Cryo-ultramicrotomy and Mass Spectrometry Imaging Analysis of Nudibranch Microstructures

In this paper, we investigate the presence of latrunculin A in the outer rim of a nudibranch <i>Chromodoris kuiteri</i> and show that by combining ultrathin cryosection methods with MALDI MSI we can achieve improved lateral (<i>x</i> and <i>y</i>) resolution and very high resolution in the <i>z</i> dimension by virtue of the ultrathin 200 nm thin cryosections. We also demonstrate that a post ionization laser increases sensitivity. Recent advances in MALDI source design have improved the lateral resolution (<i>x</i> and <i>y</i>) and sensitivity during MSI. Taken together, very high <i>z</i> resolution, from ultrathin sections, and improved lateral (<i>x</i> and <i>y</i>) resolution will allow for subcellular molecular imaging with the potential for subcellular 3D volume reconstruction.