Polymer and colloid physics
What sets the handedness of liquid crystals made of DNA origami?
Open access · cc by · source: Europe PMC
The twist direction of liquid-crystal phases formed by DNA origami rods is set by their thermal wiggling into gentle helices, not by the twist of their rigid ground-state shape.
Study at a glance
- Design
- Computational / modelling — oxDNA molecular dynamics of single six-helix-bundle origami filaments combined with an extended Onsager density functional theory of cholesteric order, compared with published experiments.
- N
- No sample; four origami twist variants were simulated, each with on the order of a thousand uncorrelated conformations.
- Population
- Simulated DNA origami six-helix bundle filaments with different designed axial twists
- Outcome
- Cholesteric pitch and handedness, backbone helicity/writhe, duplex over- or underwinding
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Using only rigid ground-state shapes predicted the wrong handedness: phases twisted opposite to the filaments, while experiments showed the same handedness. Adding electrostatic repulsion mainly loosened the pitch and did not fix the sign. Including thermal fluctuations reversed the handedness and tightened the pitch, giving good overall agreement with experiment. The fluctuating filaments writhe into long, weak helices of opposite sense to their twist, because writhing relieves over- or underwinding of the constituent DNA duplexes.
Methodology
The authors modelled four DNA origami filaments designed with different amounts of left- or right-handed twist. Using a nucleotide-level coarse-grained DNA model, they simulated each filament's thermal shape fluctuations, then fed either the ground-state shape or the full set of fluctuating shapes into a molecular theory that predicts the cholesteric pitch without adjustable parameters. Results were compared with earlier experimental measurements.
Limitations
The predicted handedness inversion happens at a slightly different filament twist than in experiment, and predicted pitches are somewhat too large. The oxDNA model uses sequence-averaged mechanics and simple electrostatics, simulations used a higher salt concentration than experiments, and the theory neglects biaxial correlations. The work is purely computational and relies on external experiments for validation.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
Not yet placed on a claim. This paper has study layers, but no concept page yet cites it as support, challenge, or qualifier.
Related papers in this topic
Same topic cluster — not a recommendation engine.