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

Abstract

DNA nanotechnology makes use of hydrophobically modified constructs to create synthetic membrane protein mimics. However, nucleic acid structures exhibit poor insertion efficiency, leading to a low activity of membrane-spanning DNA protein mimics. It is suggested that non-ionic surfactants improve insertion efficiency, partly by disrupting hydrophobicity-mediated clusters. Here, we employed confocal microscopy and single-molecule transmembrane current measurements to assess the effects of the non-ionic surfactant octylpolyoxyethylene (oPOE) on the clustering behavior and membrane activity of cholesterol-modified DNA nanostructures. Our findings uncover the role of aggregation in preventing bilayer interactions of hydrophobically decorated constructs, and we highlight that premixing DNA structures with the surfactant does not disrupt the cholesterol-mediated aggregates. However, we observed the surfactant’s strong insertion-facilitating effect, particularly when introduced to the sample separately from DNA. Critically, we report a highly efficient membrane-spanning DNA construct from combining a non-aggregating design with the addition of the oPOE surfactant.

Interplay of the mechanical and structural properties of DNA nanostructures determines their electrostatic interactions with lipid membranes

“…Attachment of DNA to lipid bilayers is most often achieved either by modifying nucleic acid strands with hydrophobic moieties 8,14,15,33 or by creating formulations involving positively-chargedcationiclipids. 4,17 Here, we analysed binding between DNA and lipid bilayers as they are mostly found in biological environments: unmodified nucleic acids and zwitterionic lipids.…”

“…DNA/lipid interactions are most frequently studied where DNA is chemically modified either with a hydrophobic moiety, ensuring its attachment to lipid bilayers, 8,14–16 or by incorporating cationic lipids to provide electrostatic attraction with negatively-charged nucleic acids. 4,17 Neither of these scenarios is representative of DNA and lipids found in biological environments.…”

“…6,7 Finally, the understanding of these interactions contributes to the development of novel biomaterials, particularly in DNA nanotechnology, aiming to construct DNAbased mimics of membrane proteins [8][9][10][11] or active membrane signalling platforms. 12,13 DNA/lipid interactions are most frequently studied where DNA is chemically modified either with a hydrophobic moiety, ensuring its attachment to lipid bilayers, 8,[14][15][16] or by incorporating cationic lipids to provide electrostatic attraction with negatively-charged nucleic acids. 4,17 Neither of these scenarios is representative of DNA and lipids found in biological environments.…”

Surfactant‐Assisted Purification of Hydrophobic DNA Nanostructures

“…Two methods have been reported to avoid the aggregation. One method involves the elongation of DNA strands from the vicinity of hydrophobic molecules [36–39] . Ohmann et al.…”

“…One method involves the elongation of DNA strands from the vicinity of hydrophobic molecules. [36][37][38][39] Ohmann et al reported that the elongation of single stranded DNA (ssDNA) from the vicinity of cholesterol modifications on DNA nanostructure prevented aggregation. [36] However, the ssDNA elongation approach is limited to certain elongation positions, which decreases the design variation of DNA nanostructures.…”