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Liposomes and blood cells: a flow cytometric study
Iren Constantinescu1, Elena Levin, Maria Gyongyossy-Issa
1Canadian Blood Services, Research & Development, c/o Department of Pathology, University of British Columbia, Vancouver, British Columbia, Canada.
Artificial Cells, Blood Substitutes, and Immobilization Biotechnology
|December 16, 2003
Summary
Liposomes rapidly interact with red blood cells, leukocytes, and platelets, regardless of their composition or the presence of plasma proteins. This interaction appears to be opsonization-independent and suggests liposome-blood cell fusion.
Area of Science:
- Biomedical science
- Nanotechnology
- Hematology
Background:
- Liposomes are widely investigated as drug delivery vehicles.
- Understanding liposome interactions with blood components is crucial for their in vivo application.
- Previous studies have yielded conflicting results regarding liposome-blood cell interactions.
Purpose of the Study:
- To elucidate the interaction mechanisms between liposomes and various human blood cells.
- To investigate the influence of liposome composition and plasma on these interactions.
- To determine if liposome-blood cell interactions occur in vivo.
Main Methods:
- Liposomes with varying compositions, labeled with fluorescent markers (carboxy fluorescein, R18, FITC-phospholipids), were used.
- Interactions were studied with purified human red blood cells, leukocytes, and platelets in buffer or plasma.
- Experiments were conducted in whole blood and in mice to assess in vivo behavior using flow cytometry.
Main Results:
- All tested liposome formulations interacted rapidly and dose-dependently with red cells, leukocytes, and platelets.
- Interactions were observed both in vitro and in vivo.
- These interactions occurred irrespective of liposome composition, presence of polyethylene glycol, or plasma proteins, suggesting opsonization-independent fusion.
Conclusions:
- Liposomes exhibit a fundamental, opsonization-independent interaction with all major blood cell types.
- The primary interaction mechanism appears to be liposome-blood cell fusion.
- These findings have significant implications for the design and application of liposomal drug delivery systems.