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Jianzhang Zhao - One of the best experts on this subject based on the ideXlab platform.
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a highly selective red emitting fret fluorescent Molecular Probe derived from bodipy for the detection of cysteine and homocysteine an experimental and theoretical study
Chemical Science, 2012Co-Authors: Jingyin Shao, Huimin Guo, Jianzhang Zhao, Haiyang Sun, Xiaolin Yuan, Chunlei Zhang, Tony D JamesAbstract:A red-emitting BODIPY-based fluorescent-resonance-energy-transfer (FRET) Molecular Probe 1 for selective detection of cysteine and homocysteine was designed. The fluorescence OFF–ON switch is triggered by cleavage of the 2,4-dinitrobenzensulfonyl (DNBS) unit from the fluorophore by thiols. The FRET energy donor (λabs = 498 nm, λem = 511 nm) is a parent BODIPY moiety and the energy acceptor is based on 4-hydroxylstyryl BODIPY moiety (λabs = 568 nm, λem = 586 nm). The unique C–C linker between the energy donor and acceptor was established using a Suzuki cross-coupling reaction. A polyether chain was also introduced into the Probe to improve solubility in aqueous solution. While Probe 1 itself is non-fluorescent, in the presence of cysteine or homocysteine a red emission at 590 nm is switched on (excitation at 505 nm), producing a pseudo-Stokes shift of up to 77 nm, which is in stark contrast to the small Stokes shift (ca. 10 nm) observed for typical BODIPY dyes. Excitation of the energy donor leads to the red emission from the acceptor of the Probe, and demonstrates a high energy transfer efficiency. The Probe was used for in vivo fluorescent imaging of cellular thiols. The fluorescence sensing mechanism of the Probe and the photophysical properties of the fluorescent intermediates were fully rationalized by DFT calculations. The lack of fluorescence of Probe 1 is attributed to the dark excited state S1 (oscillator strength f = 0.0007 for S0 → S1, based on the optimized S1 state geometry), which is due to the electron sink effect of the DNBS moiety. Cleavage of the DNBS moiety from the fluorophore by thiols re-establishes the emissive S1 state of the fluorophore (f = 1.4317 for S0 → S1), thus the red emission can be observed in the presence of thiols (fluorescence is turned on). The FRET effect of the Probe was rationalized by DFT calculations which indicated that upon excitation into the S4 excited state (localized on the energy donor unit), the S1 state (localized on the energy acceptor, i.e. styryl-BODIPY) is populated via internal conversion (IC), thus red emission from the styryl-BODIPY energy acceptor is observed (Kasha's rule).
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styryl bodipy based red emitting fluorescent off on Molecular Probe for specific detection of cysteine
Biosensors and Bioelectronics, 2011Co-Authors: Jingyin Shao, Huimin Guo, Jianzhang ZhaoAbstract:We have synthesized a styryl boron-dipyrromethene (BODIPY)/2,4-dinitrobenzenesulfonyl (DNBS) dyad based red-emitting Molecular Probe for specific detection of cysteine among the biological thiols. The Probe shows intensive absorption at 556 nm and the Probe is non-fluorescent. The DNBS moiety can be cleaved off by thiols, the red emission of the BODIPY fluorophore at 590 nm is switched on, with an emission enhancement of 46-fold. The Probe shows good specificity toward cysteine over other biological molecules, such as glutathione and amino acids. The emission of the Probe is pH-independent in the physiological pH range. The Probe is used for fluorescent imaging of cellular thiols. Theoretical calculations based on density functional theory (DFT) were used to elucidate the fluorescence sensing mechanism of the Probe, which indicate a dark excited state (S(1)) for the Probe but an emissive excited state (S(1)) for the cleaved product (i.e. the fluorophore).
Jingyin Shao - One of the best experts on this subject based on the ideXlab platform.
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a highly selective red emitting fret fluorescent Molecular Probe derived from bodipy for the detection of cysteine and homocysteine an experimental and theoretical study
Chemical Science, 2012Co-Authors: Jingyin Shao, Huimin Guo, Jianzhang Zhao, Haiyang Sun, Xiaolin Yuan, Chunlei Zhang, Tony D JamesAbstract:A red-emitting BODIPY-based fluorescent-resonance-energy-transfer (FRET) Molecular Probe 1 for selective detection of cysteine and homocysteine was designed. The fluorescence OFF–ON switch is triggered by cleavage of the 2,4-dinitrobenzensulfonyl (DNBS) unit from the fluorophore by thiols. The FRET energy donor (λabs = 498 nm, λem = 511 nm) is a parent BODIPY moiety and the energy acceptor is based on 4-hydroxylstyryl BODIPY moiety (λabs = 568 nm, λem = 586 nm). The unique C–C linker between the energy donor and acceptor was established using a Suzuki cross-coupling reaction. A polyether chain was also introduced into the Probe to improve solubility in aqueous solution. While Probe 1 itself is non-fluorescent, in the presence of cysteine or homocysteine a red emission at 590 nm is switched on (excitation at 505 nm), producing a pseudo-Stokes shift of up to 77 nm, which is in stark contrast to the small Stokes shift (ca. 10 nm) observed for typical BODIPY dyes. Excitation of the energy donor leads to the red emission from the acceptor of the Probe, and demonstrates a high energy transfer efficiency. The Probe was used for in vivo fluorescent imaging of cellular thiols. The fluorescence sensing mechanism of the Probe and the photophysical properties of the fluorescent intermediates were fully rationalized by DFT calculations. The lack of fluorescence of Probe 1 is attributed to the dark excited state S1 (oscillator strength f = 0.0007 for S0 → S1, based on the optimized S1 state geometry), which is due to the electron sink effect of the DNBS moiety. Cleavage of the DNBS moiety from the fluorophore by thiols re-establishes the emissive S1 state of the fluorophore (f = 1.4317 for S0 → S1), thus the red emission can be observed in the presence of thiols (fluorescence is turned on). The FRET effect of the Probe was rationalized by DFT calculations which indicated that upon excitation into the S4 excited state (localized on the energy donor unit), the S1 state (localized on the energy acceptor, i.e. styryl-BODIPY) is populated via internal conversion (IC), thus red emission from the styryl-BODIPY energy acceptor is observed (Kasha's rule).
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styryl bodipy based red emitting fluorescent off on Molecular Probe for specific detection of cysteine
Biosensors and Bioelectronics, 2011Co-Authors: Jingyin Shao, Huimin Guo, Jianzhang ZhaoAbstract:We have synthesized a styryl boron-dipyrromethene (BODIPY)/2,4-dinitrobenzenesulfonyl (DNBS) dyad based red-emitting Molecular Probe for specific detection of cysteine among the biological thiols. The Probe shows intensive absorption at 556 nm and the Probe is non-fluorescent. The DNBS moiety can be cleaved off by thiols, the red emission of the BODIPY fluorophore at 590 nm is switched on, with an emission enhancement of 46-fold. The Probe shows good specificity toward cysteine over other biological molecules, such as glutathione and amino acids. The emission of the Probe is pH-independent in the physiological pH range. The Probe is used for fluorescent imaging of cellular thiols. Theoretical calculations based on density functional theory (DFT) were used to elucidate the fluorescence sensing mechanism of the Probe, which indicate a dark excited state (S(1)) for the Probe but an emissive excited state (S(1)) for the cleaved product (i.e. the fluorophore).
Ralph Weissleder - One of the best experts on this subject based on the ideXlab platform.
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in vivo imaging of thrombin activity in experimental thrombi with thrombin sensitive near infrared Molecular Probe
Arteriosclerosis Thrombosis and Vascular Biology, 2002Co-Authors: Farouc A Jaffer, Chinghsuan Tung, Robert E Gerszten, Ralph WeisslederAbstract:Objective— Thrombin, a serine protease, plays an important role in thrombosis as well as other cellular and developmental processes. In this study, we investigated the ability of a novel thrombin-activatable Molecular Probe to provide in vivo images of thrombin activity in experimental thrombi. Methods and Results— The thrombin Probe consists of a near-infrared (NIR) fluorochrome attached to a delivery vehicle via a thrombin-specific oligopeptide substrate. In human blood, endogenous thrombin activated the thrombin Probe and increased the fluorescence signal by 18-fold (P=0.008). Hirudin, a specific thrombin inhibitor, suppressed Probe activation by 82% (P=0.007). Imaging of in vivo thrombin activity was then investigated in acute experimental murine thrombosis models up to 12 hours. After systemic thrombin Probe injection, focal NIR fluorescence signal enhancement was rapidly detected within acute and subacute thrombi. In contrast, no thrombosis signal enhancement was seen in similar experiments with a c...
Sivaramapanicker Sreejith - One of the best experts on this subject based on the ideXlab platform.
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a ratiometric fluorescent Molecular Probe with enhanced two photon response upon zn2 binding for in vitro and in vivo bioimaging
Chemical Science, 2014Co-Authors: Kizhmuri P Divya, Sivaramapanicker Sreejith, Pichandi Ashokkumar, Kang Yuzhan, Qiwen Peng, Swarup Kumar Maji, Yan Tong, Yanli Zhao, P RamamurthyAbstract:A bipyridine centered donor–acceptor–donor (D–π–A–π–D) type ratiometric fluorescent Molecular Probe exhibited an unprecedented enhancement in the two-photon absorption (2PA) cross section upon Zn2+ binding. Moreover, owing to the excited state charge-transfer of the fluorophore π-backbone, a significant enhancement in the two-photon (2P) excited fluorescence intensity was observed upon Zn2+ binding, resulting in a 13-fold enhancement in the 2PA cross section and a 9-fold enhancement in fluorescence brightness at 620 nm when compared to the cation-free fluorophore. The large 2PA cross section of 1433 GM and 2P action cross section (860 GM), with an excellent 2P excited fluorescence variation from 517 to 620 nm upon Zn2+ binding, facilitated the ratiometric monitoring of free zinc ions in cells. The low cytotoxicity and good photostability of the fluorophore allowed two-photon Zn2+ imaging of HeLa cells. In addition, in vivo two-photon imaging of Zn2+ ions in hepatocytes of live rats illustrated the viability of the Probe in tissue imaging and monitoring of free zinc ions in live cells.
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a zn2 specific fluorescent Molecular Probe for the selective detection of endogenous cyanide in biorelevant samples
Chemical Communications, 2010Co-Authors: Kizhumuri P Divya, Sivaramapanicker Sreejith, Bugga Balakrishna, P Jayamurthy, Palappuravan Anees, Ayyappanpillai AjayaghoshAbstract:A Zn2+-specific Molecular Probe 3 was developed for the selective detection of CN− under aqueous conditions. The fluorescent Zn2+ complex of 3 upon CN− addition generates a bright blue fluorescence that allows the detection of the latter and is useful for the screening of natural products with and without endogenous cyanide content.
Wen M - One of the best experts on this subject based on the ideXlab platform.
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Pharmacokinetics and MR imaging of SPIO-shRNA dual functional Molecular Probe in vivo
Acta pharmaceutica Sinica, 2015Co-Authors: Deng Xl, Ge Xd, Wu Xf, Li Ml, Liao Rk, Zeng Dn, Wen MAbstract:In this study, we investigated the pharmacokinetics parameters of SPIO-shRNA dual functional Molecular Probe and observed the main organ distribution by MRI in vivo. Eighteen New Zealand white rabbits were randomly divided into three groups and injected intravenously with different doses of SPIO-shRNA Molecular Probe, respectively. The blood samples were collected to analyze the pharmacokinetic parameters by measuring the iron content at 30 minutes before and after the injection. Twenty-four Kun Ming (KM) mice were randomly divided into 4 groups: the control group was injected intravenously with physiological saline 200 µL per mouse via the tail vein, the other 3 groups were injected intravenously with different doses of SPIO-shRNA Molecular Probe. MRI observation was performed in 24 hours, and the liver, spleen, kidney, brain and muscle were collected for iron quantification with Prussian blue staining to determine distribution of the SPIO-shRNA Molecular Probe in the main organ in vivo. Our results suggest that the Molecular Probe blood half-life is more than 3 hours. The data of MRI suggest the Probe was distributed in liver and spleen, and the MRI signal was reduced with the increase in Probe's doses (P < 0.05). The results of Prussian blue staining confirmed the results of MRI. Most of the Probe could escape the phagocytosis of mononuclear phagocyte system. Our data provide the pharmacokinetic and distribution of SPIO-shRNA Molecular Probe in organs. Meanwhile, it suggests the choice of the time and dose of Probe for MR imaging of tumor in vivo.