Mercury ion(Hg^(2+)),a highly noxious of heavy metalion,has detrimental effects on the ecological environment and human health.Herein,we have developed an exonuclease III(Exo III)assisted catalytic hairpin assembly fo...Mercury ion(Hg^(2+)),a highly noxious of heavy metalion,has detrimental effects on the ecological environment and human health.Herein,we have developed an exonuclease III(Exo III)assisted catalytic hairpin assembly formation of a trivalent G-quadruplex/hemin DNAzyme for colorimetric detection of Hg^(2+).A hairpin DNA(Hr)was designed with thymine-Hg^(2+)-thymine pairs that catalyzed by Exo III is prompted to happen upon binding Hg^(2+).A released DNA fragment triggers the catalytic assembly of other three hairpins(H1,H2,and H3)to form many trivalent G-quadruplex/hemin DNA enzymes for signal output.The developed sensor shows a dynamic range from 2 pM to 2μM,with an impressively low detection limit of 0.32 pM for Hg^(2+)detection.Such a sensor also has good selectivity toward Hg^(2+)detection in the presence of other common metal ions.This strategy shows the great potential for visual detection with portable type.展开更多
Triangular silver nanoprisms were prepared and applied to make colorimetric detection of cysteine based on our findings that cysteine could lead to the blue shift of the dipole plasmon resonance absorption, but other ...Triangular silver nanoprisms were prepared and applied to make colorimetric detection of cysteine based on our findings that cysteine could lead to the blue shift of the dipole plasmon resonance absorption, but other 19 kinds of natural amino acids could not. Cysteine with a concentration 160 nmol/L can result in a color change that can be discerned with naked eyes.展开更多
The exploitation of multifunctional nanocomposites is highly desired in environmental monitoring,biosensors,and medical diagnosis.In this paper,a simple approach has been proposed to fabricate MoS2 decorated N-doped c...The exploitation of multifunctional nanocomposites is highly desired in environmental monitoring,biosensors,and medical diagnosis.In this paper,a simple approach has been proposed to fabricate MoS2 decorated N-doped carbon nanotubes(NCNTs@MoS2)hybrid composites as efficient peroxidase-like mimics.The combination of the MoS2 and N-doped carbon nanotubes(NCNTs)brings about an enhanced synergistic effect,leading to remarkably decent intrinsic peroxidase-mimic activities than that of the single components.Due to the high catalytic efficiency of the resultant NCNTs@MoS2 hybrid nanotubes as peroxidase-like mimics,a co nvenient colorimetric approach for the sensitive determination of H2 O2 and ascorbic acid have been developed with a detection limit of about 0.14μmol/L and 0.12μmol/L,respectively.The work offers a new strategy for the fabrication of peroxidase-like nanomaterials with excellent catalytic activity,which indicates great promising applications in sensitive detections in real samples.展开更多
This work presents efficient tetracycline(TC) antibiotics adsorption using a functional porous phosphate/carbonate composite(PCC). The PCC was fabricated by anion-exchange of phosphate on the surface of vaterite-phase...This work presents efficient tetracycline(TC) antibiotics adsorption using a functional porous phosphate/carbonate composite(PCC). The PCC was fabricated by anion-exchange of phosphate on the surface of vaterite-phase calcium carbonate particle scaffolds. The PCC,having dense nanoporous network coverage with large surface area and pore volume, exhibited excellent TC adsorption in solution. Its adsorption isotherm fitted well to the Freundlich model, with a maximum adsorption capacity of 118.72 mg/g. The adsorption process was spontaneous, endothermic, and followed pseudo-second-order kinetics. From the XPS analysis, the hydrogen bonding and surface complexation were the key interactions in the process. In addition, a colorimetric TC detection method was developed considering its complexation with phosphate ions, originating from PCC dissolution, during adsorption.The method was used to detect TC in mg/L concentrations in water samples. Thus, the multifunctional PCC exhibited potential for use in TC removal and environmental remediation.展开更多
Aerogels have become a hot topic of research due to their extremely low density and special interconnected structure as well as their enzyme-like activity.The development of new multifunctional nano-enzyme aerogels wi...Aerogels have become a hot topic of research due to their extremely low density and special interconnected structure as well as their enzyme-like activity.The development of new multifunctional nano-enzyme aerogels with high activity and good stability is still a considerable challenge.In this paper,AuRu aerogels with peroxidase and oxidase activities were synthesized using a simple one-step method and successfully used to construct colorimetric sensors for the detection of Fe^(2+)and glucose based on their enzyme-like activities.Furthermore,we are fortunate to find that AuRu aerogels have good photothermal properties.This suggests that AuRu aerogels can be used not only for in vitro testing but also for promising applications such as disease treatment.展开更多
A new method has been proposed to realize the visual detection of D-amino acids （DAAs） via the antiaggregation of 4-mercaptobenzoic acid modified gold nanoparticles （AuNPs） in the presence of D-amino acid oxidase ...A new method has been proposed to realize the visual detection of D-amino acids （DAAs） via the antiaggregation of 4-mercaptobenzoic acid modified gold nanoparticles （AuNPs） in the presence of D-amino acid oxidase （DAAO）. The negatively charged AuNPs were prepared using sodium citrate as a reducer and stabilizer. The presence of 4-mercaptobenzoic acid （4-MBA） and Cu2＋ induces the aggregation of AuNPs, resulting in a color change from ruby red to royal purple. However, DAAO could oxidize DAAs to generate H2O2. In the presence of H2O2, the mercapto （-SH） group in 4-mercaptobenzoic acid can be oxidized to form a disulfide （-S-S-） bond. Based on these facts, the pre-incubation of DAAs and 4-mercaptobenzoic acid with DAAO would significantly reduce the concentration of free 4-mercaptobenzoic acid molecules, thus the aggregation of AuNPs was interrupted since due to the lack of inducer. As the concentration of DAAs increases, the color of the AuNPs solution would progress from royal purple to ruby red. Consequently, DAAs could be monitored by the colorimetric response of AuNPs using a UV-vis spectrophotometer or even naked eyes. This DAAO mediated visual detection method could determine D- alanine （D-Ala） as a representative DAA with concentrations ranging from 1.5 × 10^-7mol L 1 to 3.0 × 10^-5 mol L^-1, and the detection limit was as low as 7.5 × 10^-8 mol L^-1. The proposed method is convenient, low-cost and free of complex equipment, making it feasible to analyze the concentration of D-AIa in real samples of β-amyloid peptide （Aβ1-42）.展开更多
Two bis-naphthalimide-based supramolecular gelators(NN-3 and NN-4)with a little difference of position of amino groups were designed and synthesized for the detection of oxaloyl chloride and phosgene.Energy transfer c...Two bis-naphthalimide-based supramolecular gelators(NN-3 and NN-4)with a little difference of position of amino groups were designed and synthesized for the detection of oxaloyl chloride and phosgene.Energy transfer could be occurred between two naphthalimide groups in molecules NN-3 and NN-4.Yellow gels NN-3 and NN-4 were formed in some mixed solvents,and nanofibers with different size were obtained in these gels.The self-assembly processes of NN-3 and NN-4 in different solvents were investigated by UV-vis absorption,fluorescent spectra,SEM,FTIR,XRD and NMR.Gelators NN-3 and NN-4 could selectively detect oxaloyl chloride in solution and film states,but detect phosgene only in solution.NN-3exhibited the ratiometric detection ability towards oxaloyl chloride and phosgene with the low limit of detection(LOD)of 210 nmol/L and 90 nmol/L,respectively.NN-4 as the corresponding control sample,it owned the higher LOD towards oxaloyl chloride and phosgene of 12.4μmol/L and 64μmol/L,respectively.Interestingly,films NN-3 and NN-4 could sensitively detect oxaloyl chloride gases with the low LOD of2.0 ppm and 8.34 ppm,respectively.The detection mechanisms of NN-3 and NN-4 were well studied by1H NMR titration,HRMS and theoretical calculation.展开更多
A simple, cheap and non-enzymatic colorimetric strategy for glucose detection has been designed based on the interactions between a phenylboronic acid （PBA） derivative, which is coupled with gold nanoparticles （Au...A simple, cheap and non-enzymatic colorimetric strategy for glucose detection has been designed based on the interactions between a phenylboronic acid （PBA） derivative, which is coupled with gold nanoparticles （AuNPs） as the colorimetric reporters, and glucose. The PBA-AuNPs hybrid system proposed here exhibits ordered photochemistry behaviors upon the addition of glucose at different pH values. There are two linear regions of glucose concentration for the glucose sensor at different pH values, i.e., between 0.1 mmol/L and 9.8 mmol/L at pH 6 with the detection limit of 64μmol/L and between 0 and 6.5 mmol/L with the detection limit of 48 μmol/L at pH 9, respectively. To test the practicality of the sensor system, we also applied this assay to detect a glucose sample in the artificial saliva.展开更多
With natural polyphenol compound tannic acid(TA)as the ingredient,copper tannate(CuTA)nanolayer material was formed by self-assembly under the conditions of heating and copper ion.Copper ion and tannic acid could coor...With natural polyphenol compound tannic acid(TA)as the ingredient,copper tannate(CuTA)nanolayer material was formed by self-assembly under the conditions of heating and copper ion.Copper ion and tannic acid could coordinate to form Cu-O-C structure which was similar to the Fe-N-C structure of natural heme enzymes.In addition,the obtained CuTA nanomaterial possessed excellent peroxidase-like catalytic activity and stability.Based on this excellent enzymatic activity,CuTA nanomaterials could be used for colorimetric detection of hydrogen peroxide with a smartphone and decomposition of organic dyes.Based on the structural characteristics and catalytic activity,the copper tannate nanozymes could also serve as potential antibacterial reagents to effectively inhibit the growth of gram-negative and positive bacteria in a low hydrogen peroxide level.This work may promote the exploration of novel peroxidase mimetics and broaden the applications of nanozymes.展开更多
Biomimetic nanozymes opens up new opportunities for sensitive,rapid and field detection of organophosphorus pesticides(OPs).However,it still remains challenges in how to improve the sensitivity and stability of biomim...Biomimetic nanozymes opens up new opportunities for sensitive,rapid and field detection of organophosphorus pesticides(OPs).However,it still remains challenges in how to improve the sensitivity and stability of biomimetic nanozymes under harsh conditions.Herein,we synthesized a novel biomimetic nanozyme composed of hemin and bovine serum albumin(BSA)in the nanopores of poly-l-lysine methacryloyl(PLMA)inverse opal hydrogel(PLMA-Hemin-BSA).PLMA-Hemin-BSA achieves superior peroxidase-like activity and shows high stability due to the confinement effect.A multi-enzyme cascade reaction was constructed for the colorimetric detection of five widely used OPs by integrating PLMAHemin-BSA with natural choline oxidase and acetylcholinesterase.The detection limits for dichlorvos,chlorpyrifos,paraoxon,methamidophos,and parathion were as low as 0.024,0.073,0.12,0.56,and 1.4 ng/mL,respectively.More importantly,the average recovery rates and the relative standard deviations(RSD)of chlorpyrifos in paddy water,soil and wheat samples were 86.62%-100.13%and 2.08%-8.65%,which meet the standard of the International Union of Pure and Applied Chemistry(IUPAC,recoveries of 70%-120%with RSD<20%).This study represented advanced methods toward enhancing the activity and stability of biomimetic nanozymes via spatial nanopores-assisted strategy.展开更多
This review begins with an overview of the appealing properties and various applications of gold nanoparticles, and briefly summarizes recent advances in using unmodified gold nanoparticles to detect different kinds o...This review begins with an overview of the appealing properties and various applications of gold nanoparticles, and briefly summarizes recent advances in using unmodified gold nanoparticles to detect different kinds of targets including nucleic acids, proteins, metal ions and small organic molecules. The key point to the unmodified gold nanoparticle-based visual detection assay is to control dispersion and aggregation of colloidal nanoparticles by targets of interest, which usually relies on affinities between gold nanoparticles and targets. The degree of dispersion or aggregation can be visualized through the change of the solution color or the precipitation of nanoparticles from the solution. Thus, the existence of the target molecules can be trans-lated into optical signals and monitored by the naked eye conveniently. Finally, some future prospects of this research field are given.展开更多
Recently,many efforts have been dedicated to creating enzyme-mimicking catalysts to replace natural enzymes in practical fields.Inspired by the pathological biomineralization behaviour of L-cystine,in this study,we co...Recently,many efforts have been dedicated to creating enzyme-mimicking catalysts to replace natural enzymes in practical fields.Inspired by the pathological biomineralization behaviour of L-cystine,in this study,we constructed a laccase-like catalyst through the co-assembly of L-cystine with Cu ions.Structural analysis revealed that the formed catalytic Cu-cystine nanoleaves(Cu-Cys NLs)possess a Cu(I)-Cu(II)electron transfer system similar to that in natural laccase.Reaction kinetic studies demonstrated that the catalyst follows the typical Michaelis-Menten model.Compared with natural laccase,the Cu-Cys NLs exhibit superior stability during long-term incubation under extreme pH,high-temperature or high-salt conditions.Remarkably,the Cu-Cys NLs could be easily recovered and still maintained 76%of their activity after 8 cycles.Finally,this laccase mimic was employed to develop a colorimetric method for epinephrine detection,which achieved a wider linear range(9–455μmol·L^(−1))and lower limit of detection(2.7μmol·L^(−1)).The Cu-Cys NLs also displayed excellent specificity and sensitivity towards epinephrine in a test based on urine samples.展开更多
Many sensors for Cu^(2+)rely on the catalytic activity of Cu^(2+)to produce a color change,but these colorimetric sensors often suffer from poor selectivity and are susceptible to interference.In this work,we found th...Many sensors for Cu^(2+)rely on the catalytic activity of Cu^(2+)to produce a color change,but these colorimetric sensors often suffer from poor selectivity and are susceptible to interference.In this work,we found that Cu^(2+)-catalyzed TMB oxidation can be significantly improved with excessed nucleotides and nucleosides.Especially,with oversaturated guanosine 5′-monophos-phate(GMP)to form a coordination nanozyme,the catalytic efficiency was greatly accelerated.It can be attributed to the specific binding between the electron-rich oxygen and nitrogen atoms of guanine with Cu^(2+).A sensitive and selective strategy for Cu^(2+)sensing was proposed.Owing to the presence of excessed GMP,it ensures robust activity and less susceptibility to interference.This allowed us to test the sensor in complex samples such as the seawater.This work strongly suggests that by supplying excessed ligands,far exceeding the binding stoichiometry,we may produce more robust sensing systems.展开更多
Lanthanide elements(Ln)play an important role in industry and agriculture.As a result of the increasing consumption of lanthanides,environmental emission of Ln has become detrimental to the health of flora and fauna.C...Lanthanide elements(Ln)play an important role in industry and agriculture.As a result of the increasing consumption of lanthanides,environmental emission of Ln has become detrimental to the health of flora and fauna.Current methods for trace lanthanides detection mainly rely on sophisticated instruments.In this article,a Ln^(3+)dependent DNAzyme was incorporated into a hydrogel to generate Ln^(3+)sensitive DNAzyme hydrogel for portable colorimetric detection.The enzyme strand and its substrate strand act as crosslinker and functional unit of the hydrogel with polyacrylamide chains as the scaffold and gold nanoparticles(AuNPs)as the indicator of hydrogel stability.Any ions in the Ln^(3+)series can trigger the cleavage of substrate strand by activating the enzyme strand,thereby decreasing the crosslink ratio and leading to collapse of the hydrogel.The release of the encapsulated AuNPs turns the supernatant wine red.Using this colorimetric method,Ln^(3+)can be detected with high sensitivity,with a limit of detection(LOD)of 20 nM for Ce^(3+).The hydrogel responds specifically to any Ln^(3+)ion and works well with the spiked lake sample without the need of instruments and skilled operators.Our results suggest that the lanthanide responsive hydrogel can be used for portable and sensitive detection of Ln^(3+)contamination in the field.展开更多
Biological thiols（biothiols）, an important kind of functional biomolecules, such as cysteine（Cys） and glutathione（GSH）, play vital roles in maintaining the stability of the intracellular environment. In past dec...Biological thiols（biothiols）, an important kind of functional biomolecules, such as cysteine（Cys） and glutathione（GSH）, play vital roles in maintaining the stability of the intracellular environment. In past decades, studies have demonstrated that metabolic disorder of biothiols is related to many serious disease processes and will lead to extreme damage in human and numerous animals. We carried out a series of experiments to detect biothiols in biosamples, including bovine plasma and cell lysates of seven different cell lines based on a simple colorimetric method. In a typical test, the color of the test solution could gradually change from blue to colorless after the addition of biothiols. Based on the color change displayed, experimental results reveal that the percentage of biothiols in the embryonic fibroblast cell line is significantly higher than those in the other six cell lines, which provides the basis for the following biothiols-related study.展开更多
Regulating the catalytic activity of nanozymes is significant for their applications in various fields.Here,we demonstrate a new strategy to achieve reversible regulation of the nanozyme’s activity for sensing purpos...Regulating the catalytic activity of nanozymes is significant for their applications in various fields.Here,we demonstrate a new strategy to achieve reversible regulation of the nanozyme’s activity for sensing purpose.This strategy involves the use of zero-dimensional MoS;quantum dots(MQDs)as the building blocks of nanozymes which display very weak peroxidase(POD)-like activity.Interestingly,such POD-like activity of the MQDs largely enhances in the presence of Fe;while diminishes with the addition of captopril thereafter.Further investigations identify the mechanism of Fe;-mediated aggregation-induced enhancement of the POD-like activity and the inhibitory effect of captopril on the enhancement,which is highly dependent on their concentrations.Based on this finding,a colorimetric method for the detection of captopril is developed.This sensing approach exhibits the merits of simplicity,rapidness,reliability,and low cost,which has been successfully applied in quality control of captopril in pharmaceutical products.Moreover,the present sensing platform allows smartphone read-out,which has promising applications in point-of-care testing devices for clinical diagnosis and drug analysis.展开更多
In this work,a metal-organic frameworks material MIL-88 was prepared easily using solvent-thermal method,and was first found to have catalytic activities similar to those of biological enzymes such as catalase and per...In this work,a metal-organic frameworks material MIL-88 was prepared easily using solvent-thermal method,and was first found to have catalytic activities similar to those of biological enzymes such as catalase and peroxidase.The material was characterized by XRD,SEM,TEM,EDX,FT-IR techniques and an N2 adsorption method.It exhibited peroxidase-like activity through catalytic oxidation of the peroxidase substrate 3,3＇,5,5＇-tetramethylbenzidine（TMB） in the presence of H2O2,producing a blue-colored solution.Under optimal conditions,the absorbance at 652 nm is linearly correlated with the concentration of H2O2 from 2.0×10^-6 mol/L to 2.03×10^-5 mol/L（R-2=0.981） with a detection limit of 5.62×10^-7 mol/L（S/N=3）.More importantly,a sensitive and selective method for ascorbic acid detection was developed using this material as a catalyst.The analytical method for ascorbic acid detection was observed to have a linear range from 2.57×10^-6 mol/L to 1.01×10^-5 mol/L（R-2=0.989） with a detection limit of 1.03×10^-6 mol/L（S/N=3）.This work suggests MOFs have advantages of preparing biomimetic catalysts and extends applications of the functional MOFs in the field of biosensor.展开更多
Designing single-atom nanozymes with densely exposed metal atom active sites and enhancing catalytic activity to detect pollutants remain a serious challenge.Herein,we reported a single-atom nanozyme with layered stac...Designing single-atom nanozymes with densely exposed metal atom active sites and enhancing catalytic activity to detect pollutants remain a serious challenge.Herein,we reported a single-atom nanozyme with layered stacked Fe/Cu dual active sites(Fe/Cu-NC SAzyme)synthesized via hydrothermal and hightemperature pyrolysis using folic acid as a template.Compared with Fe-NC and Cu-NC SAzyme,Fe/Cu-NC SAzyme has higher peroxidase-like activity,which indicates that the doping of synthesized Fe/Cu bimetals can improve the catalytic activity and that the atomic loading of Fe and Cu in Fe/Cu-NC is 5.5 wt%and 2.27 wt%,respectively.When S^(2-)is added to the Fe/Cu-NC catalytic system,a high-sensitivity and high-selectivity S^(2-)colorimetric sensing platform can be established,with a wide linear range(0.09-6μmol/L)and a low detection limit(30 nmol/L),which can be used to detect S^(2-)in environmental water samples.What’s more,the Fe/Cu-NC SAzyme can activate peroxymonosulfate(PMS)to degrade 99.9%of rhodamine B(Rh B)within 10 min with a degradation kinetics of 0.5943 min^(-1).This work details attractive applications in Fe/Cu-NC SAzyme colorimetric sensing and dye degradation.展开更多
Circulating tumor cells(CTCs)are important markers for cancer.The part of tumor cells that are detached from the primary tumor or metastatic tumor and enter the blood circulation is called CTCs.It is crucial to develo...Circulating tumor cells(CTCs)are important markers for cancer.The part of tumor cells that are detached from the primary tumor or metastatic tumor and enter the blood circulation is called CTCs.It is crucial to develop a rapid,accurate,and easy-to-implement diagnostic system for CTCs for early tumor diagnosis and for monitoring progression of the disease.In this work,we reported a colorimetric and fluorescent dual-mode assay for the detection of CTCs.Our assay used magnetic nanoparticles and aptamer for CTCs capture and gold nanoparticles-loaded covalent organic frameworks(Au@COFs)for signal amplification,respectively.The magnetic nanoparticles were modified with folic acid to capture CTCs by interaction between folic acid and the folate receptor overexpressed on the surface of tumor cells.The covalent organic frameworks were engineered to have both nitro-reductase-like and glucose–oxidase-like activities.The nitro-reductase-like activity converted the substrate p-nitrophenol to p-nitroaniline for colorimetric detection,and the glucose-oxidase-like activity enabled fluorescence detection.Specifically,Au@COFs catalyzed glucose oxidation and generated hydrogen peroxide to oxidize Fe 2+to Fe 3+,which converted MIL(Al)-MOF to MIL(Fe)-MOF through ion exchange,resulting in the fluorescence quenching of MIL(Al)-MOF.Our assay showed high sensitivity with a detection limit of 17 cells/mL using MCF-7 cells as model cancer cells.This work provided an e fficient and ultrasensitive strategy for CTCs detection and has potential applications in cancer identification and diagnosis.Dual-mode detection system,combining colorimetric and fluorescent signals,integration of magnetic nanoparticles and aptamers for CTC capture,and utilization of covalent organic frameworks loaded with gold nanoparticles for signal amplification can improve sensitivity and accuracy.展开更多
Salmonella Enteritidis is a major public health threat of global proportions,while it is still a serious challenge to develop point-of-care detection assay.In this study,nanozymes(Fe-MOF nanoparticles)were successfull...Salmonella Enteritidis is a major public health threat of global proportions,while it is still a serious challenge to develop point-of-care detection assay.In this study,nanozymes(Fe-MOF nanoparticles)were successfully synthesized and applied as signal in a colorimetric immunoassay for naked-eye detection of Salmonella Enteritidis.After optimization,the proposed assay was able to detect Salmonella Enteritidis with a detection limit of 34 CFU/mL.The coefficients of variation(CV)of the test were less than 7.0%after 30 days storage at 4°C.The estimated recoveries in milk samples of the colorimetric immu-noassay range from 94.68 to 124%,which indicated the developed method is capable of detecting Salmonella Enteritidis in real samples.This method provides a potential platform for Salmonella detection with naked eyes,which has a significant application value for foodborne pathogen analysis at the point-of-care.展开更多
基金Supported by The Science and Technology Project of General Administration of Quality Supervision,Inspection and Quarantine (2015IK126)The Science and Technology Project of Changsha City of Hunan Province of China (KQ1602124).
文摘Mercury ion(Hg^(2+)),a highly noxious of heavy metalion,has detrimental effects on the ecological environment and human health.Herein,we have developed an exonuclease III(Exo III)assisted catalytic hairpin assembly formation of a trivalent G-quadruplex/hemin DNAzyme for colorimetric detection of Hg^(2+).A hairpin DNA(Hr)was designed with thymine-Hg^(2+)-thymine pairs that catalyzed by Exo III is prompted to happen upon binding Hg^(2+).A released DNA fragment triggers the catalytic assembly of other three hairpins(H1,H2,and H3)to form many trivalent G-quadruplex/hemin DNA enzymes for signal output.The developed sensor shows a dynamic range from 2 pM to 2μM,with an impressively low detection limit of 0.32 pM for Hg^(2+)detection.Such a sensor also has good selectivity toward Hg^(2+)detection in the presence of other common metal ions.This strategy shows the great potential for visual detection with portable type.
基金the financial support of the Ministry of Science and Technology of the People's Republic of China(No.2006CB 933100).
文摘Triangular silver nanoprisms were prepared and applied to make colorimetric detection of cysteine based on our findings that cysteine could lead to the blue shift of the dipole plasmon resonance absorption, but other 19 kinds of natural amino acids could not. Cysteine with a concentration 160 nmol/L can result in a color change that can be discerned with naked eyes.
基金financial support by the Natural Science Foundation of Shanghai City(No.18ZR1416400)the National Natural Science Foundation of China(No.21305086)Science and Technology Development Fund of Shanghai Municipal Public Security Bureau(No.2018003)。
文摘The exploitation of multifunctional nanocomposites is highly desired in environmental monitoring,biosensors,and medical diagnosis.In this paper,a simple approach has been proposed to fabricate MoS2 decorated N-doped carbon nanotubes(NCNTs@MoS2)hybrid composites as efficient peroxidase-like mimics.The combination of the MoS2 and N-doped carbon nanotubes(NCNTs)brings about an enhanced synergistic effect,leading to remarkably decent intrinsic peroxidase-mimic activities than that of the single components.Due to the high catalytic efficiency of the resultant NCNTs@MoS2 hybrid nanotubes as peroxidase-like mimics,a co nvenient colorimetric approach for the sensitive determination of H2 O2 and ascorbic acid have been developed with a detection limit of about 0.14μmol/L and 0.12μmol/L,respectively.The work offers a new strategy for the fabrication of peroxidase-like nanomaterials with excellent catalytic activity,which indicates great promising applications in sensitive detections in real samples.
文摘This work presents efficient tetracycline(TC) antibiotics adsorption using a functional porous phosphate/carbonate composite(PCC). The PCC was fabricated by anion-exchange of phosphate on the surface of vaterite-phase calcium carbonate particle scaffolds. The PCC,having dense nanoporous network coverage with large surface area and pore volume, exhibited excellent TC adsorption in solution. Its adsorption isotherm fitted well to the Freundlich model, with a maximum adsorption capacity of 118.72 mg/g. The adsorption process was spontaneous, endothermic, and followed pseudo-second-order kinetics. From the XPS analysis, the hydrogen bonding and surface complexation were the key interactions in the process. In addition, a colorimetric TC detection method was developed considering its complexation with phosphate ions, originating from PCC dissolution, during adsorption.The method was used to detect TC in mg/L concentrations in water samples. Thus, the multifunctional PCC exhibited potential for use in TC removal and environmental remediation.
基金the financial support from Sichuan Province Science and Technology Support Program(No.2020YFN0029)the One-Thousand-Talents Scheme in Sichuan Province,Scientific Start-up Research Fund of Chengdu University of Information Technology(No.KYTZ201714).
文摘Aerogels have become a hot topic of research due to their extremely low density and special interconnected structure as well as their enzyme-like activity.The development of new multifunctional nano-enzyme aerogels with high activity and good stability is still a considerable challenge.In this paper,AuRu aerogels with peroxidase and oxidase activities were synthesized using a simple one-step method and successfully used to construct colorimetric sensors for the detection of Fe^(2+)and glucose based on their enzyme-like activities.Furthermore,we are fortunate to find that AuRu aerogels have good photothermal properties.This suggests that AuRu aerogels can be used not only for in vitro testing but also for promising applications such as disease treatment.
基金supported by the National Natural Science Foundation of China(No.21272263)the State Key Laboratory of Natural and Biomimetic Drugs(No.K20130206)+1 种基金the University of Chinese Academy of Sciences(No.08JT011J01)the Twelfth Five-Year Plan for National Sciences&Technology Support Project(No.2012BAI37B03)
文摘A new method has been proposed to realize the visual detection of D-amino acids （DAAs） via the antiaggregation of 4-mercaptobenzoic acid modified gold nanoparticles （AuNPs） in the presence of D-amino acid oxidase （DAAO）. The negatively charged AuNPs were prepared using sodium citrate as a reducer and stabilizer. The presence of 4-mercaptobenzoic acid （4-MBA） and Cu2＋ induces the aggregation of AuNPs, resulting in a color change from ruby red to royal purple. However, DAAO could oxidize DAAs to generate H2O2. In the presence of H2O2, the mercapto （-SH） group in 4-mercaptobenzoic acid can be oxidized to form a disulfide （-S-S-） bond. Based on these facts, the pre-incubation of DAAs and 4-mercaptobenzoic acid with DAAO would significantly reduce the concentration of free 4-mercaptobenzoic acid molecules, thus the aggregation of AuNPs was interrupted since due to the lack of inducer. As the concentration of DAAs increases, the color of the AuNPs solution would progress from royal purple to ruby red. Consequently, DAAs could be monitored by the colorimetric response of AuNPs using a UV-vis spectrophotometer or even naked eyes. This DAAO mediated visual detection method could determine D- alanine （D-Ala） as a representative DAA with concentrations ranging from 1.5 × 10^-7mol L 1 to 3.0 × 10^-5 mol L^-1, and the detection limit was as low as 7.5 × 10^-8 mol L^-1. The proposed method is convenient, low-cost and free of complex equipment, making it feasible to analyze the concentration of D-AIa in real samples of β-amyloid peptide （Aβ1-42）.
基金financially supported by the National Natural Science Foundation of China(No.U1704164)the Basic Research Project of Henan Provincial Key Scientific Research Project(No.22ZX002)。
文摘Two bis-naphthalimide-based supramolecular gelators(NN-3 and NN-4)with a little difference of position of amino groups were designed and synthesized for the detection of oxaloyl chloride and phosgene.Energy transfer could be occurred between two naphthalimide groups in molecules NN-3 and NN-4.Yellow gels NN-3 and NN-4 were formed in some mixed solvents,and nanofibers with different size were obtained in these gels.The self-assembly processes of NN-3 and NN-4 in different solvents were investigated by UV-vis absorption,fluorescent spectra,SEM,FTIR,XRD and NMR.Gelators NN-3 and NN-4 could selectively detect oxaloyl chloride in solution and film states,but detect phosgene only in solution.NN-3exhibited the ratiometric detection ability towards oxaloyl chloride and phosgene with the low limit of detection(LOD)of 210 nmol/L and 90 nmol/L,respectively.NN-4 as the corresponding control sample,it owned the higher LOD towards oxaloyl chloride and phosgene of 12.4μmol/L and 64μmol/L,respectively.Interestingly,films NN-3 and NN-4 could sensitively detect oxaloyl chloride gases with the low LOD of2.0 ppm and 8.34 ppm,respectively.The detection mechanisms of NN-3 and NN-4 were well studied by1H NMR titration,HRMS and theoretical calculation.
基金supported by the National Natural Science Foundation of China for Young Scholars(No.21106064)the National Basic Research Program of China(No.2012CB725204)+1 种基金the National Science Foundation for Distinguished Young Scholars of China(No.21225626)the Natural Science Foundation of Jiangsu Province(Nos.BK2012822 and BK20131406)
文摘A simple, cheap and non-enzymatic colorimetric strategy for glucose detection has been designed based on the interactions between a phenylboronic acid （PBA） derivative, which is coupled with gold nanoparticles （AuNPs） as the colorimetric reporters, and glucose. The PBA-AuNPs hybrid system proposed here exhibits ordered photochemistry behaviors upon the addition of glucose at different pH values. There are two linear regions of glucose concentration for the glucose sensor at different pH values, i.e., between 0.1 mmol/L and 9.8 mmol/L at pH 6 with the detection limit of 64μmol/L and between 0 and 6.5 mmol/L with the detection limit of 48 μmol/L at pH 9, respectively. To test the practicality of the sensor system, we also applied this assay to detect a glucose sample in the artificial saliva.
基金Financial support was provided by the Natural Science Foundation of jiangsu(grant No.BK20200764)the Key Technologies R&D Program of Henan(grant No.212102310231).
文摘With natural polyphenol compound tannic acid(TA)as the ingredient,copper tannate(CuTA)nanolayer material was formed by self-assembly under the conditions of heating and copper ion.Copper ion and tannic acid could coordinate to form Cu-O-C structure which was similar to the Fe-N-C structure of natural heme enzymes.In addition,the obtained CuTA nanomaterial possessed excellent peroxidase-like catalytic activity and stability.Based on this excellent enzymatic activity,CuTA nanomaterials could be used for colorimetric detection of hydrogen peroxide with a smartphone and decomposition of organic dyes.Based on the structural characteristics and catalytic activity,the copper tannate nanozymes could also serve as potential antibacterial reagents to effectively inhibit the growth of gram-negative and positive bacteria in a low hydrogen peroxide level.This work may promote the exploration of novel peroxidase mimetics and broaden the applications of nanozymes.
基金supported by the National Natural Science Foundation of China(Nos.22125606 and 22241604)Chinese Academy of Sciences Project for Young Scientists in Basic Research(No.YSBR-086)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XBD0750000)the Research Start-up Funding Project of Kashi University(No.GCC2024ZK-014)。
文摘Biomimetic nanozymes opens up new opportunities for sensitive,rapid and field detection of organophosphorus pesticides(OPs).However,it still remains challenges in how to improve the sensitivity and stability of biomimetic nanozymes under harsh conditions.Herein,we synthesized a novel biomimetic nanozyme composed of hemin and bovine serum albumin(BSA)in the nanopores of poly-l-lysine methacryloyl(PLMA)inverse opal hydrogel(PLMA-Hemin-BSA).PLMA-Hemin-BSA achieves superior peroxidase-like activity and shows high stability due to the confinement effect.A multi-enzyme cascade reaction was constructed for the colorimetric detection of five widely used OPs by integrating PLMAHemin-BSA with natural choline oxidase and acetylcholinesterase.The detection limits for dichlorvos,chlorpyrifos,paraoxon,methamidophos,and parathion were as low as 0.024,0.073,0.12,0.56,and 1.4 ng/mL,respectively.More importantly,the average recovery rates and the relative standard deviations(RSD)of chlorpyrifos in paddy water,soil and wheat samples were 86.62%-100.13%and 2.08%-8.65%,which meet the standard of the International Union of Pure and Applied Chemistry(IUPAC,recoveries of 70%-120%with RSD<20%).This study represented advanced methods toward enhancing the activity and stability of biomimetic nanozymes via spatial nanopores-assisted strategy.
基金supported by the Ministry of Science and Technology(Grant Nos. 2009CB930000 and 2011CB933201)the National Natural Science Foundation of China (Grant Nos. 20890020, 21025520 and 90813032)+2 种基金the Chinese Academy of Sciences (Grant No. KJCX2-YW-M15)the Fundamental Research Funds for the Central Universities (Grant No.CDJXS10232211)the Ministry of Human Resources and Social Security of China
文摘This review begins with an overview of the appealing properties and various applications of gold nanoparticles, and briefly summarizes recent advances in using unmodified gold nanoparticles to detect different kinds of targets including nucleic acids, proteins, metal ions and small organic molecules. The key point to the unmodified gold nanoparticle-based visual detection assay is to control dispersion and aggregation of colloidal nanoparticles by targets of interest, which usually relies on affinities between gold nanoparticles and targets. The degree of dispersion or aggregation can be visualized through the change of the solution color or the precipitation of nanoparticles from the solution. Thus, the existence of the target molecules can be trans-lated into optical signals and monitored by the naked eye conveniently. Finally, some future prospects of this research field are given.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.21621004 and 21676191).
文摘Recently,many efforts have been dedicated to creating enzyme-mimicking catalysts to replace natural enzymes in practical fields.Inspired by the pathological biomineralization behaviour of L-cystine,in this study,we constructed a laccase-like catalyst through the co-assembly of L-cystine with Cu ions.Structural analysis revealed that the formed catalytic Cu-cystine nanoleaves(Cu-Cys NLs)possess a Cu(I)-Cu(II)electron transfer system similar to that in natural laccase.Reaction kinetic studies demonstrated that the catalyst follows the typical Michaelis-Menten model.Compared with natural laccase,the Cu-Cys NLs exhibit superior stability during long-term incubation under extreme pH,high-temperature or high-salt conditions.Remarkably,the Cu-Cys NLs could be easily recovered and still maintained 76%of their activity after 8 cycles.Finally,this laccase mimic was employed to develop a colorimetric method for epinephrine detection,which achieved a wider linear range(9–455μmol·L^(−1))and lower limit of detection(2.7μmol·L^(−1)).The Cu-Cys NLs also displayed excellent specificity and sensitivity towards epinephrine in a test based on urine samples.
基金Funding for this work was from the Natural Sciences and Engineering Research Council of Canada(NSERC).
文摘Many sensors for Cu^(2+)rely on the catalytic activity of Cu^(2+)to produce a color change,but these colorimetric sensors often suffer from poor selectivity and are susceptible to interference.In this work,we found that Cu^(2+)-catalyzed TMB oxidation can be significantly improved with excessed nucleotides and nucleosides.Especially,with oversaturated guanosine 5′-monophos-phate(GMP)to form a coordination nanozyme,the catalytic efficiency was greatly accelerated.It can be attributed to the specific binding between the electron-rich oxygen and nitrogen atoms of guanine with Cu^(2+).A sensitive and selective strategy for Cu^(2+)sensing was proposed.Owing to the presence of excessed GMP,it ensures robust activity and less susceptibility to interference.This allowed us to test the sensor in complex samples such as the seawater.This work strongly suggests that by supplying excessed ligands,far exceeding the binding stoichiometry,we may produce more robust sensing systems.
基金supported by the National Basic Research Program of China(2013CB933703)the National Natural Science Foundation of China(91313302,21205100,21275122,21075104)+2 种基金the National Instrumentation Program(2011YQ03012412)the National Found for Fostering Talents of Basic Science(J1310024)the National Science Foundation for Distinguished Young Scholars(21325522)
文摘Lanthanide elements(Ln)play an important role in industry and agriculture.As a result of the increasing consumption of lanthanides,environmental emission of Ln has become detrimental to the health of flora and fauna.Current methods for trace lanthanides detection mainly rely on sophisticated instruments.In this article,a Ln^(3+)dependent DNAzyme was incorporated into a hydrogel to generate Ln^(3+)sensitive DNAzyme hydrogel for portable colorimetric detection.The enzyme strand and its substrate strand act as crosslinker and functional unit of the hydrogel with polyacrylamide chains as the scaffold and gold nanoparticles(AuNPs)as the indicator of hydrogel stability.Any ions in the Ln^(3+)series can trigger the cleavage of substrate strand by activating the enzyme strand,thereby decreasing the crosslink ratio and leading to collapse of the hydrogel.The release of the encapsulated AuNPs turns the supernatant wine red.Using this colorimetric method,Ln^(3+)can be detected with high sensitivity,with a limit of detection(LOD)of 20 nM for Ce^(3+).The hydrogel responds specifically to any Ln^(3+)ion and works well with the spiked lake sample without the need of instruments and skilled operators.Our results suggest that the lanthanide responsive hydrogel can be used for portable and sensitive detection of Ln^(3+)contamination in the field.
基金supported by the National Natural Science Foundation of China(Nos.31502033 and 31472164)the Fundamental Research Funds for the Central Universities(No.KJQN201615)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20130688)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Biological thiols（biothiols）, an important kind of functional biomolecules, such as cysteine（Cys） and glutathione（GSH）, play vital roles in maintaining the stability of the intracellular environment. In past decades, studies have demonstrated that metabolic disorder of biothiols is related to many serious disease processes and will lead to extreme damage in human and numerous animals. We carried out a series of experiments to detect biothiols in biosamples, including bovine plasma and cell lysates of seven different cell lines based on a simple colorimetric method. In a typical test, the color of the test solution could gradually change from blue to colorless after the addition of biothiols. Based on the color change displayed, experimental results reveal that the percentage of biothiols in the embryonic fibroblast cell line is significantly higher than those in the other six cell lines, which provides the basis for the following biothiols-related study.
基金supported by the National Natural Science Foundation of China (Grant Nos.: 21775014 and 81972020)Open Foundation Project of Engineering Research Center for Biotechnology of Active Substances, Ministry of Education (Grant No.: AS201905)+1 种基金sponsored by the Chongqing Talent Program (Top-notch Youth)the Chongqing High-level Personnel of Special Support Program (Top-notch Youth), respectively
文摘Regulating the catalytic activity of nanozymes is significant for their applications in various fields.Here,we demonstrate a new strategy to achieve reversible regulation of the nanozyme’s activity for sensing purpose.This strategy involves the use of zero-dimensional MoS;quantum dots(MQDs)as the building blocks of nanozymes which display very weak peroxidase(POD)-like activity.Interestingly,such POD-like activity of the MQDs largely enhances in the presence of Fe;while diminishes with the addition of captopril thereafter.Further investigations identify the mechanism of Fe;-mediated aggregation-induced enhancement of the POD-like activity and the inhibitory effect of captopril on the enhancement,which is highly dependent on their concentrations.Based on this finding,a colorimetric method for the detection of captopril is developed.This sensing approach exhibits the merits of simplicity,rapidness,reliability,and low cost,which has been successfully applied in quality control of captopril in pharmaceutical products.Moreover,the present sensing platform allows smartphone read-out,which has promising applications in point-of-care testing devices for clinical diagnosis and drug analysis.
基金the support of the Funds for Distinguished Young Scientists of Gansu(No.1506RJDA281)the top priority program of "One-Three-Five" Strategic Planning of Lanzhou Institute of Chemical Physics,CASthe Foundation for Sci&Tech Research Project of Gansu Province(No.1606RJYA307)
文摘In this work,a metal-organic frameworks material MIL-88 was prepared easily using solvent-thermal method,and was first found to have catalytic activities similar to those of biological enzymes such as catalase and peroxidase.The material was characterized by XRD,SEM,TEM,EDX,FT-IR techniques and an N2 adsorption method.It exhibited peroxidase-like activity through catalytic oxidation of the peroxidase substrate 3,3＇,5,5＇-tetramethylbenzidine（TMB） in the presence of H2O2,producing a blue-colored solution.Under optimal conditions,the absorbance at 652 nm is linearly correlated with the concentration of H2O2 from 2.0×10^-6 mol/L to 2.03×10^-5 mol/L（R-2=0.981） with a detection limit of 5.62×10^-7 mol/L（S/N=3）.More importantly,a sensitive and selective method for ascorbic acid detection was developed using this material as a catalyst.The analytical method for ascorbic acid detection was observed to have a linear range from 2.57×10^-6 mol/L to 1.01×10^-5 mol/L（R-2=0.989） with a detection limit of 1.03×10^-6 mol/L（S/N=3）.This work suggests MOFs have advantages of preparing biomimetic catalysts and extends applications of the functional MOFs in the field of biosensor.
基金supported by the National Natural Science Foundation of China(Nos.22276150,21906129)the Natural Science Foundation of Sichuan Province of China(No.2019YJ0522)the Innovation Team of Research at China West Normal University(No.KCXTD2022–2)。
文摘Designing single-atom nanozymes with densely exposed metal atom active sites and enhancing catalytic activity to detect pollutants remain a serious challenge.Herein,we reported a single-atom nanozyme with layered stacked Fe/Cu dual active sites(Fe/Cu-NC SAzyme)synthesized via hydrothermal and hightemperature pyrolysis using folic acid as a template.Compared with Fe-NC and Cu-NC SAzyme,Fe/Cu-NC SAzyme has higher peroxidase-like activity,which indicates that the doping of synthesized Fe/Cu bimetals can improve the catalytic activity and that the atomic loading of Fe and Cu in Fe/Cu-NC is 5.5 wt%and 2.27 wt%,respectively.When S^(2-)is added to the Fe/Cu-NC catalytic system,a high-sensitivity and high-selectivity S^(2-)colorimetric sensing platform can be established,with a wide linear range(0.09-6μmol/L)and a low detection limit(30 nmol/L),which can be used to detect S^(2-)in environmental water samples.What’s more,the Fe/Cu-NC SAzyme can activate peroxymonosulfate(PMS)to degrade 99.9%of rhodamine B(Rh B)within 10 min with a degradation kinetics of 0.5943 min^(-1).This work details attractive applications in Fe/Cu-NC SAzyme colorimetric sensing and dye degradation.
基金financially supported by Major science and technology project of Yunnan Province(202302AE090022)Key Research and Development Program of Yunnan(202203AC100010)+6 种基金the National Natural Science Foundation of China(32160597,32160236,32371463)National Key Research and Development Program of China(2022YFC2601604)Cardiovascular Ultrasound Innovation Team of Yunnan Province(202305AS350021)Spring City Plan:the High-level Talent Promotion and Training Project of Kunming(2022SCP001)the Association Foundation Program of Yunnan Provincial Science and TechnologyDepar tmentKunming Medical University(202101AY070001-278)the second phase of“Double-First Class”program construction of Yunnan University。
文摘Circulating tumor cells(CTCs)are important markers for cancer.The part of tumor cells that are detached from the primary tumor or metastatic tumor and enter the blood circulation is called CTCs.It is crucial to develop a rapid,accurate,and easy-to-implement diagnostic system for CTCs for early tumor diagnosis and for monitoring progression of the disease.In this work,we reported a colorimetric and fluorescent dual-mode assay for the detection of CTCs.Our assay used magnetic nanoparticles and aptamer for CTCs capture and gold nanoparticles-loaded covalent organic frameworks(Au@COFs)for signal amplification,respectively.The magnetic nanoparticles were modified with folic acid to capture CTCs by interaction between folic acid and the folate receptor overexpressed on the surface of tumor cells.The covalent organic frameworks were engineered to have both nitro-reductase-like and glucose–oxidase-like activities.The nitro-reductase-like activity converted the substrate p-nitrophenol to p-nitroaniline for colorimetric detection,and the glucose-oxidase-like activity enabled fluorescence detection.Specifically,Au@COFs catalyzed glucose oxidation and generated hydrogen peroxide to oxidize Fe 2+to Fe 3+,which converted MIL(Al)-MOF to MIL(Fe)-MOF through ion exchange,resulting in the fluorescence quenching of MIL(Al)-MOF.Our assay showed high sensitivity with a detection limit of 17 cells/mL using MCF-7 cells as model cancer cells.This work provided an e fficient and ultrasensitive strategy for CTCs detection and has potential applications in cancer identification and diagnosis.Dual-mode detection system,combining colorimetric and fluorescent signals,integration of magnetic nanoparticles and aptamers for CTC capture,and utilization of covalent organic frameworks loaded with gold nanoparticles for signal amplification can improve sensitivity and accuracy.
基金WSU start up fund and China National Postdoctoral Program for Innovative Talents(BX20180364).
文摘Salmonella Enteritidis is a major public health threat of global proportions,while it is still a serious challenge to develop point-of-care detection assay.In this study,nanozymes(Fe-MOF nanoparticles)were successfully synthesized and applied as signal in a colorimetric immunoassay for naked-eye detection of Salmonella Enteritidis.After optimization,the proposed assay was able to detect Salmonella Enteritidis with a detection limit of 34 CFU/mL.The coefficients of variation(CV)of the test were less than 7.0%after 30 days storage at 4°C.The estimated recoveries in milk samples of the colorimetric immu-noassay range from 94.68 to 124%,which indicated the developed method is capable of detecting Salmonella Enteritidis in real samples.This method provides a potential platform for Salmonella detection with naked eyes,which has a significant application value for foodborne pathogen analysis at the point-of-care.
