Fall 2006 Table of Contents

©Fredric Weber, Penn State Campus Photography
The picture on the cover is a view into the inner workings of a new kind of microscope, based on mass spectrometry, that is under development in the laboratory of Nicholas Winograd, Evan Pugh Professor of Chemistry.

Students in Winograd’s lab are working to perfect a new kind of microscope based on mass spectrometry. With their method, highly focused energetic massive particles are shot at the sample to force molecules to leave the surface from a specific location. Repeating this process thousands of times at different locations eventually yields information akin to a picture. The resulting images provide information about the chemical composition of the material with higher spatial resolution than is possible with normal optical microscopy, which reveals just shape or color. The picture on the front cover is a view into the inner workings of the microscope.

Winograd’s group is especially interested in obtaining chemical information about single biological cells. In collaboration with Andy Ewing, holder of the J. Lloyd Huck Chair in Natural Sciences, they hope to be able to find out precisely where, within a cell, certain drug molecules eventually become localized so that the function of the drug can be more directly understood. For example, a specific drug could have a very high concentration in the blood stream, but never find its way to the target cell or tissue.

Sample preparation is a major challenge for these experiments since they need to be performed in an evacuated environment. To study cells or tissue, the team has developed a way of rapidly freezing the sample in the laboratory, and of fracturing it open directly in the microscope to preserve the chemical composition.

Recently, the team has discovered that there is correlation between highly curved surfaces of membranes and the phospholipids that make up the cell membrane. Such detailed chemical information has not been possible to achieve before, and their results are spurring many groups around the world to construct similar types of instrumentation.