Multiscale Dynamics of Lipid Vesicles in Polymeric Microenvironment

Area of Science:

• Biophysics
• Materials Science
• Cell Biology

Background:

• Biological membranes interact dynamically with extracellular matrices, influencing cell behavior.
• Polymeric scaffolds in tissue engineering aim to mimic the extracellular microenvironment.
• The effect of viscoelastic environments on lipid membrane dynamics remains poorly understood.

Purpose of the Study:

• To investigate how viscoelastic polymer solutions affect the dynamics of lipid membranes.
• To explore the multiscale dynamics and structural phase behavior of liposome-polymer mixtures.
• To understand the coupling between polymer chains and phospholipid bilayers.

Main Methods:

• Utilized poly(ethylene glycol) (PEG) solutions and DMPC/DMPG liposomes.
• Employed small-angle X-ray scattering (SAXS), dynamic light scattering, and rheology.
• Applied fluorescence lifetime spectroscopy and differential scanning calorimetry.

Main Results:

• Observed dynamic coupling between polymer chains and phospholipid bilayers across various scales.
• Found that shorter polymer chains accelerate lipid dynamics within bilayers.
• Demonstrated a thermal-stiffening effect in polymer-liposome solutions linked to bilayer phase transitions.

Conclusions:

• Polymer chain relaxation directly influences lipid bilayer microviscosity and dynamics.
• The concentration of liposomes and polymer chain length can modulate the observed thermal-stiffening.
• Findings provide insights into designing biomimetic materials for tissue engineering.