Chain Flexibility in Self-Assembled Monolayers Affects Protein Adsorption and Surface Hydration: A Molecular Dynamics...

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Computational Biophysics

Background:

• Antifouling surfaces are crucial for preventing biomolecule adsorption.
• Current strategies focus on hydration layer enthalpy.
• Chain restriction entropy also impacts protein-surface interactions.

Purpose of the Study:

• To isolate the entropic penalty of chain restriction in Self-Assembled Monolayers (SAMs).
• To investigate the effect of packing density and chain flexibility on protein adsorption.
• To identify optimal SAM configurations for antifouling properties.

Main Methods:

• Molecular dynamics simulations of lysozyme and oligo (ethylene glycol) (OEG) SAMs.
• Systematic variation of SAM packing densities (100%, 74%, 53% of maximum).
• Controlled manipulation of OEG chain flexibility by freezing monomers.

Main Results:

• SAM chain spacing significantly influences protein adsorption rates and conformations.
• Chain flexibility plays a secondary role compared to packing density.
• 74% maximum packing density exhibited the most effective antifouling properties.
• Moderate chain flexibility (2-4 free monomers) enhanced antifouling behavior.

Conclusions:

• Optimized packing density is key for effective antifouling SAMs.
• Balancing chain restriction and flexibility is crucial for minimizing protein adsorption.
• The 74% packing density with moderate flexibility represents a promising design for antifouling surfaces.