Reversible Light-Controlled Sol-Gel Transition of an Ionic Hydrogel.

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomedical Engineering

Background:

• Azobenzene photoswitches are crucial for light-controlled advanced materials.
• Developing water-soluble variants for hydrogel cross-linking presents a significant challenge.
• Optimizing light reactivity and solubility is key for practical applications.

Purpose of the Study:

• To design and synthesize a water-soluble, cationic azobenzene derivative for photoresponsive hydrogels.
• To create a novel [Azo(+)@pSAMPS(-)] hydrogel system using the synthesized cross-linker.
• To evaluate the hydrogel's photoresponsive drug delivery capabilities.

Main Methods:

• Synthesis of a water-soluble cationic azobenzene derivative.
• Hydrogel fabrication via hydrogen bonding, electrostatic interactions, and π-π stacking.
• Characterization using UV-vis, 1H NMR, FESEM, and rheological studies.
• Assessment of Doxorubicin hydrochloride (DOX) encapsulation and photo-triggered release.

Main Results:

• Successful synthesis of a water-soluble, cationic azobenzene cross-linker.
• Development of [Azo(+)@pSAMPS(-)] hydrogels with combined interaction mechanisms.
• Demonstrated efficient trans-to-cis isomerization of azobenzene within seconds under UV irradiation.
• Confirmed photoisomerization and structural integrity of the hydrogel system.
• Successful encapsulation and light-controlled release of Doxorubicin hydrochloride (DOX).

Conclusions:

• The developed azobenzene-based hydrogel system exhibits excellent photoresponsive properties for controlled drug delivery.
• The simplified synthesis approach enhances scalability and reduces production costs.
• This work provides a versatile platform for developing advanced light-responsive materials for biomedical applications.