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We herein present an approach of photo‐induced disproportionation for preparation of Type‐I photodynamic agents. As a proof of concept, BODIPY‐based photosensitizers were rationally designed and prepared. The photo‐induced intermolecular electron transfer between homotypic chromophores leads to the disproportionation reaction, resulting in the formation of charged intermediates, cationic and anionic radicals. The cationic radicals efficiently oxidize the cellularimportant coenzyme, tetrahydrobiopterin (BH4), and the anionic radicals transfer electrons to oxygen to produce superoxide radicals (O2−⋅). One of our Type‐I photodynamic agents not only self‐assembles in water but also effectively targets the endoplasmic reticulum. It displayed excellent photocytotoxicity even in highly hypoxic environments (2 % O2), with a half‐maximal inhibitory concentration (IC50) of 0.96 μM, and demonstrated outstanding antitumor efficacy in murine models bearing HeLa tumors. [ABSTRACT FROM AUTHOR]

We herein present an approach of photo‐induced disproportionation for preparation of Type‐I photodynamic agents. As a proof of concept, BODIPY‐based photosensitizers were rationally designed and prepared. The photo‐induced intermolecular electron transfer between homotypic chromophores leads to the disproportionation reaction, resulting in the formation of charged intermediates, cationic and anionic radicals. The cationic radicals efficiently oxidize the cellularimportant coenzyme, tetrahydrobiopterin (BH4), and the anionic radicals transfer electrons to oxygen to produce superoxide radicals (O2−⋅). One of our Type‐I photodynamic agents not only self‐assembles in water but also effectively targets the endoplasmic reticulum. It displayed excellent photocytotoxicity even in highly hypoxic environments (2 % O2), with a half‐maximal inhibitory concentration (IC50) of 0.96 μM, and demonstrated outstanding antitumor efficacy in murine models bearing HeLa tumors. [ABSTRACT FROM AUTHOR]

Chirality, with its intrinsic symmetry‐breaking feature, is frequently utilized in the creation of acentric crystalline functional materials that exhibit intriguing optoelectronic properties. On the other hand, the development of chiral crystals from achiral molecules offers a solution that bypasses the need for enantiopure motifs, presenting a promising alternative and thereby expanding the possibilities of the self‐assembly toolkit. Nevertheless, the rational design of achiral molecules that prefer spontaneous symmetry breaking during crystallization has so far been obscure. In this study, we present a series of six achiral molecules, demonstrating that when these conformationally flexible molecules adopt a cis‐conformation and engage in multiple non‐covalent interactions along a helical path, they collectively self‐assemble into chiral superstructures consisting of single‐handed supramolecular columns. When these homochiral supramolecular columns align in parallel, they form polar crystals that exhibit intense luminescence upon grinding or scraping. We therefore demonstrate our molecular design strategy could significantly increase the likelihood of symmetry breaking in achiral molecular synthons during self‐assembly, offering a facile access to novel chiral crystalline materials with unique optoelectronic properties. [ABSTRACT FROM AUTHOR]

Chirality, with its intrinsic symmetry‐breaking feature, is frequently utilized in the creation of acentric crystalline functional materials that exhibit intriguing optoelectronic properties. On the other hand, the development of chiral crystals from achiral molecules offers a solution that bypasses the need for enantiopure motifs, presenting a promising alternative and thereby expanding the possibilities of the self‐assembly toolkit. Nevertheless, the rational design of achiral molecules that prefer spontaneous symmetry breaking during crystallization has so far been obscure. In this study, we present a series of six achiral molecules, demonstrating that when these conformationally flexible molecules adopt a cis‐conformation and engage in multiple non‐covalent interactions along a helical path, they collectively self‐assemble into chiral superstructures consisting of single‐handed supramolecular columns. When these homochiral supramolecular columns align in parallel, they form polar crystals that exhibit intense luminescence upon grinding or scraping. We therefore demonstrate our molecular design strategy could significantly increase the likelihood of symmetry breaking in achiral molecular synthons during self‐assembly, offering a facile access to novel chiral crystalline materials with unique optoelectronic properties. [ABSTRACT FROM AUTHOR]

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]

Without external chiral intervention, it is a challenge to form homochirality from achiral molecules with conformational flexibility. We here report on a rational strategy that uses multivalent noncovalent interactions to clamp the molecular conformations of achiral D‐A molecules. These interactions overcome the otherwise dominant dipole‐dipole interactions and thus disfavor their symmetric antiparallel stacking. It in turn facilitates parallel packing, leading to spontaneous symmetry breaking during crystallization and thus the formation of homochiral conglomerates. When this emergent homochirality is coupled with optical gain characteristics of the molecules, the homochiral crystals are explored as excellent circularly polarized micro‐lasers with low lasing threshold (16.4 μJ cm−2) and high dissymmetry factor glum (0.9). This study therefore provides a facile design strategy for supramolecular chiral materials and active laser ones without the necessity of intrinsic chiral element. [ABSTRACT FROM AUTHOR]

Without external chiral intervention, it is a challenge to form homochirality from achiral molecules with conformational flexibility. We here report on a rational strategy that uses multivalent noncovalent interactions to clamp the molecular conformations of achiral D‐A molecules. These interactions overcome the otherwise dominant dipole‐dipole interactions and thus disfavor their symmetric antiparallel stacking. It in turn facilitates parallel packing, leading to spontaneous symmetry breaking during crystallization and thus the formation of homochiral conglomerates. When this emergent homochirality is coupled with optical gain characteristics of the molecules, the homochiral crystals are explored as excellent circularly polarized micro‐lasers with low lasing threshold (16.4 μJ cm−2) and high dissymmetry factor glum (0.9). This study therefore provides a facile design strategy for supramolecular chiral materials and active laser ones without the necessity of intrinsic chiral element. [ABSTRACT FROM AUTHOR]

Given that Type-I photosensitizers (PSs) have hypoxia tolerance, developing general approaches to prepare Type-I PSs is of great importance, but remains a challenge. Here, we report a supramolecular strategy for the preparation of Type-I photodynamic agents, which simultaneously generate strong oxidizing cationic radicals and superoxide radicals, by introducing electron acceptors to the existing Type-II PSs. As a proof-of-concept, three electron acceptors were designed and co-assembled with a classical PS to produce quadruple hydrogen-bonded supramolecular photodynamic agents. The photo-induced electron transfer from the PS to the adjacent electron acceptor occurs efficiently, leading to the generation of a strong oxidizing PS+• and an anionic radical of the acceptor, which further transfers an electron to oxygen to form O2−•. In addition, these photodynamic agents induce direct photocatalytic oxidation of NADH with a turnover frequency as high as 53.7 min−1, which offers an oxygen-independent mechanism to damage tumors. Tumour hypoxia is a major issue for conventional photodynamic therapies, Here, the authors report on the supramolecular assembly of electron acceptors with photosensitizers which have improved reactive oxygen species production and are able to directly oxidise NHDH and demonstrate application against hypoxic tumours. [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]

Developing Type‐I photosensitizers is considered as an efficient approach to overcome the deficiency of traditional photodynamic therapy (PDT) for hypoxic tumors. However, it remains a challenge to design photosensitizers for generating reactive oxygen species by the Type‐I process. Herein, we report a series of α,β‐linked BODIPY dimers and a trimer that exclusively generate superoxide radical (O2−.) by the Type‐I process upon light irradiation. The triplet formation originates from an effective excited‐state relaxation from the initially populated singlet (S1) to triplet (T1) states via an intermediate triplet (T2) state. The low reduction potential and ultralong lifetime of the T1 state facilitate the efficient generation of O2−. by inter‐molecular charge transfer to molecular oxygen. The energy gap of T1‐S0 is smaller than that between 3O2 and 1O2 thereby precluding the generation of singlet oxygen by the Type‐II process. The trimer exhibits superior PDT performance under the hypoxic environment. [ABSTRACT FROM AUTHOR]

Developing Type‐I photosensitizers is considered as an efficient approach to overcome the deficiency of traditional photodynamic therapy (PDT) for hypoxic tumors. However, it remains a challenge to design photosensitizers for generating reactive oxygen species by the Type‐I process. Herein, we report a series of α,β‐linked BODIPY dimers and a trimer that exclusively generate superoxide radical (O2−.) by the Type‐I process upon light irradiation. The triplet formation originates from an effective excited‐state relaxation from the initially populated singlet (S1) to triplet (T1) states via an intermediate triplet (T2) state. The low reduction potential and ultralong lifetime of the T1 state facilitate the efficient generation of O2−. by inter‐molecular charge transfer to molecular oxygen. The energy gap of T1‐S0 is smaller than that between 3O2 and 1O2 thereby precluding the generation of singlet oxygen by the Type‐II process. The trimer exhibits superior PDT performance under the hypoxic environment. [ABSTRACT FROM AUTHOR]

Excitation energy transfer (EET) as a fundamental photophysical process is well-explored for developing functional materials with tunable photophysical properties. Compared to traditional fluorophores, aggregation-induced emission luminogens (AIEgens) exhibit unique advantages for building EET systems, especially serving as energy donors, due to their outstanding photophysical properties such as bright fluorescence in aggregation state, broad absorption and emission spectra, large Stokes shift, and high photobleaching resistance. In addition, the photophysical properties of AIEgens can be modulated by energy transfer for improved luminescence performance. Therefore, a variety of EET systems based on AIEgens have been constructed and their applications in different areas have been explored. In this review, we summarize recent progress in the design strategy of AIE-based energy transfer systems for light-harvesting, fluorescent probes and theranostic systems, with an emphasis on design strategies to achieve desirable properties. The limitations, challenges and future opportunities of AIE–EET systems are briefly outlined. Design strategies and applications (light-harvesting, fluorescent probe and theranostics) of AIEgen-based excitation energy systems are discussed in this review. [ABSTRACT FROM AUTHOR]

An organic crystal of 4,4′‐bis(N‐carbazolyl)‐1,1′‐biphenyl (pCBP) exhibits time‐dependent afterglow color from blue to orange over 1 s. Both experimental and computational data confirm that the color evolution results from well‐separated, long‐persistent thermally activated delayed fluorescence (TADF) and room‐temperature phosphorescence (RTP) with different but comparable decay rates. TADF is enabled by a small S1–T1 energy gap of 0.7 kcal mol−1. The good separation of TADF and RTP is due to a 11.8 kcal mol−1 difference in the S0 energies of the S1 and T1 structures, indicating that apart from the excited‐state properties, tuning the ground state is also important for luminescence properties. This afterglow color evolution of pCBP allows its applications in anticounterfeiting and data encryption with high security levels. [ABSTRACT FROM AUTHOR]

An organic crystal of 4,4′‐bis(N‐carbazolyl)‐1,1′‐biphenyl (pCBP) exhibits time‐dependent afterglow color from blue to orange over 1 s. Both experimental and computational data confirm that the color evolution results from well‐separated, long‐persistent thermally activated delayed fluorescence (TADF) and room‐temperature phosphorescence (RTP) with different but comparable decay rates. TADF is enabled by a small S1–T1 energy gap of 0.7 kcal mol−1. The good separation of TADF and RTP is due to a 11.8 kcal mol−1 difference in the S0 energies of the S1 and T1 structures, indicating that apart from the excited‐state properties, tuning the ground state is also important for luminescence properties. This afterglow color evolution of pCBP allows its applications in anticounterfeiting and data encryption with high security levels. [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]

Abstract: The first example of the synthesis of mono‐N,O‐B‐chelated dipyrromethene (BODIPY) derivatives through an unexpected intramolecular nucleophilic displacement of the fluorine by alkenols in the presence of boron trifluoride as Lewis acid is reported. The chlorine in the indacene core allowed for further structural modifications through nucleophilic substitutions or palladium‐catalysed coupling reactions to afford new fluorophores with tuneable photophysical properties. Their expanded conjugation structure resulted in distinct red‐shifted absorption and emission spectra in organic solutions. Furthermore, the twisted steric hindrance of the benzene substitution patterns suppressed aggregation‐induced quenching, leading to an enhanced NIR emission in the aggregate/solid state, which was rarely observed for BODIPY dyes. Nanoparticles of the fluorophores formed by the assembly with the polymeric surfactant F127 were successfully used for bioimaging of living cells and for tumour‐targeted imaging in a tumour‐bearing mouse model. [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]

A carbazole-containing difluoroboron β-diketonate complex ( BCZ), which shows strong fluorescence in both the solid state and in organic solutions, is reported. The crystalline materials of BCZ obtained from different solvents display different emission colors. Single-crystal analysis reveals that the enhanced overlap between adjacent molecules induces increased excited-state delocalization and is responsible for the variation of the emission colors from yellow to red. The emission colors of the materials are effectively tuned by external stimuli such as grinding, heating, and solvent vapor. The powder X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and 1H NMR studies on materials of BCZ reveal that the thermochromic properties of BCZ are closely related to the removal of solvent molecules from the crystalline powders upon heating. Moreover, uniform 1D microstructures of BCZ obtained by solvent exchange in solution exhibit optical waveguide property with low optical loss. [ABSTRACT FROM AUTHOR]

A platinum(II) bipyridyl complex bearing bis-ureidopyrimidinone (Pt-bisUPy) has been designed and its self-assembling behavior has been thoroughly investigated by 1H NMR, DOSY NMR, Ubbelohde viscometry analysis, UV/Vis, and emission spectroscopies. Pt-bisUPy underwent concentration-dependent ring-chain polymerization in apolar solvents. Hydrogen-bonding interactions play an important role during the formation of the supramolecular polymers. Hydrogen-bonded supramolecular polymers were transformed to nanoparticles in water through the miniemulsion method. These nanoparticles showed strong π-π excimeric emission. Metal-metal-to-ligand charge transfer (MMLCT) from Pt-Pt interactions was not significant in the emission spectrum. The phosphorescence of the nanoparticle persisted even under aerobic conditions. The triplet state of these phosphorescent nanomaterials were long-lived and possessed moderate emission quantum yields. Furthermore, the low toxicity of these materials promises a place for them in in vitro and in vivo bioimaging. [ABSTRACT FROM AUTHOR]

A facile approach for the preparation of supramolecular polymer-based fluorescent nanoparticles (FNPs) is reported. FNPs with homogeneous shape and size distribution are fabricated from low-molecular-weight molecules, and thus, different compositional constituents can be efficiently incorporated via copolymerization. The emission color of the FNPs covers a wide region from blue to near infrared and can be easily tuned using efficient excitation energy transfer. The photoswitchable fluorescent nanoparticles with high on-off fluorescence contrast are also simply prepared by copolymerization of monomers containing a fluorophore and a photochromic unit. Our FNPs are successfully applied in living cell imaging and as fluorescent inks. [ABSTRACT FROM AUTHOR]

The first example of a ratiometric optical oxygen nanoprobe based on a hydrogen-bonded supramolecular polymer has been reported. The supramolecular polymer based nanoprobe (SPNP) is prepared from the co-assembly of a bis-ureidopyrimidinone (bis-UPy)-containing phosphorescent indicator (Por(Pd)-bisUPy), fluorescent reference dye (BF2-bisUPy), and skeleton unit (DPA-bisUPy) through quadruple hydrogen bonds by a mini-emulsion method. The water-dispersible SPNP is highly sensitive to oxygen ( Q = 95%), with full reversibility, excellent storage stability and photostability, and good cell-penetrating ability, and exhibits low cytotoxicity toward living cells. The preparation of the SPNP is straightforward and its function is easily tuned by changing the monomeric structure. This work is expected to lead to the design of other SPNPs for other important analytes in biological systems. [ABSTRACT FROM AUTHOR]

We report the first highly efficient artificial light-harvesting systems based on nanocrystals of difluoroboron chromophores to mimic the chlorosomes, one of the most efficient light-harvesting systems found in green photosynthetic bacteria. Uniform nanocrystals with controlled donor/acceptor ratios were prepared by simple coassembly of the donors and acceptors in water. The light-harvesting system funneled the excitation energy collected by a thousand donor chromophores to a single acceptor. The well-defined spatial organization of individual chromophores in the nanocrystals enabled an energy transfer efficiency of 95 %, even at a donor/acceptor ratio as high as 1000:1, and a significant fluorescence of the acceptor was observed up to donor/acceptor ratios of 200 000:1. [ABSTRACT FROM AUTHOR]

We report the first highly efficient artificial light-harvesting systems based on nanocrystals of difluoroboron chromophores to mimic the chlorosomes, one of the most efficient light-harvesting systems found in green photosynthetic bacteria. Uniform nanocrystals with controlled donor/acceptor ratios were prepared by simple coassembly of the donors and acceptors in water. The light-harvesting system funneled the excitation energy collected by a thousand donor chromophores to a single acceptor. The well-defined spatial organization of individual chromophores in the nanocrystals enabled an energy transfer efficiency of 95 %, even at a donor/acceptor ratio as high as 1000:1, and a significant fluorescence of the acceptor was observed up to donor/acceptor ratios of 200 000:1. [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]

The preparation of functionalized bis-ureidopyrimidinones ( Bis-UPy) through the thiol-yne reaction is described. Various Bis-UPys with different functional groups were synthesized by using the readily available functionalized alkynes and UPy-thiol to affirm the simplicity and versatility of the methodology. [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]

In this study, the volatile compounds, lipid composition, thermal behavior, and structure of wheat germ oil were analyzed. Forty-four volatile compounds, mainly alcohols, esters, alkenes, and aldehydes, were isolated by headspace solid phase micro extraction. The major constituents were found to be hexanal (15.97%), 2-methyl-2-butene (10.43%), 2,4-heptadienal (8.53%), and limonene (6.83%). The oil was rich in unsaturated fatty acid (83.45%), especially in linoleic acid (64.82%), and there were 75.49% unsaturated fatty acid distributed in Sn-2 position. The main content of unsaponifiable matters was sterol, especially β-sitosterol (64.64%). The thermogravimetric analysis results showed one major regime of weight loss over a temperature range of 280–500°C and an exothermic behavior was observed by the differential scanning calorimetry data. [ABSTRACT FROM AUTHOR]

Defatted wheat germ peptides (DWGPs) were prepared by fermentation with Bacillus Subtilis B1 and the antioxidant activities of DWGPs were investigated. The fermentation condition was optimized by response surface method (RSM) with three factors and three levels according to Box-Behnken theory. A maximal yield of DWGPs was achieved 8.69 mg/mL under optimal conditions: inoculum size 8%, fermentation temperature 31 °C and time 48 h. The main portion in the hydrolysates after fermentation was not free amino acid but peptide. The main molecular weight distribution of DWGPs was lower than 1000 Da. A positive correlation (R = 0.9911) was found between concentration of DWGPs and total antioxidant capacity (T-AOC). DWGPs presented a significant does-dependent on scavenging activities of DPPH, hydroxyl and superoxide anion radicals. The EC values for the scavenging rates of DPPH, hydroxyl and superoxide anion radicals were 3.16 mg/mL, 6.04 mg/mL and 7.46 mg/mL, respectively. The results suggested that DWGPs produced by fermentation could be used as a promising antioxidant ingredient. [ABSTRACT FROM AUTHOR]

Summary The Maillard reaction (MR) under wet reaction conditions with several common saccharides, such as xylose, glucose, lactose, dextran and maltodextrin, were applied to improve the functional properties of wheat germ protein (WGP). The MR products (MRPs) prepared with dextran at pH 11.0 heated at 90 °C in 2% aqueous dispersions heating for 20 min showed better solubility and emulsifying properties. The fluorescence intensity analysis proved the MR occurred, and thinner sheet MRPs were observed by scanning electron microscope (SEM). The relative contents of Cys, Lys and Arg were decreased, which could reduce the chance of protein aggregation through -S-S bonds. Circular dichroism (CD) spectrum expressed the difference in the secondary structures between WGP and MRPs, which may make MRPs show better functional properties than WGP. These results suggested that MR with dextran under wet reaction conditions can be a promising way to improve functional properties of WGP. [ABSTRACT FROM AUTHOR]

Au nanoparticles with diameters of ca . 15 nm were synthesized according to the well-developed citrate reduction method. It was found that the nanoparticles tended to attach and fuse into each other to form chain-like structures with the removal of the stabilizing agents. UV-Vis absorption and HRTEM characterizations provided solid evidence for the fused features. On the basis of the HRTEM observations, we believed the decreased surface energy as well as the dipole-dipole interaction is responsible for the formation of the chain-like structures. SERS activity investigation indicated that the intensities of the b2-type bands have close relation with the concentration of the probing molecules, which further confirmed the chemical effect character of the b2-type scatterings. [ABSTRACT FROM AUTHOR]

Keywords: BODIPY; hypoxia; photodynamic therapy; photosensitizers; superoxide radical EN BODIPY hypoxia photodynamic therapy photosensitizers superoxide radical 24134 24134 1 10/27/21 20211102 NES 211102 In this Research Article, the absorption and fluorescence spectra of compound B 2 b (Figure 6 b) were incorrect. Berichtigung: BODIPY-Based Photodynamic Agents for Exclusively Generating Superoxide Radical over Singlet Oxygen BODIPY, hypoxia, photodynamic therapy, photosensitizers, superoxide radical. [Extracted from the article]

BODIPY, photodynamic therapy, photosensitizers, superoxide radical, hypoxia Corrigendum: BODIPY-Based Photodynamic Agents for Exclusively Generating Superoxide Radical over Singlet Oxygen Keywords: BODIPY; hypoxia; photodynamic therapy; photosensitizers; superoxide radical EN BODIPY hypoxia photodynamic therapy photosensitizers superoxide radical 23938 23938 1 10/27/21 20211102 NES 211102 In this Research Article, the absorption and fluorescence spectra of compound B 2 b (Figure 6 b) were incorrect. [Extracted from the article]