A Surfactant Enables Efficient Membrane Spanning by Non-Aggregating DNA-Based Ion Channels

Area of Science:

• Biotechnology
• Nanotechnology
• Biophysics

Background:

• DNA nanotechnology utilizes hydrophobic modifications for synthetic membrane protein mimics.
• Poor insertion efficiency of DNA nanostructures limits the activity of membrane-spanning mimics.
• Non-ionic surfactants are hypothesized to improve insertion by disrupting hydrophobic clusters.

Purpose of the Study:

• To investigate the effect of octylpolyoxyethylene (oPOE) surfactant on DNA nanostructure clustering and membrane activity.
• To understand the role of aggregation in hindering bilayer interactions of hydrophobic DNA constructs.
• To optimize the design of membrane-spanning DNA protein mimics.

Main Methods:

• Confocal microscopy to assess DNA nanostructure clustering.
• Single-molecule transmembrane current measurements to evaluate membrane activity.
• Comparative analysis of surfactant introduction methods (premixing vs. separate addition).

Main Results:

• Hydrophobic aggregation prevents bilayer interactions of DNA nanostructures.
• Premixing oPOE with DNA does not disrupt cholesterol-mediated aggregates.
• Separate introduction of oPOE significantly enhances DNA construct insertion and membrane activity.
• A non-aggregating DNA design combined with oPOE yields highly efficient membrane-spanning constructs.

Conclusions:

• Aggregation is a key barrier to effective membrane insertion of hydrophobic DNA nanostructures.
• The timing of surfactant introduction is critical for enhancing DNA nanostructure membrane activity.
• Combining non-aggregating designs with oPOE surfactant offers a promising strategy for developing efficient synthetic membrane proteins.