Entropy-Enthalpy Compensation in Peptide Adsorption on Solid Surfaces: Dependence on Surface Hydration

Area of Science:

• Physical Chemistry
• Surface Science
• Biophysics

Background:

• Protein adsorption at solid-water interfaces is critical in many applications.
• Fundamental thermodynamic data on water's role in protein-surface interactions is scarce.
• Interfacial water dynamics significantly influence molecular adsorption behavior.

Purpose of the Study:

• To quantify entropy and enthalpy changes during molecular adsorption on solids.
• To investigate the role of interfacial water in mediating protein-surface interactions.
• To elucidate the entropy-enthalpy compensation mechanisms in water and peptide adsorption on gold and graphene surfaces.

Main Methods:

• Advanced free energy calculations were employed.
• Entropy and enthalpy changes of molecular adsorption were extracted.
• Gold and graphene surfaces were used as model systems with varying water affinities.

Main Results:

• Water adsorption is enthalpically dominated, but entropy favorably lowers free energy barriers on graphene.
• Peptide adsorption free energy profiles are jointly determined by enthalpy and entropy.
• Enthalpy and entropy act as alternative driving forces for peptide adsorption on gold versus graphene.

Conclusions:

• The interfacial water phase plays a crucial role in regulating competitive entropy-enthalpy variations.
• Distinct solid-liquid interface properties dictate the specific roles of water in adsorption.
• Understanding these thermodynamic contributions is vital for designing surfaces with controlled protein interactions.