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

Abstract

Abstract:This review provides an overview of the syntheses of photosensitive layer-by-layer (LbL) films and microcapsules modified with azobenzene derivatives and their biomedical applications. Photosensitive LbL films and microcapsules can be prepared by alternate deposition of azobenzene-bearing polymers and counter polymers on the surface of flat substrates and microparticles, respectively. Azobenzene residues in the films and microcapsules exhibit trans-to-cis photoisomerization under UV light, which causes changes in the physical or chemical properties of the LbL assemblies. Therefore, azobenzene-functionalized LbL films and microcapsules have been used for the construction of photosensitive biomedical devices. For instance, cell adhesion on the surface of a solid can be controlled by UV light irradiation by coating the surface with azobenzene-containing LbL films. In another example, the ion permeability of porous materials coated with LbL films can be regulated by UV light irradiation. Furthermore, azobenzene-containing LbL films and microcapsules have been used as carriers for drug delivery systems sensitive to light. UV light irradiation triggers permeability changes in the LbL films and/or decomposition of the microcapsules, which results in the release of encapsulated drugs and proteins.

Biomimetic Layer-by-Layer Self-Assembly of Nanofilms, Nanocoatings, and 3D Scaffolds for Tissue Engineering

“…The LbL self-assembly technique has been widely used for various biomedical applications including tissue engineering, medical implants, regenerative medicines, drug delivery, biosensors, bioreactors, and so on ( Figure 2 b) [ 35 , 51 , 52 , 53 , 54 , 55 ]. The capacity to manipulate the chemical, physical, and topographical properties of nanostructured architectures by facilely adjusting solution properties and assembly parameters, not only allows LbL self-assembly to be suitable to investigate the effects of external stimuli on cellular responsiveness but also provides a new strategy for creating two/three-dimensional (2/3D) nanostructured architectures and coatings for individual cells or scaffolds for tissue engineering ( Figure 2 c) [ 56 , 57 , 58 , 59 ]. The uses of LbL self-assembly biomaterials include nanostructured coating or materials to either promote or prevent cell adhesion, to maintain and direct cellular phenotypes, and to provide 3D scaffolds for cell culture or co-culture.…”

Host-Guest Chemistry in Layer-by-Layer Assemblies Containing Calix[n]arenes and Cucurbit[n]urils: A Review

“…Photosensitive chemical systems in which the structures and functions can be regulated by light irradiation have been widely studied [ 76 , 77 , 78 , 79 ]. In this regard, photo-sensitive LbL films have been developed using azobenzene-modified polycations and PAA to photochemically control the binding and release of guest molecules [ 80 ].…”

“…Therefore, the anti-cancer activity of DOX-loaded MSNs was tested in vivo using a mouse model containing HeLa cancer cells, in which the growth of the tumors was inhibited by 63% in mice administered with DOX-loaded MSNs compared to the untreated group (Figure 9). Photosensitive chemical systems in which the structures and functions can be regulated by light irradiation have been widely studied [76][77][78][79]. In this regard, photo-sensitive LbL films have been developed using azobenzene-modified polycations and PAA to photochemically control the binding and release of guest molecules [80].…”

Layered assembly of cationic and anionic supramolecular polymers

“…35,36 The method has since been used for the preparation of ultrathin-layers and is of high interest for the production of optics and sensors. [37][38][39][40][41][42][43] Herein, we present the synthesis, the self-assembly and the spectroscopic properties of a 3,6-dialkynyl-substituted, aminelinked phenanthrene-trimer (N-Phe 3 , Scheme 1). Additionally, the cationic oligomer was used for the formation of nanometerscaled aggregates in an electrostatic layered assembly 36,38 in combination with an anionic supramolecular polymer.…”