Poly-L-lysine-induced morphology changes in mixed anionic/zwitterionic and neat zwitterionic-supported phospholipid...

Area of Science:

• Biophysics
• Materials Science

Background:

• Supported lipid bilayers are crucial models for cell membranes.
• Understanding peptide-lipid interactions is key to biomaterials and drug delivery.

Purpose of the Study:

• To investigate the effects of poly-L-lysine on supported phospholipid bilayers.
• To characterize the resulting morphological changes and their dynamics.

Main Methods:

• Atomic force microscopy (AFM) for high-resolution imaging.
• Epifluorescence microscopy for observing dynamics.
• Studying liquid phase supported bilayers with mixed anionic/zwitterionic and neat zwitterionic phospholipids.

Main Results:

• Poly-L-lysine induced the formation of domains, defects, and aggregates.
• These structures were observed on both mixed and purely zwitterionic bilayers.
• The induced structures were immobile on timescales from 50 milliseconds to several minutes.

Conclusions:

• Poly-L-lysine can significantly alter the morphology of supported lipid bilayers.
• The peptide's interaction with both the lipid headgroups and the underlying substrate is proposed to stabilize these structures.
• These findings have implications for designing peptide-modified biomaterials and understanding membrane-associated processes.