A Core–Shell Nanoparticle Approach to Photoreversible Fluorescence Modulation of a Hydrophobic Dye in Aqueous Media

Chen, Jian; Zeng, Fang; Wu, Shuizhu; Chen, Qiming; Tong, Zhen

doi:10.1002/chem.200701994

Cited by 83 publications

(98 citation statements)

References 86 publications

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“…22 moieties consist of hydrophilic and biocompatible poly(ethyleneimine) chain segments forming the shell and a hydrophobic copolymer of methyl methacrylate, spiropyran-linked methacrylate, and cross-linker forming the core [59]. Polymeric nanoparticles were prepared by one-step miniemulsion polymerization.…”

Section: Polymeric Nanoparticlesmentioning

confidence: 99%

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Nanophotochromism

Barachevsky¹

2015

Organic Photonics and Photovoltaics

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Abstract:The review presents the state-of-the-art analysis of investigations in the field of a new line of research of photochromism -nanophotochromism. The design, properties, and possible applications of photochromic nanoparticles prepared by different methods with the use of photochromic substances (aggregates, host-guest, and polymer systems, solid nanoparticles) as well as core-shell photochromic nanostructures based on polymers, silica, quantum dots, doped upconversion nanocrystals, and Ag, Au, etc. nanoparticles have been reviewed. Keywords: photochromism; photochromic nanoparticles; core-shell photochromic nanoparticles design; photoswitching; aggregates; polymer systems, host-guest systems IntroductionPhotochromism is a very important phenomenon for different applications in photonics. The applications are based on reversible phototransformations of photochromic compounds between two states and changes of their properties that accompany these transformations At present, systems and materials containing photochromic nanopatricles have become highly significant. Among these are nanodimensional particles of photochromic substances, including aggregates, and coreshell systems. As a core, inorganic nanoparticles of gold, silver, metal oxides, quantum dots (QD), and also polymeric nanoparticles are used. The shell consists of photochromic molecules or their aggregates connected to a core surface either chemically or physically. Photochromic nanoparticles with photocontrolled fluorescence arouse a special interest because the fluorescence technique is becoming a leading strategy in biological diagnosis, imaging, and detection applications. This paper is a state-of-the-art review which presents results of studying photochromic nanoparticles including author's own data. The results of earlier research are also surveyed in some other reviews [1][2][3][4][5][6][7][8][9][10][11][12][13]. Photochromic nanoparticles:properties and applications Nanoparticles based on photochromic substances AggregatesThe most known photochromic nanoparticles are aggregates of photochromic organic compounds [14]. These compounds experience reversible photoinduced transformations between two states, Sch. 1A and Sch. 1B. Scheme 1The photoinduced colored merocyanine form B absorbing visible irradiation is formed from a colorless form A as a result of photodissociation of the -C-O-bond of the pyran heterocycle under UV radiation, and this is followed by spontaneous isomerization of the cis-form to the trans one. The colored form B can be converted back to the initial colorless form A upon absorption of visible light or spontaneously during the dark relaxation, which is accelerated by heating.The J-aggregates of nitro-substituted indoline spiropyrans Sch. 2 with long alkyl substituents are of special interest [15].The narrow absorption bands of J-aggregates of these photochromic compounds (Fig. 1) made it possible prepare a specimen of the multilayered optical disk providing freUnauthenticated Download

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Section: Polymeric Nanoparticlesmentioning

confidence: 99%

“…The diameter of the nanoparticles can be varied from 40 to 80 nm [59] - [61]. 9,10-Diphenylanthracene was also used as a fluorophore [62].…”

Section: Polymeric Nanoparticlesmentioning

confidence: 99%

Nanophotochromism

Barachevsky¹

2015

Organic Photonics and Photovoltaics

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“…Other reporting groups include the spiropyrans which, upon exposure to UV light, undergo heterocyclic ring cleavage to the open chain merocyanine form. The latter has strong absorption in the visible region, whereas the spiropyran (closed form) is colourless (Chen et al, 2008;Zhu et al, 2011;Zhu et al, 2006). This has been used in the development of spiropyranbased nanosystems which act as fluorometric and colorimetric temperature sensors .…”

Section: Synthesis Of Polymeric Nanoparticlesmentioning

confidence: 99%

Polymeric nanoparticles for optical sensing

Canfarotta

Whitcombe

Piletsky

2013

Biotechnology Advances

119

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Nanotechnology is a powerful tool for use in diagnostic applications. For these purposes a variety of functional nanoparticles containing fluorescent labels, gold and quantum dots at their cores have been produced, with the aim of enhanced sensitivity and multiplexing capabilities. This work will review progress in the application of polymeric nanoparticles in optical diagnostics, both for in vitro and in vivo detection, together with a discussion of their biodistribution and biocompatibility.

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“…Fluorescence detection can be used in non-destructive recording and detection [10,71,91] and bio-imaging [24,78,80,32,63,88], because it requires a much lower power light source than absorption detection. A candidate molecule for a non-destructive readout should possess the ability to turn fluorescence "on" or "off" by photostimulation, while the excitation should not induce ring opening or ring closure of the photochrome.…”

Section: Fluorescence In Connection With Photochromismmentioning

confidence: 99%

“…Amphiphilic core-shell nanoparticles polymerized from poly(ethyleneimine) (PEI), methyl methacrylate (MMA), acrylate-linked SP (SPMA), ethylene dimethacrylate (EDMA) using tert-butyl hydroperoxide initiator containing l'-(-carboxyethyl)-3',3'-dimethyl-6-nitrospiro[indoline-2',2-chromane] as photochromic dye were prepared in aqueous media [78]. As the copolymer of MMA, SPMA, and EDMA is hydrophobic, it built the core, whereas the biocompatible PEI chains remain hydrophilic; consequently, they constituted the shell of nanoparticles.…”

Section: Free Radical Polymerizationmentioning

confidence: 99%

Organic Nanoparticulate Photochromes

Feczkó¹,

Vončina²

2013

COC

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Photochromic organic dyes can be widely used in materials for optically rewritable data storage, photonic switches, memories, sensors, or actuators. In recent years photochromic materials based on nanoparticles became particularly focused, since they can be dispersed in colloidal aqueous suspensions or incorporated in thin films, avoiding problems of light scattering or shallow light penetration in bulk materials. Spiropyrans, spirooxazines and diarylethenes were by far the most researched photochromes in nanoparticulate systems. Great effort was made to investigate photochromic dyes incorporated into organic nanoparticles via self-assembly strategies, covalent linkage or dispersion of the molecular species in polymers (doping). Nanoparticles composed of solely photochromic dyes were prepared by laser ablation and reprecipitation techniques. Photochromic dyes were microencapsulated by self-assembly, soap free-, emulsion/microemulsion/miniemulsion or free radical-(co)polymerization. Sol-gel processing from silane precursors to poly(organo)siloxane matrix is a common method to synthesize doped or core-shell photochromic organogels. Coloured forms of some photochromes display fluorescence; however, a more effective strategy for fluorescence modulation with photochromic molecules is integrating them, covalently or noncovalently, with a separate fluorophore in the same nanoparticles. These photoresponsive nanoparticles may find applications particularly in biological fields such as cell labelling and bioimaging. The purpose of this review is to summarize the preparation methods of organic nanoparticles containing photochromic dyes and to investigate their typical properties derived from their nanoparticulate character.Keywords: photochromic nanoparticle, laser ablation, reprecipitation, polymerization, doping, fluorescence INTRODUCTIONPhotochromism is a reversible structural and colour change of a species triggered in one or both directions by electromagnetic radiation [1]. The shift of optical absorption, due to change in molecular structure or conformation results in colourization, while the coloured product decolourizes after a structure rearrangement in the back (generally thermal) reaction. The reversible transformations of photochromic compounds are usually based on ring opening/closing steps, cis/trans isomerizations, proton transfer, electron transfer or cycloadditions [2]. Like other stimuli responsive materials (e.g. heat and pH-sensitive materials), photochromic devices are responsive to an external stimulus, in this case, light. Light is the most attractive stimulus due to the fact that its wavelength, intensity and focus can be tuned. Photochromic materials have been investigated extensively during the past few decades because of optical responses and nonlinear optical, electronic and magnetic properties [3]. Photochromic materials have a high potential for applications to ophthalmic lenses [4,5] [15], and also for microstructuring and patterning surfaces [16]. Therefore, photosensitive, nanoscal...

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A Core–Shell Nanoparticle Approach to Photoreversible Fluorescence Modulation of a Hydrophobic Dye in Aqueous Media

Cited by 83 publications

References 86 publications

Nanophotochromism

Nanophotochromism

Polymeric nanoparticles for optical sensing

Organic Nanoparticulate Photochromes

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