Stiffer double-stranded DNA in two-dimensional confinement due to bending anisotropy

Area of Science:

• Soft Matter Physics
• Polymer Physics
• Biophysics

Background:

• Intrinsically twisted elastic ribbons, such as double-stranded DNA (dsDNA), display complex elastic behaviors.
• Understanding polymer behavior in confined environments is crucial for various biological and material science applications.
• Bending anisotropy significantly influences the conformational properties of polymers.

Purpose of the Study:

• To investigate the elastic behavior of intrinsically twisted elastic ribbons with bending anisotropy in two-dimensional (2D) confinement.
• To analyze the impact of bending anisotropy on the persistence length of polymers like dsDNA in 2D versus 3D.
• To explore the presence and consequences of implicit twist-bend coupling in anisotropic, twisted polymers confined to 2D.

Main Methods:

• Analytical approach.
• Monte Carlo (MC) simulations.
• Study of intrinsically twisted elastic ribbons with bending anisotropy in 2D confinement.

Main Results:

• The persistence length of dsDNA in 2D conformations is consistently greater than in three-dimensional (3D) conformations due to bending anisotropy.
• This finding aligns with experimental measurements of DNA persistence length under identical biological conditions.
• Anisotropic, intrinsically twisted polymers in 2D exhibit an implicit twist-bend coupling, causing transient curvature to increase with half helical turn periodicity.

Conclusions:

• Bending anisotropy in intrinsically twisted polymers leads to an increased persistence length in 2D confinement compared to 3D.
• The 2D confinement of such polymers induces an implicit twist-bend coupling, affecting their curvature dynamics.
• These findings provide insights into the fundamental elastic properties of polymers like dsDNA in reduced dimensions.