Developing a Noncontact Heating Matrix Spraying Apparatus with Controllable Matrix Film Formation for MALDI Mass Spectrometry Imaging

Abstract

Matrix deposition plays an important role in obtaining high-quality and reliable molecular spatial location information for matrix-assisted laser desorption/ ionization mass spectrometry imaging (MALDI-MSI). To control the matrix film formation, an automatic matrix spraying apparatus was developed with the introduction of a noncontact heating lamp. Compared with the unheated condition, the noncontact heating lamp suppressed the coffee-ring effect and the diffusion phenomenon of the analyte effectively by controllable matrix film formation. Meanwhile, the signal intensity was increased by 2−5 fold. To prove the ability of the matrix deposition apparatus, the apparatus combined with metabolomics analysis was used to show the spatial distribution of the substance in sprouted potato tubers. The potential biomarkers at m/ z 868.5049 and m/z 852.5101 were identified as α-solanine and α-chaconine, and the synthesis pathways were further searched. To further demonstrate the quality of MALDI images including localization and spatial resolution, lipid distribution in rat brain tissue was investigated by the developed noncontact heating matrix spraying apparatus. An excellent match with distinguishable compartments of lipids in the rat brain was obtained between the H&E-stained sections and MALDI-MSI images. These results indicate that the developed noncontact heating matrix spraying apparatus is reliable and provides a low-cost, high-quality, rapid approach for MALDI-MSI.

Inhibiting Protein Aggregation Using Cellulose Nanocrystal in MALDI-TOF MS Analysis: Improving the Sensitivity and Repeatability of Intact Protein in Pueraria

“…5−8 For example, Zhao group reported an automatic matrix spraying strategy with the introduction of a noncontact heating lamp to inhibit the coffee-ring effect and increase the signal intensity. 9 Han group adapted large-area graphene films as MALDI plate surfaces to improve the uniformity of matrixanalyte crystal spots. 10 Recently, researchers used a second ionizing laser (termed MALDI-2) to improve the sensitivity of conventional MALDI (MALDI-1).…”

“…In the past, numerous methodologies have emerged to improve the sensitivity and repeatability of MALDI experiment. The useful approach is to develop novel sample preparation schemes, including use of new matrix, uniform crystallization techniques, or sample deposition methods, to improve desorption/ionization efficiency and control variability. − For example, Zhao group reported an automatic matrix spraying strategy with the introduction of a noncontact heating lamp to inhibit the coffee-ring effect and increase the signal intensity . Han group adapted large-area graphene films as MALDI plate surfaces to improve the uniformity of matrix-analyte crystal spots .…”