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Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles
Published on: August 28, 2015
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Synthesis and Characterization of Polyion Complex Micelles with Glycopolymer Shells for Drug Delivery Carriers
Tomoki Ando1, Thi Ngan Vu1, Tomoya Nishimura1
1Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan.
Langmuir : the ACS Journal of Surfaces and Colloids
|November 26, 2024
Summary
Researchers synthesized polyion complex (PIC) aggregates from hydrophilic diblock copolymers. The ratio of polymer block lengths significantly impacts PIC aggregate stability and morphology, with some forming stable micelles while others aggregate over time.
Area of Science:
- Polymer Chemistry
- Materials Science
- Supramolecular Chemistry
Background:
- Hydrophilic diblock copolymers offer versatile building blocks for self-assembly.
- Controlling polymer architecture is crucial for designing functional materials.
- Polyion complex (PIC) formation relies on electrostatic interactions between oppositely charged polymers.
Purpose of the Study:
- To synthesize novel hydrophilic diblock copolymers using RAFT polymerization.
- To investigate the formation and characteristics of polyion complex (PIC) aggregates.
- To determine the influence of polymer block length ratios on PIC aggregate morphology and stability.
Main Methods:
- Reversible Addition-Fragmentation chain Transfer (RAFT) radical polymerization for diblock copolymer synthesis.
- Mixing of cationic and anionic PGEMA-based diblock copolymers to form PIC aggregates.
- Characterization of PIC aggregates using dynamic light scattering (hydrodynamic radii) and zeta potential measurements.
- Assessment of colloidal stability over time and in varying NaCl concentrations.
Main Results:
- Synthesized PGEMA-based cationic (PGEMA-b-PTMA) and anionic (PGEMA-b-PSSA) diblock copolymers.
- Formed PIC aggregates (e.g., G20A100/G20S80 and G100A98/G100S78) with hydrodynamic radii of 77.4 nm and 26.2 nm, respectively.
- Observed time-dependent aggregation for G20A100/G20S80 PIC micelles, contrasting with the stable, spherical G100A98/G100S78 PIC micelles.
- Demonstrated PIC aggregate dissociation above 0.8 M NaCl due to charge screening.
Conclusions:
- The degree of polymerization ratio between hydrophilic blocks dictates PIC aggregate morphology and colloidal stability.
- Stable, spherical PIC micelles can be achieved by carefully selecting copolymer block lengths.
- PIC aggregate stability is sensitive to ionic strength, with dissociation occurring at high salt concentrations.
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