Stimuli-Responsive Triblock Terpolymer Conversion into Multi-Stimuli-Responsive Micelles with Dynamic Covalent Bonds...

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Stimuli-responsive copolymers are crucial for advanced drug delivery systems.
• Poly(styrene)-b-poly(4-vinyl pyridine)-b-poly(ethylene oxide) (SVE) triblock terpolymers offer a versatile platform.
• Developing selective triggers for drug release remains a key challenge.

Purpose of the Study:

• To develop a controllable post-polymerization quaternization method for SVE terpolymers.
• To create stimuli-responsive micelles for targeted drug delivery.
• To investigate the selective release of a model drug (alizarin) triggered by diols.

Main Methods:

• Post-polymerization quaternization of the poly(4-vinyl pyridine) block with 2-bromomethyl-4-fluorophenylboronic acid.
• Characterization of quaternization yield using 11B and 1H NMR.
• Self-assembly of functionalized terpolymers into micelles, analyzed by light scattering and cryogenic transmission electron microscopy.
• Monitoring drug (alizarin) encapsulation and release using UV-Vis spectroscopy with various diols (fructose, galactose, ascorbic acid).

Main Results:

• A reproducible method for controlled quaternization of the P4VP block was established.
• Stable, functionalized micelles were successfully prepared.
• Ascorbic acid, containing vicinal diols on sp2-hybridized carbons, selectively triggered alizarin release.
• Fructose and galactose did not induce significant drug release.

Conclusions:

• The post-polymerization functionalization strategy enables the creation of specific stimuli-responsive systems.
• This approach holds significant potential for targeted drug delivery applications, particularly in cancer treatment.
• The selectivity observed with ascorbic acid highlights the potential for precise control over drug release mechanisms.