Simultaneous cryo X-ray ptychographic and fluorescence microscopy of green algae

Junjing Deng, David J. Vine, Si Chen, Youssef Nashed, Qiaoling Jin, Nicholas W. Phillips, Tom Peterka, Rob Ross, Stefan Vogt, Chris Jacobsen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

113 Scopus citations


Trace metals play important roles in normal and in disease-causing biological functions. X-ray fluorescence microscopy reveals trace elements with no dependence on binding affinities (unlike with visible light fluorophores) and with improved sensitivity relative to electron probes. However, X-ray fluorescence is not very sensitive for showing the light elements that comprise the majority of cellular material. Here we show that X-ray ptychography can be combined with fluorescence to image both cellular structure and trace element distribution in frozen-hydrated cells at cryogenic temperatures, with high structural and chemical fidelity. Ptychographic reconstruction algorithms deliver phase and absorption contrast images at a resolution beyond that of the illuminating lens or beam size. Using 5.2-keV X-rays, we have obtained sub-30-nm resolution structural images and ∼ 90-nm-resolution fluorescence images of several elements in frozen-hydrated green algae. This combined approach offers a way to study the role of trace elements in their structural context.

Original languageEnglish (US)
Pages (from-to)2314-2319
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number8
StatePublished - Feb 24 2015


  • Cryogenic biological samples
  • Ptychography
  • X-ray fluorescence microscopy

ASJC Scopus subject areas

  • General


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