Photosensitive Layer-by-Layer Assemblies Containing Azobenzene Groups: Synthesis and Biomedical Applications.

Area of Science:

• Materials Science
• Biomedical Engineering
• Polymer Chemistry

Background:

• Layer-by-layer (LbL) assembly is a versatile technique for fabricating multilayered thin films and microcapsules.
• Azobenzene derivatives are photoresponsive molecules that undergo reversible trans-to-cis isomerization upon UV light irradiation.
• Integrating azobenzene into LbL structures enables the creation of materials with tunable properties controlled by light.

Purpose of the Study:

• To review the synthesis of photosensitive LbL films and microcapsules incorporating azobenzene derivatives.
• To highlight the biomedical applications of these azobenzene-functionalized LbL materials.
• To discuss the mechanism of photoisomerization and its impact on LbL assembly properties.

Main Methods:

• Alternate deposition of azobenzene-bearing polymers and counter polymers onto substrates or microparticles to form LbL assemblies.
• Characterization of LbL films and microcapsules for structural integrity and azobenzene content.
• Investigation of photoisomerization behavior of azobenzene residues under UV light exposure.
• Evaluation of changes in physical/chemical properties (e.g., permeability, cell adhesion) upon light irradiation.

Main Results:

• Azobenzene-functionalized LbL films and microcapsules exhibit photoisomerization, leading to changes in their properties.
• UV light irradiation can control cell adhesion on surfaces coated with azobenzene-containing LbL films.
• Ion permeability of porous materials coated with these LbL films can be regulated by UV light.
• Azobenzene-based LbL systems serve as effective carriers for light-sensitive drug delivery, releasing drugs upon UV exposure.

Conclusions:

• Photosensitive LbL films and microcapsules modified with azobenzene derivatives offer significant potential in various biomedical applications.
• The light-induced changes in LbL assemblies provide a mechanism for precise control over biological processes and drug release.
• Further development of these smart materials could lead to advanced photosensitive biomedical devices and targeted therapies.