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Title: A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called `fixed-target' sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessary to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolutionmore » (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. In addition, the features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.« less
 [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [2] ;  [5]
  1. Univ. of California, Berkeley, CA (United States); John Hopkins Univ. School of Medicine, Baltimore, MD (United States)
  2. Stanford Univ., Stanford, CA (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States)
  4. John Hopkins Univ., Baltimore, MD (United States)
  5. John Hopkins Univ. School of Medicine, Baltimore, MD (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
AC02-06CH11357; AC03-76SF00515
Accepted Manuscript
Journal Name:
Acta Crystallographica. Section D: Biological Crystallography (Online)
Additional Journal Information:
Journal Name: Acta Crystallographica. Section D: Biological Crystallography (Online); Journal Volume: 71; Journal Issue: 10; Journal ID: ISSN 1399-0047
International Union of Crystallography
Research Org:
Argonne National Laboratory (ANL), Argonne, IL (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
microcrystals; silicon nitride; serial data collection; XFEL; microfocus beamline; X-ray crystallography; microfluidics