Mass Spectrometry Imaging Techniques: Non-Ambient and Ambient Ionization Approaches

Abstract

Molecular information can be acquired from sample surfaces in real time using a revolutionary molecular imaging technique called mass spectrometry imaging (MSI). The technique can concurrently provide high spatial resolution information on the spatial distribution and relative proportion of many different compounds. Thus, many scientists have been drawn to the innovative capabilities of the MSI approach, leading to significant focus in various fields during the past few decades. This review describes the sampling protocol, working principle and applications of a few non-ambient and ambient ionization mass spectrometry imaging techniques. The non-ambient techniques include secondary ionization mass spectrometry and matrix-assisted laser desorption ionization, while the ambient techniques include desorption electrospray ionization, laser ablation electrospray ionization, probe electro-spray ionization, desorption atmospheric pressure photo-ionization and femtosecond laser desorption ionization. The review additionally addresses the advantages and disadvantages of ambient and non-ambient MSI techniques in relation to their suitability, particularly for biological samples used in tissue diagnostics. Last but not least, suggestions and conclusions are made regarding the challenges and future prospects of MSI.

Keywords:

• Non-ambient and ambient ionization
• mass spectrometry imaging

Acknowledgements

AH is thankful that Prof. Kenzo Hiraoka of the University of Yamanashi, Japan, hired him as a postdoctoral scholar in 2011–2013 to work on developing new ion sources for mass spectrometry. This is a brief note to express gratitude to certain coworkers, organizations, or agencies that helped the authors with their work.

Authors’ contribution

SH: conceptualization, writing original draft-review, AH: conceptualization, writing original draft-review, and final review & editing, WX: final review & editing, LC: final review & editing, LB: conceptualization and funding acquisition. LW: conceptualization, supervision, final review & editing, and funding acquisition. The published version of the manuscript has been read and approved by all authors.

Disclosure statement

The authors declare that none of the work reported in this study could have been influenced by any known competing financial interests or personal relationships.

Additional information

Funding

The authors acknowledge the financial support for this work by the “Pioneer” and “Leading Goose” R&D Program of Zhejiang (Grant No. 2022C03076), Ningbo City Major Scientific and Technological Program of China (Grant No. 20211ZDYF020157 and No. 20221ZDYF020043), the Youth Science and Technology Innovation Leading Talents Project of Ningbo (Grant No. 2023QL011), the Entrepreneurial and Innovative Leading Team of Panyu District of Guangzhou of China (Grant No. 2017-R01-5) and the K.C. Wong Magna Fund in Ningbo University.