Microholography of Living Organisms

Abstract

By using intense pulsed coherent x-ray sources that are currently under development, it will be possible to obtain magnified three-dimensional images of elementary biological structures in the living state at precisely defined instants. For optimum contrast, sensitivity, and resolution, the hologram should be made with x-rays tuned to a resonance of nitrogen near 0.3 nanometer. Resolution will then be limited mainly by the hydrodynamic expansion that occurs while the necessary number of photons is being registered. Problems of technique are also briefly discussed.

X-ray imaging beyond the limits

“…It is thought that radiation damage will limit X-ray imaging of protein in water to about 10 nm resolution 17 . Solem first suggested using pulses shorter than the timescale of destruction 18,19 , and calculated that under irradiation with an intense X-ray pulse the hydrodynamic explosion of the cell would be only a few nanometres over the duration of a 120-fs pulse. More recent calculations 20 have been made with a more complete model of the X-ray interaction.…”

Femtosecond diffractive imaging with a soft-X-ray free-electron laser

“…Thermalization of the ejected electrons through collisional electron cascades is completed within 10-100 fs (refs 14,15). Heat transport, diffusion and radical reactions take place over some picoseconds to milliseconds.The effect of X-ray-induced sample damage on the recorded image or diffraction pattern could be substantially reduced, if we could collect diffraction data faster than the relevant damage processes 1,16 . This approach requires very short and very bright X-ray pulses, such as those expected from a short-wavelength FEL.…”

“…The effect of X-ray-induced sample damage on the recorded image or diffraction pattern could be substantially reduced, if we could collect diffraction data faster than the relevant damage processes 1,16 . This approach requires very short and very bright X-ray pulses, such as those expected from a short-wavelength FEL.…”

Time-resolved imaging using x-ray free electron lasers

“…In normal Xray imaging experiments it is well known that radiationinduced damage and sample movement prevents the accumulation of high-resolution scattering from micron to nanometer sized objects [34,35]. If diffraction data could be collected faster than the relevant damage processes, predictions were that the effects of radiation damage could be substantially reduced [54,69] The first experimental confirmation of these predictions came in the experiment of Chapman et.al [16] in 2006. In this experiment a simple test object -a microfabricated silicon nitride membrane -was placed in the focus of the FLASH beam.…”