High-Throughput Nano-DESI Mass Spectrometry Imaging of Biological Tissues Using an Integrated Microfluidic Probe

Anal Chem. 2022 Jul 12;94(27):9690-9696. doi: 10.1021/acs.analchem.2c01093. Epub 2022 Jun 30.

Abstract

Nanospray desorption electrospray mass spectrometry imaging (nano-DESI MSI) enables quantitative mapping of hundreds of molecules in biological samples with minimal sample pretreatment. We have recently developed an integrated microfluidic probe (iMFP) for nano-DESI MSI. Herein, we describe an improved design of the iMFP for the high-throughput imaging of tissue sections. We increased the dimensions of the primary and spray channels and optimized the spray voltage and solvent flow rate to obtain a stable operation of the iMFP at both low and high scan rates. We observe that the sensitivity, molecular coverage, and spatial resolution obtained using the iMFP do not change to a significant extent as the scan rate increases. Using a scan rate of 0.4 mm/s, we obtained high-quality images of mouse uterine tissue sections (scan area: 3.2 mm × 2.3 mm) in only 9.5 min and of mouse brain tissue (scan area: 7.0 mm × 5.4 mm) in 21.7 min, which corresponds to a 10-15-fold improvement in the experimental throughput. We have also developed a quantitative metric for evaluating the quality of ion images obtained at different scan rates. Using this metric, we demonstrate that the quality of nano-DESI MSI data does not degrade substantially with an increase in the scan rate. The ability to image biological tissues with high throughput using iMFP-based nano-DESI MSI will substantially speed up tissue mapping efforts.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Brain / diagnostic imaging
  • Brain / metabolism
  • Diagnostic Imaging
  • Mice
  • Microfluidics*
  • Solvents / metabolism
  • Spectrometry, Mass, Electrospray Ionization* / methods

Substances

  • Solvents