The authors provide at a look at the biological applications of supramolecular assemblies that have been designed for excitation energy transfer. The topics discussed include biosensors and ...bioimaging.
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Pure organic room temperature phosphorescence (RTP) has unique advantages and various potential applications. However, it is challengeable to achieve organic RTP under visible and near-infrared ...(NIR)-light excitation, especially in aqueous solution. Herein we assemble difluoroboron β-diketonate compounds to form organic nanoparticles (NPs) in water. The resulting NPs are able to show efficient RTP, effective uptake, and bright imaging of HeLa cells under both visible- and NIR-light excitation. More strikingly, spectroscopic study, single-crystal X-ray diffraction, and DFT calculation reveal that the efficient RTP in organic NPs is originated from dimers in their excited states. The multiple interactions and intermolecular charge transfer in the dimer structures are of significance in promoting the production of dimer triplet excited states and suppressing the nonradiative decays to boost the RTP under visible- and NIR-light irradiation in water.
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Depression is one of the most prevalent and life-threatening forms of mental illnesses and the neural circuitry underlying depression remains incompletely understood. Most attention in the field has ...focused on hippocampal and frontal cortical regions for their roles in depression and antidepressant action. While these regions no doubt play important roles in the mental illness, there is compelling evidence that other brain regions are also involved. Brain-derived neurotrophic factor （BDNF） is broadly expressed in the developing and adult mammalian brain and has been implicated in development, neural regeneration, synaptic transmission, synaptic plasticity and neurogenesis. Recently BDNF has been shown to play an important role in the pathophysiology of depression, however there are controversial reports about the effects of BDNF on depression. Here, we present an overview of the current knowledge concerning BDNF actions and associated intraceilular signaling in hippocampus, prefrontal cortex, nucleus accumbens （NAc） and amygdala as their relation to depression.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Hypoxia is a parameter related to many diseases. Ratiometric hypoxia probes often rely on a combination of an O2‐insensitive fluorophore and an O2‐sensitive phosphor in a polymer matrix, which ...require high cost and multi‐step synthesis of transition metal complexes. The two‐chromophore hypoxia probes encounter unfavorable energy transfer processes and different stabilities of the chromophores. Reported herein is a pure organic ratiometric hypoxia nanoprobe, assembled by a monochromophore, naphthalimide ureidopyrimidinone (BrNpA‐UPy), bridged by a bis‐UPy‐functionalized benzyl skeleton. The joint factors of quadruple hydrogen bonding, the rigid backbone of UPy, and bromine substitution of the naphthalimide derivative facilitate bright phosphorescence (ΦP=7.7 %, τP=3.2 ms) and fluorescence of the resultant nanoparticles (SNPs) at room temperature, which enable accurate, ratiometric, sensitive oxygen detection (Ksv=189.6 kPa−1) in aqueous solution as well as in living HeLa cells.
An organic hypoxia nanoprobe assembled by quadruple hydrogen bonds, shows efficient long‐lived phosphorescence (ΦP=7.7 %, τP=3.2 ms) and fluorescence from a monochromophore at room temperature and can be used for oxygen detection in water and living cells. This is the first example of ratiometric hypoxia sensing by supramolecular assemblies of an organic monochromophore.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Pure organic room temperature phosphorescence (RTP) is highly preferable because of its long lifetime and potential applications. However, these kinds of materials are still very scarce due to the ...weak spin–orbit coupling between singlet and triplet states and easily nonradiative decay of the excited states. Achieving room temperature phosphorescence under visible light excitation is particularly challenging in aqueous solution. Herein, a micelle‐assisted assembling strategy has been developed to realize pure organic RTP in water by using donor–acceptor molecules. A visible‐light responsive long‐lived RTP in water with a lifetime more than 3 ms is obtained by the prepared nanocrystals. However, the same molecules show no RTP as rigid bulk crystals. Spectroscopic studies, single‐crystal structure analysis, X‐ray diffraction patterns, and density functional theory calculations reveal that the intermolecular interactions, heavy atom effect, and the molecular packing way play critical role to the long‐lived RTP character for the assembled nanocrystals in water and thermally activated delayed fluorescence for crystals in solid.
A micelle‐assisted assembly strategy to realize long‐lived pure organic room temperature phosphorescence under visible light excitation in water is reported. The molecular packing plays a critical role to the room temperature phosphorescence character in the assembled nanocrystals and delayed fluorescence in the crystals.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Three rigid and structurally simple heterocyclic stilbene derivatives, (E)‐3H,3′H‐1,1′‐biisobenzofuranylidene‐3,3′‐dione, (E)‐3‐(3‐oxobenzoc thiophen‐1(3H)‐ylidene)isobenzofuran‐1(3H)‐one, and ...(E)‐3H,3′H‐1,1′‐bibenzoc thiophenylidene‐3,3′‐dione, are found to fluoresce in their neat solid phases, from upper (S2) and lowest (S1) singlet excited states, even at room temperature in air. Photophysical studies, single‐crystal structures, and theoretical calculations indicate that large energy gaps between S2 and S1 states (T2 and T1 states) as well as an abundance of intra and intermolecular hydrogen bonds suppress internal conversions of the upper excited states in the solids and make possible the fluorescence from S2 excited states (phosphorescence from T2 excited states). These results, including unprecedented fluorescence quantum yields (2.3–9.6 %) from the S2 states in the neat solids, establish a unique molecular skeleton for achieving multi‐colored emissions from upper excited states by “suppressing” Kasha's rule.
A unique molecular skeleton that exhibits multiple‐state emissions as neat, single‐component molecular solids at room temperature in air is reported. Mechanistic studies revealed that large energy gaps between S2 and S1 states, and an abundance of intramolecular/intermolecular hydrogen bonds, suppress internal conversions of the upper excited states in the solids and enable unprecedented fluorescence quantum yields (2.3–9.6 %) from the S2 states.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this study, a record high figure of merit (ZT) of ≈1.1 at 773 K is reported in n‐type highly distorted Sb‐doped SnSe microplates via a facile solvothermal method. The pellets sintered from the ...Sb‐doped SnSe microplates show a high power factor of ≈2.4 µW cm−1 K−2 and an ultralow thermal conductivity of ≈0.17 W m−1 K−1 at 773 K, leading a record high ZT. Such a high power factor is attributed to a high electron concentration of 3.94 × 1019 cm−3 via Sb‐enabled electron doping, and the ultralow thermal conductivity derives from the enhanced phonon scattering at intensive crystal defects, including severe lattice distortions, dislocations, and lattice bent, observed by detailed structural characterizations. This study fills in the gaps of fundamental doping mechanisms of Sb in SnSe system, and provides a new perspective to achieve high thermoelectric performance in n‐type polycrystalline SnSe.
A high figure of merit (ZT) of ≈1.1 at 773 K is achieved in n‐type highly distorted Sb‐doped SnSe microplates via tuning high carrier concentration of 3.94 × 1019 cm−3 by Sb‐enabled electron doping and realizing ultralow thermal conductivity of ≈0.17 W m−1 K−1 by inducing intensive crystal defects including severe lattice distortions, dislocations, and lattice bent.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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.
This review focuses on various strategies for the design of fluorescent probes for selective detection of biothiols, which are classified according to the unique reaction types between probes and thiols, such as cyclization with aldehydes, conjugate addition-cyclization with acrylates, native chemical ligation, and aromatic substitution-rearrangement.
A
bstract
In this work, we study the inhomogeneous BMS free fermion theory, and show that it gives a free field realization of the BMS Ising model. We find that besides the BMS symmetry there exists ...an anisotropic scaling symmetry in BMS free fermion theory. As a result, the symmetry of the theory gets enhanced to an infinite dimensional symmetry generated by a new type of BMS-Kac-Moody algebra, different from the one found in the BMS free scalar model. Besides the different coupling of the
u
(1) Kac-Moody current to the BMS algebra, the Kac-Moody level is nonvanishing now such that the corresponding modules are further enlarged to BMS-Kac-Moody staggered modules. We show that there exists an underlying
W
(2, 2, 1) structure in the operator product expansion of the currents, and the BMS-Kac-Moody staggered modules can be viewed as highest-weight modules of this
W
-algebra. Moreover we obtain the BMS Ising model by a fermion-boson duality. This BMS Ising model is not a minimal model with respect to BMS
3
, since the minimal model construction based on BMS Kac determinant always leads to chiral Virasoro minimal models. Instead, the underlying algebra of the BMS Ising model is the
W
(2, 2, 1)-algebra, which can be understood as a quantum conformal BMS
3
algebra.
We report a ratiometric fluorescent sensor based on monochlorinated BODIPY for highly selective detection of glutathione (GSH) over cysteine (Cys)/homocysteine (Hcy). The chlorine of the ...monochlorinated BODIPY can be rapidly replaced by thiolates of biothiols through thiol–halogen nucleophilic substitution. The amino groups of Cys/Hcy but not GSH further replace the thiolate to form amino-substituted BODIPY. The significantly different photophysical properties of sulfur- and amino-substituted BODIPY enable the discrimination of GSH over Cys and Hcy. The sensor was applied for detection of GSH in living cells.
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