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Single Liposome Measurements for the Study of Proton-Pumping Membrane Enzymes Using Electrochemistry and Fluorescent Microscopy
Published on: February 21, 2019
Double charge inversion in polyethylenimine-decorated liposomes.
Juan Sabín1, Carmen Vázquez-Vázquez, Gerardo Prieto
1Biophysics & Interfaces Group, Department of Applied Physics, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain. juan.sabin@usc.es
Langmuir : the ACS Journal of Surfaces and Colloids
|June 21, 2012
Summary
Polyethyleneimine (PEI) interactions with liposomes are crucial for gene therapy. Unexpected charge inversions and aggregation ranges were observed, highlighting the critical role of pH and liposome size for stable DNA delivery.
Area of Science:
- Biomaterials Science
- Nanotechnology
- Gene Therapy Vectors
Background:
- Cationic polymers like polyethyleneimine (PEI) are investigated as nonviral vectors for gene therapy.
- Understanding PEI-phospholipid interactions is vital for efficient DNA delivery into cells.
- Liposomes composed of dimyristoylphosphatidylglycerol (DMPG) and dioleoylphosphatidylcholine (DOPC) are common model systems.
Purpose of the Study:
- To characterize the interaction between PEI and DMPG/DOPC liposomes.
- To investigate the influence of charge molar ratio, pH, temperature, liposome size, and lipid headgroup on PEI-liposome complex formation.
- To elucidate the mechanisms governing PEI-liposome stability and aggregation.
Main Methods:
- Light scattering techniques to determine particle size and aggregation.
- Zeta potential measurements to assess surface charge characteristics.
- Transmission electron microscopy (TEM) for visualizing liposome-PEI complexes.
Main Results:
- Observed unexpected double charge inversion of PEI-liposome complexes.
- Identified two distinct concentration ranges for PEI-liposome aggregation.
- Demonstrated a strong dependence of complex stability on pH and initial liposome size.
- Found that small variations in pH or liposome size significantly alter stability behavior.
Conclusions:
- PEI-liposome interactions are complex and sensitive to environmental conditions.
- Precise control of pH and liposome size is essential for reproducible gene delivery experiments.
- The findings provide insights into optimizing PEI-based nonviral vectors for gene therapy applications.
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