Enhanced Peptide Molecular Ion Imaging with Time-of-Flight Secondary Ion Mass Spectrometry And Its Application with Ink-Jet Printing Technology for Bio-Material Analysis

Abstract

  A new method in time-of-flight secondary ion mass spectrometry (TOF-SIMS) imaging, the droplet-enhanced method, was developed for the molecular analysis of biomaterials. To facilitate the ionization of biomolecules, a small amount of aqueous solution containing sodium salt or an acid as ionization-enhancing agents was dropped onto peptide samples before TOF-SIMS measurement. Using this method, we have successfully obtained strong molecular secondary ion signals from molecular weight (MW) < 7649 peptide samples while maintaining their natural distribution. This method enables to visualize dot-patterned 20 amol insulin (MW 5733) with our bubble jet (BJ) printing technology. We also demonstrated the visualization of dot-patterned digested protein distribution with the BJ printing technology.