Publication Date

8-13-2019

Department

Ames Laboratory; Chemical and Biological Engineering; Biochemistry, Biophysics and Molecular Biology, Roy J. Carver Department of

Campus Units

Ames Laboratory, Chemical and Biological Engineering, Biochemistry, Biophysics and Molecular Biology, Roy J. Carver Department of

OSTI ID+

1557787

Report Number

IS-J 9972

DOI

10.1002/smtd.201900393

Journal Title

Small Methods

First Page

1900393

Abstract

Imaging of scaffolded DNA and DNA origami nanostructures has been dominated by atomic force microscopy of samples immobilized on bulk substrates. Less commonly used are electron microscopy techniques, typically carried out after negative staining of DNA structures or by using cryo‐transmission electron microscopy (TEM). Here, direct imaging of unstained DNA origami on common electron‐transparent substrates with utilizing high angular annular dark field scanning transmission electron microscopy (HAADF‐STEM) is reported. This approach establishes a method for depositing and imaging intact DNA triangles with mass‐thickness contrast sufficient to measure the scaffold‐to‐scaffold distances and the length of the triangle's seam. The signal‐to‐noise ratio (SNR) of the DNA supported on amorphous carbon as a function of the carbon thickness is measured on three types of commercially available TEM grids. This allows for edge detection of ≈1 nm height DNA triangles on carbon substrates as thick as ≈25 nm. Observations on the effect on SNR with the imaging modes are discussed. The effect of cation concentration used for pretreating the grid on the image resolution is also explored. This work presents proof‐of‐concept results demonstrating that electron microscopy can be used to resolve key elements of the DNA origami triangle without the use of staining protocols.

DOE Contract Number(s)

AC02‐07CH11358

Language

en

Department of Energy Subject Categories

36 MATERIALS SCIENCE

Publisher

Iowa State University Digital Repository, Ames IA (United States)

Available for download on Thursday, August 13, 2020

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