Laser desorption and imaging of proteins from ice via UV femtosecond laser pulses

Jamal I. Berry, Shixin Sun, Yusheng Dou, Andreas Wucher, Nicholas Winograd

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

We have employed 200-fs, 400-nm laser pulses to desorb intact protein molecular ions directly from a frozen aqueous matrix. The resulting spectra obtained using a variety of proteins varying in molecular weight from 1060 (bradykinin) to 5778 Da (insulin) are compatible with those obtained with traditional matrix-assisted laser desorption/ionization experiments. High-quality spectra could be generated using a fluence of 4.0-9.0 J/cm 2 to desorb proteins from an aqueous solution frozen onto metal substrates with a sensitivity in the femtomole range. Although the mechanism behind this effect is still not clear, we speculate that it involves explosive boiling of the ice layer due to rapid heating of the substrate. Imaging experiments conducted on the ice layer suggest that the yield of protein is approximately independent of the film thickness and is very reproducible from shot to shot. The results are particularly significant since they open the possibility of examining a range of biomaterials directly from the in vivo aqueous environment.

Original languageEnglish (US)
Pages (from-to)5146-5151
Number of pages6
JournalAnalytical chemistry
Volume75
Issue number19
DOIs
StatePublished - Oct 1 2003

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry

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