Optimization of sprayer for matrix application in MALDI mass spectrometry imaging

Successful matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI) relies on the selection of the most appropriate matrix and optimization of the matrix application parameters. In order to achieve reproducible high spatial-resolution imaging data, several commercially available automated matrix application platforms have become available. However, the high cost of these commercial matrix sprayers is restricting access into this emerging research field. Here, we report an automated platform for matrix deposition, employing a converted commercially-available 3D printer ($300) and other parts commonly found in an analytical chemistry lab as a low-cost alternative to commercial sprayers. Using printed fluorescent rhodamine B microarrays and employing experimental design, the matrix deposition parameters were optimized to minimize surface analyte diffusion. Finally, the optimized matrix application method was applied to image 3-dimensional MCF-7 cell culture spheroid sections (ca. 500 µm diameter tissue samples). Using this system, we demonstrate robust and reproducible observation of endogenous metabolite distributions with high spatial resolution.

Tucker, Lulu H. (2018). Optimization of sprayer for matrix application in MALDI mass spectrometry imaging, [dataset]. University of Edinburgh. School of Chemistry.