5 Key Takeaways

• 1

  A nano-DESI mass spectrometry imaging protocol mapped intact protein forms in tissue at approximately 10-μm spatial resolution.

• 2

  The workflow uses ethanol and chloroform washes to remove lipids and precipitate proteins, limiting ion suppression and protein movement.

• 3

  A shear-force probe stabilizes the liquid bridge and maintains the sampling tip’s distance from the tissue surface.

• 4

  Mouse brain images showed spatial distributions of proteoforms, including modified myelin basic protein and cytochrome c oxidase subunit 6B1.

• 5

  Current nano-DESI experiments typically detect tens of proteoforms, with sensitivity, ionization efficiency, spectral processing, and fragmentation identified as areas for improvement.