4 research outputs found
The 3D OrbiSIMS—label-free metabolic imaging with subcellular lateral resolution and high mass-resolving power
We report the development of a 3D OrbiSIMS instrument for label-free biomedical imaging. It combines the high spatial resolution of secondary ion mass spectrometry (SIMS; under 200 nm for inorganic species and under 2 μm for biomolecules) with the high mass-resolving power of an Orbitrap (>240,000 at m/z 200). This allows exogenous and endogenous metabolites to be visualized in 3D with subcellular resolution. We imaged the distribution of neurotransmitters—gamma-aminobutyric acid, dopamine and serotonin—with high spectroscopic confidence in the mouse hippocampus. We also putatively annotated and mapped the subcellular localization of 29 sulfoglycosphingolipids and 45 glycerophospholipids, and we confirmed lipid identities with tandem mass spectrometry. We demonstrated single-cell metabolomic profiling using rat alveolar macrophage cells incubated with different concentrations of the drug amiodarone, and we observed that the upregulation of phospholipid species and cholesterol is correlated with the accumulation of amiodarone
Argon Cluster Ion Source Evaluation on Lipid Standards and Rat Brain Tissue Samples
Argon cluster ion sources for sputtering
and secondary ion mass spectrometry use projectiles consisting of
several hundreds of atoms, accelerated to 10–20 keV, and deposit
their kinetic energy within the top few nanometers of the surface.
For organic materials, the sputtering yield is high removing material
to similar depth. Consequently, the exposed new surface is relatively
damage free. It has thus been demonstrated on model samples that it
is now really possible to perform dual beam depth profiling experiments
in organic materials with this new kind of ion source. Here, this
possibility has been tested directly on tissue samples, 14 μm
thick rat brain sections, allowing primary ion doses much larger than
the so-called static secondary ion mass spectrometry (SIMS) limit
and demonstrating the possibility to enhance the sensitivity of time-of-flight
(TOF)-SIMS biological imaging. However, the depth analyses have also
shown some variations of the chemical composition as a function of
depth, particularly for cholesterol, as well as some possible matrix
effects due to the presence or absence of this compound