Advancing the Characterization of Biological Systems via Desorption Electrospray Ionization Mass Spectrometry

Abstract

Desorption electrospray ionization(DESI) is a hybrid, soft-ionization technique that combines the benefits of traditional spray methods with the analysis of condensed phase samples usually associated with desorption-based approaches, requiring no vacuum based sampling and little to no sample preparation. One of the premiere ambient techniques, DESI is able to operate in a spatially resolved mode, allowing for both the in situ spatiochemical characterization of biological systems and the high-throughput bioanalytical screening of microbial species. In this work, DESI was implemented in the inter-domain co-culture to investigate pathogen-bacterial control agent interactions. Additionally, a rapid, single-raster workflow (“Fast-Pass”) was developed for the high-throughput screening of genetically engineered bacteria, displaying an improvement in the timescale associated with untargeted metabolic phenotyping by more than an order of magnitude. To support the Fast-Pass workflow, a humidity control chamber was designed and constructed for the DESI platform to improve reproducibility associated with environmental variability and IM-MS investigations were carried out to support carbohydrate measurements in terms of improving confidence associated with molecular annotations.