Investigating the Sequence Specific Adsorption Behavior of Polypeptides at the Solid/Liquid Interface

Area of Science:

• Polymer Science
• Surface Chemistry
• Biomaterials

Background:

• Polymer adsorption is influenced by both chemical composition and monomer sequence.
• Controlled polymer sequencing is challenging, limiting experimental studies on sequence-dependent adsorption.
• Molecular simulations are often used to study these effects due to experimental limitations.

Purpose of the Study:

• To investigate the effect of polymer sequence on adsorption behavior at the solid/liquid interface.
• To utilize polypeptide synthesis for controlled polymer sequencing in adsorption studies.
• To complement molecular simulation findings with experimental data.

Main Methods:

• Quartz crystal microbalance with dissipation monitoring (QCM-D).
• Total internal reflection ellipsometry (TIRE).
• Synthesis of polypeptides with controlled lysine and cysteine content.

Main Results:

• Initial polypeptide adsorption onto gold is driven by electrostatic interactions (polylysine).
• Cysteine residues undergo thiol-Au reactions, altering polymer conformation.
• Polypeptide chain conformation (e.g., 'train' conformation) depends on cysteine placement within the sequence.

Conclusions:

• Polypeptide sequence significantly influences adsorption mechanisms and final conformation on gold surfaces.
• The combination of QCM-D and TIRE provides a powerful experimental approach to study sequence-specific adsorption.
• This methodology can validate and guide molecular simulations in polymer adsorption research.