Photo‐Switchable Behavior of Azobenzene‐Dye‐Modified Silica Nanoparticles and Their Assembly With Cyclodextrin Derivatives

Isenbügel, Kathrin; Gehrke, Yvonne; Ritter, Helmut

doi:10.1002/macp.201100601

Cited by 11 publications

(15 citation statements)

References 21 publications

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“…3E). 46,[49][50][51] Another frequently used host is cucurbit [8]uril (CB [8], Fig. 3F), which is a ring-like molecule able to form a heteroternary complex with an electron-deficient first guest and an electron-rich second guest.…”

Section: Host-guest Mediated Colloidal Assemblymentioning

confidence: 99%

“…This approach has been implemented for the light-induced reversible association of b-CDand azobenzene-functionalised silica particles of d E 10 nm into disordered structures upon irradiation with l = 365 nm. 49 Although evidently promising as a molecular tool to guide colloidal assembly, the limited selectivity of host-guest interactions prohibits precise control in multi-component mixtures. To self-organise particles in these materials with high fidelity into single-species (or conversely mixed) clusters requires instead tuneable specific interactions.…”

Section: Host-guest Mediated Colloidal Assemblymentioning

confidence: 99%

“…The utility of photoresponsive molecules for light-controlled colloidal assembly has been demonstrated in both organic and aqueous solvents using either surface-tethering to synthesise photoresponsive particles, or instead, direct dissolution to prepare photoresponsive media. 93,154 Examples in aqueous media include host-guest mediated formation of silica supraparticles via hydrophobic, surface-grafted azobenzene molecules, 49 and dissipative assembly of 6-mercaptohexanoic acid functionalised AuNPs in the presence of water-soluble photoacids. 155 These photoacids release protons upon irradiation with visible light, which are recaptured in the dark.…”

Section: Light-controlled Toggling Of Surface Forcesmentioning

confidence: 99%

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Molecular control over colloidal assembly

Gerth

Voets

2017

Chem. Commun.

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Contemporary chemical and material engineering often takes inspiration from nature, targeting for example strong yet light materials and materials composed of highly ordered domains at multiple different lengthscales for fundamental science and applications in e.g. sensing, catalysis, coating technology, and delivery. The preparation of such hierarchically structured functional materials through guided bottom-up assembly of synthetic building blocks requires a high level of control over their synthesis, interactions and assembly pathways. In this perspective we showcase recent work demonstrating how molecular control can be exploited to direct colloidal assembly into responsive materials with mechanical, optical or electrical properties that can be adjusted post-synthesis with external cues.

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Section: Host-guest Mediated Colloidal Assemblymentioning

confidence: 99%

Section: Host-guest Mediated Colloidal Assemblymentioning

confidence: 99%

Section: Light-controlled Toggling Of Surface Forcesmentioning

confidence: 99%

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Molecular control over colloidal assembly

Gerth

Voets

2017

Chem. Commun.

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“…Disadvantageously, however the induced dipole-dipole interactions are not specific. Azobenzene-mediated colloidal assembly can however be made selective, when used in combination with cyclodextrins 15 , 35 , 36 .…”

Section: Introductionmentioning

confidence: 99%

Light induced assembly and self-sorting of silica microparticles

Vilanova

Feijter

Teunissen

et al. 2018

Sci Rep

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To tailor the properties of colloidal materials, precise control over the self-assembly of their constituents is a prerequisite. Here, we govern the assembly of silica particles by functionalization with supramolecular moieties which interact with each other via directional and reversible hydrogen bonding. Through a generally applicable synthesis protocol, two different types of self-complementary hydrogen bonding moieties, BTA-and UPy-derivatives, are anchored to silica particles. Their selfassembly is initiated by the UV-induced removal of a photolabile protecting group, allowing the formation of hydrogen bonds between tethered molecules. The light-induced assembly of BTA-and UPy-decorated colloids in single-component dispersions and colloidal self-sorting in mixed dispersions is studied. Furthermore, we demonstrate that UPy-colloids can dissasemble upon addition of traces of a competitive binder (NaPy). This work provides further insight into the utility of supramolecular handles to orchestrate the assembly of micron-sized colloids via non-oligonucleotide hydrogen-bonding units.The ability to control molecular self-assembly via non-covalent interactions is an emerging bottom-up strategy to create complex metamaterials. In turn, well-defined molecular recognition can be used as a powerful tool to direct the assembly of micron-sized 1-3 colloids or even macroscopic objects 4 and create larger aggregated structures with emergent optical 5-7 , mechanical 8 or catalytic properties 9,10 . Molecular control over the assembly of micron-sized particles can be realized through particle surface-grafting of molecules exhibiting dipole-dipole 11,12 , metal coordination 13 , hydrophobic forces 14,15 and/or hydrogen bonding (H-bonding) [16][17][18] . Ideally, the tethered motifs should be easy to synthesize, responsive, externally addressable and provide directional, dynamic and specific bonding within the assemblies. Moreover, to facilitate colloidal assembly, a precise control between the interplay of non-specific surface forces (attractive and/or repulsive) is crucial 19 .A popular strategy in the field is the functionalization of colloids with complementary DNA strands 20,21 . Great advances in insight and structural complexity have been achieved in the last 20 years, enabling the assembly of colloids into both disordered and exotic ordered states 22,23 , in a reversible 22,24,25 or irreversible 26 manner and at the nano-27,28 and mesoscale 25,29 . Notwithstanding, DNA-technology has its limitations, such as high cost and restricted environmental conditions 27,30 because the strands only assemble in water at sufficiently high ionic strengths and at low temperature, precluding material synthesis and processing from organic solvents. Furthermore, up to now, only temperature has been used as external trigger of assembly, while recent advances towards light sensitive DNA-strands can be utilized in future to develop dual-responsive systems sensitive to both temperature and light 31 . A promising alternative strategy exploits...

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“…The supramolecular system based on host-guest interactions have seen a significant breakthrough, which was shown to be partially successful for drug release [4], biological sensors [5], optically controlled catalytic system [6], molecular shuttles [7], hydrogels [8], and micelles and vesicles [9]. Particularly, photo-controlled molecular recognition of cyclodextrin (CD) with Azobenzenes (Azo) has been widely used for host-guest inclusion compound.…”

Section: Introductionmentioning

confidence: 99%

Light-controlled drug releasing polymer films combining LbL self-assembly and host-guest interactions

Li¹,

He²,

Wang³

et al. 2014

Express Polym. Lett.

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Abstract. By combining LbL (layer-by-layer) self-assembly approach and host-guest interactions, a unique multilayer film was constructed and employed for a light-controlled drug release system. The drug molecules can be loaded and released into the resulting polyelectrolyte multilayers containing azobenzene (Azo) function groups by using the irradiation of visible light and UV light alternately. The photo-sensitivity of the multilayer films was studied through UV-vis spectrum, fluorescence spectrum and confocal microscopy. The target molecules could be rapidly released from the multilayers after 300 W UV light irradiation for 20 minutes. Moreover, they could be readsorbed into the multilayers uniformly when illuminated under the 300 W visible light for 10 minutes confirmed by the observation of confocal microscopy, and the readsorption ratio exceeds 100% evidenced from UV-vis spectroscopy. After several cycles of the above-mentioned process, the multilayer films show good fatigue resistance. All these results indicate the photo-sensitivity and high-efficiency of the multilayer films, which have great potential in controlled drug delivery platform and biomedical applications. : coatings, layer-by-layer, host-guest interactions, light response, drug delivery eXPRESS Polymer Letters Vol.8, No.3 (2014) 143-153 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2014.18 * Corresponding author, e-mail: softmatter@163.com © BME-PT nating irradiation with UV and Vis light allows for reversible sliding of !-CD along the surfactant, leading to the formation of rotaxane-like vesicles. Based on this principle, light-responsive host-guest assembly and disassembly between Azo and CD hold great potential to design a reversible drug delivery profile [16,17]. Layer-by-layer (LbL) self-assembly approach is particularly well-suited for fabricating functional multilayer thin films with ultrafine nanometer-scale structure for use as drug delivery vehicles [18][19][20][21]. The traditional means of loading drugs on layers of LbL platform always uses physical adsorption or chemical bonding. However, these methods of loading drugs have a common drawback: drug loading and release is irreversible. This is a critical problem in LbL multilayers for drug delivery. Therefore, it's desired to devise a reversible LbL-based system to manipulate the drug release in a more controllable manner. In the past decade, the pioneering work on LbL assembly with supramolecular interaction has been established by Ikeda et al. [22]. Subsequently, Smith et al. [23] have reported that loading smallmolecule drugs on the layers of LbL-based system using supramolecular interaction. On another front, the light-induced drug release from a LbL-based system is the most elegant way to combine reversibly and efficiency, because light as an attractive stimulus can be applied rapidly, remotely, and locally [24,25]. While numerous well-established photoresponsive LbL-based systems are available [26,27], their applications in drug release b...

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Photo‐Switchable Behavior of Azobenzene‐Dye‐Modified Silica Nanoparticles and Their Assembly With Cyclodextrin Derivatives

Cited by 11 publications

References 21 publications

Molecular control over colloidal assembly

Molecular control over colloidal assembly

Light induced assembly and self-sorting of silica microparticles

Light-controlled drug releasing polymer films combining LbL self-assembly and host-guest interactions

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