Interaction of a charged polymer with zwitterionic lipid vesicles

Area of Science:

• Biophysics
• Materials Science
• Biochemistry

Background:

• Polyethylenimine (PEI) is crucial for DNA transfection.
• The physical mechanisms of PEI-phospholipid bilayer interactions are not fully understood.

Purpose of the Study:

• Investigate PEI's impact on 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) vesicles.
• Elucidate the role of salt concentration in these interactions.

Main Methods:

• Dynamic and static light scattering (DLS/SLS)
• Differential scanning calorimetry (DSC)
• Nuclear magnetic resonance (NMR)

Main Results:

• Low salt: PEI causes vesicle aggregation into stable clusters.
• High salt: PEI penetrates DMPC bilayers, with evidence of bilayer crossing.
• Vesicle aggregation is dependent on PEI concentration.

Conclusions:

• Salt concentration dictates PEI's interaction mode with phospholipid bilayers.
• PEI's bilayer penetration at high salt influences its DNA transfection efficacy.