Assessing the potentiality of sputtered gold nanolayers in mass spectrometry imaging for metabolomics applications (Liver MALDI-MSI assay)

Mass spectrometry imaging (MSI) is a molecular imaging technique that maps the distribution of molecules in biological tissues with high spatial resolution. The most widely used MSI modality is matrix-assisted laser desorption/ionization (MALDI), but some organic matrices used in classical MALDI may impact the quality of the molecular images due to limited lateral resolution and strong background noise in the low mass range, hindering its use in metabolomics. Here we present a matrix-free LDI technique based on the deposition by sputtering of gold nanolayers on tissue sections. This gold coating method is quick, fully automated and repetitive and allows growing highly controlled nanolayers, necessary for high quality and high resolution MS image acquisition. The performance of the developed method has been tested on the acquisition of MS images of brain. The obtained spectra showed a high number of MS peaks on the low mass region (m/z below 1000 Da) with few background peaks, demonstrating the viability of the sputtered gold nanolayers of promoting the desorption/ionization of a wide range of metabolites. These results, together with the reliable MS spectrum calibration using gold peaks, make the developed method a valuable alternative for MSI applications.

Liver MALDI MS imaging assay is reported in the current study MTBLS589.
Brain MALDI MS imaging assay is reported in MTBLS588.