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Updated: Aug 16, 2025

Assembly and Characterization of Polyelectrolyte Complex Micelles
Published on: March 2, 2020
Protein charge parameters that influence stability and cellular internalization of polyelectrolyte complex micelles
Rachel A Kapelner1, Rachel S Fisher1,2, Shana Elbaum-Garfinkle2,3
1Department of Chemical Engineering, Columbia University New York NY 10027 USA aco2134@columbia.edu +1-212-853-1215.
Researchers developed polyelectrolyte complex (PEC) micelles for delivering anionic proteins, overcoming challenges like aggregation and poor cellular uptake. These novel protein delivery vehicles show promise for intracellular delivery of therapeutic proteins.
Area of Science:
- Biomaterials Science
- Protein Engineering
- Drug Delivery Systems
Background:
- Proteins are vital biologics but face formulation and delivery hurdles, including aggregation, low loading, and inefficient cellular uptake, especially for anionic proteins unable to cross the cell membrane.
- Anionic proteins present a significant challenge for intracellular delivery due to the negatively charged plasma membrane.
- Developing effective delivery vehicles for anionic proteins is crucial for advancing protein-based therapeutics.
Purpose of the Study:
- To investigate the formation and stability of polyelectrolyte complex (PEC) micelles for anionic protein delivery.
- To evaluate the impact of protein charge and charge localization on PEC micelle formation and stability.
- To assess the efficacy of PEC micelles for delivering anionic proteins into mammalian cells.
Main Methods:
- Engineered anionic variants of green fluorescent protein (GFP) were complexed with a neutral-cationic block copolymer (POEGMA79-b-qP4VP175) synthesized via RAFT polymerization.
- Polyelectrolyte complex (PEC) micelle formation and stability were analyzed concerning protein charge distribution and ionic strength.
- Cellular delivery of GFP via PEC micelles was evaluated in mammalian cells, correlating delivery efficiency with micelle properties.
Main Results:
- Isotropically supercharged proteins formed micelles at higher ionic strength compared to proteins with localized charge.
- PEC micelles effectively delivered GFP cargo to mammalian cells, with delivery efficiency dependent on protein charge and distribution.
- An inverse relationship was observed between the critical salt concentration of PEC micelles and their cellular delivery efficiency.
Conclusions:
- Polyelectrolyte complexes offer a viable strategy for the intracellular delivery of anionic proteins.
- Requirements for forming PEC micelles stable at physiological ionic strength were identified.
- Smaller protein-polyelectrolyte complexes demonstrated effective protein delivery to Jurkat cells, highlighting their therapeutic potential.
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