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Polyion Complex Vesicles with Solvated Phosphobetaine Shells Formed from Oppositely Charged Diblock Copolymers
Keita Nakai1, Kazuhiko Ishihara2, Michael Kappl3
1Department of Applied Chemistry, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan. good.west.56@hotmail.co.jp.
Polymers
|April 12, 2019
Summary
Researchers created polyion complex vesicles (PICsomes) from oppositely charged diblock copolymers. The size of these self-assembled PICsomes can be controlled by adjusting the copolymer concentration before mixing.
Area of Science:
- Polymer Chemistry
- Materials Science
- Nanotechnology
Background:
- Diblock copolymers offer versatile platforms for self-assembly into complex nanostructures.
- Poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC) is a hydrophilic polymer block with biocompatibility.
- Cationic and anionic polymer blocks can form polyion complexes through electrostatic interactions.
Purpose of the Study:
- To synthesize novel diblock copolymers of PMPC with cationic (PMAPTAC) or anionic (PAMPS) blocks.
- To investigate the self-assembly of these oppositely charged copolymers into polyion complex vesicles (PICsomes).
- To characterize the structure and size of the formed PICsomes and explore methods for size control.
Main Methods:
- Synthesis of PMPC-PMAPTAC and PMPC-PAMPS diblock copolymers via reversible addition-fragmentation chain transfer (RAFT) polymerization.
- Characterization of PICsomes using ¹H NMR, static and dynamic light scattering, transmission electron microscopy (TEM), and atomic force microscopy (AFM).
- Investigation of PICsome formation and size dependence on diblock copolymer concentration and charge balance.
Main Results:
- Spontaneous formation of polyion complex vesicles (PICsomes) upon mixing PMPC-PMAPTAC and PMPC-PAMPS solutions.
- PICsomes exhibited a spherical hollow vesicle structure with a maximum hydrodynamic radius (Rh) of 78.0 nm at neutral charge balance.
- PICsome size (Rh) and aggregation number (Nagg) were found to increase with the concentration of the precursor diblock copolymer solutions.
Conclusions:
- Novel PMPC-based diblock copolymers can self-assemble into well-defined PICsomes.
- The size of the self-assembled PICsomes can be effectively controlled by adjusting the concentration of the diblock copolymer solutions prior to mixing.
- These findings provide a pathway for designing tunable nanovesicles for potential applications in drug delivery or nanotechnology.
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