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Intercalating Electron Dyes for TEM Visualization of DNA at the Single‐Molecule Level
Author(s) -
Kabiri Yoones,
Angelin Alessandro,
Ahmed Ishtiaq,
Mutlu Hatice,
Bauer Jens,
Niemeyer Christof M.,
Zandbergen Henny,
Dekker Cees
Publication year - 2019
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201800638
Subject(s) - uranyl acetate , intercalation (chemistry) , biomolecule , molecule , dna , uranyl , osmium tetroxide , chemistry , transmission electron microscopy , photochemistry , crystallography , nanotechnology , electron microscope , materials science , staining , organic chemistry , biochemistry , biology , ion , genetics , physics , optics
Staining compounds containing heavy elements (electron dyes) can facilitate the visualization of DNA and related biomolecules by using TEM. However, research into the synthesis and utilization of alternative electron dyes has been limited. Here, we report the synthesis of a novel DNA intercalator molecule, bis‐acridine uranyl (BAU). NMR spectroscopy and MS confirmed the validity of the synthetic strategy and gel electrophoresis verified the binding of BAU to DNA. For TEM imaging of DNA, two‐dimensional DNA origami nanostructures were used as a robust microscopy test object. By using scanning transmission electron microscopy (STEM) imaging, which is favored over conventional wide‐field TEM for improved contrast, and therefore, quantitative image analysis, it is found that the synthesized BAU intercalator can render DNA visible, even at the single‐molecule scale. For comparison, other staining compounds with a purported affinity towards DNA, such as dichloroplatinum, cisplatin, osmium tetroxide, and uranyl acetate, have been evaluated. The STEM contrast is discussed in terms of the DNA–dye association constants, number of dye molecules bound per base pair, and the electron‐scattering capacity of the metal‐containing ligands. These findings pave the way for the future development of electron dyes with specific DNA‐binding motifs for high‐resolution TEM imaging.