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Quantitative X‐ray phase contrast waveguide imaging of bacterial endospores
Author(s) -
Wilke R. N.,
Hoppert M.,
Krenkel M.,
Bartels M.,
Salditt T.
Publication year - 2015
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576715003593
Subject(s) - endospore , phase contrast microscopy , phase contrast imaging , contrast (vision) , optics , phase (matter) , chemistry , materials science , physics , microbiology and biotechnology , biology , spore , organic chemistry
Quantitative waveguide‐based X‐ray phase contrast imaging has been carried out on the level of single, unstained, unsliced and freeze‐dried bacterial cells of Bacillus thuringiensis and Bacillus subtilis using hard X‐rays of 7.9 keV photon energy. The cells have been prepared in the metabolically dormant state of an endospore. The quantitative phase maps obtained by iterative phase retrieval using a modified hybrid input–output algorithm allow for mass and mass density determinations on the level of single individual endospores but include also large field of view investigations. Additionally, a direct reconstruction based on the contrast transfer function is investigated, and the two approaches are compared. Depending on the field of view and method, a resolution down to 65 nm was achieved at a maximum applied dose of below 5 × 10 5 Gy. Masses in the range of about ∼110–190 (20) fg for isolated endospores have been obtained.