In a collaboration with Nick Winograd at the Penn State University we
are working to implement mass spectrometry imaging, specifically SIMS,
directly on single biological cells. We have produced some spectacular
images of mating tetrahymena, that show lipids changing when the
curvature changes. We are working on the use of molecular imaging to
examine lipid domains to understand the structure and biophysics of the
membrane in regulating exocytosis and to probe cholesterol as a marker
of lipid domains that might play a role in determining, for example,
Alzheimer’s and autoimmune disease states. In addition, transmitter
release patterns from individual sites and the hypothesis that
transmitters are stored in large amounts in the vesicle halo are being
tested. Finally, we are developing QStar MALDI technology from
MDS/Sciex for SIMS imaging at higher mass resolution and better
sensitivity to measure events happening near the neuronal membrane.