Intact lipid imaging of mouse brain samples: MALDI, nanoparticle-laser desorption ionization, and 40 keV argon cluster secondary ion mass spectrometry

• Published in: Analytical and bioanalytical chemistry Vol. 408; no. 24; pp. 6857 - 6868
• Main Authors: Mohammadi, Amir Saeid, Phan, Nhu T.N., Fletcher, John S., Ewing, Andrew G.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2016; Springer; Springer Nature B.V
• Subjects: ALZHEIMERS-DISEASE; Analytical Chemistry; Analytisk kemi; Animal tissues; Animals; Argon - chemistry; Atom and Molecular Physics and Optics; Atom- och molekylfysik och optik; BEAMS; Biochemistry; Biological samples; BIOLOGICAL TISSUE; Brain; Brain Chemistry; CELLS; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Clusters; Desorption; DESORPTION/IONIZATION; DROSOPHILA BRAIN; Food Science; Gas cluster; Imaging; Ion beams; Ionization; Laboratory Medicine; Lasers; Lipids; Lipids - analysis; Mass spectrometry; Mass spectrometry imaging; MATRIX; Methods; Mice; Monitoring/Environmental Analysis; Nanoparticle-LDI; Nanoparticles; Nanoparticles - chemistry; Nanostructure; Phospholipids - analysis; Physiological aspects; Radiologi och bildbehandling; Radiology, Nuclear Medicine and Medical Imaging; Research Paper; RESOLUTION; Scientific imaging; Secondary ion mass spectrometry; Signal transduction; SIMSMALDI; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Spectrometry, Mass, Secondary Ion - methods; TOF-SIMS; Trifluoroacetic Acid - chemistry; Sweden; Lipids; Nanoparticle-LDI; MALDI; Gas cluster SIMS; Mass spectrometry imaging; MATRIX; CELLS; SIMSMALDI; DROSOPHILA BRAIN; ALZHEIMERS-DISEASE; MS; BEAMS; RESOLUTION; Gas cluster; DESORPTION/IONIZATION; BIOLOGICAL TISSUE; TOF-SIMS
• ISSN: 1618-2642; 1618-2650; 1618-2650
• DOI: 10.1007/s00216-016-9812-5

We have investigated the capability of nanoparticle-assisted laser desorption ionization mass spectrometry (NP-LDI MS), matrix-assisted laser desorption ionization (MALDI) MS, and gas cluster ion beam secondary ion mass spectrometry (GCIB SIMS) to provide maximum information available in lipid analysis and imaging of mouse brain tissue. The use of Au nanoparticles deposited as a matrix for NP-LDI MS is compared to MALDI and SIMS analysis of mouse brain tissue and allows selective detection and imaging of groups of lipid molecular ion species localizing in the white matter differently from those observed using conventional MALDI with improved imaging potential. We demonstrate that high-energy (40 keV) GCIB SIMS can act as a semi-soft ionization method to extend the useful mass range of SIMS imaging to analyze and image intact lipids in biological samples, closing the gap between conventional SIMS and MALDI techniques. The GCIB SIMS allowed the detection of more intact lipid compounds in the mouse brain compared to MALDI with regular organic matrices. The 40 keV GCIB SIMS also produced peaks observed in the NP-LDI analysis, and these peaks were strongly enhanced in intensity by exposure of the sample to trifluororacetic acid (TFA) vapor prior to analysis. These MS techniques for imaging of different types of lipids create a potential overlap and cross point that can enhance the information for imaging lipids in biological tissue sections. Graphical abstract Schematic of mass spectral imaging of a mouse brain tissue using GCIB-SIMS and MALDI techniques