Degradable Diblock Copolymer Vesicles via Radical Ring-Opening Polymerization-Induced Self-Assembly in Aqueous Media

Area of Science:

• Polymer Chemistry
• Materials Science
• Biomedical Engineering

Background:

• Degradable polymeric vesicles are crucial for controlled delivery and responsive materials in therapy and diagnostics.
• Achieving precise control over their synthesis and degradation remains a significant challenge in polymer science.

Purpose of the Study:

• To synthesize degradable diblock copolymer vesicles with controlled degradation behavior using a novel polymerization technique.
• To investigate the impact of a controlled feeding strategy on copolymer composition and vesicle properties.

Main Methods:

• Radical ring-opening polymerization-induced self-assembly (rROPISA) in aqueous media.
• Radical ring-opening copolymerization (rROP) of dibenzo[c,e]oxepane-5-thione (DOT) with 2-methoxyethyl acrylate (MEA) using RAFT polymerization.
• Comonomer-starved feed strategy to control copolymer composition and DOT incorporation.
• Characterization using cryo-TEM, DLS, SAXS, and SEC to confirm vesicle formation and degradation.

Main Results:

• Successfully synthesized well-defined degradable diblock copolymer vesicles with tunable degradation profiles.
• The comonomer-starved feed strategy improved DOT incorporation (up to ~4 mol%), composition control, and overall conversion.
• Hydrolytic degradation in basic media led to efficient vesicle disintegration, confirmed by various characterization techniques.
• SEC analysis demonstrated efficient hydrolytic degradation of the membrane-forming block.

Conclusions:

• This study presents a robust method for designing degradable vinyl-based diblock copolymer vesicles with controlled synthesis and degradation.
• The developed rROPISA approach offers superior control compared to conventional methods, paving the way for advanced biomedical applications.