Fig. 5.

Application of mass spectrometry imaging (MSI) technology. (A) A nanoscale resolution mass spectrometry imaging technique using micro-lensed fiber as a laser desorption ion source is proposed. Combining this system with a time-of-flight mass spectrometer, it achieved the visualization of drug distribution inside a single cell at the resolution of 300 nm (Meng et al., 2020). Reprinted with permission from Ref. Meng et al., 2020. Copyright © 2020 Wiley‐VCH GmbH. (B) The work investigates the suitability of MSI in quantitatively visualizing intestinal transmural drug distribution. One- and 7-h postdose sections of the ileum, proximal- and distal-colon from rats that received an oral solution of Tofa were subjected to matrix-assisted laser desorption ionization (MALDI)-MSI. A dilution series of individual concentrations sprayed over an entire tissue section allowed for tissue type-specific quantitation (Huizing et al., 2021). Reprinted with permission from Ref. Huizing et al., 2021. Copyright © 2021 American Chemical Society.