Advances in desorption electrospray ionization mass spectrometry imaging: Research progress and applications

Desorption electrospray ionization mass spectrometry imaging (DESI-MSI) is regarded as a novel molecular imaging approach that integrates DESI source with conventional mass spectrometry to provide spatial information and molecular composition on the sample's surface. In this review, the principle of DESI-MSI was elucidated, including its desorption process and ionization mechanism. Through the applications in biological tissues and organs, the advantages of DESI-MSI technology were demonstrated in exploring the tissue functional roles and disease mechanisms, including brain, liver, kidney, and lung. Building on these findings, we review DESI-MSI's unique capability to map both exogenous and endogenous biomolecules, thereby providing insights into spatial distribution of exogenous organisms and endogenous metabolic of transformation pathways and pharmacokinetics. Finally, the recent applications of DESI-MSI in biomedicine, environmental monitoring, and food safety are also reviewed. With the continuous improvement of instruments and analysis methods, DESI-MSI is expected to bring meaningful changes across a growing number of fields, opening up exciting opportunities to support innovative technologies and applied research.