A new ratiometric fluorescent sensor based on the bifunctional carbon quantum dots(CQDs)@metal-organic framework(MOF)nanocomposite possessing peroxidase-mimicking catalytic and luminescent characteristics was develope...A new ratiometric fluorescent sensor based on the bifunctional carbon quantum dots(CQDs)@metal-organic framework(MOF)nanocomposite possessing peroxidase-mimicking catalytic and luminescent characteristics was developed for hydrogen peroxide(H_(2)O_(2))and cholesterol detection.The incorporation of fluorescent CQDs into the cavities of MIL-101(Fe)MOF with peroxidase-like activities endows the nanocomposite with bifunctional properties.The CQDs@MOF can oxidize o-phenylene-diamine to 2,3-diaminophenolazine by H_(2)O_(2)with yellow fluorescence(556 nm).Meantime,the intrinsic fluorescence signal(455 nm)of CQDs@MOF is inhibited due to the inner filter effect.Therefore,the ratio of the fluorescent intensity is employed as the signal output to construct the H_(2)O_(2)ratiometric biosensor.In addition,the cholesterol can be determined by the ratiometric sensor with high sensitivity.In addition,the total cholesterol in human serum is determined with high accuracy using our ratiometric biosensor.This ratiometric fluorescent platform based on the bifunctional CQDs@MOF provides new insights in the field of bio-sensing.展开更多
Long-term excessive intake of nitrite(NO_(2)^(-))poses a great threat to human health,needing a simple and fast method to detect NO_(2)-in food.Herein,via a simple and feasible strategy,Mn/Yb/Er triple-doped CeO_(2) n...Long-term excessive intake of nitrite(NO_(2)^(-))poses a great threat to human health,needing a simple and fast method to detect NO_(2)-in food.Herein,via a simple and feasible strategy,Mn/Yb/Er triple-doped CeO_(2) nanozyme(Mn/Yb/Er/CeO_(2))was synthesized for highly sensitive ratiometric detection of nitrite.By doping Mn,Yb,Er into CeO_(2) lattice structure,Mn/Yb/Er/CeO_(2) nanozyme showed enhanced oxidase-like activity,obtaining a higher density of oxygen vacancy and a higher ratio of Ce^(3+)to Ce~(4+)than that of CeO_(2).The 3,3,5,5-tetramethylbenzidine(TMB)can be effectively oxidized by Mn/Yb/Er/CeO_(2) to produce the oxidized TMB(ox TMB),showing a significant absorption signal at 652 nm.Additionally,nitrite can react with ox TMB to produce yellow diazotized ox TMB,which is accompanied by an elevated absorption signal at 445 nm and a decreased absorption signal at 652 nm.Thus,based on the oxidase-mimetic activity of Mn/Yb/Er/CeO_(2) and the diazotization reaction between NO_(2)^(-)and ox TMB,a ratiometric colorimetric assay was established for NO_(2)^(-)detection in food.Furthermore,by integrating Mn/Yb/Er/CeO_(2) with a smartphone,a colorimetric smartphone-sensing platform was successfully fabricated for visualization and quantitative detection of NO_(2)^(-).Notably,this two-detection mode showed excellent sensitivity,selectivity,reliability and practicability in monitoring the NO_(2)^(-)in real samples,impling its great potential for food safety.展开更多
Levofloxacin(LVFX)as a representative drug of quinolone antibiotics is widely used in clinical,and its residues enriched in water bodies and sideline products seriously damage human health.It is imperative to develop ...Levofloxacin(LVFX)as a representative drug of quinolone antibiotics is widely used in clinical,and its residues enriched in water bodies and sideline products seriously damage human health.It is imperative to develop a real-time/on-site sensing method for monitoring residual antibiotics.Here,we report a portable sensing platform by utilizing a composite fluorescent nanoprobe constructed by the cerium ions(Ce^(3+))coordination functionalized Cd Te quantum dots(QDs)for the visual and quantitative detection of LVFX residues.This fluorescent probe provides a distinct color variation from red to green,which shows a good linear relationship to LVFX residues concentrations in the range of 0-6.0μmol/L with a sensitive limit of detection(LOD)of 16.3 nmol/L.The smartphone platform with Color Analyzer App installed,which could accomplish quantified detection of LVFX in water,milk,and raw pork with a LOD of 27.9nmol/L.The facile sensing method we proposed realizes rapid visualization of antibiotics residual in the environment and provides a practical application pathway in food safety and human health.展开更多
Multiplexed intracellular detection is desirable in biomedical sciences for its higher eficiency and accuracy compared to the single-analyte detection.However,it is very challenging to construct nanoprobes that posses...Multiplexed intracellular detection is desirable in biomedical sciences for its higher eficiency and accuracy compared to the single-analyte detection.However,it is very challenging to construct nanoprobes that possess multiple fluorescent signals to recognize the different intracellular species synchronously.Herein,we proposed a novel dual-excitation/dual-emission upconversion strategy for multiplexed detection through the design of upconversion nanoparticles(UCNP)loaded with two dyes for sensitization and quenching of the upconversion luminescence(UCL),respectively.Based on the two independent energy transfer processes of near-infrared(NIR)dye IR845 to UCNP and UCNP to visible dye PAPS-Zn,CIO-and Zn2+were simultaneously detected with a limit of detection(LOD)of41.4 and 10.5 nM,respectively.By tilizing a purpose built 830/980 nm dual-laser confocal microscope,both intrinsic and exogenous CIO and Zn2+in live MCF-7 cells have been accurately quantified.Such dual-excitation/dual-emission ratiometric UCL detection mode enables not only monitoring multiple intracellular analytes but also eliminating the detection deviation caused by inhomogeneous probe distribution in cells.Through modulation of NIR dye and visible dye with other reactive groups,the nanoprobes can be extended to analyze various intraellular species,which provides a promising tool to study the biological activities in live cells and diagnose diseases.展开更多
The pH values of lysosomes in cancer cells is slightly lower than that in normal cells, which can be used to distinguish cancer cells from normal cells. According to this, a naphthalimide-rhodamine based fluorescent p...The pH values of lysosomes in cancer cells is slightly lower than that in normal cells, which can be used to distinguish cancer cells from normal cells. According to this, a naphthalimide-rhodamine based fluorescent probe（hereafter referred to as RBN） with a pK_a of 4.20 was designed and synthesized for ratiometric sensing of cellular pH via fluorescence resonance energy transfer（FRET）, which can respond to different pH precisely through ratiometric fluorescence intensity（Ⅰ_（577）/Ⅰ_（540））. RBN can be employed to distinguish cancer cells from normal cells on the basis of different fluorescent response, in particular, RBN showed excellent water solubility and low cell toxicity, all these are quite significant for potential application in cancer diagnose and therapy.展开更多
Hypochlorous acid（HOCl） plays a vital role in many physiological and pathological processes as one of reactive oxygen species（ROS）. Developing highly sensitive and selective methods for HOCl detection is of signif...Hypochlorous acid（HOCl） plays a vital role in many physiological and pathological processes as one of reactive oxygen species（ROS）. Developing highly sensitive and selective methods for HOCl detection is of significant interest. In this work, we developed a benzothiazole based probe 1 for ratiometric fluorescence detection of hypochlorite in living cells. The probe can detect HOCl with high selectivity, fast response（within 30 s） as well as low detection limit（0.18 mmol/L）. Fluorescence co-localization studies demonstrated that probe 1 was a mitochondria-targeted fluorescent probe. Furthermore, confocal fluorescence images of He La cell indicated that probe 1 could be used for monitoring intracellular HOCl in living cells. Finally, test strips experiment suggests that the probe 1 can detect the hypochlorous acid in tap water accompanied by remarkable color change.展开更多
Ratiometric biosensor is among the promising strategies for the advanced analysis;its applicability in multiple scenarios,however,is seriously limited for the fixed analytical feature.Here,we reported ratiometric elec...Ratiometric biosensor is among the promising strategies for the advanced analysis;its applicability in multiple scenarios,however,is seriously limited for the fixed analytical feature.Here,we reported ratiometric electrochemical biosensors with programmable analytical feature by alternating the binding site of ferrocene(Fc)to DNA duplex for the detection of aflatoxin B1(AFB1).DNA duplex was synthesized with AFB1 aptamer and its complementary DNA(cDNA)with Fc molecular tagged on aptamer or cDNA.For analysis,aptamer-AFB1 complex stripped from the electrode,and free cDNA triggered hybridization chain reaction to produce double-stranded DNA for methylene blue(MB)absorption.In this way,redox currents of Fc(I_(Fc))and absorbed MB(I_(MB))at the electrode were collected to produce the ratiometric signal of I_(MB)/I_(Fc)as a yardstick for AFB1.When Fc was tagged on aptamer,IFc decreased with higher concentration of AFB1(C_(AFB1)),the resultant biosensor allowed detection with an On/Off(I_(MB)/I_(Fc))mode;when Fc was tagged on cDNA,I_(Fc) kept constant as C_(AFB1)varying,offering an On/Constant(I_(MB)/I_(Fc))mode for the detection.Consequently,biosensor with On/Off mode showed a linear range of 0.1—100 pg/mL with a limit of detection(LOD)of 0.0650 pg/mL,while biosensor with On/Constant mode offered a wider linear rang of 1—10000 pg/mL but a relatively poor LOD of 0.330 pg/mL.Our work revealed the vital importance of binding site of probes to DNA,and this principle can endow ratiometric biosensor with programmable analytical feature(e.g.,linear range,LOD),allowing detections in various scenarios.展开更多
基金support from the NSFC(21705141,22076161,21675140,21575124)the Green Yang Jinfeng Talent Project of Yangzhou+1 种基金the High-end talent Support Program of Yangzhou Universitythe Interdisciplinary Research Foundation for Chemistry Discipline of Targeted Support of Yangzhou University(yzuxk202009)
文摘A new ratiometric fluorescent sensor based on the bifunctional carbon quantum dots(CQDs)@metal-organic framework(MOF)nanocomposite possessing peroxidase-mimicking catalytic and luminescent characteristics was developed for hydrogen peroxide(H_(2)O_(2))and cholesterol detection.The incorporation of fluorescent CQDs into the cavities of MIL-101(Fe)MOF with peroxidase-like activities endows the nanocomposite with bifunctional properties.The CQDs@MOF can oxidize o-phenylene-diamine to 2,3-diaminophenolazine by H_(2)O_(2)with yellow fluorescence(556 nm).Meantime,the intrinsic fluorescence signal(455 nm)of CQDs@MOF is inhibited due to the inner filter effect.Therefore,the ratio of the fluorescent intensity is employed as the signal output to construct the H_(2)O_(2)ratiometric biosensor.In addition,the cholesterol can be determined by the ratiometric sensor with high sensitivity.In addition,the total cholesterol in human serum is determined with high accuracy using our ratiometric biosensor.This ratiometric fluorescent platform based on the bifunctional CQDs@MOF provides new insights in the field of bio-sensing.
基金supported by the National Natural Science Foundation of China(Nos.22004111 and 21974125)the Tackle Key Problems in Science and Technology Project of Henan Province,China(No.222102310386)+3 种基金China Postdoctoral Science Foundation(No.2020M682327)Henan Postdoctoral Foundation(No.202002009)Program for Innovative Research Team(in Science and Technology)in University of Henan Province(No.22TRTSTHN002)Excellent Youth Foundation of Henan Scientific Committee(No.232300421021)。
文摘Long-term excessive intake of nitrite(NO_(2)^(-))poses a great threat to human health,needing a simple and fast method to detect NO_(2)-in food.Herein,via a simple and feasible strategy,Mn/Yb/Er triple-doped CeO_(2) nanozyme(Mn/Yb/Er/CeO_(2))was synthesized for highly sensitive ratiometric detection of nitrite.By doping Mn,Yb,Er into CeO_(2) lattice structure,Mn/Yb/Er/CeO_(2) nanozyme showed enhanced oxidase-like activity,obtaining a higher density of oxygen vacancy and a higher ratio of Ce^(3+)to Ce~(4+)than that of CeO_(2).The 3,3,5,5-tetramethylbenzidine(TMB)can be effectively oxidized by Mn/Yb/Er/CeO_(2) to produce the oxidized TMB(ox TMB),showing a significant absorption signal at 652 nm.Additionally,nitrite can react with ox TMB to produce yellow diazotized ox TMB,which is accompanied by an elevated absorption signal at 445 nm and a decreased absorption signal at 652 nm.Thus,based on the oxidase-mimetic activity of Mn/Yb/Er/CeO_(2) and the diazotization reaction between NO_(2)^(-)and ox TMB,a ratiometric colorimetric assay was established for NO_(2)^(-)detection in food.Furthermore,by integrating Mn/Yb/Er/CeO_(2) with a smartphone,a colorimetric smartphone-sensing platform was successfully fabricated for visualization and quantitative detection of NO_(2)^(-).Notably,this two-detection mode showed excellent sensitivity,selectivity,reliability and practicability in monitoring the NO_(2)^(-)in real samples,impling its great potential for food safety.
基金financially supported by National Natural Science Foundation of China(No.21876175)National Key Research and Development Program(No.2021YFD2000200)Key Research and Development Program of Anhui Province(No.202004d07020013)。
文摘Levofloxacin(LVFX)as a representative drug of quinolone antibiotics is widely used in clinical,and its residues enriched in water bodies and sideline products seriously damage human health.It is imperative to develop a real-time/on-site sensing method for monitoring residual antibiotics.Here,we report a portable sensing platform by utilizing a composite fluorescent nanoprobe constructed by the cerium ions(Ce^(3+))coordination functionalized Cd Te quantum dots(QDs)for the visual and quantitative detection of LVFX residues.This fluorescent probe provides a distinct color variation from red to green,which shows a good linear relationship to LVFX residues concentrations in the range of 0-6.0μmol/L with a sensitive limit of detection(LOD)of 16.3 nmol/L.The smartphone platform with Color Analyzer App installed,which could accomplish quantified detection of LVFX in water,milk,and raw pork with a LOD of 27.9nmol/L.The facile sensing method we proposed realizes rapid visualization of antibiotics residual in the environment and provides a practical application pathway in food safety and human health.
基金the Science and Technology Cooperation Fund between Chinese and Australian Governments(No.2017YFE0132300)the Strategic Priority Research Program of the CAS(No.XDB20000000)+2 种基金the National Natural Science Foundation of China(Nos.51672272,21771185,21771178,and 21975257)Youth Innovation Promotion Association of CAS(No.2017347)the CAS/SAFEA International Partnership Program for Creative Research Teams.
文摘Multiplexed intracellular detection is desirable in biomedical sciences for its higher eficiency and accuracy compared to the single-analyte detection.However,it is very challenging to construct nanoprobes that possess multiple fluorescent signals to recognize the different intracellular species synchronously.Herein,we proposed a novel dual-excitation/dual-emission upconversion strategy for multiplexed detection through the design of upconversion nanoparticles(UCNP)loaded with two dyes for sensitization and quenching of the upconversion luminescence(UCL),respectively.Based on the two independent energy transfer processes of near-infrared(NIR)dye IR845 to UCNP and UCNP to visible dye PAPS-Zn,CIO-and Zn2+were simultaneously detected with a limit of detection(LOD)of41.4 and 10.5 nM,respectively.By tilizing a purpose built 830/980 nm dual-laser confocal microscope,both intrinsic and exogenous CIO and Zn2+in live MCF-7 cells have been accurately quantified.Such dual-excitation/dual-emission ratiometric UCL detection mode enables not only monitoring multiple intracellular analytes but also eliminating the detection deviation caused by inhomogeneous probe distribution in cells.Through modulation of NIR dye and visible dye with other reactive groups,the nanoprobes can be extended to analyze various intraellular species,which provides a promising tool to study the biological activities in live cells and diagnose diseases.
基金supported by the National Natural Science Foundation of China (Nos. 21272030, 21472016, 21306019, 21576042)
文摘The pH values of lysosomes in cancer cells is slightly lower than that in normal cells, which can be used to distinguish cancer cells from normal cells. According to this, a naphthalimide-rhodamine based fluorescent probe（hereafter referred to as RBN） with a pK_a of 4.20 was designed and synthesized for ratiometric sensing of cellular pH via fluorescence resonance energy transfer（FRET）, which can respond to different pH precisely through ratiometric fluorescence intensity（Ⅰ_（577）/Ⅰ_（540））. RBN can be employed to distinguish cancer cells from normal cells on the basis of different fluorescent response, in particular, RBN showed excellent water solubility and low cell toxicity, all these are quite significant for potential application in cancer diagnose and therapy.
基金supported by the National Natural Science Foundation of China(Nos.21376117,21406109 and 31401588)the Jiangsu Natural Science Funds for Distinguished Young Scholars(No.BK20140043)+1 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.14KJA150005)the Qing Lan Project and the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Hypochlorous acid（HOCl） plays a vital role in many physiological and pathological processes as one of reactive oxygen species（ROS）. Developing highly sensitive and selective methods for HOCl detection is of significant interest. In this work, we developed a benzothiazole based probe 1 for ratiometric fluorescence detection of hypochlorite in living cells. The probe can detect HOCl with high selectivity, fast response（within 30 s） as well as low detection limit（0.18 mmol/L）. Fluorescence co-localization studies demonstrated that probe 1 was a mitochondria-targeted fluorescent probe. Furthermore, confocal fluorescence images of He La cell indicated that probe 1 could be used for monitoring intracellular HOCl in living cells. Finally, test strips experiment suggests that the probe 1 can detect the hypochlorous acid in tap water accompanied by remarkable color change.
基金supported by the National Natural Science Foundation of China(Nos.61901193,22074055)the Natural Science Foundation of Jiangsu Province(No.BK20200104)the Innovation/Entrepreneurship Program of Jiangsu Province,the Project of Faculty of Agricultural Equipment of Jiangsu University,and Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Ratiometric biosensor is among the promising strategies for the advanced analysis;its applicability in multiple scenarios,however,is seriously limited for the fixed analytical feature.Here,we reported ratiometric electrochemical biosensors with programmable analytical feature by alternating the binding site of ferrocene(Fc)to DNA duplex for the detection of aflatoxin B1(AFB1).DNA duplex was synthesized with AFB1 aptamer and its complementary DNA(cDNA)with Fc molecular tagged on aptamer or cDNA.For analysis,aptamer-AFB1 complex stripped from the electrode,and free cDNA triggered hybridization chain reaction to produce double-stranded DNA for methylene blue(MB)absorption.In this way,redox currents of Fc(I_(Fc))and absorbed MB(I_(MB))at the electrode were collected to produce the ratiometric signal of I_(MB)/I_(Fc)as a yardstick for AFB1.When Fc was tagged on aptamer,IFc decreased with higher concentration of AFB1(C_(AFB1)),the resultant biosensor allowed detection with an On/Off(I_(MB)/I_(Fc))mode;when Fc was tagged on cDNA,I_(Fc) kept constant as C_(AFB1)varying,offering an On/Constant(I_(MB)/I_(Fc))mode for the detection.Consequently,biosensor with On/Off mode showed a linear range of 0.1—100 pg/mL with a limit of detection(LOD)of 0.0650 pg/mL,while biosensor with On/Constant mode offered a wider linear rang of 1—10000 pg/mL but a relatively poor LOD of 0.330 pg/mL.Our work revealed the vital importance of binding site of probes to DNA,and this principle can endow ratiometric biosensor with programmable analytical feature(e.g.,linear range,LOD),allowing detections in various scenarios.
