X-ray holographic microscopy with zone plates applied to biological samples in the water window using 3rd harmonic radiation from the free-electron laser FLASH

Abstract

Abstract:The imaging of hydrated biological samples -especially in the energy window of 284-540 eV, where water does not obscure the signal of soft organic matter and biologically relevant elements -is of tremendous interest for life sciences. Free-electron lasers can provide highly intense and coherent pulses, which allow single pulse imaging to overcome resolution limits set by radiation damage. One current challenge is to match both the desired energy and the intensity of the light source. We present the first images of dehydrated biological material acquired with 3rd harmonic radiation from FLASH by digital in-line zone plate holography as one step towards the vision of imaging hydrated biological material with photons in the water window. We also demonstrate the first application of ultrathin molecular sheets as suitable substrates for future free-electron laser experiments with biological samples in the form of a rat fibroblast cell and marine biofouling bacteria Cobetia marina. ©2011 Optical Society of America References and links1. C. A. Brau, "Free-electron lasers," Science 239(4844), 1115-1121 (1988). 2. J. Feldhaus, J. Arthur, and J. Hastings, "X-ray free-electron lasers," J. Phys. B: At. Mol. Opt. Phys. 38(9), S799-S819 (2005

X-ray holography with a customizable reference

“…3f, reproduces an image of the URA reference itself. This is the contribution from the A ref term in equation (2). The ILRUFT reconstruction demonstrates a distinct advantage for working with missing data over a reconstruction by convolution.…”

“…3b). Before performing the convolution, a high-pass filter was applied to the autocorrelation function defined by 1 À e À r 2 = 2s 2 ð Þ , where r is a radial coordinate and s was set to an eighth of the detector width. The filter reduced artifacts in the exit-wave autocorrelation function because of the missing data region, and the optimal width of the filter was chosen by visual inspection of the result.…”

“…X -ray Fourier-transform holography (FTH) [1][2][3] is a robust coherent imaging technique that has found wide-ranging applications to biology 2 and material science 3 . The technique is particularly suited to imaging magnetic domains and other magnetic samples because holograms generated with circularly polarized X-rays can be used to separate charge scattering from magnetic scattering [3][4][5] .…”

Investigating Cellular Nanoscale with X-rays

“…Moreover, a time-resolved study showed the structural changes of hair keratin induced by synchrotron radiation. 48 Three levels of structural changes were identified while increasing the exposure: (i) after 4 s the coiled-coil architecture of the keratin dimers is disrupted, (ii) after 30 s the long-range organization along the filament is lost and (iii) after 50 s the lateral organization of the filament packing is disturbed. Considering the different characteristics of the setups used (energy, intensity, exposure time and beam dimensions) we estimated to be below the appearance of structural changes to keratin dimers.…”

“…In order to present the pertinence of this thesis, a non-exhaustive review of the aforementioned group of techniques will be discussed. These X-ray techniques have been successfully applied to, and adapted to image biological specimens, such as ptychography [44][45][46][47], holography [48][49][50][51], computed tomography [52][53][54], phase contrast [55,56] and scanning nano-diffraction [57][58][59][60][61].…”