Physiologically relevant, pH-responsive PEG-based block and statistical copolymers with N,N-diisopropylamine units

Area of Science:

• Polymer Chemistry
• Biomaterials Science
• Materials Engineering

Background:

• Polyethylene glycol (PEG)-based biomaterials lack inherent pH-responsiveness crucial for physiological applications.
• Developing adaptable materials that respond to specific pH changes is essential for advanced drug delivery and tissue engineering.

Purpose of the Study:

• To synthesize and characterize a novel tertiary amine-containing monomer, DEGE, for creating pH-responsive PEG-based copolymers.
• To investigate the copolymerization behavior of DEGE with ethylene oxide (EO) and allyl glycidyl ether (AGE).
• To develop and evaluate pH-responsive hydrogels and nanoparticles using DEGE-containing copolymers.

Main Methods:

• Anionic ring-opening polymerization was used to incorporate DEGE into statistical and block copolymers with EO and AGE.
• Spectroscopy was employed to determine reactivity ratios during copolymerization.
• Macroscopic hydrogels were formed from triblock copolymers, and nanoparticles were prepared via miniemulsion crosslinking.

Main Results:

• The novel monomer DEGE was successfully incorporated into PEG-based copolymers.
• DEGE-containing copolymers exhibit a pKa of approximately 9, enabling pH-responsive behavior.
• Triblock copolymers formed hydrogels with sol-to-gel transitions between pH 5.8-6.6.
• Nanoparticles demonstrated reversible swelling and volume phase transitions around physiological pH (6.5-7.5).

Conclusions:

• The developed DEGE monomer provides a versatile building block for creating tunable, pH-responsive biomaterials.
• These materials exhibit significant potential for applications requiring precise control over drug release or material properties in response to physiological pH changes.