Coherent Diffractive Imaging of Single Particles

Our group develops novel methods to achieve the foundational goals of single-particle diffractive imaging using XFEL pulses.

Description will follow soon.

Figure 1. XFEL single-particle diffractive imaging pipeline involves recording single-shot diffraction patterns of the target-object before the destruction due to ionization and Coloumb explosion (top), computational purification for expected single-particle diffraction patterns, orientation determination, classification into 2D class averages, and the 3D merging of intensities in the reciprocal space—after this step, an inverse Fourier transform of the intensities alone is not enough and one needs to determine the missing phase information to solve the electron density map of the structure—this is achieved using iterative phase retrieval algorithms (bottom). Note: the lensless imaging method also can be used with coherent electrons to reconstruct the Coulomb potential map of the target sample. Image source: Henry Chapman, CFEL. Science, 2007, 316, 1444-48.

 

DNA NANOTECHNOLOGY

Structural DNA nanotechnology offers the possibility of creating almost any desired nanoscale DNA-origami shapes, which can be model samples for XFEL imaging and also customizable devices/platforms to carry out single-molecule imaging studies. Programmable nature of DNA enables the organization of non-nucleic acid materials, such as nanoparticles, viruses, and proteins at spatially addressable locations, in complex three-dimensional geometries, with sub-nm scale precision and likely helps in molecular scaffold or holographic reference based imaging of weakly diffracting single-molecules at high-resolution.

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