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Journal ArticleDOI

A Photoresponsive Orthogonal Supramolecular Complex Based on Host–Guest Interactions

21 Feb 2017-Chemistry: A European Journal (John Wiley & Sons, Ltd)-Vol. 23, Iss: 11, pp 2628-2634
TL;DR: A photoresponsive orthogonal supramolecular system is developed by combining the UV-light-responsive Azo/α-CD and green- light-responsive ipAzo/γ-CD host-guest complexes, which forms a strong host-Guest complex with γ-cyclo dextrin whereas trans-ipAzo binds weakly.
Abstract: We synthesized a novel green-light-responsive tetra-ortho-isopropoxy-substituted azobenzene (ipAzo). Cis-ipAzo forms a strong host-guest complex with γ-cyclo dextrin (γ-CD) whereas trans-ipAzo binds weakly. This new photoresponsive host-guest interaction is reverse to the well-known azobenzene (Azo)/α-cyclodextrin (α-CD) complex, which is strong only between trans-Azo and α-CD. By combining the UV-light-responsive Azo/α-CD and green-light-responsive ipAzo/γ-CD host-guest complexes, a photoresponsive orthogonal supramolecular system is developed.
Citations
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Journal ArticleDOI
TL;DR: In this review, recent progress in CD‐based supramolecular nano assemblies that are sensitive to chemical, biological, and physical stimuli is updated and reviewed, and intriguing examples of the biological functions of these nanoassemblies are presented.
Abstract: Cyclodextrins (CDs), which are a class of cyclic oligosaccharides extracted from the enzymatic degradation of starch, are often utilized in molecular recognition and assembly constructs, primarily via host-guest interactions in water. In this review, recent progress in CD-based supramolecular nanoassemblies that are sensitive to chemical, biological, and physical stimuli is updated and reviewed, and intriguing examples of the biological functions of these nanoassemblies are presented, including pH- and redox-responsive drug and gene delivery, enzyme-activated specific cargo release, photoswitchable morphological interconversion, microtubular aggregation, and cell-cell communication, as well as a geomagnetism-controlled nanosystem for the suppression of tumor invasion and metastasis. Moreover, future perspectives and challenges in the fabrication of intelligent CD-based biofunctional materials are also discussed at the end of this review, which is expected to promote the translational development of these nanomaterials in the biomedical field.

226 citations

Journal ArticleDOI
TL;DR: This Review introduces azobenzene compounds that exhibit photoinduced reversible solid-to-liquid transitions, discusses the mechanisms and design principles, and shows their potential applications in healable coatings, adhesives, transfer printing, lithography, actuators, fuels, and gas separation.
Abstract: Heating and cooling can induce reversible solid-to-liquid transitions of matter. In contrast, athermal photochemical processes can induce reversible solid-to-liquid transitions of some newly developed azobenzene compounds. Azobenzene is photoswitchable. UV light induces trans-to-cis isomerization; visible light or heat induces cis-to-trans isomerization. Trans and cis isomers usually have different melting points (Tm ) or glass transition temperatures (Tg ). If Tm or Tg of an azobenzene compound in trans and cis forms are above and below room temperature, respectively, light may induce reversible solid-to-liquid transitions. In this Review, we introduce azobenzene compounds that exhibit photoinduced reversible solid-to-liquid transitions, discuss the mechanisms and design principles, and show their potential applications in healable coatings, adhesives, transfer printing, lithography, actuators, fuels, and gas separation. Finally, we discuss remaining challenges in this field.

168 citations

Journal ArticleDOI
TL;DR: In this article, the authors discuss the recent progress in biofilm interference and smart antibacterial surfaces and discuss the major topics discussed are: (i) smart anti-biofilm surfaces via the prevention of biofilm formation or promoting mature biofilm dissolution, (ii) smart materials for reversible killing and/or release of bacteria, (iii) smart surfaces responsive to bacterial infection microenvironments or external stimuli and (iv) bio-inspired surfaces with antifouling and bactericidal properties.
Abstract: Since their development over 70 years, antibiotics are still the most effective strategy to treat bacterial biofilms and infections. However, the overuse of antibiotics in human healthcare and industrial applications has resulted in the development of serious antibiotic-resistant bacteria. Therefore, alternative ways to prevent bacteria attachment and biofilm formation are urgently needed. Recently, mediated biofilm formation processes and smart antibacterial surfaces have emerged as promising strategies to prevent and treat bacterial infections. This review discusses the recent progress in biofilm interference and smart antibacterial surfaces. Smart antibacterial and anti-biofilm surfaces should be responsive to the bacterial infection environment, switchable between various antibacterial functions and have a special bio-inspired structure and function. The major topics discussed are: (i) smart anti-biofilm surfaces via the prevention of biofilm formation or promoting mature biofilm dissolution, (ii) smart materials for reversible killing and/or release of bacteria, (iii) smart surfaces responsive to bacterial infection microenvironments or external stimuli and (iv) bio-inspired surfaces with antifouling and bactericidal properties.

155 citations

Journal ArticleDOI
Philipp Weis1, Si Wu1
TL;DR: The strategies for constructing visible and near-infrared (NIR) light-responsive azo-macromolecules are reviewed, and the potential applications of visible- and NIR-light-responsiveAzo-Macromolecule in biomedicine and solar energy conversion are highlighted.
Abstract: Azobenzene-containing macromolecules (azo-macromolecules) such as azobenzene-containing polymers (azopolymers) and azobenzene-functionalized biomacromolecules are photoswitchable macromolecules. Trans-to-cis photoisomerization in conventional azo-macromolecules is induced by ultraviolet (UV) light. However, UV light cannot penetrate deeply into issue and has a very small fraction in sunlight. Therefore, conventional azo-macromolecules are problematic for biomedical and solar-energy-related applications. In this Feature Article, the strategies for constructing visible and near-infrared (NIR) light-responsive azo-macromolecules are reviewed, and the potential applications of visible- and NIR-light-responsive azo-macromolecules in biomedicine and solar energy conversion are highlighted. The remaining challenges in the field of photoswitchable azo-macromolecules are discussed.

129 citations

Journal Article
TL;DR: This review discusses the recent progress in biofilm interference and smart antibacterial surfaces and discusses bio-inspired surfaces with antifouling and bactericidal properties.
Abstract: Since their development over 70 years, antibiotics are still the most effective strategy to treat bacterial biofilms and infections. However, the overuse of antibiotics in human healthcare and industrial applications has resulted in the development of serious antibiotic-resistant bacteria. Therefore, alternative ways to prevent bacteria attachment and biofilm formation are urgently needed. Recently, mediated biofilm formation processes and smart antibacterial surfaces have emerged as promising strategies to prevent and treat bacterial infections. This review discusses the recent progress in biofilm interference and smart antibacterial surfaces. Smart antibacterial and anti-biofilm surfaces should be responsive to the bacterial infection environment, switchable between various antibacterial functions and have a special bio-inspired structure and function. The major topics discussed are: (i) smart anti-biofilm surfaces via the prevention of biofilm formation or promoting mature biofilm dissolution, (ii) smart materials for reversible killing and/or release of bacteria, (iii) smart surfaces responsive to bacterial infection microenvironments or external stimuli and (iv) bio-inspired surfaces with antifouling and bactericidal properties.

96 citations

References
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Journal ArticleDOI
TL;DR: This critical review details the studies completed to date on the 3 main classes of azobenzene derivatives and explains the mechanism behind the isomerization mechanism.
Abstract: Azobenzene undergoes trans → cisisomerization when irradiated with light tuned to an appropriate wavelength. The reverse cis →transisomerization can be driven by light or occurs thermally in the dark. Azobenzene's photochromatic properties make it an ideal component of numerous molecular devices and functional materials. Despite the abundance of application-driven research, azobenzene photochemistry and the isomerization mechanism remain topics of investigation. Additional substituents on the azobenzene ring system change the spectroscopic properties and isomerization mechanism. This critical review details the studies completed to date on the 3 main classes of azobenzene derivatives. Understanding the differences in photochemistry, which originate from substitution, is imperative in exploiting azobenzene in the desired applications.

2,062 citations

Journal ArticleDOI
02 Jun 2000-Science
TL;DR: The light-driven motion of a fluid substance in a surface-modified glass tube suggests potential applicability to microscale chemical process systems.
Abstract: The macroscopic motion of liquids on a flat solid surface was manipulated reversibly by photoirradiation of a photoisomerizable monolayer covering the surface. When a liquid droplet several millimeters in diameter was placed on a substrate surface modified with a calix[4]resorcinarene derivative having photochromic azobenzene units, asymmetrical photoirradiation caused a gradient in surface free energy due to the photoisomerization of surface azobenzenes, leading to the directional motion of the droplet. The direction and velocity of the motion were tunable by varying the direction and steepness of the gradient in light intensity. The light-driven motion of a fluid substance in a surface-modified glass tube suggests potential applicability to microscale chemical process systems.

1,352 citations

Journal ArticleDOI

1,198 citations

Journal ArticleDOI
TL;DR: Moving from supramolecular systems in solution to surfaces and finally to bulk materials, important design concepts are discussed, emphasizing both the challenges as well as the great promise of such truly advanced materials.
Abstract: Small organic molecules, capable of undergoing efficient and reversible photochemical reactions to switch them between (at least) two (meta)stable isomers associated with markedly different properties, continue to impact the materials world. Such photoswitches are being implemented in a variety of materials for applications ranging from optical devices to "smart" polymers. All approaches exploit the photoswitching molecular entities as gates, which translate an incoming light stimulus to trigger macroscopic property changes of the materials. In this progress report, the most promising recent examples in this field are highlighted and put in perspective. Moving from supramolecular systems in solution to surfaces and finally to bulk materials, important design concepts are discussed, emphasizing both the challenges as well as the great promise of such truly advanced materials.

836 citations