Neutron reflectometry of supported hybrid bilayers with inserted peptide

Area of Science:

• Membrane biophysics
• Materials science
• Surface chemistry

Background:

• Supported hybrid bilayer membranes (HBMs) are crucial models for cell membranes.
• Understanding peptide-membrane interactions is key to drug delivery and biomaterial design.
• Synthetic amphiphilic peptides offer tunable properties for membrane manipulation.

Purpose of the Study:

• To investigate the nanostructure of a hybrid bilayer membrane (HBM) after the insertion of a synthetic amphiphilic, α-helical peptide.
• To determine the location and mode of peptide incorporation within the HBM.

Main Methods:

• Neutron reflectometry was employed to analyze the membrane's nanostructure.
• Contrast variation techniques were utilized to enhance structural details.
• The HBM was constructed with a self-assembled monolayer of octadecanethiol on gold and a phosphatidylcholine (d-DMPC) leaflet.
• Reflectivity spectra were recorded and modeled throughout the film fabrication process.

Main Results:

• The analysis of neutron reflectivity data provided insights into the membrane's nanostructure.
• Modeling indicated that the synthetic peptide was successfully incorporated into the HBM.
• The data strongly suggested that the peptide inserted into the d-DMPC lipid leaflet.

Conclusions:

• The synthetic amphiphilic peptide preferentially inserts into the lipid leaflet of the hybrid bilayer membrane.
• Neutron reflectometry is a powerful tool for characterizing peptide-membrane interactions at the nanoscale.
• This study provides fundamental insights into the behavior of synthetic peptides within model membrane systems.