title: Cryogenic coherent X-ray diffraction imaging of biological samples at SACLA: a correlative approach with cryo-electron and light microscopy.
abstract: Coherent X-ray diffraction imaging at cryogenic temperature (cryo-CXDI) allows the analysis of internal structures of unstained, non-crystalline, whole biological samples in micrometre to sub-micrometre dimensions. Targets include cells and cell organelles. This approach involves preparing frozen-hydrated samples under controlled humidity, transferring the samples to a cryo-stage inside a vacuum chamber of a diffractometer, and then exposing the samples to coherent X-rays. Since 2012, cryo-coherent diffraction imaging (CDI) experiments have been carried out with the X-ray free-electron laser (XFEL) at the SPring-8 Ångstrom Compact free-electron LAser (SACLA) facility in Japan. Complementary use of cryo-electron microscopy and/or light microscopy is highly beneficial for both pre-checking samples and studying the integrity or nature of the sample. This article reports the authors' experience in cryo-XFEL-CDI of biological cells and organelles at SACLA, and describes an attempt towards reliable and higher-resolution reconstructions, including signal enhancement with strong scatterers and Patterson-search phasing.
authors.affiliation: Biostructural Mechanism Laboratory, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Takayama
authors.affiliation: Biostructural Mechanism Laboratory, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Yonekura
mesh_terms: D020285:Cryoelectron Microscopy / Q000379:methods*; D003952:Diagnostic Imaging / Q000379:methods*; D004583:Electrons; D005615:Freezing; D014961:X-Ray Diffraction / Q000379:methods*
keywords: X-ray free-electron lasers; coherent X-ray diffraction imaging; correlative microscopy; frozen-hydrated non-crystalline samples; structural analysis