Abstract

Nuclear magnetic resonance and high-performance liquid chromatography mass spectrometry are the “gold standards” for molecular identification. However, they have limited spatial information. Conversely, techniques with high spatial resolution such as electron microscopy, have low molecular identification information. Generally, from an analytical perspective, this creates what can be termed the “Molecular Uncertainty Principle”, where the more certain we are about a molecule’s identity, the less certain we are about its localization. This is a frustrating limit for measurements at the frontiers.

In 2017, we introduced the OrbiSIMS technology [1] bringing the performance of an Orbitrap mass spectrometer together with the high-resolution imaging capability of secondary ion mass spectrometry (SIMS). [2] We were able to map the distribution of lipids and neurotransmitters in mouse brain with sub-cellular resolution. We also demonstrated the ability for single-cell metabolic profiling of macrophage cells incubated with the anti-arrhythmia drug, amiodarone, revealing strong heterogeneity of drug uptake. However, with single-cell resolution a clear correlation of drug uptake with upregulation of specific lipids was found. The unique ability of OrbiSIMS to simultaneously provide high-confidence in a molecule’s location and identity has led to strong uptake in a wide range of science and technologies, with now over 20 instruments installed worldwide.

Inspired by advances in Cryo-EM, we introduced the cryo-OrbiSIMS which allows imaging in the native biological state [3]. For example, we demonstrated the ability to undertake in-situ metabolomics of biofilm formation [3] and in collaboration with the Francis Crick Institute we mapped the distribution of metabolites on the cuticular surface of drosophila. [4] An introduction to the cryo-OrbiSIMS will be given along with example biological applications from us and others. In a look to the future, the concept for a quantum detector to boost Orbitrap sensitivity by an order of magnitude will be presented [5].

References

[1] M K Passarelli et al., The 3D OrbiSIMS-label-free metabolic imaging with subcellular lateral resolution and high mass-resolving power, Nature Methods, 2017. 14 (12): p. 1175 [2] N. P. Lockyer et al. Secondary ion mass spectrometry, Nat Rev Methods Primers 2024, 4, 32 [3] J. Zhang et al., Cryo-OrbiSIMS for 3D molecular imaging of a bacterial biofilm in its native state”, Anal. Chem. 2020, 92, 13, 9008–9015. [4] C. L. Newell et al, Cryogenic OrbiSIMS Localizes Semi-Volatile Molecules in Biological Tissues, Angewandte Chemie Int. 2020, 59 (41), 18194-18200 [5] PCT /GB2024/050690 – Improved Spectrometer or Imaging Assembly (2024).