Degradable Ureido-Polycarbonate Block Copolymers with a Complex UCST Thermoresponse

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Amphiphilic block copolymers (BCs) are crucial for self-assembly and drug delivery applications.
• Thermoresponsive polymers offer dynamic control over material properties and drug release.
• Developing polymers with tunable upper critical solution temperature (UCST) behavior is an active research area.

Purpose of the Study:

• To synthesize and characterize novel amphiphilic block copolymers (BCs) with a hydrophilic poly(ethylene glycol) methyl ether (PEG) block and a degradable polycarbonate block.
• To incorporate ureido units into the polycarbonate block to induce UCST-type thermoresponsive behavior in water.
• To evaluate the potential of these BCs and their self-assemblies as thermoresponsive drug nanocarriers.

Main Methods:

• Synthesis of polymers via ring-opening polymerization (ROP) and thiol-ene/yne functionalization.
• Incorporation of ureido groups to promote UCST behavior.
• Formation of stable self-assemblies through direct dispersion, co-solvent methods, or microfluidics.
• Analysis of thermoresponsiveness based on ureido group density and polycarbonate block length.
• Evaluation of drug delivery potential using curcumin as a model hydrophobic drug.

Main Results:

• Homopolycarbonates with increased ureido group density exhibited enhanced UCST-type thermoresponse in water.
• Amphiphilic BCs formed stable self-assemblies that swelled and collapsed upon heating due to polycarbonate block hydration.
• Thermoresponsiveness was tunable by adjusting ureido group content and polycarbonate block length.
• Self-assemblies demonstrated potential as drug nanocarriers for hydrophobic drugs like curcumin.

Conclusions:

• Novel amphiphilic block copolymers with UCST-type thermoresponsive behavior were successfully synthesized.
• The developed polymers and their self-assemblies offer a tunable platform for smart materials.
• These materials show promise for applications in drug delivery systems, particularly for hydrophobic drugs.