DNA-Guided Delivery of Single Molecules into Zero-Mode Waveguides

Area of Science:

• Biophysics
• Nanotechnology
• Molecular Biology

Background:

• Zero-mode waveguides (ZMWs) enable single-molecule fluorescence experiments at physiological concentrations.
• Massively parallel ZMW arrays are limited by Poissonian distribution, preventing full single-molecule occupancy.
• Current methods lack a way to achieve uniform single-molecule loading in ZMW arrays.

Purpose of the Study:

• To develop a method for achieving full single-molecule occupancy in massively arrayed ZMWs.
• To overcome the Poissonian distribution limitations in ZMW loading.
• To enhance the efficiency of single-molecule analysis using ZMW technology.

Main Methods:

• A DNA-guided method utilizing steric exclusion properties of large DNA molecules was employed.
• DNA molecules with a free-biotinylated extremity were designed for ZMW floor binding.
• Both random-coiled and condensed DNA conformations were tested for their effect on molecule delivery.

Main Results:

• Non-Poissonian statistics were achieved, indicating biased delivery of single molecules.
• DNA molecules reduced the accessibility for secondary molecule binding, promoting single occupancy.
• Both DNA conformations successfully drove non-Poissonian single-molecule delivery into ZMW arrays.

Conclusions:

• The DNA-guided method effectively biases molecule delivery, achieving non-Poissonian statistics.
• An optimal balance of DNA rigidity and flexibility is crucial for efficient single occupancy.
• This method enables the full exploitation of massively parallelized ZMW analytical tools.