- Photoreponsive Hybrid Nanoparticles with Inherent FRET Activity
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The photoactivated inherent fluorescence resonance energy transfer (FRET) properties of a hard-and-soft hybrid nanosystem comprising poly(1′-(2-methacryloxyethyl)-3′,3′-dimethyl-6-nitrospiro-(2H-1-benzopyran-2,2′-indoline))-co-poly[2-(dimethylamino)ethyl methacrylate] (PSPMA-co-PDMAEMA) random copolymer brushes on silica nanoparticles are described. This unique FRET process is switched on by the simultaneous generation of isomer X and merocyanine (MC), which are bipolar in nature and comprise donor-acceptor dyads, from a single spiropyran (SP) chromophore upon UV irradiation. These X-MC species exhibit sufficient lifetimes to allow the read-out of the FRET process. The phenomenon is gradually switched off because of the thermal relaxation of the bipolar chromophores. This inherent property of the nanoemitters is employed in the development of biosensors of high specificity by monitoring variations in the FRET efficiency and lifetime of the hybrids in the presence of biological substances. More specifically, bovine serum albumin (BSA) augments the formation of MC species and retards the MC photobleaching process, leading to the enhancement of the FRET efficiency and lifetime, respectively. On the other hand, amino acid l-histidine further retards the MC thermal relaxation and prolongs the FRET process. We envisage that this platform opens new perspectives in the development of novel, optical nanosensors for applications in various fields including healthcare products and environmental monitoring.
- Achilleos, Demetra S.,Hatton, T. Alan,Vamvakaki, Maria
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- Synthesis and characterization of new spiropyran micrometer-sized photochromic fluorescent polymeric particles of narrow size distribution by a swelling process
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Photochromic fluorescent uniform micrometer-sized particles were prepared in two ways: (1) Swelling of polystyrene (PS) and poly(styrene-butylmethacrylate) (P(S-BMA)) template particles with spiropyran dye (FSP) to obtain PS/FSP and P(S-BMA)/FSP uniform particles; (2) A similar swelling process, replacing FSP by AIBN, styrene and a spiropyran monomer (MSP), followed by co-polymerization of the monomers within the swollen microspheres to obtain P(S-BMA)/P(S-MSP) uniform particles. The spiropyran dyes are not fluorescent in water or in non-polar organic solvents. In contrast, the dyes encapsulated within the particles exhibit strong red fluorescence in the merocyanine conformation. Fluorescence measurements reveal that the P(S-BMA)/FSP microspheres exhibit higher fluorescence than the PS/FSP particles. The microspheres aqueous dispersion was exposed to alternate UV and visible light cycles and it was found that the fluorescence intensity of the PS/FSP and the P(S-BMA)/FSP particles decreased by 30% of its original value after 5 photoswitching cycles while that of the P(S-BMA)/P(S-MSP) particles remained the same.
- Bretler, Sharon,Margel, Shlomo
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- Reversible photoswitching aggregation and dissolution of spiropyran-functionalized copolymer and light-responsive FRET process
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Well-defined, reversibly light-responsive amphiphilic diblock copolymer grafted with spiropyran, was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. The copolymer self-assembles into polymeric micelles in water and exhibits reversible dissolution and re-aggregation characteristics upon ultraviolet (UV) and visible (Vis)-light irradiation. The fluorescence response of spiropyran immobilized onto the copolymer was light switchable. When nitrobenzoxadiazolyl derivative (NBD) dyes are encapsulated into the core of the micelles, a reversible, light-responsive, dual-color fluorescence resonance energy transfer (FRET) system is constructed and processed, which is well regulated by alternatively UV/vis irradiation. We anticipate these photoswitchable and FRET lighting up nanoparticles will be useful in drug delivery and cell imaging or tracking synchronously.
- Yu, Lei-Xiao,Liu, Yang,Chen, Si-Chong,Guan, Yue,Wang, Yu-Zhong
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- Spectroscopic analysis of metal ion binding in spiropyran containing copolymer thin films
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In this article, we describe the synthesis and characterization of a series of spiropyran containing copolymers that were used as colorimetric sensors for a series of divalent metal ions. The composition of spiropyran contained in the polymer backbone was varied from 10?100 mol % to investigate the influence of free volume and sterics on the photochromic response. Fourier transform-infrared (FT-IR) spectroscopy was used to characterize the photoinduced conversion, as well as the merocyanine?metal ion (MC?M2+) interaction. FT-IR spectra were analyzed using chemometric methods to elucidate the chemical binding environment between MC and M2+ and to selectively identify different metal ions bound to MC. By means of UV?vis absorption spectroscopy, we also demonstrate that each metal ion gives rise to a unique colorimetric response that is dependent on the amount of spiropyran comonomer contained in the polymer backbone and that by increasing the concentration of chromophore in the copolymer, the selectivity between different metal ions decreases. With the use of chemometric methods, UV?vis spectra can be analyzed to quantitatively identify metal ions in a concentration range from 1 ?M to 100 mM.
- Fries, Kristen H.,Driskell, Jeremy D.,Samanta, Satyabrata,Locklin, Jason
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- Amphiphilic BODIPY-Based Photoswitchable Fluorescent Polymeric Nanoparticles for Rewritable Patterning and Dual-Color Cell Imaging
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Photoswitchable fluorescent polymeric nanoparticles (PFPNs) with controllable molecular weight, high contrast, biocompatibility, and prominent photostability are highly desirable but still scarce for rewritable printing, super-resolution bioimaging, and r
- Chen, Jian,Zhong, Weibang,Tang, Ying,Wu, Zhan,Li, Ya,Yi, Pinggui,Jiang, Jianhui
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- Photo, pH, and thermo triple-responsive spiropyran-based copolymer nanoparticles for controlled release
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A spiropyran-based amphiphilic random copolymer was synthesized and self-assembled into photo-, pH-, and thermo-responsive micellar nanoparticles. The triple-stimuli triggered morphological changes of the nanoparticles were revealed by TEM and DLS. Highly efficient controlled release of encapsulated molecules, coumarin 102, from the nanoparticles under stimulation of UV light, acid and the combined stimuli could be realized.
- Chen, Shuo,Jiang, Fengjuan,Cao, Ziquan,Wang, Guojie,Dang, Zhi-Min
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- Synthesis of photochromic monomers derived from 1′-(2- methacryloxyethyl)-3,3-dimethyl-2-[2H]-spirobenzopyran indoline
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The syntheses of five photochromic monomers derived from N- (2-methacryloxyethyl)-3′, 3′-dimethylspiro-[2H-1] benzopyrane-2,2′-indoline are reported. The preparation of these compounds involves the heterogeneous reaction between the N-(hydroxyethyl)-2,3,3- trimethylindolenonium bromide and methacryloyl chloride in a polar solvent. The esterificated salt is easily purified by crystallization in chloroform-hexane. Further condensation with the proper 2-hydroxybenzaldehyde produces the photochromic monomer in high yield. This method can also be applied in the preparation of other spiropyrane derivatives.
- Elizalde, Luis Ernesto,Ledezma, Raquel,Lopez, Raul G.
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- Unlocking Chemically Encrypted Information Using Three Types of External Stimuli
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Encryption is critical to information security; however, existing chemical-based information encryption strategies are still in their infancy. We report here a new approach to chemical encryption involving a supramolecular gel QR (quick response) code wit
- Zhang, Hanwei,Li, Qingyun,Yang, Yabi,Ji, Xiaofan,Sessler, Jonathan L.
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p. 18635 - 18642
(2021/11/16)
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- Photoactive nano composite as well as preparation method thereof and application thereof
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The invention discloses photoactive nano composite as well as a preparation method thereof and application thereof. The nano composite is prepared from nucleic acid molecules and a cationic polymer; the cationic polymer consists of a positive electrical chain segment, a hydrophilic chain segment, and a photosensitive chain segment which is a spiropyrane chain segment. The preparation method for the nano composite comprises the steps of putting the cationic polymer solution in ultraviolet light to irradiate, then, mixing the cationic polymer solution with nucleic acid molecules, and standing toobtain the photoactive nano composite. The preparation method has the advantage that the photoactive nano composite is formed by spontaneous interaction of the cationic polymer and nucleic acid molecules with negative electricity. The preparation method is simple process; and the photoactive nano composite can be used as a photoswitch and also can be used as a photosensitizer, and has a wide prospect in the field of guiding disease diagnosis and treatment and photodynamics therapy.
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Paragraph 0021; 0070; 0071
(2018/05/16)
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- Light-responsive amphiphilic copolymer coated nanoparticles as nanocarriers and real-time monitors for controlled drug release
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Herein, light-responsive nanocarriers based on hollow mesoporous silica (HMS) nanoparticles modified with spiropyran-containing light-responsive copolymer (PRMS-FA) were fabricated via a simple self-assembly process. HMS modified with long-chain hydrocarb
- Xing, Qingjian,Li, Najun,Chen, Dongyun,Sha, Wenwei,Jiao, Yang,Qi, Xiuxiu,Xu, Qingfeng,Lu, Jianmei
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p. 1182 - 1189
(2014/03/21)
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- Development of light-responsive porous polycarbonate membranes for controlled caffeine delivery
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For controlled caffeine release, light-responsive membranes were developed. It was possible to produce membranes that reduced their caffeine permeability resistance by about 97% when irradiated with UV-light compared to measurements at daylight. This was achieved by grafting polymers possessing photochromic units onto track-edged polycarbonate membranes. Covalently linked coatings on porous polycarbonate membranes were obtained by plasma activation of the membrane surface followed by plasma-induced graft polymerization. Copolymerization of spiro-compounds during the coating process as well as postmodification of preformed coatings with spiropyran resulted in photochromic membranes. For the copolymerization process, the synthesis of five photochromic methacrylic and acrylic spiropyrans and spirooxazines was successfully performed. Additionally, a spiropyran with carboxylic acid functionality was synthesized for the postmodification process. This enabled us to postmodify polymeric materials containing alcohol or amine groups to obtain photochromic materials. UV-irradiation of these light-responsive membranes resulted in a strong colouration of the membrane, in a reduction of surface tension, which resulted in a decreased caffeine permeability resistance. The membranes were characterized using XPS for the elemental composition of the coating, contact angle measurements for the surface tension, solid-state UV/VIS measurements for the determination of the kinetic and stability properties, and two-photon microscopy for the localisation of the photochromic substance in the porous membrane.
- Baumann, Lukas,Schoeller, Katrin,De Courten, Damien,Marti, Dominik,Frenz, Martin,Wolf, Martin,Rossi, Rene M.,Scherer, Lukas J.
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p. 23317 - 23326
(2013/11/19)
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- Synthesis and photochromic properties of methacryloxy 6- nitrospirobenzopyrans
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The synthesis and spectroscopic characterization of several methacryloxy-modified spiropyran dyes is reported. The dyes were found to have similar photochromic isomerization rates relative to a commercially available reference compound in solution. The methacryloxy-modified dyes were also successfully incorporated into polymer matrices, where they retained their ability to photoisomerize and complex with cobalt (II) and zinc (II) ions.
- Sennett, Kelly A.,Lindner, Brian K.,Kaur, Navdeep,Fetner, Shannon M.,Stitzel, Shannon E.
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p. 437 - 441
(2013/07/25)
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- Synthesis and photoresponsive behavior of optically active methacrylic homopolymers containing side-chain spiropyran chromophores
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Novel optically-active methacrylic homopolymers bearing in the side chain one or more chiral groups of one single configuration (based on the l-lactic acid residue) linked to the spiropyran chromophore, have been successfully synthesized and fully characterized. These intrinsically chiral polymers exhibit remarkable thermal stability, with glass transition temperatures in the range 100-130 °C and decomposition temperatures around 270°C. The chiroptical characterization indicates the occurrence of asymmetric induction on the electronic transitions of the side-chain chromophore related to the number of l-lactic acid residues interposed between the main chain and the spiropyran chromophore. In the presence of acid, these systems can be used to modulate the protonation of polymeric azopyridine moieties upon photoisomerization of the spiropyran group. In addition to UV-Vis spectroscopy, the proton transfer process occurring between the macromolecular components can be also followed by CD spectroscopy, the system thus behaving as a chiroptical switch.
- Angiolini, Luigi,Benelli, Tiziana,Bicciocchi, Erika,Giorgini, Loris,Raymo, Fran?isco M.
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experimental part
p. 469 - 477
(2012/09/07)
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- Controlling contact electrification with photochromic polymers
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Charge switching: Control of contact electrification was achieved using a combination of photoreactive polymers and light. Upon UV irradiation, polymers substituted with photochromic spiropyrans reversibly switch their rate, and depending on chemical structure, their sign of charging by contact electrification (see picture). Consistent with empirical predictions, these photochromic polymers tended to charge positively upon irradiation with UV light.
- Friedle, Simone,Thomas III, Samuel W.
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supporting information; experimental part
p. 7968 - 7971
(2011/01/07)
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- Photo-patterning of honeycomb films prepared from amphiphilic copolymer containing photochromic spiropyran
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Honeycomb films were prepared by using a photo-responsive amphiphilic copolymer containing photochromic spiropyran. Through the photo-responsivity of spiropyran, the molecular polarities provide solubility changes against chloroform vapor after UV irradiation. The merocyanine area formed with UV irradiation retained its honeycomb-pattern against chloroform vapor, though the spiropyran area without UV irradiation dissolved.
- Kojima, Miki,Nakanishi, Takayuki,Hirai, Yuji,Yabu, Hiroshi,Shimomura, Masatsugu
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scheme or table
p. 3970 - 3972
(2010/08/06)
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