E. Lima

Biological imaging by soft x-ray diffraction microscopy

We have used the method of x-ray diffraction microscopy to image the complex-valued exit wave of an intact and unstained yeast cell. The images of the freeze-dried cell, obtained by using 750-eV x-rays from different angular orientations, portray several of the cells major internal components to 30-nm resolution. The good agreement among the independently recovered structures demonstrates the accuracy of the imaging technique. To obtain the best possible reconstructions, we have implemented procedures for handling noisy and incomplete diffraction data, and we propose a method for determining the reconstructed resolution. This work represents a previously uncharacterized application of x-ray diffraction microscopy to a specimen of this complexity and provides confidence in the feasibility of the ultimate goal of imaging biological specimens at 10-nm resolution in three dimensions.

SOFT X-RAY MICROSCOPY AT THE NSLS

TOBIAS BEETZ, MICHAEL FESER, HOLGER FLECKENSTEIN, BENJAMIN HORNBERGER, CHRIS JACOBSEN, JANOS KIRZ, MIRNA LEROTIC, ENJU LIMA, MING LU, 1 DAVID SAYRE, DAVID SHAPIRO, AARON STEIN, D O N TENNANT, AND SUE WIRICK 1 Department of Physics & Astronomy, Stony Brook University, Stony Brook NY 11794, USA 2 Brookhaven National Laboratory, Upton, NY 11973-5000, USA New Jersey Nanotechnology Consortium, 600-700 Mountain Ave, Murray Hill, NJ 07974, USA

Cryogenic X-ray diffraction microscopy with hard X-rays for biological samples

25th European Crystallographic Meeting, ECM 25, İstanbul, 2009 Acta Cryst. (2009). A65, s 224 Page s 224 FA3-MS01-P03 Cryogenic X-ray Diffraction Microscopy with Hard X-rays for Biological Samples. Enju Limaa, Lutz Wiegartb, Petra Pernotb, Malcolm Howellsb,c, Federico Zontoneb, Anders Madsenb. aNSLS 2, Brookhaven National Laboratory, Upton NY 119735000, USA. bEuropean Synchrotron Radiation Facility, BP 220 F-38043 Grenoble, France. cAdvanced Light Source, Lawrence Berkeley Laboratory, Berkeley, CA 94720, USA. E-mail: elima@bnl.gov

Diffraction imaging of the yeast cell: first results

Characterization of the microstructure of materials with spatial resolution is one of key issues in materials related fields from nanotechnology to non-destructive testing of manufactured articles. Depth resolved strain/stress measurements by diffraction methods are of particular interest. In order to improve depth resolution of x-ray diffraction, we are developing novel technique for synchrotron beam lines – energy-variable diffraction (EVD) [1]. The method is based on our ability to precisely change energy of synchrotron radiation and, in a result, to accurately control the x-ray penetration depth. Comprehensive analysis of x-ray trajectories, taking into account the instrument misalignment, change of the height of an incident x-ray beam with energy, and variable penetration of x-rays into the sample depth, allowed us to receive analytic expression for the diffraction profile measured by EVD and to show that the maximum diffraction intensity registered in the detector is coming from certain depth, which is energy-dependent [2]. This finding opens a way for measuring residual strains with high depth resolution by changing the x-ray energy in small enough steps. Experimental examples taken with differently scaled metal/metal and metal/ceramic multilayers as well as structures from nature (seashells) demonstrate the capabilities of the method.

X-ray spectromicroscopy: high resolution chemical state imaging in complex organic systems

With known absorption spectra, maps of component concentrations can be obtained; with unknown spectra, multivariate statistical analysis methods can be used to understand the number and distribution of components and to find common spectra. Applications in biology and geochemistry are described. In addition, the status of experiments in diffraction and holographic imaging of frozen hydrated specimens will be described.