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Mass Spectrometry Imaging (MSI) of Fresh Bones using Infrared Matrix-Assisted Laser Desorption Electrospray Ionization (IR-MALDESI).

ABSTRACT: We report an effective strategy for direct analysis and two-dimensional (2D) matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging (MSI) of mouse bones that underwent no chemical treatments prior to analysis. To unravel the chemistry in bones under near-physiological conditions, we cut a flash-frozen bone in half longitudinally, placed it in a mold facing flat side down, and poured Plaster of Paris on top of and around the bone. After Plaster of Paris had set, the bone with embedding material was removed from the mold, and placed on the IR-MALDESI imaging stage. Plaster of Paris acted as a fixture to keep every spot on the sample surface the same distance away from the laser focus. To demonstrate the feasibility of IR-MALDESI MSI for analyses of unmodified bones, we imaged bones derived from healthy and stroke-affected mice and generated ion heatmaps showing the spatial distribution of putatively annotated features.

SUBMITTER: Khodjaniyazova S

PROVIDER: S-EPMC8018523 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Lipidomic profiling of single mammalian cells by infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI).

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| S-EPMC7606626 | biostudies-literature

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| S-EPMC3689149 | biostudies-literature

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| S-EPMC9696666 | biostudies-literature

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| S-EPMC4197142 | biostudies-literature

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| S-EPMC3781580 | biostudies-literature

Quantitative mass spectrometry imaging of glutathione in healthy and cancerous hen ovarian tissue sections by infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI).

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| S-EPMC5788707 | biostudies-literature

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| S-EPMC4701606 | biostudies-other

Three-Dimensional Imaging with Infrared Matrix-Assisted Laser Desorption Electrospray Ionization Mass Spectrometry.

Project description:Mass spectrometry imaging as a field has pushed its frontiers to three dimensions. Most three-dimensional mass spectrometry imaging (3D MSI) approaches require serial sectioning that results in a loss of biological information between analyzed slices and difficulty in reconstruction of 3D images. In this contribution, infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) was demonstrated to be applicable for 3D MSI that does not require sectioning because IR laser ablates material on a micrometer scale. A commercially available over-the-counter pharmaceutical was used as a model to demonstrate the feasibility of IR-MALDESI for 3D MSI. Depth resolution (i.e., z-resolution) as a function of laser energy levels and density of ablated material was investigated. The best achievable depth resolution from a pill was 2.3 μm at 0.3 mJ/pulse. 2D and 3D MSI were performed on the tablet to show the distribution of pill-specific molecules. A 3D MSI analysis on a region of interest of 15 × 15 voxels across 50 layers was performed. Our results demonstrate that IR-MALDESI is feasible with 3D MSI on a pill, and future work will be focused on analyses of biological tissues.

| S-EPMC8284694 | biostudies-literature

Direct screening of enzyme activity using infrared matrix-assisted laser desorption electrospray ionization.

Project description:RationaleHigh-throughput screening (HTS) is a critical step in the drug discovery process. However, most mass spectrometry (MS)-based HTS methods require sample cleanup steps prior to analysis. In this work we present the utility of infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) for monitoring an enzymatic reaction directly from a biological buffer system with no sample cleanup and at high throughput.MethodsIR-MALDESI was used to directly analyze reaction mixtures from a well plate at different time points after reaction initiation. The percent conversion of precursors to products was used to screen the enzyme activity. The reaction was performed with two different concentrations of precursors and enzyme in order to assess the dynamic range of the assay. Eventually, a pseudo-HTS study was designed to investigate the utility of IR-MALDESI screening enzyme activity in a high-throughput manner.ResultsIR-MALDESI was able to readily monitor the activity of IDH1 over time at two different concentrations of precursors and enzyme. The calculated Z-factors of 0.65 and 0.41 confirmed the suitability of the developed method for screening enzyme activity in HTS manner. Finally, in a single-blind pseudo-HTS analysis IR-MALDESI was able to correctly predict the identity of all samples, where 8/10 samples were identified with high confidence and the other two samples with lower confidence.ConclusionsThe enzymatic activity of IDH1 was screened by directly analyzing the reaction content from the buffer in well plates with no sample cleanup steps. This proof-of-concept study demonstrates the robustness of IR-MALDESI for direct analysis of enzymatic reactions from biological buffers with no sample cleanup and its immense potential for HTS applications.

| S-EPMC5653407 | biostudies-literature

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