Reduced Non-Specific Binding of Super-Resolution DNA-PAINT Markers by Shielded DNA-PAINT Labeling Protocols.

Area of Science:

• Molecular Biology
• Microscopy
• Biotechnology

Background:

• DNA-PAINT is a DNA-based super-resolution imaging technique achieving nanometer resolution.
• Non-specific binding of DNA-conjugated secondary antibodies causes significant background noise.
• This background interference limits the precision of DNA-PAINT imaging, particularly in nuclear targets.

Purpose of the Study:

• To introduce Shielded DNA-PAINT, a novel labeling method to reduce non-specific binding.
• To evaluate the efficacy of Shielded DNA-PAINT in minimizing background signals.
• To enable high-precision super-resolution imaging of nuclear targets with reduced noise.

Main Methods:

• Development of Shielded DNA-PAINT using partially or fully double-stranded docking strands.
• Application of increased ionic strength buffers during the labeling procedure.
• Widefield imaging to observe probe localization and widefield imaging to assess background signals.

Main Results:

• Shielded DNA-PAINT reduced non-specific probe accumulation in the nucleus by approximately five-fold.
• The method effectively reduced non-specific binding across both nuclear and cytoplasmic compartments.
• Achieved low non-specific backgrounds comparable to more expensive methods.

Conclusions:

• Shielded DNA-PAINT is a cost-effective and straightforward adaptation of existing DNA-PAINT protocols.
• This technique significantly enhances the signal-to-noise ratio for super-resolution imaging.
• Enables high-resolution imaging of intracellular structures, especially nuclear targets, with improved clarity.