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Fibronectin conformational changes induced by adsorption to liposomes
Michael Halter1, Meher Antia, Viola Vogel
1Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.
Summary
Liposomes carrying drugs are cleared quickly. Protein structure changes on liposomes, not just quantity, affect how cells interact, impacting drug delivery efficiency.
Area of Science:
- Biochemistry
- Materials Science
- Nanotechnology
Background:
- Liposomes are common drug carriers but face rapid clearance from circulation.
- Serum protein adsorption to liposomes influences their interaction with phagocytic cells.
- Minimizing protein adsorption is a strategy to improve liposome drug delivery.
Purpose of the Study:
- To investigate the conformational changes of fibronectin (Fn) upon interaction with phosphatidylcholine (PC) liposomes using fluorescence resonance energy transfer (FRET).
- To determine the impact of protein conformation on liposome-cell interactions in drug delivery.
Main Methods:
- Utilized FRET to measure structural alterations in fibronectin.
- Quantified fibronectin adsorption to gel phase PC liposomes.
- Estimated the dissociation constant (KD) for the fibronectin-liposome interaction.
Main Results:
- Fibronectin transitions from a compact, inactive state to an open conformation when interacting with gel phase PC liposomes.
- A dissociation constant of 1.1 nM was determined for this interaction.
- Conformational changes in fibronectin may expose new recognition sites.
Conclusions:
- Protein conformation, not just adsorption quantity, significantly influences liposome interactions with phagocytic cells.
- Understanding fibronectin's conformational changes on liposomes is crucial for designing effective liposomal drug delivery systems.
- These findings suggest new strategies for optimizing liposome-based therapeutics by controlling protein structure.