Lecture
Development and Application of Laser Ablation Rapid Evaporative Ionisation Mass Spectrometry – From Cellular Imaging to High-Throughput Phenomics
- at -
- ICM Saal 4b
- Type: Lecture
Lecture description
Dr. D. Simon1, Dr. Y. Wang2, Mr. G. Horkovics-Kovats1, Dr. R. Battle2, Prof. Y. Xiang1, Dr. R. T. Murray2, Prof. Z. Takats1,2
1 Regensburg University / 2 Imperial College London
The highly-multiplexed subcellular imaging of clinical samples has been a longstanding goal in clinical mass spectrometry. Laser Ablation – Rapid Evaporative Ionisation Mass Spectrometry (LA-REIMS) is based on resonant laser desorption of tissues and subsequent ionisation in an atmospheric interface, allowing use in numerous scenarios, from high resolution – single cell imaging to in vivo diagnostics. Here we present our recent work in developing the subcellular workflow and the results in clinical sample analysis with our imaging platform. [1,2]
A Xevo G2-XS and G3-XS QToF (Waters) mass spectrometers with a prototype REIMS source were used for the experiments. A motorized XYZ stage coupled with focusing optics was used for laser ablation. Three mid-IR laser setups were used to conduct the
experiments: an Opolette HE2731 Optical Parametric Oscillator (OPO) laser (Opotek) operating at 20Hz tuneable between 2700 – 3100nm, Glucoloop Ivy (operating at 10 – 1500 Hz, 2710 nm) and high-brightness laser setup (optical parametric amplifier), operating at 100 psec pulse width, 200 nJ/pulse energy, 500kHz at 2940 nm. 10 µm fresh frozen mouse brain, human HNSCC tissues and grown various grown cell cultures grown and prepared in 96-deep well plates were used analysis. Spot sizes of <10 microns were achieved on tissues. Two orders of magnitude increase in sensitivity was observed with the shorter-pulsed picosecond laser due to stress confinement.
Using these conditions, imaging experiments were conducted on different tissue samples using different raster sizes. At raster sizes below 5 - 3 microns, features such as cell nuclei were observable on the images through Adenine (m/z 134.046 [M-H]-). The images were matched with optical microscopy images and the positions of ‘adenine hotspots’ matched with the locations of cell nuclei. At 3-micron raster sizes, the sensitivity was reduced due to oversampling, however individual Purkinje-cell features were observable in the cerebellum region. The metabolomics data obtained from the clinical samples enable the phenotypical characterisation of tissues at a very high-resolution.
The presented metabolic tools have the capability to provide single and subcellular data from various clinical samples at resolutions that is to our understanding is unmatched in ambient ionisation mass spectrometry. The sample-preparation independent nature of the tool enables the method to be a widely deployable easy-touse molecular pathology tool, a step towards introducing mass spectrometry as a
routine clinical tool.
Literature:
[1] D. Simon et al., Anal. Chem. 2025, 97, 32, 17433–17443.
[2] S. Maneta-Stavrakaki et al., Anal. Chem. 2025, 97, 48, 26549–26559
1 Regensburg University / 2 Imperial College London
The highly-multiplexed subcellular imaging of clinical samples has been a longstanding goal in clinical mass spectrometry. Laser Ablation – Rapid Evaporative Ionisation Mass Spectrometry (LA-REIMS) is based on resonant laser desorption of tissues and subsequent ionisation in an atmospheric interface, allowing use in numerous scenarios, from high resolution – single cell imaging to in vivo diagnostics. Here we present our recent work in developing the subcellular workflow and the results in clinical sample analysis with our imaging platform. [1,2]
A Xevo G2-XS and G3-XS QToF (Waters) mass spectrometers with a prototype REIMS source were used for the experiments. A motorized XYZ stage coupled with focusing optics was used for laser ablation. Three mid-IR laser setups were used to conduct the
experiments: an Opolette HE2731 Optical Parametric Oscillator (OPO) laser (Opotek) operating at 20Hz tuneable between 2700 – 3100nm, Glucoloop Ivy (operating at 10 – 1500 Hz, 2710 nm) and high-brightness laser setup (optical parametric amplifier), operating at 100 psec pulse width, 200 nJ/pulse energy, 500kHz at 2940 nm. 10 µm fresh frozen mouse brain, human HNSCC tissues and grown various grown cell cultures grown and prepared in 96-deep well plates were used analysis. Spot sizes of <10 microns were achieved on tissues. Two orders of magnitude increase in sensitivity was observed with the shorter-pulsed picosecond laser due to stress confinement.
Using these conditions, imaging experiments were conducted on different tissue samples using different raster sizes. At raster sizes below 5 - 3 microns, features such as cell nuclei were observable on the images through Adenine (m/z 134.046 [M-H]-). The images were matched with optical microscopy images and the positions of ‘adenine hotspots’ matched with the locations of cell nuclei. At 3-micron raster sizes, the sensitivity was reduced due to oversampling, however individual Purkinje-cell features were observable in the cerebellum region. The metabolomics data obtained from the clinical samples enable the phenotypical characterisation of tissues at a very high-resolution.
The presented metabolic tools have the capability to provide single and subcellular data from various clinical samples at resolutions that is to our understanding is unmatched in ambient ionisation mass spectrometry. The sample-preparation independent nature of the tool enables the method to be a widely deployable easy-touse molecular pathology tool, a step towards introducing mass spectrometry as a
routine clinical tool.
Literature:
[1] D. Simon et al., Anal. Chem. 2025, 97, 32, 17433–17443.
[2] S. Maneta-Stavrakaki et al., Anal. Chem. 2025, 97, 48, 26549–26559
