Rapid diagnosis of Salmonella is crucial for the effective control of food safety incidents, especially in regions with poor hygiene conditions. Polymerase chain reaction(PCR), as a promising tool for Salmonella detec...Rapid diagnosis of Salmonella is crucial for the effective control of food safety incidents, especially in regions with poor hygiene conditions. Polymerase chain reaction(PCR), as a promising tool for Salmonella detection, is facing a lack of simple and fast sensing methods that are compatible with field applications in resource-limited areas. In this work, we developed a sensing approach to identify PCR-amplified Salmonella genomic DNA with the naked eye in a snapshot. Based on the ratiometric fiuorescence signals from SYBR Green Ⅰ and Hydroxyl naphthol blue, positive samples stood out from negative ones with a distinct color pattern under UV exposure. The proposed sensing scheme enabled highly specific identification of Salmonella with a detection limit at the single-copy level. Also, as a supplement to the intuitive naked-eye visualization results, numerical analysis of the colored images was available with a smartphone app to extract RGB values from colored images. This work provides a simple, rapid, and user-friendly solution for PCR identification, which promises great potential in molecular diagnosis of Salmonella and other pathogens in field.展开更多
Manganese(Mn),an essential trace element in the human body,plays critical roles in many biological processes.Recent studies have discovered that Mn^(2+)may promote or directly activate the cGAS-STING pathway,thereby s...Manganese(Mn),an essential trace element in the human body,plays critical roles in many biological processes.Recent studies have discovered that Mn^(2+)may promote or directly activate the cGAS-STING pathway,thereby subsequently initiating the natural immune response and augmenting antitumor therapy.However,the current lack of accurate methods for Mn^(2+)determination in cells significantly limits their mechanism investigation;hence,it is urgent to establish novel tools to detect Mn^(2+)in cells.In this study,the dual-emission carbon dots were initially synthesized via the one-pot hydrothermal method employing L-aspartic acid and p-phenylenediamine as raw materials.In the presence of Mn^(2+),the emission peak centered at 350 nm exhibited significant enhancement,whereas another peak at 610 nm remained stable.Consequently,a ratiometric sensor for Mn^(2+)determination was established using the signal at 350 nm as the responsive signal and the signal at 610 nm as an internal reference.Under the optimal condition,a good linear relationship was achieved between the F350/F610 value and Mn^(2+)concentration ranging from 0.9 to 15μmol/L,with a calculated LOD of 61 nmol/L.Benefiting from the special Mn^(2+)-induced ratiometric approach,this method demonstrates outstanding sensitivity,selectivity,and stability,rendering it applicable for Mn^(2+)determination in complex biological samples,as well as Mn^(2+)imaging in MKN-45 and LO2 cells.展开更多
Photodynamic therapy(PDT)has emerged as a promising approach for tumor treatment due to its noninvasiveness and high selectivity.However,the off-target activation of phototoxicity and the limited availability of tumor...Photodynamic therapy(PDT)has emerged as a promising approach for tumor treatment due to its noninvasiveness and high selectivity.However,the off-target activation of phototoxicity and the limited availability of tumor-specific biomarkers pose challenges for effective PDT.Here,we present the development of a novel ratiometric near-infrared-II(NIR-II)fluorescent organic nanoprobe,BTz-IC@IR1061,which responds specifically to hypochlorite(HClO)within tumors.This nanoprobe allows ratiometric fluorescence imaging to monitor and guide activated tumor PDT.BTz-IC@IR1061 nanoparticles were synthesized by codoping the small molecule dye BTz-IC,which generates reactive oxygen species(ROS),with the commercial dye IR1061.The presence of HClO selectively activates the fluorescence and photodynamic properties of BTz-IC while destroying IR1061,enabling controlled release of ROS for tumor therapy.We demonstrated the high selectivity of the nanoprobe for HClO,as well as its excellent photostability,photoacoustic imaging capability,and photothermal effects.Furthermore,in vivo studies revealed effective tumor targeting and remarkable tumor growth inhibition through tumor-activated PDT.Our findings highlight the potential of BTz-IC@IR1061 as a promising tool for tumor-specific PDT,providing new opportunities for precise and controlled cancer therapy.展开更多
Cancer is a serious global health issue,and exploring effective treatment methods is of great significance for cancer prevention and control.Carbon monoxide(CO),as an important gas signaling molecule in the life syste...Cancer is a serious global health issue,and exploring effective treatment methods is of great significance for cancer prevention and control.Carbon monoxide(CO),as an important gas signaling molecule in the life system,has been proven to have good anti-cancer effects.However,how to controllably,safely,and effectively deliver CO to the tumor site for clinical treatment remains a challenge.Herein,a new metal-free CO-releasing molecule COR-XAC was developed for controlling CO release and cancer therapy.COR-XAC is based on the hybrid of 3-hydroxyl flavone and oxanthracene fluorophores,showing visible light-controlled CO-releasing properties and near-infrared(NIR)ratiometric fluorescence changes at 690 and 760 nm.COR-XAC shows low cytotoxicity and can be successfully applied to release CO in cells and tumors,and the CO-releasing and delivery process could be monitored by its own NIR ratiometric fluorescence changes.More importantly,the anti-cancer performance of COR-XAC was evaluated in 4T1 tumor mice,and it was found that COR-XAC plus light illumination showed excellent tumor inhibition effect,which provided a promising new effective method for cancer treatment.展开更多
Mitochondria are crucial organelles responsible for maintaining cell growth,and their homeostasis is closely linked to p H regulation.Physiologically,mitochondria exhibit a weakly alkaline state(pH~8.0).However,when s...Mitochondria are crucial organelles responsible for maintaining cell growth,and their homeostasis is closely linked to p H regulation.Physiologically,mitochondria exhibit a weakly alkaline state(pH~8.0).However,when subjected to stress stimuli that cause damage,cells initiate the process of mitophagy,resulting in mitochondrial acidification.Therefore,monitoring changes in mitochondrial p H to comprehend the physiological processes associated with mitophagy is essential.In this study,we developed an asymmetric pentamethine cyanine dye Cy5.5-H-Cy N as a probe for continuous monitoring of mitophagy in living cells.By incorporating an azaindole structure into the dye molecule,a ratiometric fluorescence response was achieved that is specifically responsive to p H variations while preserving its ability to target mitochondria and emit near-infrared fluorescence.Through various methods inducing mitophagy,Cy5.5-H-Cy N was employed to determine mitochondrial p H quantitatively,demonstrating its suitability as an ideal probe for continuous monitoring of mitophagy in living cells.展开更多
The fabrication of bioreceptor-free method for accurate and sensitive detection of ochratoxin A(OTA) in cereal is critical, but still a significant challenge to mitigate risks to food industries and public health. In ...The fabrication of bioreceptor-free method for accurate and sensitive detection of ochratoxin A(OTA) in cereal is critical, but still a significant challenge to mitigate risks to food industries and public health. In this study, a smartphone-ratiometric fiuorescence sensor for the ultrasensitive detection of OTA is developed based on a porphyrinic metal-organic framework and silica nanoparticle composite(Zr-MOF/Si NPs)away from the use of antibodies and aptamers. Due to the excellent recognition ability of Zr-MOF and good storage stability of Si NPs, OTA is detected by Zr-MOF/Si NPs with a wide linear range of 0.05–1000 ng/m L and low detection limit of 0.016 ng/m L. Moreover, the red–blue ratio values of the fiuorescence images are extracted through the smartphone color recognizer application with a limit of detection of 1.74 ng/m L, lower than the permissible content of OTA in cereal prescribed by World Health Organization. This sensing platform has been successfully applied in maize samples with superior repeatability and satisfactory recoveries, providing a novel way for simple and label-free analysis of OTA in cereal.展开更多
Developing an accurate and visual sensing strategy for trace levels of fluoroquinolone residues that pose threat to food safety and human health is highly desired but remains challenging.Herein,a target selfcalibratio...Developing an accurate and visual sensing strategy for trace levels of fluoroquinolone residues that pose threat to food safety and human health is highly desired but remains challenging.Herein,a target selfcalibration ratiometric fluorescent sensing platform has been designed for sensitive visual detection of levofloxacin(LEV)based on fluorescent europium metal-organic framework(Eu-MOF)probe.Specifically,the Eu-MOF was facilely synthesized via directly mixing Eu^(3+)with 1,10-phenanthroline-2,9-dicarboxylic acid(PDA)ligand at room temperature,which exhibited well-stable red fluorescence at 612 nm.Upon the addition of target LEV,the significant fluorescence quenching from Eu^(3+)was observed owing to the inner filter effect between the Eu-MOF and LEV.While the intrinsic fluorescence for LEV at 462nm was gradually enhanced,thereby realizing the self-calibration ratiometric fluorescence responses to LEV.Through this strategy,LEV can be detected down to 27 nmol/L.Furthermore,a test paper-based Eu-MOF integrated with the smartphone assisted RGB color analysis was exploited for the quantitative monitoring of LEV through the multi-color changes from red to blue,thus achieved portable,convenient and visual detection of LEV in honey and milk samples.Therefore,the developed strategy could provide a useful tool for supporting the practical on-site test in food samples.展开更多
Gallstones are a common disease worldwide,often leading to obstruction and inflammatory complications,which seriously affect the quality of life of patients.Research has shown that gallstone disease is associated with...Gallstones are a common disease worldwide,often leading to obstruction and inflammatory complications,which seriously affect the quality of life of patients.Research has shown that gallstone disease is associated with ferroptosis,lipid droplets(LDs),and abnormal levels of nitric oxide(NO).Fluorescent probes provide a sensitive and convenient method for detecting important substances in life systems and diseases.However,so far,no fluorescent probes for NO and LDs in gallstone disease have been reported.In this work,an effective ratiometric fluorescent probe LR-NH was designed for the detection of NO in LDs.With an anthracimide fluorophore and a secondary amine as a response site for NO,LR-NH exhibits high selectivity,sensitivity,and attractive ratiometric capability in detecting NO.Importantly,it can target LDs and shows excellent imaging ability for NO in cells and ferroptosis.Moreover,LR-NH can target the gallbladder and image NO in gallstone disease models,providing a unique and unprecedented tool for studying NO in LDs and gallbladder.展开更多
Mixed-lanthanide(Ln) luminescent materials have important application values in ratiometric temperature sensing.Hydrogen-bonded organic frameworks(HOFs) offer a self-supporting network to conveniently tune multiple Ln...Mixed-lanthanide(Ln) luminescent materials have important application values in ratiometric temperature sensing.Hydrogen-bonded organic frameworks(HOFs) offer a self-supporting network to conveniently tune multiple Ln^(3+)ions,but challenges still exist in material design.In this work,we selected two simple organic molecules as hydrogen-bonded building blocks,which are melamine(MA) and 2,5-pyridinedicarboxylic acid(PDC) owning the suitable energy to sensitize Tb^(3+)and Eu^(3+)ions.MA assists PDC molecules to support the network in a new HOF(MA-PDC),where the abundant carboxylic groups enable Ln^(3+)ions to combine with the HOF.Based on the effective energy transfer process,the emission of Tb^(3+)and Eu^(3+)from TbxEu1-x@MA-PDC(x=0.75,0.85,0.90) shows the obvious temperature dependence,which benefits ratiometric temperature detection.Taking Tb0.85Eu0.15@MA-PDC as an example,when temperature varies from 303 to 443 K,the intensity ratio exhibits distinct S-type response based on Mott-Seitz model.It also behaves good relative sensitivity(1.03%/K at 383 K),low temperature resolution(0.059 K) and large reproducibility(>96%).This work demonstrates that functionalization of a simple-component HOF with mixed Ln^(3+)ions is a fantastic strategy to develop novel ratiometric thermometers of both low cost and good performance.展开更多
A 12-metal Zn(Ⅱ)-Nd(Ⅲ) cluster 1(sizes:1.8 nm×2.0 nm×2.0 nm) was synthesized from a long-chain type Schiff base ligand.It displays ratiometric fluorescence response to neopterin(Neo) with high selectivity ...A 12-metal Zn(Ⅱ)-Nd(Ⅲ) cluster 1(sizes:1.8 nm×2.0 nm×2.0 nm) was synthesized from a long-chain type Schiff base ligand.It displays ratiometric fluorescence response to neopterin(Neo) with high selectivity and sensitivity,which can be expressed by the equation I_(545)_(nm)/I_(1060)_(nm)=A·[Neo]^(2)+B·[Neo]+C.1 is used to quantitatively test Neo concentrations in fetal calf serum(FCS) and urine,and the recovery ranges are 98.57%-103.82% and 99.25%-103.50%,respectively,while the relative standard deviations(RSDs) are 7.89%-9.46% and 1.85%-4.16%,respectively.The limits of detection of 1 to Neo in FCS and urine are 0.034 and 0.021 μmol/L,respectively.展开更多
Introduction of porosity and fluorescent properties into lanthanide metal-organic frameworks(MOFs)with rational design to achieve multifunctional use is of great significance from the energy and environmental viewpoin...Introduction of porosity and fluorescent properties into lanthanide metal-organic frameworks(MOFs)with rational design to achieve multifunctional use is of great significance from the energy and environmental viewpoint.In this study,a microporous Tb(Ⅲ)-based MOF with the formula of{[Tb2(oba)3(Phen)2](DMF)2(H2O)4}_n(1)was solvothermally prepared via using the mixed ligands of 1,10-phenanthroline(Phen)and 4,4'-oxybis(benzoic acid)(H_(2)oba)as organic connecters.The structural evaluation results indicate that complex 1 is composed of binuclear Tb2(CO_(2))6(Phen)2clusters which are extended by the oba^(2-)ligands to afford a two-fold interpenetrated framework with one-dimensional microporous channels along the b-axis.Gas sorption studies show that the activated 1 demonstrates a high ideal adsorption solution theory(IAST)sorption selectivity of 7.4 toward C_(2)H_(2)in a C_(2)H_(2)/CO_(2)gas mixture,which are further supported by the dynamic breakthrough experiments.The grand canonical Monte Carlo(GCMC)simulation results indicate that the synergistic effects of the H-bond interactions of C_(2)H_(2)with oba^(2-)ligands and the C-H…πinteractions with Phen ligand contribute to the strong binding of the framework toward C_(2)H_(2)molecules.What's more,the luminescent measurements reveal that the emission of 1 features both the characteristic peaks of Phen ligand and Tb(Ⅲ)ion,which could be further applied as a self-calibrating sensor for the Cr(Ⅵ)detection in water.To the best of our knowledge,complex 1 represents the first example of Tb-MOF holding such a high C_(2)H_(2)/CO_(2)selectivity together with ratiometric Cr(Ⅵ)detection performances.展开更多
A novel Eu^(2+)-Eu^(3+)co-activated ratiometric thermo-sensitive phosphor was developed and synthesized by solid-state reaction.The valence state of Eu,photoluminescence and thermo-sensitive performance of the phospho...A novel Eu^(2+)-Eu^(3+)co-activated ratiometric thermo-sensitive phosphor was developed and synthesized by solid-state reaction.The valence state of Eu,photoluminescence and thermo-sensitive performance of the phosphor prepared either in ambient air or carbothermally were investigated and discussed.The phosphor shows high sensitivity(Sa=0.0173 K^(-1),S_(r)=0.461%/K)and superior signal discriminability(Δν∼10380 cm^(−1)).The thermo-sensitive performance is subject to the dual effects of different thermo-responses by Eu^(2+)versus Eu^(3+)combined with energy transfer from Eu^(2+)to Eu^(3+),so that the sensitivity of the phosphor in the temperature range presents a non-monotonic trend.The development of the BaAl_(2)B_(2)O_(7):Eu^(2+),Eu^(3+)phosphor is not only expected to be relevant for application in the field of temperature sensing,but also of reference significance for improving the sensitivity by means of energy transfer between co-activator ions over a wider temperature range of Eu^(2+)-Eu^(3+)co-activated ratiometric thermo-sensitive phosphors.展开更多
A ratiometric fluorescent probe for hypoxanthine(Hx)detection was established based on the mimic enzyme and fluorescence characteristics of cobalt-doped graphite-phase carbon nitride(Co doped g-C_(3)N_(4)).In addition...A ratiometric fluorescent probe for hypoxanthine(Hx)detection was established based on the mimic enzyme and fluorescence characteristics of cobalt-doped graphite-phase carbon nitride(Co doped g-C_(3)N_(4)).In addition to emitting strong fluorescence,the peroxidase activity of Co doped g-C_(3)N_(4)can catalyze the reaction of O-phenylenediamine and H_(2)O_(2)to produce diallyl phthalate which can emit yellow fluorescence at 570 nm.Through the decomposition of Hx by xanthine oxidase,Hx can be indirectly detected by the generating hydrogen peroxide based on the measurement of fluorescent ratio I(F_(570)/F_(370)).The linear range was 1.7-272.2 mg/kg(R^(2)=0.997),and the detection limit was 1.52 mg/kg(3σ/K,n=9).The established method was applied to Hx detection in bass,grass carp,and shrimp,and the data were verified by HPLC.The result shows that the established probe is sensitive,accurate,and reliable,and can be used for Hx detection in aquatic products.展开更多
Oxygen(O_(2))-sensing matrices are promising tools for the live monitoring of extracellular O_(2) consumption levels in long-term cell cultures.In this study,ratiometric O_(2)-sensing membranes were prepared by electr...Oxygen(O_(2))-sensing matrices are promising tools for the live monitoring of extracellular O_(2) consumption levels in long-term cell cultures.In this study,ratiometric O_(2)-sensing membranes were prepared by electrospinning,an easy,low-cost,scalable,and robust method for fabricating nanofibers.Poly(ε-caprolactone)and poly(dimethyl)siloxane polymers were blended with tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II)dichloride,which was used as the O_(2)-sensing probe,and rhodamine B isothiocyanate,which was used as the reference dye.The functionalized scaffolds were morphologically characterized by scanning electron microscopy,and their physicochemical profiles were obtained by Fourier transform infrared spectroscopy,thermogravimetric analysis,and water contact angle measurement.The sensing capabilities were investigated by confocal laser scanning microscopy,performing photobleaching,reversibility,and calibration curve studies toward different dissolved O_(2)(DO)concentrations.Electrospun sensing nanofibers showed a high response to changes in DO concentrations in the physiological-pathological range from 0.5%to 20%and good stability under ratiometric imaging.In addition,the sensing systems were highly biocompatible for cell growth promoting adhesiveness and growth of three cancer cell lines,namely metastatic melanoma cell line SK-MEL2,breast cancer cell line MCF-7,and pancreatic ductal adenocarcinoma cell line Panc-1,thus recreating a suitable biological environment in vitro.These O_(2)-sensing biomaterials can potentially measure alterations in cell metabolism caused by changes in ambient O_(2)content during drug testing/validation and tissue regeneration processes.展开更多
Accurate and sensitive strategies for Concanavalin A(Con A)sensing are conducive to the better cognition of various important biological and physiological processes.Here,by designing dextran-functionalized fluorescent...Accurate and sensitive strategies for Concanavalin A(Con A)sensing are conducive to the better cognition of various important biological and physiological processes.Here,by designing dextran-functionalized fluorescent microspheres(DxFMs)and boric acid-modified carbon dots(BCDs)as recognition unit and built-in signal reference respectively,a ratiometric fluorescent detection platform was proposed for Con A detection with high reliability.In this protocol,the BCDs/DxFMs precipitation was formed due to the covalent interactions between cis-diol of DxFMs and boronic acid groups of BCDs,thus only fluorescence of BCDs could be detected in the supernatant.When Con A was presented,it could bind to DxFMs through its carbohydrate recognition ability and suppress the subsequent assembly between DxFMs and BCDs,leading to the simultaneous capture of DxFMs and BCDs fluorescence in the supernatant.Since the BCDs content was superfluous,their fluorescence intensities were basically constant in all cases.Based on the unchanged BCDs fluorescence signal and target-dependent DxFMs fluorescence signal in supernatant,the ratiometric detection of Con A was realized.Under optimized conditions,this ratiometric fluorescent platform displayed a linear detection range from 0.125μg/mL to 12.5μg/mL with a detection limit of 0.089μg/mL.Moreover,satisfied analytical outcomes for Con A detection in serum samples were obtained,manifesting huge application potential of this ratiometric fluorescent platform in clinical diagnosis.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
Mercury(Hg^(2+))has been recognized as a global pollutant with a toxic,mobile,and persistent nature.It adversely affects the ecosystem and human health.Already developed biosensors for Hg^(2+)detection majorly suffer ...Mercury(Hg^(2+))has been recognized as a global pollutant with a toxic,mobile,and persistent nature.It adversely affects the ecosystem and human health.Already developed biosensors for Hg^(2+)detection majorly suffer from poor sensitivity and specificity.Herein,a colorimetric/fluorimetric dual-mode sensing approach is designed for the quantitative detection of Hg^(2+).This novel sensing approach utilizes nanofluorophores,i.e.,fluorescent copper nanoclusters-doped zirconia metal-organic framework(CuNCs@Zr-MOF)nanoconjugate(blue color)and N-methyl mesoporphyrin IX(NMM)(red color)in combination with peroxidase-mimicking G-quadruplex DNAzyme(PMDNAzyme).In the presence of Hg^(2+),dabcyl conjugated complementary DNA with T-T mismatches form the stable duplex with the CuNCs@Zr-MOF@G-quadruplex structure through T-Hg^(2+)-T base pairing.It causes the quenching of fluorescence of CuNCs@Zr-MOF(463 nm)due to the Förster resonance energy transfer(FRET)system.Moreover,the G-quadruplex(G4)structure of the aptamer enhances the fluorescence emission of NMM(610 nm).Besides this,the peroxidase-like activity of G4/hemin DNAzyme offers the colorimetric detection of Hg^(2+).The formation of duplex with PMDNAzyme increases the catalytic activity.This novel biosensing probe quantitatively detected Hg^(2+)using both fluorimetry and colorimetry approaches with a low detection limit of 0.59 and 36.3 nM,respectively.It was also observed that the presence of interfering metal ions in case of real aqueous samples does not affect the performance of this novel biosensing probe.These findings confirm the considerable potential of the proposed biosensing probe to screen the concentration of Hg^(2+)in aquatic products.展开更多
A ratiometric fluorescence probe,NClO,for the rapid and selective detection of HClO had been designed and synthesized based on a 1,8-naphthalimide derivative.Probe NClO displayed a red emission(λmax=615 nm).In the pr...A ratiometric fluorescence probe,NClO,for the rapid and selective detection of HClO had been designed and synthesized based on a 1,8-naphthalimide derivative.Probe NClO displayed a red emission(λmax=615 nm).In the presence of HClO,the solution of probe NClO gave off a strong green fluorescence(λem,max=520 nm)with a rapid response(within seconds).This probe had been applied to image HClO in living cells and zebra fish.展开更多
Intracellular pH plays a significant role in various biological processes, including cell proliferation,apoptosis, metabolism, enzyme activity and homeostasis. In this work, a novel design strategy for the preparation...Intracellular pH plays a significant role in various biological processes, including cell proliferation,apoptosis, metabolism, enzyme activity and homeostasis. In this work, a novel design strategy for the preparation of pH responsive carbon dots(CDs-pH) for ratiometric intracellular imaging was reported. By using SciFinder database, fluorescent CDs-pH with the required p Kavalue of 6.84 were rationally designed, which is vital important for precise sensing of intracellular pH. As a result, the synthesized CDspH demonstrated robust ability to test pH fluctuations within the physiological range of 5.4-7.4. The CDspH was further utilized for fluorescent ratiometric imaging of pH in living HeLa cells, effectively avoided the influence of autofluorescence from native cellular species. Moreover, real-time monitoring of intracellular pH fluctuation under heat shock was successfully realized. This SciFinder-guided design strategy is simple and flexible, which has a great potential to be used for the development of other types of CDs for various applications.展开更多
The reactive oxygen species(ROS) are tightly associated with endoplasmic reticulum(ER) stress.Thus,the deep and visual insight of aberrant ROS fluctuations in the ER can help us better investigate the ER stress-associ...The reactive oxygen species(ROS) are tightly associated with endoplasmic reticulum(ER) stress.Thus,the deep and visual insight of aberrant ROS fluctuations in the ER can help us better investigate the ER stress-associated pathology.In this work,a fluorescent probe ERC for HOCI detection in the ER based on phenothiazine-derived coumarin platform was developed.In the presence of HOCI,ERC exhibited an emission change from 609 nm to 503 nm within seconds.It also showed high sensitivity(0.44 μmol/L)and superb photostability.Significantly,ERC displayed low cytotoxicity,good cell membrane permeability,and appreciable ER-targetability.Ultimately,the probe was successfully utilized to image exogenous and endogenous HOCl in living cells and reveal the HOCI burst in cisplatin-treated cancer cells.展开更多
基金supported by the Macao Science and Technology Development Fund(FDCT)(Nos.FDCT 0029/2021/A1,FDCT0002/2021/AKP,004/2023/SKL,0036/2021/APD)University of Macao(No.MYRG-GRG2023-00034-IME,SRG2024-00057IME)+2 种基金Dr.Stanley Ho Medical Development Foundation(No.SHMDF-OIRFS/2024/001)Zhuhai Huafa Group(No.HF-006-2021)Guangdong Science and Technology Department(No.2022A0505030022)。
文摘Rapid diagnosis of Salmonella is crucial for the effective control of food safety incidents, especially in regions with poor hygiene conditions. Polymerase chain reaction(PCR), as a promising tool for Salmonella detection, is facing a lack of simple and fast sensing methods that are compatible with field applications in resource-limited areas. In this work, we developed a sensing approach to identify PCR-amplified Salmonella genomic DNA with the naked eye in a snapshot. Based on the ratiometric fiuorescence signals from SYBR Green Ⅰ and Hydroxyl naphthol blue, positive samples stood out from negative ones with a distinct color pattern under UV exposure. The proposed sensing scheme enabled highly specific identification of Salmonella with a detection limit at the single-copy level. Also, as a supplement to the intuitive naked-eye visualization results, numerical analysis of the colored images was available with a smartphone app to extract RGB values from colored images. This work provides a simple, rapid, and user-friendly solution for PCR identification, which promises great potential in molecular diagnosis of Salmonella and other pathogens in field.
基金Supported by National Natural Science Foundation of China(22264023)Natural Science Foundation of Shaanxi Province(2024JC-YBQN-0150)+2 种基金Yan'an Science and Technology Bureau Project(2023-SFGG-057)Scientific Research Projects of Education Department of Shaanxi Province(22JK0614)PhD Start Fund of Yan'an University(YDBK2022-15)。
文摘Manganese(Mn),an essential trace element in the human body,plays critical roles in many biological processes.Recent studies have discovered that Mn^(2+)may promote or directly activate the cGAS-STING pathway,thereby subsequently initiating the natural immune response and augmenting antitumor therapy.However,the current lack of accurate methods for Mn^(2+)determination in cells significantly limits their mechanism investigation;hence,it is urgent to establish novel tools to detect Mn^(2+)in cells.In this study,the dual-emission carbon dots were initially synthesized via the one-pot hydrothermal method employing L-aspartic acid and p-phenylenediamine as raw materials.In the presence of Mn^(2+),the emission peak centered at 350 nm exhibited significant enhancement,whereas another peak at 610 nm remained stable.Consequently,a ratiometric sensor for Mn^(2+)determination was established using the signal at 350 nm as the responsive signal and the signal at 610 nm as an internal reference.Under the optimal condition,a good linear relationship was achieved between the F350/F610 value and Mn^(2+)concentration ranging from 0.9 to 15μmol/L,with a calculated LOD of 61 nmol/L.Benefiting from the special Mn^(2+)-induced ratiometric approach,this method demonstrates outstanding sensitivity,selectivity,and stability,rendering it applicable for Mn^(2+)determination in complex biological samples,as well as Mn^(2+)imaging in MKN-45 and LO2 cells.
基金supported by the National Natural Science Foundation of China(Nos.22374040,U21A20287,21974039,21890744)the Key Projects of National Natural Science Foundation of China(No.22234003)+1 种基金the National Key R&D Program of China(No.2019YFA0210100)the Fundamental Research Funds for the Central Universities.
文摘Photodynamic therapy(PDT)has emerged as a promising approach for tumor treatment due to its noninvasiveness and high selectivity.However,the off-target activation of phototoxicity and the limited availability of tumor-specific biomarkers pose challenges for effective PDT.Here,we present the development of a novel ratiometric near-infrared-II(NIR-II)fluorescent organic nanoprobe,BTz-IC@IR1061,which responds specifically to hypochlorite(HClO)within tumors.This nanoprobe allows ratiometric fluorescence imaging to monitor and guide activated tumor PDT.BTz-IC@IR1061 nanoparticles were synthesized by codoping the small molecule dye BTz-IC,which generates reactive oxygen species(ROS),with the commercial dye IR1061.The presence of HClO selectively activates the fluorescence and photodynamic properties of BTz-IC while destroying IR1061,enabling controlled release of ROS for tumor therapy.We demonstrated the high selectivity of the nanoprobe for HClO,as well as its excellent photostability,photoacoustic imaging capability,and photothermal effects.Furthermore,in vivo studies revealed effective tumor targeting and remarkable tumor growth inhibition through tumor-activated PDT.Our findings highlight the potential of BTz-IC@IR1061 as a promising tool for tumor-specific PDT,providing new opportunities for precise and controlled cancer therapy.
基金supported by the National Natural Science Foundation of China(Nos.22077044 and 21672080)the Natural Science Foundation of Hubei Province(No.2022CFA033)the funding from Wuhan Institute of Photochemistry and Technology(No.GHY2023KF008).
文摘Cancer is a serious global health issue,and exploring effective treatment methods is of great significance for cancer prevention and control.Carbon monoxide(CO),as an important gas signaling molecule in the life system,has been proven to have good anti-cancer effects.However,how to controllably,safely,and effectively deliver CO to the tumor site for clinical treatment remains a challenge.Herein,a new metal-free CO-releasing molecule COR-XAC was developed for controlling CO release and cancer therapy.COR-XAC is based on the hybrid of 3-hydroxyl flavone and oxanthracene fluorophores,showing visible light-controlled CO-releasing properties and near-infrared(NIR)ratiometric fluorescence changes at 690 and 760 nm.COR-XAC shows low cytotoxicity and can be successfully applied to release CO in cells and tumors,and the CO-releasing and delivery process could be monitored by its own NIR ratiometric fluorescence changes.More importantly,the anti-cancer performance of COR-XAC was evaluated in 4T1 tumor mice,and it was found that COR-XAC plus light illumination showed excellent tumor inhibition effect,which provided a promising new effective method for cancer treatment.
基金supported by the Fundamental Research Funds for the Central Universities(Nos.DUT23YG137 and DUT22LAB601)Liaoning Binhai Laboratory(No.LBLB-202303)+1 种基金Liaoning Province Science and Technology Joint Fund(Nos.2023JH2/101800039 and 2023JH2/101800037)National Natural Science Foundation of China(Nos.21925802,22090011,and 21878039)。
文摘Mitochondria are crucial organelles responsible for maintaining cell growth,and their homeostasis is closely linked to p H regulation.Physiologically,mitochondria exhibit a weakly alkaline state(pH~8.0).However,when subjected to stress stimuli that cause damage,cells initiate the process of mitophagy,resulting in mitochondrial acidification.Therefore,monitoring changes in mitochondrial p H to comprehend the physiological processes associated with mitophagy is essential.In this study,we developed an asymmetric pentamethine cyanine dye Cy5.5-H-Cy N as a probe for continuous monitoring of mitophagy in living cells.By incorporating an azaindole structure into the dye molecule,a ratiometric fluorescence response was achieved that is specifically responsive to p H variations while preserving its ability to target mitochondria and emit near-infrared fluorescence.Through various methods inducing mitophagy,Cy5.5-H-Cy N was employed to determine mitochondrial p H quantitatively,demonstrating its suitability as an ideal probe for continuous monitoring of mitophagy in living cells.
基金funding from the National Natural Science Foundation of China (No. 31871877)the National Key Research and Development Program of China (No. 2019YFC1606303)。
文摘The fabrication of bioreceptor-free method for accurate and sensitive detection of ochratoxin A(OTA) in cereal is critical, but still a significant challenge to mitigate risks to food industries and public health. In this study, a smartphone-ratiometric fiuorescence sensor for the ultrasensitive detection of OTA is developed based on a porphyrinic metal-organic framework and silica nanoparticle composite(Zr-MOF/Si NPs)away from the use of antibodies and aptamers. Due to the excellent recognition ability of Zr-MOF and good storage stability of Si NPs, OTA is detected by Zr-MOF/Si NPs with a wide linear range of 0.05–1000 ng/m L and low detection limit of 0.016 ng/m L. Moreover, the red–blue ratio values of the fiuorescence images are extracted through the smartphone color recognizer application with a limit of detection of 1.74 ng/m L, lower than the permissible content of OTA in cereal prescribed by World Health Organization. This sensing platform has been successfully applied in maize samples with superior repeatability and satisfactory recoveries, providing a novel way for simple and label-free analysis of OTA in cereal.
基金supported by the National Natural Science Foundation of China(Nos.32260247 and 22064010)the Natural Science Foundation of Jiangxi Province(Nos.20232BAB215071 and 20224BAB213009).
文摘Developing an accurate and visual sensing strategy for trace levels of fluoroquinolone residues that pose threat to food safety and human health is highly desired but remains challenging.Herein,a target selfcalibration ratiometric fluorescent sensing platform has been designed for sensitive visual detection of levofloxacin(LEV)based on fluorescent europium metal-organic framework(Eu-MOF)probe.Specifically,the Eu-MOF was facilely synthesized via directly mixing Eu^(3+)with 1,10-phenanthroline-2,9-dicarboxylic acid(PDA)ligand at room temperature,which exhibited well-stable red fluorescence at 612 nm.Upon the addition of target LEV,the significant fluorescence quenching from Eu^(3+)was observed owing to the inner filter effect between the Eu-MOF and LEV.While the intrinsic fluorescence for LEV at 462nm was gradually enhanced,thereby realizing the self-calibration ratiometric fluorescence responses to LEV.Through this strategy,LEV can be detected down to 27 nmol/L.Furthermore,a test paper-based Eu-MOF integrated with the smartphone assisted RGB color analysis was exploited for the quantitative monitoring of LEV through the multi-color changes from red to blue,thus achieved portable,convenient and visual detection of LEV in honey and milk samples.Therefore,the developed strategy could provide a useful tool for supporting the practical on-site test in food samples.
基金supported by the National Natural Science Foundation of China(No.22077044)the Natural Science Foundation of Hubei Province(No.2022CFA033).
文摘Gallstones are a common disease worldwide,often leading to obstruction and inflammatory complications,which seriously affect the quality of life of patients.Research has shown that gallstone disease is associated with ferroptosis,lipid droplets(LDs),and abnormal levels of nitric oxide(NO).Fluorescent probes provide a sensitive and convenient method for detecting important substances in life systems and diseases.However,so far,no fluorescent probes for NO and LDs in gallstone disease have been reported.In this work,an effective ratiometric fluorescent probe LR-NH was designed for the detection of NO in LDs.With an anthracimide fluorophore and a secondary amine as a response site for NO,LR-NH exhibits high selectivity,sensitivity,and attractive ratiometric capability in detecting NO.Importantly,it can target LDs and shows excellent imaging ability for NO in cells and ferroptosis.Moreover,LR-NH can target the gallbladder and image NO in gallstone disease models,providing a unique and unprecedented tool for studying NO in LDs and gallbladder.
基金Project supported by the Zhejiang Provincial Natural Science Foundation of China (LY24E020005)Industrial Key Projects of Jinhua City(2023-1-090)。
文摘Mixed-lanthanide(Ln) luminescent materials have important application values in ratiometric temperature sensing.Hydrogen-bonded organic frameworks(HOFs) offer a self-supporting network to conveniently tune multiple Ln^(3+)ions,but challenges still exist in material design.In this work,we selected two simple organic molecules as hydrogen-bonded building blocks,which are melamine(MA) and 2,5-pyridinedicarboxylic acid(PDC) owning the suitable energy to sensitize Tb^(3+)and Eu^(3+)ions.MA assists PDC molecules to support the network in a new HOF(MA-PDC),where the abundant carboxylic groups enable Ln^(3+)ions to combine with the HOF.Based on the effective energy transfer process,the emission of Tb^(3+)and Eu^(3+)from TbxEu1-x@MA-PDC(x=0.75,0.85,0.90) shows the obvious temperature dependence,which benefits ratiometric temperature detection.Taking Tb0.85Eu0.15@MA-PDC as an example,when temperature varies from 303 to 443 K,the intensity ratio exhibits distinct S-type response based on Mott-Seitz model.It also behaves good relative sensitivity(1.03%/K at 383 K),low temperature resolution(0.059 K) and large reproducibility(>96%).This work demonstrates that functionalization of a simple-component HOF with mixed Ln^(3+)ions is a fantastic strategy to develop novel ratiometric thermometers of both low cost and good performance.
基金Project supported by the National Natural Science Foundation of China (21771141)。
文摘A 12-metal Zn(Ⅱ)-Nd(Ⅲ) cluster 1(sizes:1.8 nm×2.0 nm×2.0 nm) was synthesized from a long-chain type Schiff base ligand.It displays ratiometric fluorescence response to neopterin(Neo) with high selectivity and sensitivity,which can be expressed by the equation I_(545)_(nm)/I_(1060)_(nm)=A·[Neo]^(2)+B·[Neo]+C.1 is used to quantitatively test Neo concentrations in fetal calf serum(FCS) and urine,and the recovery ranges are 98.57%-103.82% and 99.25%-103.50%,respectively,while the relative standard deviations(RSDs) are 7.89%-9.46% and 1.85%-4.16%,respectively.The limits of detection of 1 to Neo in FCS and urine are 0.034 and 0.021 μmol/L,respectively.
基金Project supported by the National Natural Science Foundation of China(U23A20579)。
文摘Introduction of porosity and fluorescent properties into lanthanide metal-organic frameworks(MOFs)with rational design to achieve multifunctional use is of great significance from the energy and environmental viewpoint.In this study,a microporous Tb(Ⅲ)-based MOF with the formula of{[Tb2(oba)3(Phen)2](DMF)2(H2O)4}_n(1)was solvothermally prepared via using the mixed ligands of 1,10-phenanthroline(Phen)and 4,4'-oxybis(benzoic acid)(H_(2)oba)as organic connecters.The structural evaluation results indicate that complex 1 is composed of binuclear Tb2(CO_(2))6(Phen)2clusters which are extended by the oba^(2-)ligands to afford a two-fold interpenetrated framework with one-dimensional microporous channels along the b-axis.Gas sorption studies show that the activated 1 demonstrates a high ideal adsorption solution theory(IAST)sorption selectivity of 7.4 toward C_(2)H_(2)in a C_(2)H_(2)/CO_(2)gas mixture,which are further supported by the dynamic breakthrough experiments.The grand canonical Monte Carlo(GCMC)simulation results indicate that the synergistic effects of the H-bond interactions of C_(2)H_(2)with oba^(2-)ligands and the C-H…πinteractions with Phen ligand contribute to the strong binding of the framework toward C_(2)H_(2)molecules.What's more,the luminescent measurements reveal that the emission of 1 features both the characteristic peaks of Phen ligand and Tb(Ⅲ)ion,which could be further applied as a self-calibrating sensor for the Cr(Ⅵ)detection in water.To the best of our knowledge,complex 1 represents the first example of Tb-MOF holding such a high C_(2)H_(2)/CO_(2)selectivity together with ratiometric Cr(Ⅵ)detection performances.
基金Project supported by the Central Funding Project for Local Science and Technology Development(2022JH6/100100048)the National Natural Science Foundation of China(52103038)Shenyang Science and Technology Plan Project(20-202-1-12)。
文摘A novel Eu^(2+)-Eu^(3+)co-activated ratiometric thermo-sensitive phosphor was developed and synthesized by solid-state reaction.The valence state of Eu,photoluminescence and thermo-sensitive performance of the phosphor prepared either in ambient air or carbothermally were investigated and discussed.The phosphor shows high sensitivity(Sa=0.0173 K^(-1),S_(r)=0.461%/K)and superior signal discriminability(Δν∼10380 cm^(−1)).The thermo-sensitive performance is subject to the dual effects of different thermo-responses by Eu^(2+)versus Eu^(3+)combined with energy transfer from Eu^(2+)to Eu^(3+),so that the sensitivity of the phosphor in the temperature range presents a non-monotonic trend.The development of the BaAl_(2)B_(2)O_(7):Eu^(2+),Eu^(3+)phosphor is not only expected to be relevant for application in the field of temperature sensing,but also of reference significance for improving the sensitivity by means of energy transfer between co-activator ions over a wider temperature range of Eu^(2+)-Eu^(3+)co-activated ratiometric thermo-sensitive phosphors.
基金supported by the National Natural Science Foundation of China(21804050)the National Key R and D Program of China(2018YFD0901003)+2 种基金the Science and Technology Planning Project of Xiamen,China(3502Z20183031)the Fujian Provincial Fund Project(2018J01432)the Xiamen Science and Technology Planning Project,China(3502Z20183031)。
文摘A ratiometric fluorescent probe for hypoxanthine(Hx)detection was established based on the mimic enzyme and fluorescence characteristics of cobalt-doped graphite-phase carbon nitride(Co doped g-C_(3)N_(4)).In addition to emitting strong fluorescence,the peroxidase activity of Co doped g-C_(3)N_(4)can catalyze the reaction of O-phenylenediamine and H_(2)O_(2)to produce diallyl phthalate which can emit yellow fluorescence at 570 nm.Through the decomposition of Hx by xanthine oxidase,Hx can be indirectly detected by the generating hydrogen peroxide based on the measurement of fluorescent ratio I(F_(570)/F_(370)).The linear range was 1.7-272.2 mg/kg(R^(2)=0.997),and the detection limit was 1.52 mg/kg(3σ/K,n=9).The established method was applied to Hx detection in bass,grass carp,and shrimp,and the data were verified by HPLC.The result shows that the established probe is sensitive,accurate,and reliable,and can be used for Hx detection in aquatic products.
基金funding from the European Research Council (ERC) under the European Union’s (EU’s) Horizon 2020 research and innovation program ERC Starting Grant “INTERCELLMED” (No. 759959)the EU’s Horizon 2020 research and innovation program under grant agreement No. 953121 (FLAMIN-GO)+7 种基金the Associazione Italiana per la Ricerca contro il Cancro (AIRCMFAG-2019No. 22902)the “Tecnopolo per la medicina di precisione” (Tecno Med Puglia)-Regione Puglia: DGR n.2117 of 21/11/2018, B84I18000540002the Italian Ministry of Research (MUR) in the framework of the National Recovery and Resilience Plan (NRRP), “NFFA-DI” Grant (n. B53C22004310006), “I-PHOQS” Grant (n. B53C22001750006) and under the complementary actions to the NRRP, “Fit4MedRob” Grant (PNC0000007, n. B53C22006960001), “ANTHEM” Grant (PNC0000003, n. B53C22006710001), funded by Next Generation EUthe PRIN 2022 (2022CRFNCP_PE11_PRIN2022) funded by European Union-Next Generation EUthe financial support provided under the project “HEALTH-UNORTE: Setting-up biobanks and regenerative medicine strategies to boost research in cardiovascular, musculoskeletal, neurological, oncological, immunological, and infectious diseases” (reference NORTE-01-0145FEDER-000039) funded by the Norte Portugal Regional Coordination and Development Commission (CCDR-N) under the NORTE2020 Programthe AIRC Short-term Fellowship program
文摘Oxygen(O_(2))-sensing matrices are promising tools for the live monitoring of extracellular O_(2) consumption levels in long-term cell cultures.In this study,ratiometric O_(2)-sensing membranes were prepared by electrospinning,an easy,low-cost,scalable,and robust method for fabricating nanofibers.Poly(ε-caprolactone)and poly(dimethyl)siloxane polymers were blended with tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II)dichloride,which was used as the O_(2)-sensing probe,and rhodamine B isothiocyanate,which was used as the reference dye.The functionalized scaffolds were morphologically characterized by scanning electron microscopy,and their physicochemical profiles were obtained by Fourier transform infrared spectroscopy,thermogravimetric analysis,and water contact angle measurement.The sensing capabilities were investigated by confocal laser scanning microscopy,performing photobleaching,reversibility,and calibration curve studies toward different dissolved O_(2)(DO)concentrations.Electrospun sensing nanofibers showed a high response to changes in DO concentrations in the physiological-pathological range from 0.5%to 20%and good stability under ratiometric imaging.In addition,the sensing systems were highly biocompatible for cell growth promoting adhesiveness and growth of three cancer cell lines,namely metastatic melanoma cell line SK-MEL2,breast cancer cell line MCF-7,and pancreatic ductal adenocarcinoma cell line Panc-1,thus recreating a suitable biological environment in vitro.These O_(2)-sensing biomaterials can potentially measure alterations in cell metabolism caused by changes in ambient O_(2)content during drug testing/validation and tissue regeneration processes.
基金supported by the Key Project of Science and Technology of Henan Province(No.212102310334)National Natural Science Foundation of China(Nos.21974125,22174131).
文摘Accurate and sensitive strategies for Concanavalin A(Con A)sensing are conducive to the better cognition of various important biological and physiological processes.Here,by designing dextran-functionalized fluorescent microspheres(DxFMs)and boric acid-modified carbon dots(BCDs)as recognition unit and built-in signal reference respectively,a ratiometric fluorescent detection platform was proposed for Con A detection with high reliability.In this protocol,the BCDs/DxFMs precipitation was formed due to the covalent interactions between cis-diol of DxFMs and boronic acid groups of BCDs,thus only fluorescence of BCDs could be detected in the supernatant.When Con A was presented,it could bind to DxFMs through its carbohydrate recognition ability and suppress the subsequent assembly between DxFMs and BCDs,leading to the simultaneous capture of DxFMs and BCDs fluorescence in the supernatant.Since the BCDs content was superfluous,their fluorescence intensities were basically constant in all cases.Based on the unchanged BCDs fluorescence signal and target-dependent DxFMs fluorescence signal in supernatant,the ratiometric detection of Con A was realized.Under optimized conditions,this ratiometric fluorescent platform displayed a linear detection range from 0.125μg/mL to 12.5μg/mL with a detection limit of 0.089μg/mL.Moreover,satisfied analytical outcomes for Con A detection in serum samples were obtained,manifesting huge application potential of this ratiometric fluorescent platform in clinical diagnosis.
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Funding:S.K.thanks the Department of Biotechnology(DBT),Government of India,for research grant(award BT/PR18868/BCE/8/1370/2016 dated 2018 January 31)M.N.is grateful to CSIR for the SRA fellowship(no.B-12857,dated 2021 October 21).
文摘Mercury(Hg^(2+))has been recognized as a global pollutant with a toxic,mobile,and persistent nature.It adversely affects the ecosystem and human health.Already developed biosensors for Hg^(2+)detection majorly suffer from poor sensitivity and specificity.Herein,a colorimetric/fluorimetric dual-mode sensing approach is designed for the quantitative detection of Hg^(2+).This novel sensing approach utilizes nanofluorophores,i.e.,fluorescent copper nanoclusters-doped zirconia metal-organic framework(CuNCs@Zr-MOF)nanoconjugate(blue color)and N-methyl mesoporphyrin IX(NMM)(red color)in combination with peroxidase-mimicking G-quadruplex DNAzyme(PMDNAzyme).In the presence of Hg^(2+),dabcyl conjugated complementary DNA with T-T mismatches form the stable duplex with the CuNCs@Zr-MOF@G-quadruplex structure through T-Hg^(2+)-T base pairing.It causes the quenching of fluorescence of CuNCs@Zr-MOF(463 nm)due to the Förster resonance energy transfer(FRET)system.Moreover,the G-quadruplex(G4)structure of the aptamer enhances the fluorescence emission of NMM(610 nm).Besides this,the peroxidase-like activity of G4/hemin DNAzyme offers the colorimetric detection of Hg^(2+).The formation of duplex with PMDNAzyme increases the catalytic activity.This novel biosensing probe quantitatively detected Hg^(2+)using both fluorimetry and colorimetry approaches with a low detection limit of 0.59 and 36.3 nM,respectively.It was also observed that the presence of interfering metal ions in case of real aqueous samples does not affect the performance of this novel biosensing probe.These findings confirm the considerable potential of the proposed biosensing probe to screen the concentration of Hg^(2+)in aquatic products.
基金supported by the National Natural Science Foundation of China(No.U1608222)the State Key Laboratory of Fine Chemicals(No.KF1606)the financial support from Fundamental Research Funds for the Central Universities of Central South University(No.2018zzts109)
文摘A ratiometric fluorescence probe,NClO,for the rapid and selective detection of HClO had been designed and synthesized based on a 1,8-naphthalimide derivative.Probe NClO displayed a red emission(λmax=615 nm).In the presence of HClO,the solution of probe NClO gave off a strong green fluorescence(λem,max=520 nm)with a rapid response(within seconds).This probe had been applied to image HClO in living cells and zebra fish.
基金financial support from the National Natural Science Foundation of China (No. 21205108)the Foundation for University Key Teacher by Henan Province (No. 2017GGJS007)+1 种基金China Postdoctoral Science Foundation (Nos. 2017M620302, 2018T110736)the Key Scientific Research Project in Universities of Henan Province (No. 19A150048)
文摘Intracellular pH plays a significant role in various biological processes, including cell proliferation,apoptosis, metabolism, enzyme activity and homeostasis. In this work, a novel design strategy for the preparation of pH responsive carbon dots(CDs-pH) for ratiometric intracellular imaging was reported. By using SciFinder database, fluorescent CDs-pH with the required p Kavalue of 6.84 were rationally designed, which is vital important for precise sensing of intracellular pH. As a result, the synthesized CDspH demonstrated robust ability to test pH fluctuations within the physiological range of 5.4-7.4. The CDspH was further utilized for fluorescent ratiometric imaging of pH in living HeLa cells, effectively avoided the influence of autofluorescence from native cellular species. Moreover, real-time monitoring of intracellular pH fluctuation under heat shock was successfully realized. This SciFinder-guided design strategy is simple and flexible, which has a great potential to be used for the development of other types of CDs for various applications.
基金This work was supported by the Hubei Provincial Department of Education Science and Technology Research Projects(No.Q20182704).
文摘The reactive oxygen species(ROS) are tightly associated with endoplasmic reticulum(ER) stress.Thus,the deep and visual insight of aberrant ROS fluctuations in the ER can help us better investigate the ER stress-associated pathology.In this work,a fluorescent probe ERC for HOCI detection in the ER based on phenothiazine-derived coumarin platform was developed.In the presence of HOCI,ERC exhibited an emission change from 609 nm to 503 nm within seconds.It also showed high sensitivity(0.44 μmol/L)and superb photostability.Significantly,ERC displayed low cytotoxicity,good cell membrane permeability,and appreciable ER-targetability.Ultimately,the probe was successfully utilized to image exogenous and endogenous HOCl in living cells and reveal the HOCI burst in cisplatin-treated cancer cells.
