Photoswitchable Azobenzene/Cyclodextrin Host‐Guest Complexes: From UV‐ to Visible/Near‐IR‐Light‐Responsive Systems

Wang, Dongsheng; Zhao, Weifeng; Wei, Qiang; Zhao, Changsheng; Zheng, Yonghao

doi:10.1002/cptc.201700233

Cited by 53 publications

(48 citation statements)

References 120 publications

(48 reference statements)

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“…To enable photochemical shape morphing of hydrogels, we consider here reversible host–guest interactions with α-cyclodextrin (α-CD), wherein trans -azobenzene inserts into the hydrophobic cavity of α-CD while the cis -isomer is expelled. 42 Using this scheme, azobenzene- and α-CD-functionalized hydrogels have been used to drive substantial volumetric changes 43 − 46 through on-demand changes in cross-link density. However, this work has been limited to thick gels where moderate light penetration, slow cross-linking kinetics, and diffusion-limited mass transport result in modest shape changes.…”

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confidence: 99%

Reconfiguring Gaussian Curvature of Hydrogel Sheets with Photoswitchable Host–Guest Interactions

et al. 2020

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Photoinduced shape morphing has implications in fields ranging from soft robotics to biomedical devices. Despite considerable effort in this area, it remains a challenge to design materials that can be both rapidly deployed and reconfigured into multiple different three-dimensional forms, particularly in aqueous environments. In this work, we present a simple method to program and rewrite spatial variations in swelling and, therefore, Gaussian curvature in thin sheets of hydrogels using photoswitchable supramolecular complexation of azobenzene pendent groups with dissolved α-cyclodextrin. We show that the extent of swelling can be programmed via the proportion of azobenzene isomers, with a 60% decrease in areal swelling from the all trans to the predominantly cis state near room temperature. The use of thin gel sheets provides fast response times in the range of a few tens of seconds, while the shape change is persistent in the absence of light thanks to the slow rate of thermal cis–trans isomerization. Finally, we demonstrate that a single gel sheet can be programmed with a first swelling pattern via spatially defined illumination with ultraviolet light, then erased with white light, and finally redeployed with a different swelling pattern.

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confidence: 99%

Reconfiguring Gaussian Curvature of Hydrogel Sheets with Photoswitchable Host–Guest Interactions

et al. 2020

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“…Sparsely substituted azobenzenes are known to bind within the hydrophobic cavities of cyclodextrins (in aqueous solution) and the selective recognition of the cis or trans isomers has been exploited to control self-assembly of functional materials. 13 For this study, we screened a number of different substituted azobenzenes (ESI Table S1) and identified a set of water soluble azobenzene photoswitches (1 -5) exhibiting markedly different cis/trans isomeric ratios in ambient light and when irradiated with UV light at 365 nm (Table 1 and ESI Figs S2 and S3).…”

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confidence: 99%

Light-controlled out-of-equilibrium assembly of cyclodextrins in an enzyme-mediated dynamic system

2019

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“…In addition to the aforementioned photoactive hydrogels, a difference in binding affinity between cyclodextrins and trans versus cis azobenzene has been exploited for many interesting biomimetic applications . Examples of applications of these azobenzene/cyclodextrin host/guest systems include acting as a cation carrier, shielding and exposing a catalytic site, controlling self‐aggregation in aqueous media, and as externally controllable hydrophobic drug‐delivery systems .…”

Section: Interfacing Azo To Bio: An Eye Toward Influencing Living Sysmentioning

confidence: 99%

“…Bian et al used a similar β‐cyclodextrin/azobenzene and cell capture aptamer‐functionalized material for photocontrolled capture and release of cancer cells . Further examples of biological applications of cyclodextrin/azobenzene‐functionalized materials can be found in a review by Zhan et al As many early examples of these systems are UV‐responsive, recent work has endeavored to redshift the absorption toward visible and near‐IR–responsive systems for greater biocompatibility . Further information and examples of azobenzene/cyclodextrin host/guest systems can be found in reviews by Harada et al and Wang et al…”

Section: Interfacing Azo To Bio: An Eye Toward Influencing Living Sysmentioning

confidence: 99%

Photoreversible Soft Azo Dye Materials: Toward Optical Control of Bio‐Interfaces

Chang

Fedele

Priimägi

et al. 2019

Advanced Optical Materials

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systems interact with artificial materials, researchers have now assembled a versatile toolkit of materials and processes that allows one to fine-tune interactions at the interface, tailoring specific biological responses on demand. These strategies for biocontrol can be broadly categorized as chemical (charge, ligand presence, surface groups), material changes (moisture content, stiffness), or morphological changes (molecular orientation, surface topography, or mechanical actuation). Rational design of materials for biological interface applications has a unique set of challenges due to the unique requirements of a wide range of biological systems, since different tissues present specific compositions, with their own elasticity, structural organization, and triggering mechanisms. Even within a single organ or tissue, mechanical properties can vary widely depending on the region. A recent study of viscoelasticity in live mouse brain tissue for example found a tenfold difference within the brain depending on the region and morphological structure studied. [2] However, most biological tissues are far less stiff, and far more viscoelastic than typical artificial materials employed at their interface, especially early artificial cell culture materials, which can be much stiffer than in vivo extracellular matrix by many orders of magnitude. [3] In vivo, cells interface with a surrounding microenvironment consisting of an intricate macromolecular network of proteins and sugars swollen in an aqueous media gel. Therefore, the interaction between cells and the extracellular matrix (ECM) in the body is complex and involves a variety of cues related to topography, chemical markers, protein composition, solubility factors, and mechanical properties such as stiffness and elasticity (Figure 1a). [4] Yet much research over the past decades was focused on studying in vitro the effects of each of these signals on cell behavior, with a particular interest on the chemical factors, whereas only recently more advanced biomaterials with controlled physicomechanical properties have been developed, such as those with tunable and variable stiffness, alignment and orientation of key functional groups, and mechanical actuation. There is a large range of stiffness in human tissue, where bone (≈100 GPa) is nine orders of magnitude harder than brain tissue (≈0.1 kPa). [4] Therefore, biomaterial researchers assume a complex task of providing materials and processing technologies for controlling stiffness and micro-and nanostructures in Photoreversible optically switchable azo dye molecules in polymer-based materials can be harnessed to control a wide range of physical, chemical, and mechanical material properties in response to light, that can be exploited for optical control over the bio-interface. As a stimulus for reversibly influencing adjacent biological cells or tissue, light is an ideal triggering mechanism, since it can be highly localized (in time and space) for precise and dynamic control over a biosystem, and low-power visible light...

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Photoswitchable Azobenzene/Cyclodextrin Host‐Guest Complexes: From UV‐ to Visible/Near‐IR‐Light‐Responsive Systems

Cited by 53 publications

References 120 publications

Reconfiguring Gaussian Curvature of Hydrogel Sheets with Photoswitchable Host–Guest Interactions

Reconfiguring Gaussian Curvature of Hydrogel Sheets with Photoswitchable Host–Guest Interactions

Light-controlled out-of-equilibrium assembly of cyclodextrins in an enzyme-mediated dynamic system

Photoreversible Soft Azo Dye Materials: Toward Optical Control of Bio‐Interfaces

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