Azobenzene Based Photo-Responsive Hydrogel: Synthesis, Self-Assembly, and Antimicrobial Activity

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Biomaterials Science

Background:

• Azobenzene-based amphiphiles are known for their photo-responsive properties.
• Self-assembly of amphiphiles can lead to the formation of various mesophases, including hydrogels.
• Photo-responsive hydrogels have potential applications in drug delivery and tissue engineering.

Purpose of the Study:

• To synthesize and characterize a new azobenzene-based symmetric amphiphile.
• To investigate the self-assembly and photo-responsive behavior of the amphiphile in solution and gel states.
• To evaluate the antimicrobial activity of the derived quaternary ammonium salt.

Main Methods:

• Synthesis and characterization of the azobenzene amphiphile using 1H NMR spectroscopy.
• Investigation of self-assembly into fiber mesophases in aqueous solutions.
• Photoisomerization studies upon UV irradiation, leading to gel destruction.
• In vitro cell viability assays (Live/Dead) using human fibroblasts L929.
• Conversion to a quaternary ammonium salt and assessment of antimicrobial activity against Escherichia coli.

Main Results:

• The synthesized amphiphile self-assembles into fiber mesophases in water.
• UV irradiation induces rapid trans-to-cis photoisomerization, leading to hydrogel destruction.
• High temperature also causes a significant decrease in hydrogel viscosity.
• The azobenzene quaternary ammonium salt exhibits notable antimicrobial biocidal activity against Escherichia coli in vitro.

Conclusions:

• The novel azobenzene amphiphile forms photo-responsive hydrogels that can be controllably degraded.
• The derived quaternary ammonium salt possesses promising antimicrobial properties.
• This azobenzene-based material holds potential for applications requiring light-triggered disassembly and antimicrobial action.