiSIMS – Label-Free Metabolic Imaging with Sub-cellular Lateral Resolution and High Mass Resolving Power

We have developed the
3D OrbiSIMS for label-free biomedical imaging. It has an unparalleled
simultaneous combination of spatial resolution (under 200 nm for inorganics and
under 1.5 µm for biomolecules) and mass resolving power of > 240,000 at
m/z 200. This allows the distribution
of exogenous and endogenous metabolites to be visualized in 3D with
sub-cellular resolution. We image the distribution of neurotransmitters—gamma-aminobutyric
acid (GABA), dopamine and serotonin with high spectroscopic confidence in the
CA3 and CA1 regions of the hippocampus (murine). GABA is most abundant in the stratum oriens. We identify and map the sub-cellular
localisation of 53 glycosphingolipid sulfatide species and demonstrate the
ability of tandem mass spectrometry to confirm lipid identity. Single cell
metabolomic profiling is demonstrated using rat alveolar macrophage cells
incubated with different concentrations of the drug amiodarone. The up-regulation
of phospholipid species and cholesterol is correlated with the accumulation of
amiodarone.