Concentration effects on peptide elution from pendant PEO layers

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Drug Delivery Systems

Background:

• Responsive drug delivery systems can be developed by modulating peptide structure and amphiphilicity within pendant polyethylene oxide (PEO) brush layers.
• Peptide amphiphilicity is crucial for retention within the hydrophobic core of PEO brush layers.

Purpose of the Study:

• To investigate the impact of peptide surface density on conformational changes and subsequent elution from PEO brush layers.
• To determine how peptide-peptide interactions influence elution kinetics based on peptide structure and density.

Main Methods:

• Utilized circular dichroism (CD) to assess peptide structure at varying surface densities on silica nanoparticles (uncoated and PEO-coated).
• Employed UV spectroscopy and quartz crystal microbalance with dissipation monitoring (QCM-D) to quantify peptide elution.
• Studied three cationic peptides: amphiphilic WLBU2, scrambled S-WLBU2, and non-amphiphilic poly-L-arginine (PLR).

Main Results:

• High surface density of amphiphilic peptides induced peptide-peptide interactions, leading to conformational changes that reduced their resistance to elution.
• Elution of the non-amphiphilic peptide (PLR) was independent of surface density, suggesting minimal peptide-peptide interactions.
• Conformational changes significantly affected the rate and extent of peptide elution from PEO layers.

Conclusions:

• Peptide surface density is a critical factor controlling the release profile of bioactive peptides from PEO brush layers.
• Modulating peptide amphiphilicity and surface density offers a strategy for tuning drug release kinetics.
• Understanding peptide-peptide interactions is key to designing effective responsive drug delivery systems.