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1.
Artigo em Inglês | MEDLINE | ID: mdl-32423197

RESUMO

Photoswitchable fluorescent diarylethenes are promisingly widely applied in the fields of optical memory, all-optical transistors, bioimaging, and super-resolution imaging, and so on. However, they face the problems of fluorescence quenching in an aggregated/solid state, the inadequate fluorescence ON/OFF switching ratio, and the necessity of UV-light irradiation. Herein, we report a novel kind of high-performance diarylethenes with aggregated-induced emission (AIE) by conjugating two diarylethene groups on one AIE-gen (i.e., TPE-2DTE (blue-green fluorescent) and OTPE-2DTE (orange fluorescence)). Their open forms show enhanced fluorescence in the aggregated and solid states. The closed form of TPE-2DTE/OTPE-2DTE was effectively generated upon short-wavelength visible-light (400 nm-450 nm) irradiation, whose fluorescence was dramatically quenched by intra- and inter-molecular energy transfer. Remarkably, 405 nm purple irradiation gives fluorescence ON/OFF ratios of 1196:1 and 1983:1 for TPE-2DTE and OTPE-2DTE, respectively. The reverse process can be accomplished after another longer wavelength irradiation such as 621 nm and shows considerable fatigue resistance. Taking advantage of superior photoswitching properties under visible-light irradiation, TPE-2DTE and OTPE-2DTE were used for super-resolution imaging with a high resolution of sub 50 nm. This work offers guidance to design bright-emitting and high-performance visible-light-controlled diarylethene photoswitches for practical applications.

2.
J Am Chem Soc ; 142(16): 7497-7505, 2020 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-32223234

RESUMO

A water-soluble probe, TPA-1OH, with aggregation-induced emission activity is synthesized and used for expedient real-time fluorescence in situ visualization of latent fingerprints (LFPs). A TPA-1OH aqueous solution exhibits nonfluorescence in pure water while strong fluorescence upon molecular aggregation induced by addition of poor solvent. Fluorescence images of LFPs on a variety of substrates, including rough surfaces such as walls, bricks, and paper, are developed under 405 nm light, by soaking in or spraying with a TPA-1OH aqueous solution (30 µM) without any necessity of organic cosolvents and post-treatment steps. The probe is noncytotoxic at a concentration lower than 50 µM. The development process of LFPs is demonstrated by real-time fluorescence in situ imaging. The exponential relationship between the relative fluorescence intensity and time is deduced from the fitting curve. The LFP images developed by TPA-1OH are evident and intact enough to allow that the level 1-3 details are displayed and analyzed. Noteworthily, the level 3 details of LFPs such as the fingerprint ridge width and the characteristics of the sweat pores are evidently visible under fluorescence microscopy. Even the nanoscopic details exceeding level 3 are visualized under super-resolution microscopy with sub-50 nm optical resolution.

3.
Angew Chem Int Ed Engl ; 59(22): 8560-8570, 2020 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-31532862

RESUMO

Unprecedented dual aggregation-induced emission (AIE) behavior based on a steric-hindrance photochromic system is presented, with incorporation one or two bulky aryl groups, resulting in different flexibleness. The dual AIE behavior of open and closed isomers can be explained by restriction of intramolecular rotation (RIR), restriction of intramolecular vibration (RIV), and intermolecular stacking. The large bulky benzothiophene causes restricted rotation, enhancing the emission of open form in solution and weak π-π molecular packing, thereby efficiently enhancing the luminescence performance in the solid state. With incorporation of two large bulky benzothiophene groups, BBTE possesses the most outstanding AIE activity, undergoing highly efficient and reversible off-to-on fluorescence in film upon alternating UV and visible light irradiation along with excellent fatigue resistance. The off-to-on fluorescent photoswitch is successfully established in super resolution imaging.

4.
ACS Appl Mater Interfaces ; 11(26): 23750-23756, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31179680

RESUMO

A near-infrared fluorescence-switchable molecule, dithienylethene-terrylenediimide (TDI-4DTE) exhibits high near-infrared fluorescence and on/off ratio, decent reversibility, and fatigue resistance upon alternating UV/vis (305/621 nm) irradiation. Photoinduced electron transfer mainly contributes to the fluorescence quenching of TDI-4DTE. As an information storage unit, single molecular TDI-4DTE in the polymer film can be written by red light (621 nm) and erased by UV light (305 nm), while nondestructive fluorescence readout (750 nm) of a single molecular memory has been obtained upon excitation with near-infrared light (720 nm). The fluorescence patterning of TDI-4DTE in the polymer film demonstrates that the erasing/writing/reading wavelengths are deciphered to minimize the signal crosstalk in nonvolatile fluorescent molecular memories.

5.
ACS Appl Mater Interfaces ; 11(26): 23623-23631, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31184463

RESUMO

The magical fantasy of decades-old transformer characters is becoming closer to scientific reality, as transformable materials can change their shapes in response to thermal, mechanical, electrical, and chemical stimuli. However, precise and prompt control of plastic shaping remains to be wanted. Photoresponsive materials provide a promising alternative for rapid optomechanical shaping with limited success. Here, we report a new class of photoplastic transformation based on dynamic covalently crosslinked polytriazole (PTA) networks, in which crosslinking points are comprised of photocleaveable hexaarylbiimidazole (HABI). Upon sub-500 nm light irradiation, HABI is dissociated into two triphenylimidazole radicals (TPIRs) followed by spontaneous recombination back to the initial state. This photoswitching effect is demonstrated to generate nonthermal shape change in the PTA-HABI gel network at will upon light stimulus. A unique photoalignment phenomenon has also been discovered which can form oriented nanoscale patterning in the PTA-HABI gel network upon laser irradiation. The solvent-free PTA-HABI elastomer exhibits photoenhanced automatic self-healing properties at temperatures ranging from 25 °C to freezing points, which is attributed to the dynamic equilibrium between TPIRs and HABI. A photoplastic spring is fabricated and exhibits photoswitchable plastic behavior, i.e., a reversible transformation between plastic strain and elastic strain upon light irradiation. HABI-based polymer networks, including solvated gel and solvent-free elastomer, are promising as smart materials for nonthermal photoactivated shape changing, transformation, and self-healing applications.

6.
Chemistry ; 24(61): 16251-16256, 2018 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-30242911

RESUMO

A new photoswitchable near-infrared fluorophore (TDI-4DTE) with a symmetric structure exhibited reversible photo-controllable self-assembly and disassembly. The modification of π-conjugated terrylenediimide with four dithienylethene groups not only induced photoswitchable near-infrared fluorescence, but also photoregulated reversible precipitation-dissolution with microscopic and macroscopic polymorphism. Upon 302 nm UV-light irradiation, a noticeable precipitation was observed within seconds. The precipitate was gradually dissolved again in half an hour upon visible light irradiation. Different microscopic morphologies of the precipitates, including nanoparticles, nanofibrils and nanosheets, were observed when altering the intensity of the 302 nm light irradiation, indicating the dynamic control process of self-assembly. Upon UV-light irradiation, TDI-4DTE nanosheets were also obtained as a solid polymeric film, whereas well-defined nanoribbons with molecular monolayer thickness formed at the oil/water interface with slower assembly dynamics.

7.
J Agric Food Chem ; 66(22): 5433-5438, 2018 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-29745662

RESUMO

Eucommia ulmoides Oliver (EUO), a traditional Chinese herb, contains a variety of bioactive chemicals, including lignans, iridoids, phenolics, steroids, terpenoids, flavonoids, etc. These bioactive chemicals possess the effective function in nourishing the liver and kidneys and regulating blood pressure. The composition of bioactive chemicals extracted from EUO vary in the different functional parts (leaves, seeds, bark, and staminate flower) and planting models. The bioactive parts of EUO are widely used as raw materials for medicine and food, powdery extracts, herbal formulations, and tinctures. These capabilities hold potential for future development and commercial exploitation of the bioactive products from EUO.


Assuntos
Ração Animal/análise , Eucommiaceae/química , Extratos Vegetais/química , Animais , Suplementos Nutricionais/análise , Suplementos Nutricionais/estatística & dados numéricos , Tratamento Farmacológico , Eucommiaceae/metabolismo , Humanos , Extratos Vegetais/metabolismo , Extratos Vegetais/farmacologia
8.
Chem Commun (Camb) ; 54(29): 3617-3620, 2018 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-29577126

RESUMO

Neutral conjugated tetraarylethenes OFn (n = 1-3) and the corresponding cationic conjugated oligoelectrolytes OFn+ (n = 1-3) with aggregation-induced emission activity have been designed and synthesized using geminal cross-coupling. OFn+ (n = 1-3) feature ion-induced emission in aqueous solution. They are used for lysosomal fluorescence imaging and tracing of lysosome events.


Assuntos
Corantes Fluorescentes/química , Lisossomos/metabolismo , Polieletrólitos/química , Compostos de Amônio Quaternário/química , Permeabilidade da Membrana Celular/efeitos dos fármacos , Fluorenos/síntese química , Fluorenos/química , Fluorescência , Corantes Fluorescentes/síntese química , Células HeLa , Humanos , Polieletrólitos/síntese química , Compostos de Amônio Quaternário/síntese química , Xantenos/síntese química , Xantenos/química
9.
ACS Omega ; 3(12): 17466-17473, 2018 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-31458352

RESUMO

Two-dimensional layer-structure materials are now of great interest in energy storage devices, owing to their graphene-like structure and high theoretical capacity. Herein, graphene-like molybdenum disulfide (MoS2) nanosheets were uniformly grown on carbon fabrics by using a hydrothermal method. They were evaluated as binder-free electrodes for Li-ion batteries (LIBs) and supercapacitors. As expected, long cycling life and high capacity/capacitance are achieved. When used as self-standing electrodes for LIBs, they deliver a high area capacity of ∼0.5 mAh/cm2 even after 400 cycles and remarkable rate capability in the charge/discharge potential range of 1-3 V. In addition, a three-dimensional integrated electrode of the MoS2 nanosheet exhibits a high capacitance of 103.5 mF/cm2 and long cycling stability up to at least 15 000 cycles at a current density of 3 mA/cm2 for supercapacitors. The great cycling stability of MoS2 in supercapacitors is promising in the enhancement of cycling stability through their integration with other materials as alternatives to graphene in some special fields.

10.
ACS Appl Mater Interfaces ; 9(12): 10338-10343, 2017 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-28281748

RESUMO

We have designed and synthesized an amphiphilic photoswitchable fluorophore, PEGylated perylenemonoimide-dithienylethene (PEG-PMI-DTE), which exhibits evident bistable photochromism, fluorescence switching, and fatigue resistance. The fine nanostructures of liposomes can be observed directly under super-resolution fluorescent microscopy by aid of the amphiphilic photoswitchable fluorophore as a staining agent, with an optical resolution of 30 nm.


Assuntos
Imidas/química , Perileno/análogos & derivados , Lipossomos , Microscopia de Fluorescência , Perileno/química
11.
Bioresour Technol ; 232: 159-167, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28222385

RESUMO

Eucommia ulmoides Oliver (EU) wood was consecutively treated by autohydrolysis pretreatment and chemical carbonization post-treatment based on a biorefinery process. Results showed that the optimal condition of the autohydrolysis pretreatment and carbonization process yielded 10.37kg xylooligosaccharides (XOS), 1.39kg degraded hemicellulosic products, 17.29kg other degraded products from hemicelluloses and 40.72kg activated carbon (SBET of 1534.06m2/g) from the 100kg raw materials. Simultaneously, 29.14kg gas products generated from the optimum integrated process was significantly lower than that from the direct carbonization process (68.84kg). Besides, the optimal activated carbon (AC170-1.0) also showed a moderate catalytic activity and high stability for hydrogen production by catalytic methane decomposition. Overall, the data presented indicated that the integrated process is an eco-friendly and efficient process to produce XOS and activated carbon, which is beneficial for value-added and industrial application of EU wood.


Assuntos
Carvão Vegetal/química , Carvão Vegetal/isolamento & purificação , Carvão Vegetal/farmacocinética , Eucommiaceae/química , Madeira/química , Adsorção , Reatores Biológicos , Carbono/química , Carbono/isolamento & purificação , Catálise , Glucuronatos/química , Glucuronatos/isolamento & purificação , Hidrólise , Oligossacarídeos/química , Oligossacarídeos/isolamento & purificação , Polissacarídeos/química , Polissacarídeos/isolamento & purificação
12.
Chem Commun (Camb) ; 53(18): 2669-2672, 2017 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-28217792

RESUMO

Self-assembly of an amphiphilic photoswitchable fluorescent macrocycle methoxy-tetraethylene glycol-substituted hexaarylbiimidazole-borondipyrromethene can be observed directly under a super-resolution fluorescence microscope, with the nanoscale resolution beyond the optical diffraction limitation.

17.
Faraday Discuss ; 196: 439-454, 2017 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-27905612

RESUMO

We report the design and synthesis of a tetraphenylethene substituted with naphthalimide at the 4, 6 positions, named NI-2TPE. NI-2TPE exhibits strong solvent-dependent emission properties with combined ICT and AIE characteristics in THF-H2O systems. This probe was used directly on test papers to distinguish normal organic solvents using their emission colours under UV light based on its AIE and ICT nature. Thanks to the vinyl group in NI-2TPE, we synthesized a copolymer of NIPAM and NI-2TPE, termed P(NIPAM-co-NI-2TPE). The resulting polymer is highly soluble and fluorescent in water (ΦF = 15.4%). Due to the well-known thermo-responsive character of NIPAM, P(NIPAM-co-NI-2TPE) exhibits an interesting fluorescence change in response to various temperatures. Due to the thermo-induced shrinking of the PNIPAM chain, the fluorescence intensity gradually increased from 20 to 34 °C. As the temperature further increased from 34 to 90 °C, the fluorescence intensity decreased sharply, which was caused by the well-known thermal effects. Furthermore, we synthesized a P(HEA-co-NI-2TPE-TPP acrylate) copolymer, in which HEA is a hydrophilic unit, TPP is a mitochondria label and NI-2TPE a fluorescent probe. The corresponding polymer probe is highly soluble in water with FLQY = 7% and we have further applied this probe as a mitochondria targeted imaging tracker in HeLa cells successfully.


Assuntos
Células/química , Fluorescência , Corantes Fluorescentes/química , Naftalimidas/química , Imagem Óptica , Estilbenos/química , Corantes Fluorescentes/síntese química , Células HeLa , Humanos , Imagem Molecular , Estrutura Molecular , Polimerização , Raios Ultravioleta
18.
Photochem Photobiol Sci ; 15(11): 1433-1441, 2016 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-27739551

RESUMO

Photoswitchable fluorophores are promising in single-molecule optical devices and super-resolution fluorescence imaging, especially in single-molecule photo-activated localization microscopy (PALM) or stochastic optical reconstruction microscopy (STORM). However, the scarcity of current photoswitchable fluorophores stimulates researchers to develop complicated optical systems and processing software, in accordance with the limited photoswitchable fluorescent proteins and organic fluorophores. Previous efforts to develop synthetic photoswitchable fluorophores have exhibited their promising potential in super-resolution fluorescence imaging. Here, we have designed and synthesized a fluorescence molecular switch with reversible green emission, a napthalimide-hexaarylbiimidazole conjugate (NI-N-HABI), which exhibits strong fluorescence in the emissive state, with fast thermal fading of the photochromism and spontaneous fluorescence recovery after photobleaching (FRAP) induced by blue-light. The photoswitchable fluorophore enables the red-edge wavelength of the optical response to red-shift from the initial near-UV region at less than 400 nm, to 500 nm. The relatively fast fading speed of NI-N-HABI and its sensitivity to longer blue-light irradiation (400-500 nm) have allowed simplification of the optical microscopic system from a two-wavelength laser source to a single-wavelength laser. We applied NI-N-HABI in single-wavelength-controlled in situ dynamic super-resolution fluorescence imaging for the self-assembly and solvent annealing of amphiphilic block polymers, with 50 nm of optical resolution. Single-wavelength-controlled dynamic super-resolution fluorescence imaging facilitates nanoscale optical visualization for the dynamic physical and chemical fluctuation processes of stimuli-responsive nanostructures.

19.
Small ; 12(47): 6547-6552, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27555445

RESUMO

Monodisperse AIE (aggregation-induced emission)-active conjugated polymer nanoparticles are synthesized by dispersion polymerization using geminal Suzuki cross-coupling of 1,1-dibromoolefins. The size of the nanoparticles can be adjusted by varying the concentration of the initial monomer.

20.
Biotechnol Biofuels ; 9: 142, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27418947

RESUMO

BACKGROUND: The requirement for efficient and green conversion technologies has prompted hydrothermal processing as a promising treatment option for sustainable biorefinery industry. The treatment has been applied to process plenty of lignocellulose materials, yielding abundant high value-degraded products, especially the products in the liquid fraction. Therefore, it is essential to systematically evaluate the degraded products in aqueous fraction by comprehensive analysis and structural characterization during the treatment. RESULTS: Rapeseed straw was hydrothermally treated at temperature ranging from 145 to 205 °C for various retention time (15, 30, 60 and 120 min), and the degraded polysaccharides and lignin products in aqueous phase were systematically evaluated by comprehensive analysis and structural characterization. Results showed that with an increase of severity, the polymers were gradually depolymerized resulting in a decrease of the molecular weight from 8430 (log R 0 3.26) to 2130 g/mol (log R 0 5.08), an increase of oligosaccharides from 19.44 (log R 0 2.88) to 99.94 g/kg (log R 0 4.32) and an increase of monosaccharides from 0.91 (log R 0 2.88) to 30.43 g/kg (log R 0 4.37). With the increase of monosaccharide degradation components (8.26 to 125.68 g/kg), the saccharides gradually decreased after its maximum value. The maximum yield of oligosaccharides (99.94 g/kg) accompanying a relatively low level of monosaccharides (17.77 g/kg) was obtained at a high temperature (190 °C) for a short reaction time (15 min). The degraded polysaccharides had a linear backbone of (1 â†’ 4)-linked ß-d-xylopyranosyl xylan decorated with branches based on 2D NMR spectra analysis. Lignin was strongly condensed with a decrease of S/G ratio as the severity increased. The yields of the degraded constitutions have a incomplete linear correlation with the treatment severity. CONCLUSIONS: The liquid fractions obtained from hydrothermal treatment were subjected to comprehensive analysis and structural characterization. Results indicated that hydrothermal treatment had a significant influence on the composition and structure of the polysaccharides and lignin in the aqueous phase. The treatment could be adopted to obtain XOS-rich fraction with limited formation of by-products. In addition, the result was expected to further reveal the mechanisms of hydrothermal treatment on rapeseed straw and to facilitate the value-added applications of agricultural residues in the biorefinery industry.

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