During the past several years, scanning transmission x-ray microscopy has become a reality. The objective of this project is to develop auxiliary equipment, and the required knowledge base, to make this form of microscopy useful for biological studies of whole cultured cells. This work is intended to make it practical to view whole, wet, unstained cells with a spatial resolution ten times finer than that of the light microscope. The cells may be either alive or fixed. This new kind of microscopy has broad significance for researchers in cell biology and neurobiology, particularly those studying the relation of cellular ultrastructure to function. We will develop a specimen system appropriate for imaging live cultured cells. Prototype images will then be obtained to determine the extent to which the natural contrast of unstained specimens reveals their ultrastructure. Immunostaining techniques for whole fixed cells will also be characterized. Studies of radiation damage effects will be made to define the acceptable range of exposures for maintaining both short-term and long-term integrity of live cells and fixed specimens. A modified system optimal for imaging specimens smaller than whole mammalian cells, such as bacteria or myofibrils, will also be developed.
