Streamlined Multimodal DESI and MALDI Mass Spectrometry Imaging on a Singular Dual-Source FT-ICR Mass Spectrometer

Abstract

The study of biological specimens by mass spectrometry imaging (MSI) has had a profound influence in the various forms of spatial-omics over the past two decades including applications for the identification of clinical biomarker analysis; the metabolic fingerprinting of disease states; treatment with therapeutics; and the profiling of lipids, peptides and proteins. No singular approach is able to globally map all biomolecular classes simultaneously. This led to the development of many complementary multimodal imaging approaches to solve analytical problems: fusing multiple ionization techniques, imaging microscopy or spectroscopy, or local extractions into robust multimodal imaging methods. However, each fusion typically requires the melding of analytical information from multiple commercial platforms, and the tandem utilization of multiple commercial or third-party software platforms—even in some cases requiring computer coding. Herein, we report the use of matrix-assisted laser desorption/ionization (MALDI) in tandem with desorption electrospray ionization (DESI) imaging in the positive ion mode on a singular commercial orthogonal dual-source Fourier transform ion cyclotron resonance (FT-ICR) instrument for the complementary detection of multiple analyte classes by MSI from tissue. The DESI source was 3D printed and the commercial Bruker Daltonics software suite was used to generate mass spectrometry images in tandem with the commercial MALDI source. This approach allows for the generation of multiple modes of mass spectrometry images without the need for third-party software and a customizable platform for ambient ionization imaging. Highlighted is the streamlined workflow needed to obtain phospholipid profiles, as well as increased depth of coverage of both annotated phospholipid, cardiolipin, and ganglioside species from rat brain with both high spatial and mass resolution.

Image to insight: exploring natural products through mass spectrometry imaging

“…77 Zemaitis et al coupled a 3D printed DESI ion source onto a commercial MALDI MS instrument. 78 This approach allows the generation of multiple modes of MS images without the need to exchange ion sources and application of additional external soware. In fact, an MS instrument equipped with multimodal MALDI and DESI imaging is already on the market, which delivers multi-layered, information-rich data from a single sample (e.g., Waters™).…”

Spatially Mapping the Baseline and Bisphenol-A Exposed Daphnia magna Lipidome Using Desorption Electrospray Ionization—Mass Spectrometry

“…For example, further DESI-MS experiments could be conducted using both ionization polarities, different solvent compositions, and/or capillary temperatures. In addition, a single orthogonal MSI technique such as MALDI could be applied, as has recently been achieved by Zemaitis et al for the study of rat brain tissue [41]. This takes advantage of the non-destructive nature of DESI and would be especially beneficial in studies aiming, for example, to additionally characterize the exposure chemical (and its biotransformation products) with spatial resolution.…”

Build, Share and Remix: 3D Printing for Speeding Up the Innovation Cycles in Ambient Ionisation Mass Spectrometry (AIMS)

“…They optimised parameters such as the incidence angle, collection angle, emitter distance from capillary to sample, and the distance of capillary to sample [23]. Subsequently, they used the 3D-DESI source for multimodal mass spectrometry imaging (MSI), analysing phospholipid profiles of rat brain tissues with DESI and matrix-assisted laser desorption/ionisation (MALDI) [28].…”