MALDI Imaging with Softlanded Silver Nanoparticles

Matrix-assisted laser desorption ionization (MALDI) is an ionization technique commonly utilized for imaging mass spectrometry (IMS). Through the use of MALDI-IMS, images are constructed from the mass spectra from thousands of spots on the surface of tissues or samples to show the distribution of compounds located within the sample. Improvements in the instrumentation available for IMS allow for this method to investigate the chemical composition of a surface with fine spatial resolution and chemical localization.
Our group has developed a method through which silver nanoparticles are used as a MALDI matrix substitute for IMS. The deposition of nanoparticles takes place in our SLIM (Soft-landing Ion Mobility) system, which allows clusters to land on a surface at low kinetic energies (<1eV). These low energies allow for the sample of interest to remain intact when the nanoparticles come into contact with the surface of the sample. Additionally, usage of nanoparticles for a MALDI matrix facilitates the analysis of low mass compounds without the concern of matrix effects.