pH-Responsive Micellar Nanoassemblies from Water-Soluble Telechelic Homopolymers Endcoding Acid-Labile Middle-Chain...

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Development of advanced nanocarriers is crucial for targeted drug delivery and stimuli-responsive systems.
• Existing nanocarriers often face challenges in controlled disassembly and cargo release.
• Sequence-defined polymers offer precise control over material properties and self-assembly behavior.

Purpose of the Study:

• To synthesize a middle-chain cleavable telechelic poly(oligoethylene glycol) methyl ether acrylate) (MCCT-POEGA-Br) using single-electron transfer living radical polymerization (SET-LRP).
• To investigate the self-assembly of MCCT-POEGA-Br into nanogel-like micelles in aqueous media.
• To evaluate the pH-responsive disassembly and cargo release capabilities of the self-assembled nanostructures.

Main Methods:

• Synthesis of MCCT-POEGA-Br via SET-LRP using a sequence-defined difunctional initiator.
• Characterization of polymer self-assembly into micelles above a critical concentration in aqueous solution.
• pH-triggered disassembly studies using dye release assays to assess responsiveness.
• Thio-bromo 'click' modification for creating fluorescently tagged nanoassemblies.

Main Results:

• Successfully synthesized MCCT-POEGA-Br, a hydrophilic homopolymer capable of self-assembly.
• The self-assembled micelles demonstrated encapsulation of both hydrophobic and hydrophilic cargo.
• Precise middle-chain cleavage, triggered by acidic conditions, led to quantitative disassembly of nanoobjects.
• Fluorescently tagged nanoassemblies were prepared, enabling visualization and tracking.

Conclusions:

• The developed MCCT-POEGA-Br system provides a novel design for pH-responsive nanocarriers.
• Sequence-defined cleavage enables controlled disassembly and cargo release, particularly in acidic environments.
• This strategy offers a versatile platform for creating diverse multistimuli-responsive nanocarriers using accessible monomers and initiators.