The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Jinmao You - One of the best experts on this subject based on the ideXlab platform.

  • fluorometric determination and imaging of glutathione based on a thiol triggered Inner Filter Effect on the fluorescence of carbon dots
    Mikrochimica Acta, 2017
    Co-Authors: Xuefeng Chen, Guang Chen, Nannan Qiu, Xuexiang Shi, Zhiwei Sun, Jinmao You
    Abstract:

    The authors describe a sensitive method for determination of glutathione (GSH) that is based on a thiol-triggered Inner Filter Effect on the fluorescence of N-doped carbon dots (N-doped CDs). N-doped CDs with a quantum yield as high as 31% were prepared by a one-pot procedure, and 5,5′-dithiobis-(2-nitrobenzoic acid) was employed as a reagent for GSH recognition. The reaction product (5-thio-2-nitrobenzoic acid; TNB) acts as an absorber of the 410-nm light used to photo-excite the N-doped CDs. Hence, the fluorescence of N-doped CDs (peaking at 510 nm) is reduced with increasing concentrations of GSH. As little as 30 nM of GSH can be detected by this method. The approach was successfully applied to (a) food analysis, (b) an investigation of an oxidative stress model, and (c) to live cells imaging. The method does not require the surface of N-doped CDs to be chemically modified, and a linkage between receptor and fluorophore is not needed. In our perception, the method may become a viable tool for the detection and imaging of thiols.

  • facile and sensitive fluorescence sensing of alkaline phosphatase activity with photoluminescent carbon dots based on Inner Filter Effect
    Analytical Chemistry, 2016
    Co-Authors: Xuejie Che, Peiwei Gong, Guang Che, Lia Xia, Hua Wang, Jinmao You
    Abstract:

    A simple and sensitive fluorescent assay for detecting alkaline phosphatase (ALP) based on the Inner Filter Effect (IFE) has been proven, which is conceptually different from the previously reported ALP fluorescent assays. In this sensing platform, N-doped carbon dots (CDs) with a high quantum yield of 49% were prepared by one-pot synthesis and were directly used as a fluorophore in IFE. p-Nitrophenylphosphate (PNPP) was employed to act as an ALP substrate, and its enzyme catalytic product (p-nitrophenol (PNP)) was capable of functioning as a powerful absorber in IFE to influence the excitation of fluorophore (CDs). When in the presence of ALP, PNPP was transformed into PNP and induced the absorption band transition from 310 to 405 nm, which resulted in the complementary overlap between the absorption of PNP and the excitation of CDs. Because of the competitive absorption, the excitation of CDs was significantly weakened, resulting in the quenching of CDs. The present IFE-based sensing strategy showed a g...

  • facile and sensitive fluorescence sensing of alkaline phosphatase activity with photoluminescent carbon dots based on Inner Filter Effect
    Analytical Chemistry, 2016
    Co-Authors: Xuejie Chen, Peiwei Gong, Hua Wang, Jinmao You, Guang Chen, Lian Xia
    Abstract:

    A simple and sensitive fluorescent assay for detecting alkaline phosphatase (ALP) based on the Inner Filter Effect (IFE) has been proven, which is conceptually different from the previously reported ALP fluorescent assays. In this sensing platform, N-doped carbon dots (CDs) with a high quantum yield of 49% were prepared by one-pot synthesis and were directly used as a fluorophore in IFE. p-Nitrophenylphosphate (PNPP) was employed to act as an ALP substrate, and its enzyme catalytic product (p-nitrophenol (PNP)) was capable of functioning as a powerful absorber in IFE to influence the excitation of fluorophore (CDs). When in the presence of ALP, PNPP was transformed into PNP and induced the absorption band transition from 310 to 405 nm, which resulted in the complementary overlap between the absorption of PNP and the excitation of CDs. Because of the competitive absorption, the excitation of CDs was significantly weakened, resulting in the quenching of CDs. The present IFE-based sensing strategy showed a good linear relationship from 0.01 to 25 U/L (R(2) = 0.996) and provided an exciting detection limit of 0.001 U/L (signal-to-noise ratio of 3). The proposed sensing approach was successfully applied to ALP sensing in serum samples, ALP inhibitor investigation and phosphatase cell imaging. The presented IFE-based CDs fluorescence sensing strategy gives new insight on the development of the facile and sensitive optical probe for enzyme activity assay because the surface modification or the linking between the receptor and the fluorophore is no longer required.

Feng Gao - One of the best experts on this subject based on the ideXlab platform.

  • colorimetric and phosphorimetric dual signaling strategy mediated by Inner Filter Effect for highly sensitive assay of organophosphorus pesticides
    Journal of Agricultural and Food Chemistry, 2015
    Co-Authors: Rong Zhang, Junyong Sun, Feng Gao
    Abstract:

    We describe here a colorimetric and phosphorimetric dual-signaling strategy for sensitive assay of organophosphorus pesticides (OPPs). The principle for assay depends on the phenomenon that the phosphorescence of Mn-ZnS quantum dots (QDs) can be dramatically quenched by Au nanoparticles (AuNPs) through the Inner Filter Effect (IFE) and the activity of acetylcholinesterase (AChE), an enzyme that catalytically hydrolyzes acetylthiocholine to thiocholine that can be inhibited by OPPs. By virtue of the variations of absorbance and phosphorescence of the analytical system, a dual-readout assay for OPPs has been proposed. The limits of detection for different OPPs including paraoxon, parathion, omethoate, and dimethyl dichlorovinyl phosphate (DDVP) are found to be 0.29, 0.59, 0.67, and 0.44 ng/L, respectively. The proposed assay was allowed to detect pesticides in real spiked samples and authentic contaminated apples with satisfactory results, suggesting its potential applications to detect pesticides in compli...

  • Colorimetric and Phosphorimetric Dual-Signaling Strategy Mediated by Inner Filter Effect for Highly Sensitive Assay of Organophosphorus Pesticides
    2015
    Co-Authors: Rong Zhang, Junyong Sun, Feng Gao
    Abstract:

    We describe here a colorimetric and phosphorimetric dual-signaling strategy for sensitive assay of organophosphorus pesticides (OPPs). The principle for assay depends on the phenomenon that the phosphorescence of Mn-ZnS quantum dots (QDs) can be dramatically quenched by Au nanoparticles (AuNPs) through the Inner Filter Effect (IFE) and the activity of acetylcholinesterase (AChE), an enzyme that catalytically hydrolyzes acetylthiocholine to thiocholine that can be inhibited by OPPs. By virtue of the variations of absorbance and phosphorescence of the analytical system, a dual-readout assay for OPPs has been proposed. The limits of detection for different OPPs including paraoxon, parathion, omethoate, and dimethyl dichlorovinyl phosphate (DDVP) are found to be 0.29, 0.59, 0.67, and 0.44 ng/L, respectively. The proposed assay was allowed to detect pesticides in real spiked samples and authentic contaminated apples with satisfactory results, suggesting its potential applications to detect pesticides in complicated samples

Erkang Wang - One of the best experts on this subject based on the ideXlab platform.

  • universal platform for ratiometric sensing based on catalytically induced Inner Filter Effect by cu2
    Analytical Chemistry, 2020
    Co-Authors: Chao Peng, Huanhuan Xing, Yuan Xue, Erkang Wang, Yongchao Fan
    Abstract:

    Integrating two kinds of fluorescent probes in one system to develop a ratiometric sensing platform is of prime importance for achieving an accurate assay. Inspired by the efficient overlapped spectrum of 2-aminoterephthalic acid (PTA-NH2) and 2,3-diaminophenazine (DAP), a new sensitive ratiometric fluorescent sensor has been developed for Cu2+ on the basis of in situ converting o-phenylenediamine (OPD) into DAP through the catalysis of Cu2+. Here, the presence of Cu2+ induced the emission of DAP, which acted as an energy acceptor to inhibit the emission of PTA-NH2. This dual-emission reverse change ratiometric profile based on the Inner-Filter Effect improved sensitivity and accuracy, and the highly sensitive determination of Cu2+ with a detection limit of 1.7 nmol·L-1 was obtained. The proposed sensing platform displayed the wide range of detection of Cu2+ from 5 to 200 nmol·L-1 by modulating the reaction time between Cu2+ and OPD. Moreover, based on the specific interaction between glutathione (GSH) and Cu2+, this fluorescent sensor showed high response toward GSH in a range of 0.5-80 μmol·L-1 with a detection limit of 0.16 μmol·L-1. The successful construction of this simple ratiometric sensing platform without the participation of enzymes provides a new route for the detection of small biological molecules that are closely related to human health.

  • glutathione regulated Inner Filter Effect of mno2 nanosheets on boron nitride quantum dots for sensitive assay
    Analytical Chemistry, 2019
    Co-Authors: Chao Peng, Huanhuan Xing, Xiushuang Fan, Yuan Xue, Erkang Wang
    Abstract:

    Glutathione (GSH) can help the body maintain the function of the normal immune system and its level change is associated with a variety of diseases. To achieve the ultrasensitive assay of GSH, a "switch on" nanosensor is designed on the basis of GSH regulating the Inner Filter Effect (IFE) of MnO2 nanosheets (MnO2 NS) on boron nitride quantum dots (BNQDs). Here, the fluorescence of BNQDs is quenched efficiently in the presence of redoxable MnO2 NS because of the superior light absorption capability; however, the introduction of GSH can trigger the decomposition of MnO2 to Mn2+ and weaken the IFE, causing the partial fluorescence recovery. The recovered fluorescence is dependent on the concentration of GSH. Under the optimal conditions, this sensing platform shows the response to GSH in the range of 0.5-250 μM with the detection limit of 160 nM. On the basis of the GSH activated reduction of MnO2 NS, the MnO2 NS/BNQDs nanoprobes exhibit good selectivity to GSH. The practical application of the proposed system is demonstrated by detecting the GSH in human plasma samples with satisfying results.

Rong Zhang - One of the best experts on this subject based on the ideXlab platform.

  • colorimetric and phosphorimetric dual signaling strategy mediated by Inner Filter Effect for highly sensitive assay of organophosphorus pesticides
    Journal of Agricultural and Food Chemistry, 2015
    Co-Authors: Rong Zhang, Junyong Sun, Feng Gao
    Abstract:

    We describe here a colorimetric and phosphorimetric dual-signaling strategy for sensitive assay of organophosphorus pesticides (OPPs). The principle for assay depends on the phenomenon that the phosphorescence of Mn-ZnS quantum dots (QDs) can be dramatically quenched by Au nanoparticles (AuNPs) through the Inner Filter Effect (IFE) and the activity of acetylcholinesterase (AChE), an enzyme that catalytically hydrolyzes acetylthiocholine to thiocholine that can be inhibited by OPPs. By virtue of the variations of absorbance and phosphorescence of the analytical system, a dual-readout assay for OPPs has been proposed. The limits of detection for different OPPs including paraoxon, parathion, omethoate, and dimethyl dichlorovinyl phosphate (DDVP) are found to be 0.29, 0.59, 0.67, and 0.44 ng/L, respectively. The proposed assay was allowed to detect pesticides in real spiked samples and authentic contaminated apples with satisfactory results, suggesting its potential applications to detect pesticides in compli...

  • Colorimetric and Phosphorimetric Dual-Signaling Strategy Mediated by Inner Filter Effect for Highly Sensitive Assay of Organophosphorus Pesticides
    2015
    Co-Authors: Rong Zhang, Junyong Sun, Feng Gao
    Abstract:

    We describe here a colorimetric and phosphorimetric dual-signaling strategy for sensitive assay of organophosphorus pesticides (OPPs). The principle for assay depends on the phenomenon that the phosphorescence of Mn-ZnS quantum dots (QDs) can be dramatically quenched by Au nanoparticles (AuNPs) through the Inner Filter Effect (IFE) and the activity of acetylcholinesterase (AChE), an enzyme that catalytically hydrolyzes acetylthiocholine to thiocholine that can be inhibited by OPPs. By virtue of the variations of absorbance and phosphorescence of the analytical system, a dual-readout assay for OPPs has been proposed. The limits of detection for different OPPs including paraoxon, parathion, omethoate, and dimethyl dichlorovinyl phosphate (DDVP) are found to be 0.29, 0.59, 0.67, and 0.44 ng/L, respectively. The proposed assay was allowed to detect pesticides in real spiked samples and authentic contaminated apples with satisfactory results, suggesting its potential applications to detect pesticides in complicated samples

Xueqin Ren - One of the best experts on this subject based on the ideXlab platform.

  • sensitive arginine sensing based on Inner Filter Effect of au nanoparticles on the fluorescence of cdte quantum dots
    Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2017
    Co-Authors: Haijian Liu, Linye Jiang, Feng Shen, Xueqin Ren
    Abstract:

    Abstract Arginine plays an important role in many biological functions, whose detection is very significant. Herein, a sensitive, simple and cost-Effective fluorescent method for the detection of arginine has been developed based on the Inner Filter Effect (IFE) of citrate-stabilized gold nanoparticles (AuNPs) on the fluorescence of thioglycolic acid-capped CdTe quantum dots (QDs). When citrate-stabilized AuNPs were mixed with thioglycolic acid-capped CdTe QDs, the fluorescence of CdTe QDs was significantly quenched by AuNPs via the IFE. With the presence of arginine, arginine could induce the aggregation and corresponding absorption spectra change of AuNPs, which then IFE-decreased fluorescence could gradually recover with increasing amounts of arginine, achieving fluorescence “turn on” sensing for arginine. The detection mechanism is clearly illustrated and various experimental conditions were also optimized. Under the optimum conditions, a decent linear relationship was obtained in the range from 16 to 121 μg L − 1 and the limit of detection was 5.6 μg L − 1 . And satisfactory results were achieved in arginine analysis using arginine injection, compound amino acid injection, even blood plasma as samples. Therefore, the present assay showed various merits, such as simplicity, low cost, high sensitivity and selectivity, making it promising for sensing arginine in biological samples.

  • a turn on fluorescent sensor for selective and sensitive detection of alkaline phosphatase activity with gold nanoclusters based on Inner Filter Effect
    ACS Applied Materials & Interfaces, 2017
    Co-Authors: Haijian Liu, Yining Xia, Xueqin Ren
    Abstract:

    In this work, a novel approach for simple and sensitive determination of alkaline phosphatase (ALP) is developed on the basis of an Inner Filter Effect of p-nitrophenylphosphate (PNPP) on the fluorescence of gold nanoclusters (AuNCs). AuNCs with a high quantum yield of 12% were synthesized by one-pot strategy and were directly applied as fluorescent substance. When AuNCs were mixed with PNPP, the fluorescence of the AuNCs was remarkably quenched or was decreased via the Inner Filter Effect since the absorption spectrum of PNPP overlaps well with the excitation spectrum of the AuNCs. While in the presence of ALP, PNPP was catalytically hydrolyzed into p-nitrophenol, which has different absorption characteristics from those of PNPP, resulting in the recovery of the AuNCs fluorescence. Thus, a novel “turn-on” fluorescent sensor for detecting ALP was established with a detection limit as low as 0.002 U/L (signal-to-noise ratio of 3). The turn-on fluorescent sensor exhibits many merits such as high sensitivity...