Search

A multifunctional undecapeptide, YYDPLGLADYY, was designed and synthesized for the photowrapping of silica-coated gold nanorods. The obtained nanocapsules, bearing a well-defined core–shell structure, were able to encapsulate a therapeutic drug, respond to an MMP-upregulated tumor microenvironment, and achieve NIR-triggered anticancer chemo-photothermal therapy with favorable efficacy. [ABSTRACT FROM AUTHOR]

We report a multi-stimuli-responsive luminescent material containing rotor moieties. It forms two types of crystals, G and O. The emission of G can be modulated by multiple external stimuli, whereas O does not show such responsiveness. The X-ray structure analysis reveals that the rotors are critical for the polymorphic emission and stimuli response properties. [ABSTRACT FROM AUTHOR]

We report J-aggregates of a boron dipyrromethene derivative (BDP-Nit) as an H2S-activatable nano-photosensitizer. The closely packed BDP-Nit in J-aggregates exhibits high selectivity to H2S over biothiols to produce an active photosensitizer. [ABSTRACT FROM AUTHOR]

We report N,O-boron-chelated dipyrromethene derivatives exhibiting circularly polarized luminescence (CPL) in the red/near-infrared region, both in solution and the aggregated state. The CPL is originated from the helical chirality through intramolecular substitution of fluorine by an alkenolic substituent. The self-assembly of the fluorophores significantly enhances the ‖glum‖ values from 10−4 to 10−2. [ABSTRACT FROM AUTHOR]

We report a series of difluoroboron β-diketonate fluorophores that manifest temperature-dependent emission wavelength accompanied by a change of fluorescence from green to orange. The distinct emission changes allow convenient and accurate measurements of temperature. [ABSTRACT FROM AUTHOR]

SO2, an important gasotransmitter, plays significant roles in human physiological activities. The reported probes for the detection of SO2 derivatives are mostly based on the quenching or blue-shift of fluorescence, leading to interference from the background signal. Herein, we develop a novel FRET-based nanoprobe that shows turn-on fluorescence at 615 nm in the presence of SO32−/HSO3−. The nanoprobe consists of N,O,B-chelated dipyrromethene (BDP) as the energy donor, and hemicyanine derivatives of HEM-CO-Ph with a responsive site to SO32−/HSO3− as the energy acceptor. Initially, the fluorescence of BDP is quenched by HEM-CO-Ph due to the efficient FRET process. In the presence of sulfites, the nucleophilic addition interrupts the conjugation of HEM-CO-Ph and results in a 200 nm blue-shift of the absorption, leading to the suppression of the FRET process and recovery of the red fluorescence of BDP. The nanoprobe shows fast response to SO32−/HSO3− with high selectivity, great biocompatibility and cellular uptake. It is the first supramolecular nanoprobe for the detection of SO32−/HSO3− by using intermolecular energy transfer, ingeniously turning the nanoprobe from "OFF" state to "ON" state. The nanoprobe is applied to monitor exogenous and endogenous SO2 derivatives in the mitochondria of living cells. [ABSTRACT FROM AUTHOR]

We report an unexpected coupling–reduction tandem reaction as a general and efficient one-pot synthesis of alkenyl-substituted boron dipyrromethene (BODIPY) from chlorinated-BODIPY and alkyne. This unique synthesis combined the Sonogashira coupling reaction and reduction reaction without adding an additional reagent, which shows higher yields, broader substrate scope and faster reaction rate compared with the conventional methods of the Knoevenagel reaction and Heck coupling reaction. [ABSTRACT FROM AUTHOR]

We report a series of organic fluorophores that undergo selective self-sensitized photooxidation upon light irradiation in air accompanied by a change of fluorescence from yellow to blue on the seconds timescale. The distinct emission changes allow the ratiometric quantitation of O2 concentration. [ABSTRACT FROM AUTHOR]

We report a new molecular design for optically triggered nm-scale translation of a submolecular component relative to another. We used a rotaxane-like molecule terminated at one end with stiff stilbene that served both as a chromophore to trigger the translation of the pillar[5]arene “wheel” and as a stopper to prevent its dethreading. [ABSTRACT FROM AUTHOR]

Artificial light-harvesting nanoparticles were prepared from supramolecular polymers comprised of pillar[5]arene with anthracene-derived donors and acceptors through host–guest interactions. The resulting water-dispersible nanoparticles displayed efficient energy transfer and excellent light harvesting ability in part because the steric bulk of pillar[5]arene suppressed the self-quenching of the chromophores. [ABSTRACT FROM AUTHOR]

Mechanochromic luminescent (MCL) materials have attracted considerable attention in recent years because of their potential applications in various fields and the fundamental importance of understanding the mechanism of mechanochromic luminescence. The most reported MCL materials show a bathochromic shift after external mechanical stimulus. Here we report new MCL materials with hypochromic shift of the emission after grinding. These materials are based on carbazole-containing difluoroboron β-diketonate complexes. These complexes show strong fluorescence in both the solid state and organic solutions. Our study reveals that the emission of structural symmetrical complexes is less influenced by the polarity of the solvent than those of unsymmetrical complexes and they retain strong fluorescence in highly polar solvents. In addition, the good planarity of the carbazole group and the ICT character of the complexes make them exhibit obvious two-photon excited fluorescence. In the solid state, their emission colours can be tuned reversibly by external stimuli, and they exhibit an unusual hypochromic shift after grinding. Single crystal X-ray analysis of the complexes reveals that the initial close molecular packing is responsible for the blue-shifted emission. Interestingly, both hypsochromic and bathochromic shifts of the emission are realized by different treatments of the samples. Our work provides information on the mechanism of the mechanochromic luminescent properties of organic luminescent materials and expands the potential applications of MCL materials. [ABSTRACT FROM AUTHOR]

Simple thiol derivatives, such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH), play key roles in biological processes, and the fluorescent probes to detect such thiols in vivo selectively with high sensitivity and fast response times are critical for understanding their numerous functions. However, the similar structures and reactivities of these thiols pose considerable challenges to the development of such probes. This review focuses on various strategies for the design of fluorescent probes for the selective detection of biothiols. We classify the fluorescent probes for discrimination among biothiols according to reaction types between the probes and thiols such as cyclization with aldehydes, conjugate addition–cyclization with acrylates, native chemical ligation, and aromatic substitution-rearrangement. [ABSTRACT FROM AUTHOR]

By using sensing technology, the individual component analysis at trace level in complex samples remains problematic simply because of various interfering species. For example, the determination of Cd2+ in rice is difficult due to the co-existing interfering metal cations at thousands or even millions of times higher concentrations. In this study, a heavy-metal ion sensitive BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene)-based fluorometric paper sensor with assistance of solid phase extraction (SPE) was developed for the highly selective and sensitive determination of trace Cd2+ in rice. SPE column packed with prepared sulfonated PS–DVB microspheres was employed to enrich trace Cd2+ and meanwhile remove most interfering heavy-metal ions in simulated complex rice sample with oxalic acid as eluent, which was theoretically selected on the basis of f values. Mn2+, as a major coexistent heavy-metal ion, could not be easily removed by SPE, but showed little fluorescent response for BODIPY fluorometric paper sensor even in excess amounts. Combining the separation and enrichment capability of SPE column with the selectivity of BODIPY-based fluorometric paper sensor, we were able to detect trace Cd2+ in complex samples. The response of fluorometric paper sensor was linearly related with Cd2+ concentrations in the range of 0.5–4 μM, with a detection limit of 0.5 μM. Twelve real rice samples spiked with Cd2+ were analysed using this method and the results are in good agreement with ICP-MS measurements. [ABSTRACT FROM AUTHOR]

Biological thiols, including cysteine (Cys), homocystein (Hcy) and glutathione (GSH), play crucial roles in maintaining the appropriate redox status of biological systems. An abnormal level of biothiols is associated with different diseases, therefore, the discrimination between them is of great importance. Herein, we present two fluorescent sensors for selective detection of biothiols based on our recently reported intramolecular displacement mechanism. We expanded this mechanism to commercially available chromophores, 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) and heptamethine cyanine dye IR-780. The sensors operate by undergoing displacement of chloride by thiolate. The amino groups of Cys/Hcy further replace the thiolate to form amino-substituted products, which exhibit dramatically different photophysical properties compared to sulfur-substituted products from the reaction with GSH. NBD-Cl is highly selective towards Cys/Hcy and exhibits significant fluorescence enhancement. IR-780 showed a variation in its fluorescence ratio towards Cys over other thiols. Both of the sensors can be used for live-cell imaging of Cys. The wide applicability of the mechanism may provide a powerful tool for developing novel fluorescent sensors for selective detection of biothiols. [ABSTRACT FROM AUTHOR]

We report a turn-on fluorescent sensor based on nitrothiophenolate boron dipyrromethene (BODIPY) derivatives for the discrimination of cystein (Cys) from homocystein (Hcy) and glutathione (GSH). The sensor was applied for detection of Cys in living cells. [ABSTRACT FROM AUTHOR]

We report J-aggregates of a boron dipyrromethene derivative (BDP-Nit) as an H 2 S-activatable nano-photosensitizer. The closely packed BDP-Nit in J-aggregates exhibits high selectivity to H 2 S over biothiols to produce an active photosensitizer.

SO2, an important gasotransmitter, plays significant roles in human physiological activities. The reported probes for the detection of SO2 derivatives are mostly based on the quenching or blue-shift of fluorescence, leading to interference from the background signal. Herein, we develop a novel FRET-based nanoprobe that shows turn-on fluorescence at 615 nm in the presence of SO32-/HSO3-. The nanoprobe consists of N,O,B-chelated dipyrromethene (BDP) as the energy donor, and hemicyanine derivatives of HEM-CO-Ph with a responsive site to SO32-/HSO3- as the energy acceptor. Initially, the fluorescence of BDP is quenched by HEM-CO-Ph due to the efficient FRET process. In the presence of sulfites, the nucleophilic addition interrupts the conjugation of HEM-CO-Ph and results in a 200 nm blue-shift of the absorption, leading to the suppression of the FRET process and recovery of the red fluorescence of BDP. The nanoprobe shows fast response to SO32-/HSO3- with high selectivity, great biocompatibility and cellular uptake. It is the first supramolecular nanoprobe for the detection of SO32-/HSO3- by using intermolecular energy transfer, ingeniously turning the nanoprobe from "OFF" state to "ON" state. The nanoprobe is applied to monitor exogenous and endogenous SO2 derivatives in the mitochondria of living cells.

We report a series of organic fluorophores that undergo selective self-sensitized photooxidation upon light irradiation in air accompanied by a change of fluorescence from yellow to blue on the seconds timescale. The distinct emission changes allow the ratiometric quantitation of O 2 concentration.

We report a photoresponsive monofunctionalized pillar[5]arene based on stiff stilbene. The Z isomer, Z-1, tends to form self-complexing [1]pseudorotaxanes and [c2] daisy chains, whereas the E analog, E-1, forms supramolecular polymers.

By using sensing technology, the individual component analysis at trace level in complex samples remains problematic simply because of various interfering species. For example, the determination of Cd(2+) in rice is difficult due to the co-existing interfering metal cations at thousands or even millions of times higher concentrations. In this study, a heavy-metal ion sensitive BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene)-based fluorometric paper sensor with assistance of solid phase extraction (SPE) was developed for the highly selective and sensitive determination of trace Cd(2+) in rice. SPE column packed with prepared sulfonated PS-DVB microspheres was employed to enrich trace Cd(2+) and meanwhile remove most interfering heavy-metal ions in simulated complex rice sample with oxalic acid as eluent, which was theoretically selected on the basis of f values. Mn(2+), as a major coexistent heavy-metal ion, could not be easily removed by SPE, but showed little fluorescent response for BODIPY fluorometric paper sensor even in excess amounts. Combining the separation and enrichment capability of SPE column with the selectivity of BODIPY-based fluorometric paper sensor, we were able to detect trace Cd(2+) in complex samples. The response of fluorometric paper sensor was linearly related with Cd(2+) concentrations in the range of 0.5-4 μM, with a detection limit of 0.5 μM. Twelve real rice samples spiked with Cd(2+) were analysed using this method and the results are in good agreement with ICP-MS measurements.

Herein we report the first example of a difluoroboron dibenzoyl based fluorescent probe for Cd(2+) detection. The probe displays high selectivity and sensitivity toward Cd(2+) over Zn(2+) in aqueous solution under physiological conditions. Fluorescence imaging experiments demonstrate its potential application for detecting Cd(2+) in living cells.