Translational diffusion of proteins in nanochannels

Area of Science:

• Physics
• Biophysics
• Nanotechnology

Background:

• Hydrodynamic interactions significantly influence analyte transport in nanoscale devices.
• No-slip boundary conditions critically affect drag coefficients for confined particles and molecules.

Purpose of the Study:

• To investigate the diffusion coefficients of proteins within nanoscale cylindrical channels.
• To evaluate the accuracy of continuum fluid mechanics models for predicting diffusion in nanochannels.

Main Methods:

• Coarse-grained molecular dynamics simulations were employed.
• Diffusion coefficients of proteins were measured in nanochannels of varying sizes.
• Simulations were compared against theoretical expressions and experimental data.

Main Results:

• Finite-size corrected bulk diffusion coefficients aligned with experimental findings.
• Theoretical expressions based on continuum fluid mechanics accurately predicted the reduction in translational diffusion coefficients for proteins in nanochannels.
• The findings held true across various protein-to-channel size ratios.

Conclusions:

• Molecular simulations can quantitatively predict hydrodynamic effects on diffusion at the nanoscale (around 1 nm).
• Continuum fluid mechanics provides a reliable framework for understanding diffusion in confined geometries.