Optically triggered dissociation of kinetically stabilized block copolymer vesicles in aqueous solution

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Block copolymer (BCP) vesicles are self-assembled nanostructures with potential applications in drug delivery and materials science.
• Controlling the stability and disassembly of BCP vesicles is crucial for their effective utilization.
• Existing methods for vesicle dissociation may lack precision or require harsh conditions.

Purpose of the Study:

• To demonstrate a light-triggered strategy for the dissociation of BCP vesicles in aqueous solution.
• To investigate the mechanism of UV-induced vesicle disassembly.
• To explore the potential of spiropyran-containing BCPs for controlled release applications.

Main Methods:

• Synthesis of a block copolymer (BCP) comprising poly(ethylene oxide) (PEO) and poly(methacrylic acid) with spiropyran comonomer units (P(MAA-co-SPMA)).
• Self-assembly of BCP into vesicles in aqueous solution at pH=3.
• Stabilization of vesicles at pH=8.
• Triggering vesicle dissociation using UV light via spiropyran isomerization.

Main Results:

• BCP vesicles were successfully formed and stabilized at pH=8.
• UV irradiation induced the isomerization of spiropyran to merocyanine within the vesicle membrane.
• This isomerization triggered a cascade of events leading to the rapid dissociation of the BCP vesicles.
• The dissociation process was confirmed to be light-dependent.

Conclusions:

• A novel optical stimulus-responsive strategy for BCP vesicle dissociation has been successfully demonstrated.
• The P(MAA-co-SPMA) BCP system provides a platform for light-controlled disassembly of nanostructures.
• This approach offers potential for advanced applications requiring precise control over vesicle stability and release.