Intercalating Electron Dyes for TEM Visualization of DNA at the Single-Molecule Level

Area of Science:

• Biochemistry
• Molecular Biology
• Microscopy

Background:

• Heavy element staining compounds (electron dyes) are crucial for visualizing DNA and biomolecules using Transmission Electron Microscopy (TEM).
• Limited research exists on synthesizing and utilizing alternative electron dyes for enhanced DNA imaging.

Purpose of the Study:

• To synthesize a novel DNA intercalator, bis-acridine uranyl (BAU), as an alternative electron dye.
• To evaluate the efficacy of BAU for high-resolution TEM imaging of DNA.

Main Methods:

• Synthesis of bis-acridine uranyl (BAU) molecule.
• Confirmation of synthesis using NMR spectroscopy and Mass Spectrometry (MS).
• Verification of DNA binding using gel electrophoresis and Scanning Transmission Electron Microscopy (STEM) on DNA origami nanostructures.

Main Results:

• The synthesized BAU molecule effectively binds to DNA.
• STEM imaging demonstrated that BAU renders DNA visible at the single-molecule scale.
• BAU's performance was compared to other DNA-binding compounds like uranyl acetate.

Conclusions:

• The novel BAU intercalator is a viable electron dye for high-resolution TEM imaging of DNA.
• Findings support the development of tailored electron dyes with specific DNA-binding motifs for advanced microscopy.
• This research enhances the capability for quantitative analysis of DNA structures at the nanoscale.