Partial hydrodynamic screening of confined linear and circular double-stranded DNA dynamics

Area of Science:

• Polymer Physics
• Biophysics
• Nanotechnology

Background:

• Understanding polymer dynamics in confined environments is crucial for nanotechnology and biological applications.
• Hydrodynamic interaction (HI) significantly influences polymer diffusion, but its behavior under confinement is not fully understood.

Purpose of the Study:

• To investigate the impact of hydrodynamic interaction on the diffusion dynamics of circular and linear DNA within nanoslits.
• To determine the conditions under which hydrodynamic interaction is screened in confined polymer systems.

Main Methods:

• Performed experiments and computational simulations.
• Analyzed the diffusion dynamics of lambda (λ)-DNA in nanoslits of varying heights.
• Investigated the role of confinement on intrachain hydrodynamic interaction.

Main Results:

• Found that hydrodynamic interaction is only partially screened in nanoslits, even when channel height is smaller than the radius of gyration.
• Complete screening of HI is observed only when the radius of gyration is much smaller than the channel height.
• For λ-DNA, HI is nearly completely screened when channel height is smaller than the Kuhn length.
• DNA dynamics in strong confinement are independent of chain topology (circular vs. linear).

Conclusions:

• Challenges the assumption of complete screening of intrachain HI in confined polymers.
• Highlights the importance of the Kuhn length in determining HI screening in nanoslits.
• Demonstrates that polymer topology does not affect dynamics under strong confinement.