betadex and azobenzene

Switchable assemblies relevant for bio-applications may be accessed from water-soluble tetra-ortho-substituted azobenzenes that reversibly self-assemble and form complexes with β-cyclodextrin under visible light.. Two azobenzenes bearing either four fluorines or two chlorines and two fluorines in the ortho positions were synthesised with short poly(ethylene oxide) tails for water solubility. Photophysical properties were determined by UV-vis and. Both molecules underwent trans-cis isomerization at 530 nm and cis-trans isomerization at 415 nm, with the cis forms exhibiting thermal half-lives > 300 days at room temperature. Both molecules formed inclusion complexes with β-cyclodextrin in water, with cis-4F-AZO-PEO binding 3-fold stronger than trans, and 2Cl2F-AZO-PEO binding significantly weaker. Self-assembly of pure 2Cl2F-AZO-PEO in water showed an open association process regardless of configuration, while 4F-AZO-PEO showed an open association process for cis (N

Topics: Azo Compounds; beta-Cyclodextrins; Ethylene Oxide; Light; Water

Although paraquat is a widely used herbicide, it is toxic to humans if ingested or absorbed through an open wound. To improve the safety of paraquat, a new formulation of paraquat based on photoresponsive polymers was exploited. Photoresponsive β-cyclodextrin polymer microspheres (AZO-CD) were synthesized via a host-guest interaction between β-cyclodextrin and azobenzene. AZO-CD were characterized by Fourier transform infrared spectrometry, circular dichroism, ultraviolet (UV) spectrophotometry, and thermogravimetric analysis, and their photoresponsiveness was also evaluated. AZO-CD were used to load paraquat, which yielded photoresponsive paraquat-loaded microspheres. For the paraquat-loaded microspheres, irradiation with UV light or sunlight induced the isomerization of azobenzene into the cis form. Then, the cis-azobenzene was liberated from the cavities of the β-cyclodextrin. The paraquat-loaded microspheres released paraquat continuously over time. Furthermore, under UV light, the herbicidal capacity of the paraquat-loaded microspheres against barnyard grass was comparable to that of free paraquat at the same dose. Our findings show that loading paraquat into AZO-CD provides a safe and environmentally friendly herbicide formulation.

Topics: Azo Compounds; beta-Cyclodextrins; Herbicides; Humans; Microspheres; Paraquat; Polymers

Injectable stimuli-responsive hydrogels could offer an opportunity for local administration at the tumor site and a sustained drug release. In this paper, a copolymer of azobenzene derivative and N-isopropyl acrylamide (NIPAM) was synthesized, which are performed as light- and thermo-sensitive parts, respectively. The DAS@SCD/NIPAZO hydrogel was prepared upon the establishment of host-guest interactions between the hydrophobic core of CD and azobenzene moiety. The LCST of the synthesized copolymer was modified from 31.3 °C to 36.5 °C by the incorporation of the hydrophilic host moieties of the modified starch into the NIPAM copolymer structure. The LCST-based property of the hydrogel made it syringable in low temperatures and switch to a gel state after local injection. The drug release profile of the hydrogel was explored in four different conditions involving two distinct temperatures combined with two different light wavelengths to examine the light- and thermo-sensitivity of the hydrogel. Moreover, a Paclitaxel-loaded hydrogel was prepared to study the in vitro efficiency of the sample and was investigated by MTT assay against the cancerous fibroblastic cells (A-431), which revealed a sharp decline in cell viability under 365 nm light irradiation; furthermore, to evaluate the in vivo effects of the PTX-loaded hydrogel, histological studies based on staining techniques were carried out.

Topics: beta-Cyclodextrins; Humans; Hydrogels; Melanoma; Paclitaxel; Polymers; Temperature

β-cyclodextrin (βCyD) derivatives equipped with aromatic appendages at the secondary face exhibit tailorable self-assembling capabilities. The aromatic modules can participate in inclusion phenomena and/or aromatic-aromatic interactions. Supramolecular species can thus form that, at their turn, can engage in further co-assembling with third components in a highly regulated manner; the design of nonviral gene delivery systems is an illustrative example. Endowing such systems with stimuli responsiveness while keeping diastereomeric purity and a low synthetic effort is a highly wanted advancement. Here, we show that an azobenzene moiety can be "clicked" to a single secondary O-2 position of βCyD affording 1,2,3-triazole-linked βCyD-azobenzene derivatives that undergo reversible light-controlled self-organization into dimers where the monomer components face their secondary rims. Their photoswitching and supramolecular properties have been thoroughly characterized by UV-vis absorption, induced circular dichroism, nuclear magnetic resonance, and computational techniques. As model processes, the formation of inclusion complexes between a water-soluble triazolylazobenzene derivative and βCyD as well as the assembly of native βCyD/βCyD-azobenzene derivative heterodimers have been investigated in parallel. The stability of the host-guest supramolecules has been challenged against the competitor guest adamantylamine and the decrease of the medium polarity using methanol-water mixtures. The collective data support that the

Topics: Azo Compounds; beta-Cyclodextrins; Dimerization; Polymers; Water

Most structural self-healing materials were developed based on either reversible supramolecular interaction or dynamic covalent bonding. It seems a good idea to incorporate self-healing properties into high-performance materials. In this study, we fabricated the alginate-based cyclodextrin and polyacrylamide azobenzene highly stretchable and tough interpenetrating composite hydrogel with self-repairing behavior under light irradiation. Initially, the alginate-based cyclodextrin and polyacrylamide azobenzene were designed and synthesized. The corresponding structural, thermal, and morphological properties of hydrogels were characterized. The reversible transformation of the sol-gel can be achieved by the irradiation upon ultraviolet light and visible light. The self-healing behavior of this composited gel is based on the host-guest interaction between cyclodextrin and azobenzene. The recovery gel elongation at 48 h healing in the dark condition was is 0.04 MPa, with an elongation of 1140 %. Therefore, this gel can achieve self-healing ability while maintaining highly stretchable and tough performance.

Topics: Acrylamides; Acrylic Resins; Alginates; Azo Compounds; beta-Cyclodextrins; Cyclodextrins; Hydrogels; Light; Materials Testing; Molecular Structure; Molecular Weight; Phase Transition; Polymers; Pressure; Spectroscopy, Fourier Transform Infrared; Stress, Mechanical; Ultraviolet Rays

Poly (ADP-ribose) polymerase-1 (PARP-1) was defined as a new biomarker, which has achieved wide attention in recent years. In this work, we designed a renewable electrochemical sensor based on host-guest recognition for the detection of PARP-1 activity. Mono-(6-Mercapto-6-deoxy)-beta-Cyclodextrin (SH-β-CD) was modified on the electrode surface to recognize the trans-azobenzene labeled dsDNA (Abz-dsDNA). In the presence of PARP-1, PAR with abundant PO

Topics: Azo Compounds; beta-Cyclodextrins; Biosensing Techniques; Cell Line; Cell Line, Tumor; DNA; Electrochemical Techniques; Electrodes; Humans; Limit of Detection; Poly (ADP-Ribose) Polymerase-1

Here, we introduce a nanophotonics concept for optically triggered activation of microglia. Specifically, we synthesized a yolk-shell structured mesoporous silica coated core-shell upconverting nanoparticles (UCNP@ysSiO

Topics: Azo Compounds; beta-Cyclodextrins; Brain; Cell Line; Doxorubicin; Humans; Indocyanine Green; Lipopolysaccharides; Microglia; Nanoparticles; Optics and Photonics

We report a supramolecular photo-responsive antibiotic (azobenzene-norfloxacin/αCD). This supramolecule exhibited a higher "on-off" ratio of antibacterial ability than azobenzene-norfloxacin alone under UV irradiation. It offers an approach to efficiently regulate the activity of antibiotics by combining the supramolecular and light-regulating strategies together.

Topics: Anti-Bacterial Agents; Azo Compounds; Bacteria; beta-Cyclodextrins; Drug Resistance, Bacterial; Isomerism; Norfloxacin; Temperature; Ultraviolet Rays

A near-infrared (NIR)-sensitive gated assembly of supramolecular conjugated unimicelles based on robust host-guest recognition between a β-cyclodextrin-grafted hyperbranched conjugated polymer and azobenzene-functionalized poly(ethylene glycol) was constructed. Utilized as a drug carrier, these unimicelles exhibited controlled drug release through the NIR-triggered photoisomerization of azobenzene in cancer cells via a two-photon excited fluorescence resonance energy transfer (TP-FRET) approach, leading to efficient cancer therapy.

Topics: Azo Compounds; beta-Cyclodextrins; Doxorubicin; Drug Carriers; Drug Liberation; Fluorescence Resonance Energy Transfer; HeLa Cells; Humans; Infrared Rays; Isomerism; Micelles; Microscopy, Confocal; Photons; Polyethylene Glycols; Polymers

Biomimetic hydrogels fabricated from biologically derived polymers, such as hyaluronic acid (HA), are useful for numerous biomedical applications. Due to the dynamic nature of biological processes, it is of great interest to synthesize hydrogels with dynamically tunable network properties where various functions (e.g., cargo delivery, mechanical signaling) can be changed over time. Among the various stimuli developed to control hydrogel properties, light stands out for its exquisite spatiotemporal control; however, most light-based chemistries are unidirectional in their ability to manipulate network changes. Here, we report a strategy to reversibly modulate HA hydrogel properties with light, using supramolecular cross-links formed via azobenzene bound to β-cyclodextrin. Upon isomerization with 365 nm or 400-500 nm light, the binding affinity between azobenzene and β-cyclodextrin changed and altered the network connectivity. The hydrogel mechanical properties depended on both the azobenzene modification and isomeric state (lower for cis state), with up to a 60% change in storage modulus with light exposure. Furthermore, the release of a fluorescently labeled protein was accelerated with light exposure under conditions that were cytocompatible to encapsulated cells. These results indicate that the developed hydrogels may be suitable for applications in which temporal regulation of material properties is important, such as drug delivery or mechanobiology studies.

Topics: Animals; Azo Compounds; beta-Cyclodextrins; Biomimetic Materials; Cattle; Delayed-Action Preparations; Drug Liberation; Fluorescein-5-isothiocyanate; Hyaluronic Acid; Hydrogels; Isomerism; Light; Materials Testing; Mice; NIH 3T3 Cells; Serum Albumin, Bovine

Here we report a facile method to construct reversible visible-light-responsive switching from antibacterial to bioadhesion by host-guest self-assembly of β-cyclodextrin (β-CD) and azobenzene functionalized polycation/polyanion. The visible-light-responsible azobenzene functionalized polycation, poly{6-[(2,6-dimethoxyphenyl)azo-4-(2',6'-dimethoxy)phenoxy]propyl dimethylaminoethyl methacrylate-random-poly(2-(N,N-dimethylaminoethyl) methacrylate) (Azo-PDMAEMA), was synthesized via quaternization reaction between 2,6,2',6'-tetramethoxy-4-(3-bromopropoxy)azobenzene (AzoOMeBr) and poly(2-(N,N-dimethylaminoethyl) methacrylate) (PDMAEMA), and the polyanion, poly{6-[(2,6-dimethoxyphenyl)azo-4-(2',6'-dimethoxy) phenoxy]hexyl acrylate-random-acrylic acid} (Azo-PAA), was synthesized via esterification reaction between 2,6,2',6'-tetramethoxy-4-(6-hydroxyhexyloxy) azobenzene (AzoOMeOH) and poly(acryloyl chloride) (PAC) and subsequent hydrolysis reactions. The switch surface could be achieved via the alternate host-guest assembly of Azo-PDMAEMA and Azo-PAA onto a β-CD-terminated substratum (Sub-CD) through visible light irradiation. The positively charged Azo-PDMAEMA with quaternary ammonium groups exhibited antimicrobial properties and few bacteria were adhered on the surface, while the negatively charged Azo-PAA with carboxyl acid groups exhibited excellent bioadhesive properties and a large number of bacteria were adhered. Interestingly, the switch between antibacterial and bioadhesive could be realized upon visible light irradiation via alternate assembly of Azo-PDMAEMA and Azo-PAA. The proposed approach to manufacturing visible-light-responsive surface with reversible and alterable biofunctionality switching between antibacterial and bioadhesive is simple and efficient, which is promising for preparation of multifunctional polymeric surfaces to encounter multifarious demands for the biomedical and biotechnological applications.. Light has attracted great attention in building biointerfaces for its precise spatiotemporal control and convenient operation. However, UV light may damage to biological samples and living tissues, which will limit its applications. This study demonstrates a novel visible-light-responsive surface fabricated through reversible assembly of azobenzene functionalized polycations/polyanions on cyclodextrin (CD)-terminated substrate by host-guest interactions between the visible-light-responsive azobenzene mAzo and CD, which has not been examined previously. It is noted that the azobenzene functionalized polycations show strong antibacterial activities, while the polyanions show excellent bioadhesive properties, as can be switched through the alternate assembly upon visible-light irradiation. This facile and versatile approach to visible-light-responsive surfaces holds great potential for switching of bioadhesion.

Topics: Azo Compounds; Bacterial Adhesion; beta-Cyclodextrins; Escherichia coli; Photochemical Processes; Polymethacrylic Acids; Staphylococcus aureus

Despite the fact that progress has been made in the application of supramolecular prodrug self-assemblies to enhance the functionality of drug-delivery systems, corresponding research on multi-responsive supramolecular prodrug self-assemblies for programmed drug delivery is still limited. In this paper, the synthesis and self-assembly behavior of supramolecular prodrug complexes (SPCs) with β-cyclodextrin-acylhydrazone-doxorubicin (β-CD-hydrazone-DOX) and the targeting of azobenzene-terminated poly[2-(dimethylamino)ethyl methacrylate] (Azo-PDMA-FA) as a building block were investigated. The obtained SPCs could also form self-assemblies on the basis of their amphiphilic nature. Next, SPC-based multi-compartment vesicles and complex micelles, which were confirmed by transmission electron microscopy and dynamic/static light scattering, were obtained with good reversibility under alternative visible light or UV irradiation. Furthermore, three-stage programmed drug-delivery behavior was observed from dual-responsive SPC-based self-assemblies by utilizing UV and pH stimuli. Specifically, the SPCs first self-assembled into multicompartmental vesicles, which was accompanied by a slow release of DOX. Next, UV-light irradiation induced the dissociation of β-CD/Azo, which led to morphology transition and a slight increase in the rate of release of DOX. Upon transferring the self-assemblies to phosphate-buffer solution (pH 5.0), the release rates increased notably as a result of the broken acylhydrazone bond. Finally, basic cell experiments further demonstrated that the SPC-based self-assemblies could be internalized into cancer cells, which suggests their promise for applications in cancer therapy.

Topics: Antibiotics, Antineoplastic; Azo Compounds; beta-Cyclodextrins; Cell Survival; Delayed-Action Preparations; Doxorubicin; Drug Delivery Systems; Drug Liberation; Humans; Hydrogen-Ion Concentration; MCF-7 Cells; Neoplasms; Prodrugs; Ultraviolet Rays

Contrast agents for bioimaging suffer from low accumulation at lesion area and high uptake in the reticuloendothelial system (RES). Assembly of nanoparticles in vivo improves their enrichment at tumors and inflamed areas. However, uncontrollable assembly also occurs at the liver and spleen owing to the uptake of nanoparticles by the RES. This is known to probably cause a higher bioimaging background and more severe health hazards, which may hamper the clinical application. Herein, a new near-infrared (NIR)-controlled supramolecular engineering strategy is developed for in vivo assembly and disassembly between lanthanide upconversion nanoparticles and second near-infrared window (NIR-II, 1000-1700 nm) nanoprobes to realize precision bioimaging of tumors. A supramolecular structure is designed to realize assembly via host-guest interactions of azobenzene and β-cyclodextrin to enhance the retention of NIR-II nanoprobes in the tumor area. Meanwhile NIR-laser-controllable nanoprobes disassembly brings about a reduction in the bioimaging background as well as acceleration of their RES clearance rate. This strategy may also be used in other nano-to-micro-scale contrast agents to improve bioimaging signal-to-noise ratio and reduce long-term cytotoxicity.

Topics: Animals; Azo Compounds; beta-Cyclodextrins; Cell Line, Tumor; Humans; Infrared Rays; Lanthanoid Series Elements; Lasers; Liver; Mice, Nude; Nanoparticles; Neoplasm Transplantation; Neoplasms, Experimental; Optical Imaging

The synthesis and characterization of a linear supramolecular polymer formed by dual host-guest recognitions is presented. The polymer linked by the orthogonal interactions of azobenzene with β-cyclodextrin and methyl viologen with sulfonatocalix[4]arene is constructed, and the morphology change along with the formation and vanishment of host-guest interaction is investigated. The reversible disassembly-reassembly of the polymer induced by light and the redox process are monitored by UV-vis and cyclic voltammetry, respectively. The interesting morphology differences between the monomer guest (G), supramolecular polymer (P), and light dissembled product pseudorotaxane (D1) are observed and analyzed. G conducts self-assembly into a short rod with average width of 83 nm due to the molecular amphipathy and π-π interaction between naphthalene nucleuses, while P exhibits 20 nm wide line morphology. Irradiating P with 365 nm light, the corresponding aggregation D1 shows as 35 nm wide short rod.

Topics: Azo Compounds; beta-Cyclodextrins; Macromolecular Substances; Oxidation-Reduction; Paraquat; Polymers; Rotaxanes

Red-light-responsive supramolecular valves constructed by tetra-ortho-methoxy-substituted azobenzene (mAzo) and β-cyclodextrin (β-CD) were used to control drug release from mesoporous silica nanoparticles (MSNs). Doxorubicin (DOX) was used as a model drug and loaded into nanopores of mAzo modified MSNs. β-CD formed supramolecular valves with mAzo by host-guest interaction and closed the nanopores. Red light was able to open the supramolecular valves and induce DOX release even in deep tissue.

Topics: Azo Compounds; beta-Cyclodextrins; Delayed-Action Preparations; Doxorubicin; Drug Compounding; Drug Liberation; Hydrogen-Ion Concentration; Light; Nanoparticles; Nanopores; Porosity; Silicon Dioxide

This article describes the supramolecular host-guest polycationic gene delivery system based on poly(β-cyclodextrin) (PCD) and azobenzene-terminated polycations. The azobenzene-terminated linear (Az-LPDM) and branched (Az-BPDM) cationic polymers were synthesized by atom transfer radical polymerization (ATRP) of 2-dimethylamino ethyl methacrylate (DMAEMA). The formation and photosensitive behavior of the supramolecular polycations of azobenzene-terminated polycations Az-LPDM and Az-BPDM with PCD were confirmed by UV-vis and NMR analysis. The supramolecular PCD/Az-BPDM/DNA and PCD/Az-LPDM/DNA polyplexes showed smaller size and were less positive than those of their corresponding polyplexes without PCD. Moreover, the UV irradiation may promote release of DNA from the photosensitive supramolecular polyplexes due to dissociation of supramoelcular polyplexes. In vitro experiments revealed that the photosensitive supramolecular polycationic polyplexes (PCD/Az-LPDM/DNA and PCD/Az-BPDM/DNA) exhibited enhancement of cellular uptake, higher transfection efficiency, and lower cytoxicity compared to the azobenzene-terminated polycation/DNA polyplexes in the absence of PCD. Branched polycationic polyplexes showed higher transfection efficiency than its linear polycationic polyplexes. Furthermore, after UV irradiation, the transfection efficiency of photosensitive supramolecular polyplexes was improved resulting from more DNAs delivered and released inside of the cell nuclei. Thus this photoresponsive supramolecular host-guest system containing azobenzene-terminated branched cationic polymers and PCD is a promising gene vector.

Topics: Azo Compounds; beta-Cyclodextrins; Cell Nucleus; DNA; Gene Transfer Techniques; Genetic Vectors; HEK293 Cells; HeLa Cells; Hep G2 Cells; Humans; Polyamines; Polyelectrolytes; Polymers; Propylene Glycols; Transfection

Manipulation of cell-cell interactions has potential applications in basic research and cell-based therapy. Herein, using a combination of metabolic glycan labelling and bio-orthogonal click reaction, we engineer cell membranes with β-cyclodextrin and subsequently manipulate cell behaviours via photo-responsive host-guest recognition. With this methodology, we demonstrate reversible manipulation of cell assembly and disassembly. The method enables light-controllable reversible assembly of cell-cell adhesion, in contrast with previously reported irreversible effects, in which altered structure could not be reused. We also illustrate the utility of the method by designing a cell-based therapy. Peripheral blood mononuclear cells modified with aptamer are effectively redirected towards target cells, resulting in enhanced cell apoptosis. Our approach allows precise control of reversible cell-cell interactions and we expect that it will promote further developments of cell-based therapy.

Topics: Apoptosis; Azo Compounds; beta-Cyclodextrins; Biomedical Engineering; Breast Neoplasms; Cell Adhesion; Cell Communication; Cell Membrane; Female; Flow Cytometry; HeLa Cells; Humans; Leukocytes, Mononuclear; Ligands; MCF-7 Cells; Polymers; Polysaccharides; Spatio-Temporal Analysis

Polymeric vesicles constructed from cyclodextrin- and azobenzene-grafted poly(glycidyl methacrylate)s showed excellent stability owing to the multiple host-guest complexation. Upon culturing in Na2S2O4-contained buffer solution, cargo-loaded vesicles disassembled, for potential applications in colon-specific drug delivery.

Topics: Azo Compounds; beta-Cyclodextrins; Biocompatible Materials; Cell Line, Tumor; Cell Survival; Colonic Neoplasms; Drug Delivery Systems; Humans; Polymethacrylic Acids

A photochemically interconvertible supramolecular nanotube-nanoparticle system was constructed through secondary assembling of self-aggregates of amphiphilic porphyrin derivatives mediated by trans- and cis-azobenzene-bridged bis(permethyl-β-cyclodextrin). Significantly, these nanotubes and nanoparticles were able to interconvert upon irradiation at different wavelengths, and this photocontrolled morphological conversion is reversible and recyclable for tens of times, which will provide a feasible and convenient way to construct the ordered nanostructure with various morphologies that can be smartly controlled by the environmentally benign external stimulus.

Topics: Azo Compounds; beta-Cyclodextrins; Circular Dichroism; Dimerization; Isomerism; Light; Nanoparticles; Nanotubes; Spectrometry, Fluorescence

We report a novel red-light-responsive supramolecule. The tetra-ortho-methoxy-substituted azobenzene (mAzo) and β-cyclodextrin (β-CD) spontaneously formed a supramolecular complex. The substituted methoxy groups shifted the responsive wavelength of the azo group to the red light region, which is in the therapeutic window and desirable for biomedical applications. Red light induced the isomerization of mAzo and the disassembly of the mAzo/β-CD supramolecular complex. We synthesized a mAzo-functionalized polymer and a β-CD-functionalized polymer. Mixing the two polymers in an aqueous solution generated a supramolecular hydrogel. Red light irradiation induced a gel-to-sol transition as a result of the disassembly of the mAzo/β-CD complexes. Proteins were loaded in the hydrogel. Red light could control protein release from the hydrogel in tissue due to its deep penetration depth in tissue. We envision the use of red-light-responsive supramolecules for deep-tissue biomedical applications.

Topics: Animals; Azo Compounds; beta-Cyclodextrins; Cattle; Delayed-Action Preparations; Hydrogel, Polyethylene Glycol Dimethacrylate; Isomerism; Light; Serum Albumin, Bovine

Three types of azobenzene-based telechelic guest polymers, PEG-azo, azo-PEG-azo, and PEG-azo4, were synthesized by a facile method. Subsequently, a series supramolecular amphiphiles with three distinct topological structures (hemitelechelic, ditelechelic, and quadritelechelic) were constructed through coupling with host polymer β-cyclodextrin-poly(l-lactide) (β-CD-PLLA) by combined host-guest complexation. Research on the self-assembly behavior of these amphiphiles demonstrated that the variation in self-assembly was tuned by the synergistic interaction of hydrophilicity and the curvature of the polymer chains, and very importantly, the topological structure of amphiphiles demonstrated effective control of the self-assembly behavior.

Topics: Azo Compounds; beta-Cyclodextrins; Hydrophobic and Hydrophilic Interactions; Magnetic Resonance Spectroscopy; Microscopy, Electron, Transmission; Models, Molecular; Molecular Structure; Polyethylene Glycols; Polymers

This article describes light-responsive vesicles that can release their contents in response to a light-sensitive molecular trigger. To this end, liposomes were equipped with amphiphilic β-cyclodextrin that was covalently labeled with azobenzene. Using dye encapsulation and confocal laser scanning microscopy, we show that the permeability of these vesicles strongly increases upon UV irradiation (λ = 350 nm) with concomitant isomerization of apolar trans-azobenzene to polar cis-azobenzene on the liposome surface.

Topics: Azo Compounds; beta-Cyclodextrins; Liposomes; Models, Molecular; Molecular Structure; Particle Size; Photochemical Processes; Surface Properties; Surface-Active Agents; Ultraviolet Rays

Chemical, photochemical and electrical stimuli are versatile possibilities to exert external control on self-assembled materials. Here, a trifunctional molecule that switches between an "adhesive" and a "non-adhesive" state in response to metal ions, or light, or oxidation is presented. To this end, an azobenzene-ferrocene conjugate with a flexible N,N'-bis(3-aminopropyl)ethylenediamine spacer was designed as a multistimuli-responsive guest molecule that can form inclusion complexes with β-cyclodextrin. In the absence of any stimulus the guest molecule induces reversible aggregation of host vesicles composed of amphiphilic β-cyclodextrin due to the formation of intervesicular inclusion complexes. In this case, the guest molecule operates as a noncovalent cross-linker for the host vesicles. In response to any of three external stimuli (metal ions, UV irradiation, or oxidation), the conformation of the guest molecule changes and its affinity for the host vesicles is strongly reduced, which results in the dissociation of intervesicular complexes. Upon elimination or reversal of the stimuli (sequestration of metal ion, visible irradiation, or reduction) the affinity of the guest molecules for the host vesicles is restored. The reversible cross-linking and aggregation of the cyclodextrin vesicles in dilute aqueous solution was confirmed by isothermal titration calorimetry (ITC), optical density measurements at 600 nm (OD600 ), dynamic light scattering (DLS), ζ-potential measurements and cyclic voltammetry (CV). To the best of our knowledge, a dynamic supramolecular system based on a molecular switch that responds orthogonally to three different stimuli is unprecedented.

Topics: Azo Compounds; beta-Cyclodextrins; Delayed-Action Preparations; Ethylenediamines; Ferrous Compounds; Ions; Light; Metallocenes; Metals; Molecular Conformation; Oxidation-Reduction

Topics: Azo Compounds; beta-Cyclodextrins; Camptothecin; Drug Delivery Systems; Fluorescence; Humans; Imaging, Three-Dimensional; MCF-7 Cells; Nanoparticles; Photons; Porosity; Propidium; Silicon Dioxide

In this communication we report for the first time the use of azobenzene modified glycoconjugates to establish optical control over bioactive ligands at a supramolecular β-cyclodextrin (β-CD) surface. Several studies were conducted to investigate the photoresponsive immobilization of proteins and bacteria on these supramolecular surfaces.

Topics: Azo Compounds; beta-Cyclodextrins; Immobilized Proteins; Ligands; Macrocyclic Compounds; Microscopy, Fluorescence; Quartz Crystal Microbalance Techniques; Surface Properties

The synthesis, supramolecular complexation, and switching of new bifunctional azobenzene-oligoglycerol conjugates in different environments is reported. Through the formation of host-guest complexes with surface immobilized β-cyclodextrin receptors, the bifunctional switches were coupled to gold surfaces. The isomerization of the amphiphilic azobenzene derivatives was examined in solution, on gold nanoparticles, and on planar gold surfaces. The wettability of functionalized gold surfaces can be reversibly switched under light-illumination with two different wavelengths. Besides the photoisomerization processes and concomitant effects on functionality, the thermal cis to trans isomerization of the conjugates and their complexes was monitored. Thermal half-lives of the cis isomers were calculated for different environments. Surprisingly, the half-lives on gold nanoparticles were significantly smaller compared to planar gold surfaces.

Topics: Azo Compounds; beta-Cyclodextrins; Glycerol; Gold; Half-Life; Metal Nanoparticles

A novel surface-modification strategy has been developed for the construction of a photocontrolled silicon wafer surface with switchable wettability based on host-guest inclusion complexation. The silicon wafer was first modified by guest molecule azobenzene (Azo) via a silanization reaction. Subsequently, a series of polymers with different polarities were attached to host molecule β-cyclodextrin (β-CD) to prepare β-CD-containing hemitelechelic polymers via click chemistry. Finally, a photocontrolled silicon wafer surface modified with polymers was fabricated by inclusion complexation between β-CD and Azo, and the surface properties of the substrate are dependent on the polymers we used. The elemental composition, surface morphology, and hydrophilic/hydrophobic property of the modified surfaces were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscope, and contact angle measurements, respectively. The antifouling property of the PEG-functionalized surface was evaluated by a protein adsorption assay using bovine serum albumin, which was also characterized by XPS. The results demonstrate that the surface modified with PEG possesses good protein-resistant properties.

Topics: Animals; Azo Compounds; beta-Cyclodextrins; Cattle; Click Chemistry; Particle Size; Photochemical Processes; Serum Albumin, Bovine; Silicon; Surface Properties; Wettability

A star polymer, β-cyclodextrin-poly(l-lactide) (β-CD-PLLA), and a linear polymer, azobenzene-poly(ethylene glycol) (Azo-PEG), could self-assemble into a supramolecular amphiphilic copolymer (β-CD-PLLA@Azo-PEG) based on the host-guest interaction between β-CD and azobenzene moieties. This linear-star supramolecular amphiphilic copolymer further self-assembled into a variety of morphologies, including sphere-like micelle, carambola-like micelle, naan-like micelle, shuttle-like lamellae, tube-like fiber, and random curled-up lamellae, by tuning the length of hydrophilic or hydrophobic chains. The variation of morphology was closely related to the topological structure and block ratio of the supramolecular amphiphiles. These self-assembly structures could disassemble upon an ultraviolet (UV) light irradiation.

Topics: Azo Compounds; beta-Cyclodextrins; Hydrophobic and Hydrophilic Interactions; Models, Molecular; Molecular Conformation; Molecular Weight; Polyesters; Polyethylene Glycols

We demonstrate a supramolecular approach to the fabrication of self-powered micropumps based on "host-guest" molecular recognition between α- and β-cyclodextrin and trans-azobenzene. Both hydrogels and surface coatings based on host-guest partners were used as scaffolds to devise the micropumps. These soft micropumps are dual stimuli-responsive and can be actuated either by light or by introducing guest molecules. Furthermore, the micropumps can be recharged through reversible host-guest interaction.

Topics: Azo Compounds; beta-Cyclodextrins; Delayed-Action Preparations; Equipment Design; Equipment Failure Analysis; Infusion Pumps, Implantable; Materials Testing; Microfluidics; Miniaturization; Nanocapsules; Stress, Mechanical

The formation of effective and precise linkages in bottom-up or top-down processes is important for the development of self-assembled materials. Self-assembly through molecular recognition events is a powerful tool for producing functionalized materials. Photoresponsive molecular recognition systems can permit the creation of photoregulated self-assembled macroscopic objects. Here we demonstrate that macroscopic gel assembly can be highly regulated through photoisomerization of an azobenzene moiety that interacts differently with two host molecules. A photoregulated gel assembly system is developed using polyacrylamide-based hydrogels functionalized with azobenzene (guest) or cyclodextrin (host) moieties. Reversible adhesion and dissociation of the host gel from the guest gel may be controlled by photoirradiation. The differential affinities of α-cyclodextrin or β-cyclodextrin for the trans-azobenzene and cis-azobenzene are employed in the construction of a photoswitchable gel assembly system.

Topics: alpha-Cyclodextrins; Azo Compounds; beta-Cyclodextrins; Circular Dichroism; Dimethyl Sulfoxide; Gels; Hydrogels; Kinetics; Light; Magnetic Resonance Spectroscopy; Materials Testing; Models, Chemical; Nitriles; Photochemistry; Polymers; Spectrophotometry, Infrared; Ultraviolet Rays; Water

A photoresponsive microgel is designed by the combination of a noncovalent assembly strategy with a covalent cross-linking method. End-functionalized poly(ethylene glycol) with azobenzene [(PEG-(Azo)(2))] was mixed with acrylate-modified β-CD (β-CD-MAA) to form photoresponsive inclusion complex through host-guest interaction. The above photoresponsive complex was cross-linked by thiol-functionalized PEG (PEG-dithiol) via Michael addition click reaction. The photoreversibility of resulted microgel was studied by TEM, UV-Vis spectroscopy, and (1)H NMR measurements. The characterization results indicated that the reversible size changes of the microgel could be achieved by alternative UV-Vis irradiations with good repeatability.

Topics: Azo Compounds; beta-Cyclodextrins; Gels; Light; Polyethylene Glycols; Sulfhydryl Compounds; Ultraviolet Rays

Hollow mesoporous silica nanoparticles (HMSs) were modified by β-cyclodextrin via a "click" reaction, an amphiphilic copolymer with a trans-azobenzene structure was then assembled onto β-cyclodextrin to cover the surface of the HMSs. The prepared nanocomposites can release drugs in a "release-stop-release" manner by converting light irradiation.

Topics: Azo Compounds; beta-Cyclodextrins; Delayed-Action Preparations; Light; Models, Molecular; Nanoparticles; Porosity; Silicon Dioxide; Surface-Active Agents

PEG-detachable polyplexes were constructed for the first time via host-guest interactions between β-cyclodextrin and azobenzene. The polyplexes had excellent colloidal stability and competition stability. Moreover, the intracellular light-regulated dePEGylation facilitated DNA release and nuclear entry, thus resulting in efficient transfection.

Topics: Azo Compounds; beta-Cyclodextrins; DNA; Drug Carriers; HEK293 Cells; Hep G2 Cells; Humans; Light; Polyethylene Glycols; Transfection

Topics: Acrylic Resins; Antineoplastic Agents; Azo Compounds; beta-Cyclodextrins; Cell Line, Tumor; Doxorubicin; Drug Carriers; Endocytosis; Humans; Ultraviolet Rays

A competitive photoresponsive supramolecular system is formed in a dilute aqueous solution of three components: vesicles of amphiphilic α-cyclodextrin host 1a, divalent p-methylphenyl guest 2 or divalent p-methylbenzamide guest 3, and photoresponsive azobenzene monovalent guest 5. Guests 2 and 3 form weak inclusion complexes with 1a (K(a)≈10(2) M(-1)), whereas azobenzene guest 5 forms a strong inclusion complex (K(a)≈10(4) M(-1)), provided it is in the trans state. The aggregation and adhesion of vesicles of host 1a is mediated by guest 2 (or 3) due to the formation of multiple intervesicular noncovalent links, as confirmed by using isothermal titration calorimetry (ITC), optical density measurements at 600 nm (OD600), dynamic light scattering (DLS), and cryogenic transmission electron microscopy (cryo-TEM). The addition of excess monovalent guest trans-5 to vesicles of 1a aggregated by divalent guest 2 (or 3) causes the dispersion of vesicles of 1a because trans-5 displaces 2 (as well as 3) from the vesicle surface. Upon UV irradiation of a dilute ternary mixture of vesicles of 1a, guest 2 (or 3), and competitor trans-5, compound trans-5 isomerizes to cis-5, and renewed aggregation of vesicles of 1a by guest 2 (or 3) occurs because 2 (as well as 3) displaces cis-5 from the vesicle surface. Subsequent visible irradiation causes the redispersion of vesicles of 1a because cis-5 reisomerizes into trans-5, which again displaces guest 2 (or 3) from the vesicle surface. In this way, the competitive photoresponsive aggregation and dispersion of vesicles can be repeated for several cycles.

Topics: alpha-Cyclodextrins; Azo Compounds; beta-Cyclodextrins; Molecular Structure; Photochemical Processes; Stereoisomerism; Water

Herein is presented a strategy for the enantioseparation of amino acids enantiomers using β-CD functionalized Fe(3)O(4) nanospheres, in which β-CD provides the ability to chirally discriminate amino acids enantiomers, while the Fe(3)O(4) nanoparticles serve as magnetic separators.

Topics: Absorption; Amino Acids; Azo Compounds; beta-Cyclodextrins; Chemical Fractionation; Magnetite Nanoparticles; Stereoisomerism

Topics: Artificial Cells; Azo Compounds; beta-Cyclodextrins; Biomimetic Materials; Cell Aggregation; Light; Models, Chemical; Polymers

On the basis of the host-guest interactions between azobenzenes and cyclodextrins, a new strategy for the preparation of a dually functionalized poly(dimethylsiloxane) (PDMS) surface was investigated using surface-initiated atom-transfer radical polymerization (SI-ATRP) and click chemistry. The PDMS substrates were first oxidized in a H(2)SO(4)/H(2)O(2) solution to transform the surface Si-CH(3) groups into Si-OH groups. Then, the SI-ATRP initiator 3-(2-bromoisobutyramido)propyl(trime-thoxy)silane was grafted onto the substrates through a silanization reaction. Sequentially, the poly(ethylene glycol) (PEG) units were introduced onto the PDMS-Br surfaces via SI-ATRP reaction using oligo(ethylene glycol) methacrylate. Afterward, the bromide groups on the surface were converted to azido groups via nucleophilic substitution reaction with NaN(3). Finally, the azido-grafted PDMS surfaces were subjected to a click reaction with alkynyl and PEG-modified β-cyclodextrins, resulting in the grafting of cyclodextrins onto the PDMS surfaces. The composition and chemical state of the modified surfaces were characterized via X-ray photoelectron spectroscopy, and the stability and dynamic characteristics of the cyclodextrin-modified PDMS substrates were investigated via attenuated total reflection-Fourier transform infrared spectroscopy and temporal contact angle experiments. The surface morphology of the modified PDMS surfaces was characterized through imaging using a multimode atomic force microscope. A protein adsorption assay using Alexa Fluor594-labeled bovine serum albumin, Alexa Fluor594-labeled chicken egg albumin, and FITC-labeled lysozyme shows that the prepared PDMS surfaces possess good protein-repelling properties. On-surface studies on the interactions between azobenzenes and the cyclodextrin-modified surfaces reveal that the reversible binding of azobenzene to the cyclodextrin-modified PDMS surfaces and its subsequent release can be reversibly controlled using UV irradiation. Sandwich fluoroimmunoassay of the cardiac markers myoglobin and fatty acid-binding protein demonstrates that the cyclodextrin-modified PDMS surfaces can be repeatedly utilized in disease biomarker analysis.

Topics: Animals; Azo Compounds; beta-Cyclodextrins; Biomarkers; Cardiovascular Diseases; Cattle; Dimethylpolysiloxanes; Fatty Acid-Binding Proteins; Fluoroimmunoassay; Humans; Muramidase; Myoglobin; Organic Chemicals; Photoelectron Spectroscopy; Polyethylene Glycols; Serum Albumin, Bovine; Surface Properties

Topics: Animals; Azo Compounds; beta-Cyclodextrins; Chemistry, Pharmaceutical; Cross-Linking Reagents; Delayed-Action Preparations; Dextrans; Drug Carriers; Drug Compounding; Green Fluorescent Proteins; Hydrogels; Hydrophobic and Hydrophilic Interactions; Kinetics; Maleimides; Pharmaceutical Preparations; Photochemistry; Polymers; Solubility; Technology, Pharmaceutical; Ultraviolet Rays; Zebrafish

A new unsymmetric guest compound comprising ferrocene and azobenzene moieties was synthesized and can form a host-guest system with beta-cyclodextrin (beta-CD) complexed. The complexation stoichiometries and sites of the ensembles can be selectively controlled by reversible redox and photoirradiation.

Topics: Azo Compounds; beta-Cyclodextrins; Circular Dichroism; Ferrous Compounds; Metallocenes; Oxidation-Reduction; Photochemical Processes; Spectrophotometry, Ultraviolet

Mesoporous silica (MCM-41) nanoparticles modified by azobenzene derivatives, capable of storing small molecules and releasing them following light irradiation, have been fabricated and characterized. In the presence of the beta-cyclodextrin and/or pyrene-modified beta-cyclodextrin rings, the beta-cyclodextrin and/or pyrene-modified beta-cyclodextrin rings will thread onto the azobenzene-containing stalks and bind to trans-azobenzene units to form the pseudorotaxanes, thus sealing the nanopores and stopping release of the cargo. Upon irradiation, the isomerization of trans-to-cis azobenzene units leads to the dissociation of the beta-cyclodextrin and/or pyrene-modified beta-cyclodextrin rings from the stalks, thus opening the gates to the nanopores and releasing the cargo.

Topics: Azo Compounds; beta-Cyclodextrins; Delayed-Action Preparations; Light; Luminescent Measurements; Models, Molecular; Nanoparticles; Photochemical Processes; Pyrenes; Silicon Dioxide

A gated synthetic ion channel with beta-cyclodextrin as the pore and azobenzene as the gate is reported. Irradiation converts a tethered trans-azobenzene to cis-azobenzene which likely transforms the channel from a self-inclusion complex to a dissociated structure. This transformation results in an increase in anion transport and a decrease in cation transport across a phospholipid vesicle membrane.

Topics: Azo Compounds; beta-Cyclodextrins; Ion Channel Gating; Ion Channels; Phospholipids; Photochemistry; Ultraviolet Rays

To study environment-friendly determination of azobenzene in trace amounts using beta-cyclodextrin (beta-CD)-modified Au electrode.. beta-CD-modified Au electrode was fabricated with a two-step approach, and then a gold electrode modified with beta-CD was used to detect azobenzene by employing Osteryoung square wave voltammetry.. The modified electrode could detect azobenzene, showing a good linearity between the electrochemical current and concentration.. Although the electrochemical current is related with concentration, the detection limit is around 1.0 x 10(-10) mol/L. This study may provide a new environment-friendly approach for monitoring water quality.

Topics: Azo Compounds; beta-Cyclodextrins; Electrochemistry; Electrodes; Environmental Monitoring; Gold; Reproducibility of Results; Sensitivity and Specificity; Water Supply

Photoresponsive poly(N,N-dimethylacrylamide-co-methacryloyloxyazobenzene) (DMA-MOAB) and temperature-responsive Pluronic F127 (F127) copolymers were blended to obtain systems responsive to both stimuli that are potentially useful for pharmaceutical formulations. The random DMA-MOAB copolymer undergoes a trans to cis isomerization when irradiated by 366 nm light, which modifies both the air-water interfacial behavior and the self-associative properties of the copolymer. Under dark conditions the azobenzene groups of DMA-MOAB in the trans conformation self-associate and the interactions with F127 are minimal. The cis conformation of the azobenzene groups of the DMA-MOAB copolymer is relatively more hydrophilic than the trans conformation, which causes the copolymer micelles to dissociate upon irradiation, allowing the unimers to form mixed micelles with the F127. This causes the sol-gel transition temperature of the DMA-MOAB:F127 blend to be 10 degrees C lower upon irradiation at 366 nm compared to that for the dark conditions. It has been found that F127 (10-12 wt %):DMA-MOAB (5-6 wt %) aqueous solutions have at body temperature a low viscosity when equilibrated in the dark and undergo a sol-gel transition when irradiated. Such a transition strongly alters the diffusion of solutes such as methylene blue within the solutions. This light-induced interaction between the azobenzene moieties of DMA-MOAB and F127 micelles disappears when hydroxypropyl-beta-cyclodextrin (HPbetaCD) is added to the medium. In the presence of HPbetaCD, the cis-azobenzene groups are hosted in the cyclodextrin cavities and the mixed micelles are not formed. Therefore, changes in HPbetaCD concentration could be used to modulate the response of the copolymer blends to light.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Acrylic Resins; Air; Azo Compounds; beta-Cyclodextrins; Light; Methacrylates; Micelles; Pharmaceutical Preparations; Phase Transition; Poloxamer; Solutions; Spectrophotometry, Ultraviolet; Stereoisomerism; Temperature; Time Factors; Water

Topics: Azo Compounds; beta-Cyclodextrins; Carbon Dioxide; Drug Design; Solvents