Complexes Covered with Phosphorylcholine Groups Prepared by Mixing Anionic Diblock Copolymers and Cationic...

Area of Science:

• Polymer Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Anionic diblock copolymers offer versatile applications in nanotechnology and drug delivery.
• Polybetaines like PMPC provide biocompatibility, while sulfonate groups offer anionic charge.
• Controlled polymerization techniques are crucial for synthesizing well-defined block copolymers.

Purpose of the Study:

• To synthesize and characterize anionic diblock copolymers of PMPC and PAMPS.
• To investigate the self-assembly behavior of these copolymers with cationic surfactants (CTAB).
• To explore the potential of the resulting complexes for encapsulating guest molecules.

Main Methods:

• Reversible addition-fragmentation chain transfer (RAFT) radical polymerization was used to synthesize PMPC-b-PAMPS diblock copolymers.
• Complexation was achieved by mixing anionic PMPC-b-PAMPS with cationic cetyltrimethylammonium bromide (CTAB) micelles in aqueous solution.
• The morphology of the complexes (vesicles or micelles) was determined by copolymer composition, and their dissociation behavior in response to NaCl was studied.
• Encapsulation of uncharged hydrophilic molecules within the PMPC-grafted vesicles was demonstrated.

Main Results:

• Two types of anionic diblock copolymers, P24A217 and P100A99, were successfully synthesized with varying PMPC and PAMPS block lengths.
• Complexation with CTAB resulted in the formation of PMPC-coated vesicles (using P24A217) and micelles (using P100A99).
• The electrostatic interactions holding the complexes together were disrupted by the addition of NaCl, leading to dissociation.
• The P24A217/CTAB vesicles demonstrated the ability to encapsulate uncharged hydrophilic guest molecules within their aqueous core.

Conclusions:

• Anionic PMPC-b-PAMPS diblock copolymers can form well-defined supramolecular structures with CTAB micelles.
• The morphology of these self-assembled complexes is tunable by adjusting the copolymer composition.
• The PMPC corona provides a biocompatible and hydrophilic shell, while the internal structure allows for cargo encapsulation.
• These PMPC-grafted complexes show promise as nanocarriers for hydrophilic molecules.