Open AccessThree-dimensional (3D) imaging of lipids in skin tissues with infrared matrix-assisted laser desorption electrospray ionization (MALDESI) mass spectrometry
Author(s) -
Hongxia Bai,
Keith E. Linder,
David C. Muddiman
Publication year - 2021
Publication title -
analytical and bioanalytical chemistry/analytical and bioanalytical chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.86
H-Index - 166
eISSN - 1618-2650
pISSN - 1618-2642
DOI - 10.1007/s00216-020-03105-6
Subject(s) - mass spectrometry imaging , mass spectrometry , chemistry , maldi imaging , resolution (logic) , laser , chemical imaging , matrix assisted laser desorption/ionization , laser ablation , analytical chemistry (journal) , desorption , chromatography , optics , hyperspectral imaging , adsorption , artificial intelligence , physics , organic chemistry , computer science
Three-dimensional (3D) mass spectrometry imaging (MSI) has become a growing frontier as it has the potential to provide a 3D representation of analytes in a label-free, untargeted, and chemically specific manner. The most common 3D MSI is accomplished by the reconstruction of 2D MSI from serial cryosections; however, this presents significant challenges in image alignment and registration. An alternative method would be to sequentially image a sample by consecutive ablation events to create a 3D image. In this study, we describe the use of infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) in ablation-based 3D MSI for analyses of lipids within fresh frozen skin tissue. Depth resolution using different laser energy levels was explored with a confocal laser scanning microscope to establish the imaging parameters for skin. The lowest and highest laser energy level resulted in a depth resolution of 7 μm and 18 μm, respectively. A total of 594 lipids were putatively detected and detailed lipid profiles across different skin layers were revealed in a 56-layer 3D imaging experiment. Correlated with histological information, the skin structure was characterized with differential lipid distributions with a lateral resolution of 50 μm and a z resolution of 7 μm.