80results about How to "Fluorescence stabilization" patented technology

A method of making a colloidal solution of ternary semiconductor nanocrystals, includes providing binary semiconductor cores; forming first shells on the binary semiconductor cores containing one of the components of the binary semiconductor cores and another component which when combined with the binary semiconductor will form a ternary semiconductor, thereby providing core / shell nanocrystals; and annealing the core / shell nanocrystals to form ternary semiconductor nanocrystals containing a gradient in alloy composition.

The invention discloses a preparation method of metal halide perovskite quantum dots. The method is characterized in that a liquid state hydrophobic fluorine-containing reagent and a precursor aqueoussolution used for preparing a metal halide perovskite material are mixed to obtain an emulsion, the metal halide perovskite quantum dots are synthesized in the emulsion, the surface of the metal halide perovskite quantum dots are tightly coated with the hydrophobic fluorine-containing reagent, so that the metal halide perovskite quantum dots which can dispersed in an aqueous solution as a singleparticle state are obtained. Through key integral process flow design and each technological step improvement for the preparation method, compared with the prior art, the problem of poor stability ofCsPbX3 quantum dots can be effectively solved, and the CsPbX3 metal halide perovskite quantum dots prepared by the invention have good dispersibility.

The invention relates to a preparation method of an Escherichia coli (E.coli) biosensor and a product obtained thereby. The preparation method comprises the following steps: (1) knocking out three genes, namely copA, cueO and cusA in a wild-type E.coli MC4100 genome by a Red recombination system; (2) constructing a fusion reporter gene PcopA::gfpmut2 by adopting a cross PCR (Polymerase Chain Reaction) technology; (3) cloning the segment obtained in step (2) to a pMD18-T vector; (4) carrying out double digestion on a PcopA::gfpmut2-T vector to obtain a target strip, and then connecting the target strip to a pET28a vector; and (5) converting a fusion reporter vector obtained in the step (4) to a deltacopA-deltacueO-deltacusA tri-gene mutant strain obtained in the step (1). In the preparation method, the three genes such as the copA, the cueO and the cusA are deleted from wild-type E.coli MC4100, and then the genes are converted to the fusion reporter vector PcopA::gfpmut2-pET28a so as to finally obtain the product. The product obtained by the method has the characteristics of high specificity, high sensitivity, high speed, high efficiency, high cost performance and the like, and is simple and convenient to use, thus being applicable to real-time field monitoring of copper ions.

The invention relates to a novel water-soluble sulfydryl fluorescent probe which is a 2-(2'-hydroxyphenyl) benzimidazole (HPBI) compound modified by quaternary ammonium salt. The compound has the structure of 2-[5-(trimethyl quaternary ammonium salt)-acetamido-2'-hydroxyphenyl) benzimidazole. The fluorescent probe can be used for detecting a biological sulfhydryl compound in aqueous solution and living tumor cell, i.e. the novel water-soluble sulfydryl fluorescent probe is selectively coordinated with cupric ions and an obtained coordination compound can enter the living cell to be reacted with the sulfhydryl compound, so that a fluorescent compound is changed into ionic molecules again and fluorescent light is recovered. The novel water-soluble sulfydryl fluorescent probe has the advantages that the novel water-soluble sulfydryl fluorescent probe has excellent water solubility and biocompatibility and high sulfhydryl measurement sensitivity; before and after GSH (glutathione) reaction, the fluorescent light is rapidly changed and is stable; the novel water-soluble sulfydryl fluorescent probe can be stored and used for a long time; and according to the fluorescent probe, a good research method is provided for researching a biological signal channel related to the biological sulfydryl and the significance and diagnosis of the sulfydryl in the in vivo process of diseases or organisms.

The invention discloses a CsPbX3@TiO2 nanomaterial as well as a preparation method and application thereof. The preparation method comprises the following steps: first, dissolving CsX and PbX2 in a surfactant and an N,N-dimethylformamide solution system, and heating to form a CsPbX3 precursor solution; then hydrolyzing and coating TiOx onto the surface of CsPbX3 in a titanate solution through a sol-gel method to obtain CsPbX3@TiOx; calcining under the protection of argon to obtain the CsPbX3@TiO2 nanomaterial. The CsPbX3@TiO2 nanometer material with an obvious structure and uniform coating isprepared with a 'one pot method', and has high fluorescence stability. The material powder can be placed stably at room temperature for two months or more, keeps ultrasonically stable in an aqueous solution for 60 minutes or more, and can be widely applied in various fields such as solar cells, photocatalysis, display devices, lasers, light detection devices and biological fluorescence labels.

The invention belongs to the technical field of biological detection, which particularly relates to a fluorescent probe which can be applied in measuring active mercapto image in living cells and the application. The fluorescent probe is 2-(2-hydroxyphenyl) hydroxyphenyl compound which is decorated by maleimide or maleimide acid, the structure of the compound is N-{3-(2- benzimidazolyl)-4-hydroxyphenyl}maleimide and N-{3-(2- benzimidazolyl)-4-hydroxyphenyl}malemide acid. The compound can simply and rapidly get into living cells, which has a reaction with free active mercapto group in cells, and fluorescence intensity of the compound is led to be obviously enhancing, thereby the fluorescent probe can be used in fluorescent measurement or fluorescent image of fluactive mercapto group (such as glutathione and the like) in living cells.

The invention provides a method for preparing a fluorescent polymer rare earth complex nano-microsphere. The method comprises the steps: allowing a monomer I to be subjected to miniemulsion polymerization to obtain a polymer seed microsphere emulsion I; adding a monomer II to the polymer seed microsphere emulsion I to be subjected to seed emulsion polymerization to obtain a core-shell nano-microsphere emulsion II; extracting core-shell nano-microspheres by high-speed centrifugation or freeze-drying of the core-shell nano-microsphere emulsion II to be dispersed in an organic solvent, and then adding a rare earth compound and a small molecule ligand to be subjected to a coordination reaction to obtain the solvent-resistant fluorescent polymer rare earth complex nano-microsphere. The prepared nano-microsphere has a uniform size, the preparation method is simple and practicable, high-intensity fluorescent lights of different colors can be obtained by adding different rare earth compounds, the environmental stability is particularly excellent, and the nano-microsphere still can be used after being stored for a year, can be stably dispersed in various organic solvents, and has good development prospects.

The invention discloses a preparation method of a water-soluble nitrogen-phosphorus-boron codoped carbon quantum dot. The preparation method comprises the following steps: step I, dissolving phenylphosphinic acid in ultra pure water to obtain a precursor solution I, dissolving 3-aminobenzene boronic acid in ultra pure water to obtain a precursor solution II, and uniformly mixing the precursor solution I with the precursor solution II in the volume ratio of the precursor solution I to the precursor solution II being (1-6) to 1 so as to obtain a mixed solution; step II, performing a hydrothermal reaction on the mixed solution prepared in the step I so as to obtain the water-soluble nitrogen-phosphorus-boron codoped carbon quantum dot. According to the preparation method disclosed by the invention, the water-soluble nitrogen-phosphorus-boron codoped carbon quantum dot is prepared by the one-step hydrothermal method, carbon sources are rich, a preparation process is simple and easy, the whole preparation process is pollution-free, non-toxic, green and environmentally-friendly, and the water-soluble nitrogen-phosphorus-boron codoped carbon quantum dot can be prepared in a large-scale manner.

The invention relates to a newly designed liquid phase chip of quantum dot coding microspheres. The liquid phase chip of the quantum dot coding microspheres comprises macromolecular polymer microspheres, probe molecules and specific fluorescent protein labeled report molecules, wherein the surfaces of the macromolecular polymer microspheres are chemically modified, and a quantum dot nano material is embedded into the microspheres; and the probe molecules are coupled on the chemically modified microsphere surfaces. The liquid phase chip improves the coding property of the microspheres; an organic fluorescent dye is replaced by quantum dots, so the liquid phase chip has the advantages of stable fluorescence, strong fluorescence, difficult photo-bleaching and the like; the liquid phase chip also has the advantages of excitation bandwidth and narrow emission spectrum, so the stability, sensitivity and resolution are higher; meanwhile, the liquid phase chip simplifies an optical detection system, improves detection speed, reduces the cost of instruments, and is easier to operate.

The invention discloses a double sandwich immunoassay test kit labeled by HE4 quantum dots. The kit comprises HE4 protein standards, an ELISA plate coated with HE4 specific polyclonal antibodies, and CdTe quantum dots labeled monoclonal antibodies in specific binding with HE4 proteins. The invention further discloses an application of the kit in diagnosis of ovarian tumor. According to the invention, the test kit can directly determine test results through fluorescent ELISA, emitted fluorescence spectral peaks are narrow, autofluorescence is weak, and a sensitivity is high. The kit is high in fluorescence intensity and long in stable time, and can relatively effectively facilitate early detection and risk assessment of the ovarian tumor.

The invention relates to a microbiological method for detecting heavy-metal cadmium, particularly a construction method of an Escherichia coli engineering strain for detecting cadmium and a method for detecting cadmium in water by using the Escherichia coli engineering strain. The construction method of the engineering strain comprises the following steps: knocking out Escherichia coli cadmium-resistant zntA and zntR genes by using a Red recombination system, and substituting a pmerR-MerR(M)-pmerR-gfpmut2 report gene to the zntR coding gene position by using a gene knock-in technique. The lowest detection range of the engineering strain for cadmium conforms to Sewage Comprehensive Discharge Standard-GB8978-1996. The engineering strain overcomes the defects of high fluorescent background level, poor detection signal and the like in the plasmid-vector-based engineering strain. The engineering strain provided by the invention can be complementary with AAS (atomic absorption spectroscopy) and other physicochemical analysis processes to analyze the biological availability and total amount of the cadmium, thereby providing references for objective evaluation on biological toxicity of the cadmium.

The invention discloses a preparation method of water-soluble nitrogen-doped carbon quantum dots, comprising the following steps: Step 1, dissolving citric acid in ultrapure water to prepare precursor solution I, dissolving p-aminobenzamide in Prepare precursor solution II in pure water, uniformly mix precursor solution I and precursor solution II at a volume ratio of 1 to 10:1 to obtain a mixed solution; step 2, perform hydrothermal reaction on the mixed solution prepared in step 1, Water-soluble nitrogen-doped carbon quantum dots can be obtained. The invention adopts a one-step hydrothermal method to prepare water-soluble nitrogen-doped carbon quantum dots. The carbon source is rich and cheap, the preparation process is simple, the whole preparation process is pollution-free, non-toxic, green and environmentally friendly, and can be prepared in large quantities.

The invention discloses a ratio fluorescence probe for detecting pyrogallic acid. The visual ratio fluorescence probe is formed by red CdTe quantum dots and blue carbon quantum dots through amido bonds. An experiment finds that a fluorescence quenching phenomenon is gradually enhanced along with the increase of the addition of the pyrogallic acid, and a good linear relationship exists when the linear range is 0.05-2 mu m. An experiment result indicates that a method has the capability of detecting the pyrogallic acid in a water sample simply, conveniently and rapidly.

The invention relates to luminescent nano micro-spheres with positive charge on surface and possessing aggregation induced fluorescence enhancement property and a biological application thereof, which belongs to the technical field of high-molecular material. According to the invention, the nano micro-spheres with positive charge on surface is synthesized, the fluorescence molecules with positive charge and AIE effect are modified to the surface of the nano micro-spheres through electrostatic interactions. Molecule internal rotation of fluorescence molecule is restricted by Coulombian force effect, the absorbed energy can be basically released through fluorescence radiation, accordingly fluorescence from the fluorescence molecule modified to the nano micro-spheres can be enhanced by a hundred times, and excellent AIE property can be generated. The prepared the luminescent nano micro-spheres have the advantages of stable fluorescence property, good biological compatibility and low toxicity, and the positive charge on the surface is easily introduced to cell and biology detection. The luminescent nano micro-spheres with positive charge on surface has wide application prospect on the biology fields such as cell imaging.

The invention discloses a method for preparing a water-soluble yellow fluorescent carbon quantum dot by taking bagasse as a raw material. The method comprises the following steps of 1) performing bagasse pretreatment; 2) mixing ultrapure water and glycerol according to the volume ratio of (2-5):1 to obtain a mixed solution for later use; 3) adding the bagasse obtained through pretreatment into the mixed solution obtained in the step 2) to obtain a mixed solution, stirring, putting the mixed solution under a microwave environment and performing microwave treatment to obtain a brown solution; 4) filtering the brown solution to obtain filtrate; 5) dialyzing the filtrate to obtain dialysate; and 6) evaporating the dialysate under the condition of constant temperature to obtain the water-soluble yellow fluorescent carbon quantum dot. The water-soluble yellow fluorescent carbon quantum dot prepared by the method has the advantages of high water solubility, fluorescence stability, high biocompatibility, no pollution and no toxin, and has an important application value in the fields of biomarkers, biosensing, fluorescence probes, anti-fake markers and immunochromatography products.

The present invention relates to a carboxyl functionalized micro-scale rod-like upconversion fluorescence material and a preparation method thereof, wherein a micro-scale upconversion fluorescence material is subjected to one-step synthesis through a hydrothermal method, different colors of the upconversion fluorescence materials having a length of about 1-2 [mu]m can be prepared, and the preparation process is simple and convenient. According to the present invention, during the synthesis process, the required raw materials are added to a mixed solvent of oleic acid and ethanol according to a certain ratio, reaction is performed for 8-12 h at a temperature of 180-200 DEG C, and the product is subjected to centrifugal washing so as to obtain the purified upconversion micrometer rod; the amino can be introduced onto the upconversion material surface through the classical method and the carboxyl functionalization is successfully achieved by adding PAA through the amide bond coupling so as to enhance the dispersity in the aqueous solution and provide a large number of the reactive sites for coupling biomolecules; and the prepared material has characteristics of low production cost, good fluorescence stability and easy surface modification, can be used for detection of biological macromolecules, and can further be widely used for rapid detection of antigens, nucleic acids and the like.

The invention discloses a ratiometric fluorescence biosensor for detecting aflatoxin-producing genes as well as preparation and application of the ratiometric fluorescence biosensor. A fluorescence energy donor of the fluorescence biosensor is a CQDsI-coated-SiO2-coated CQDsII hybrid nanosphere with a three-layer coating structure, a hairpin structure DNA sequence with two ends respectively modified with -SH and -NH2 is selected as a capture probe, and an energy receptor is AuNPs; when no toxin-producing gene appears, the AuNPs and the CQDsII are close in spatial distance, and FRET is triggered, so that fluorescence quenching of the CQDsII is caused; and when a toxin-producing gene exists, the toxin-producing gene is specifically paired with the fluorescent probe, so that the energy resonance transfer is blocked, the fluorescence of the CQDsII is recovered, and the fluorescence emission characteristic of the CQDsI is not changed due to the protection of the SiO2 nanospheres in the middle layer. The ratiometric fluorescent probe can provide a new thought for rapidly detecting aflatoxin toxin producing genes from the source.

The invention relates to the field of immunochromatographic assay, in particular to a quality control detection card and detection kit of a fluorescent immunochromatography instrument, and a preparation method and detection method thereof. The quality control detection card is characterized in that a detection window is formed in a PVC bottom plate, thin cellulose nitrate film is fixed in the detection window, a QC line and a QT line are arranged on the thin cellulose nitrate film, and both the QC line and the QT line are touched with a fluorescent microsphere solution. At least two quality control detection cards are selected to combine into the quality control detection kit. The QT / QC area ratio of each quality control detection card is calculated in sequence and compared with a standard curve, and when an error is higher than certain value, the measuring result of an instrument is low in reliability. According to the quality control detection method applied to the fluorescent immunochromatography instrument, operation is simple and convenient, and the method can be applied to field detection; instrument quality testing is initially carried out before samples are detected, so that the reliability of sample measuring results is improved.

The invention discloses a screening system for a beta-secretase specific inhibitor. The system is a micro-micelle-APP system formed by encapsulating APP protein with a fluorescent label by a micro-micelle solution; the APP protein is amyloid precursor protein; the micro-micelle solution is prepared by adopting amphiphilic polymer molecule modified quantum dots; and the APP protein with the fluorescent label is prepared by carrying out fixed-point fluorescence labeling on the APP protein by utilizing an orthogonal reaction system. In addition, the invention also discloses a screening method for the beta-secretase specific inhibitor. According to the screening system and the screening method disclosed by the invention, BACE natural substrate molecules are used as targets, the condition that the screened medicine precursor molecules have accurate substrate specificity can be achieved, and sensitive real-time monitoring can be achieved.

The invention discloses a method for preparing fluorescent carbon dots by pyrolyzing ammonium carboxylate .The method includes the following steps that 1, polycarboxylic acid is dissolved in deionized water, ultrasonic oscillation is carried out, diamine is added for a reaction under nitrogen protection, a reaction product is washed with petroleum ether after the reaction is complete, an aqueous layer is separated out, reduced-pressure rotary evaporation is carried out to remove unreacted diamine, and a yellow solid is obtained; 2, the yellow solid is put into a tube furnace and heated under nitrogen protection, grinding is carried out after heat preservation, and black powder is obtained; 3, the black powder is dissolved in absolute ethyl alcohol, dialysis is carried out with a dialysis bag, a solution outside the dialysis bag is subjected to rotary evaporation, and the fluorescent carbon dots are obtained .The preparation method is easy to implement, raw materials are easy to get, cost is low, no environmental pollutant is released in the preparation process, and the preparation method is an environment-friendly preparation technology; the mean grain size of the fluorescent carbon dots prepared with the method is 11 nm, water solubility is good, fluorescence is stable, the fluorescence quantum yield reaches 22.46%, and the fluorescent carbon dots can be applied to Fe3+ detection.

The invention belongs to the field of materials chemistry, and relates to a synthetic method of polymer-wrapped nitrogen-doped fluorescent carbon nanodots. The invention uses an ordinary polar solvent NMP as a carbon source and a nitrogen source, and conducts a one-step solvent thermal reaction, removal of residual impurities such as NMP and drying to obtain a polymer-wrapped nitrogen-doped fluorescent carbon nanodots. The present invention provides a novel method for preparing a polymer-wrapped nitrogen-doped fluorescent carbon nanodots. The prepared nanodots have the advantages of uniform size, stable and tunable fluorescence emission, high water dispersibility and good biocompatibility, and can be widely applied to cancer fluorescent imaging and fluorescence sensors. The method is simple for operation, low in cost, and suitable for large-scale production.

The invention discloses a method for screening glutathione reductase inhibitors based on fluorescence recovery of carbon dots. Yellow fluorescence carbon dots for Ag<+> ion specific quenching serve asa fluorescence probe; glutathione reductase can perform catalytic reduction on oxidized glutathione to produce reduced glutathione in the presence of a coenzyme NADPH (Nicotinamide Adenine Dinucleotide Phosphate), and the reduced glutathione can perform competitive binding with the Ag<+> ion so as to further recover fluorescence of the carbon dots; and the glutathione reductase treated and inactivated by the glutathione reductase inhibitor cannot perform catalytic reduction on the oxidized glutathione, therefore, the fluorescence of the carbon dots cannot be recovered. On this basis, screening of the glutathione reductase inhibitors can be realized by virtue of the fluorescence recovery situation. The method for screening glutathione reductase inhibitors disclosed by the invention has thecharacteristics of being high in sensitivity, excellent in selectivity, low in cost, low in toxicity, environment-friendly, high in stability and the like, and has significances for screening relateddrugs based on the glutathione reductase inhibitor.

The invention discloses a preparation method of a water-soluble nitrogen-sulfur-phosphorus codoped carbon quantum dot. The preparation method comprises the following steps: I, dissolving sulfanilic acid in ultra pure water to obtain a precursor solution I, dissolving phenylphosphinic acid in ultra pure water to obtain a precursor solution II, and uniformly mixing the precursor solution I with the precursor solution II in the volume ratio of the precursor solution I to the precursor solution II being (1-6) to 1 so as to obtain a mixed solution; step II, performing a hydrothermal reaction on the mixed solution prepared in the step I so as to obtain the water-soluble nitrogen-sulfur-phosphorus codoped carbon quantum dot. According to the preparation method disclosed by the invention, the water-soluble nitrogen-sulfur-phosphorus codoped carbon quantum dot is prepared by the one-step hydrothermal method, carbon sources are rich and cheap, a preparation process is simple and easy, the whole preparation process is pollution-free, non-toxic, green and environmentally-friendly, and the water-soluble nitrogen-sulfur-phosphorus codoped carbon quantum dot can be prepared in a large-scale manner.

The invention discloses a nano-diamond-based anti-counterfeiting method, a corresponding medicine, anti-counterfeiting ink and an application thereof. The nano-diamond-based anti-counterfeiting methodcomprises: coating the surface of the article to be subjected to anti-counterfeiting treatment with nano-diamond particles or adding nano-diamond particles into the article to be subjected to anti-counterfeiting treatment. The nano-diamond particle contains nitrogen-vacancy center NV<-> in a negatively charged state and produces fluorescence emitted by the excitation light at the wavelength of 400 nm to 600 nm so that anti-counterfeiting effects are obtained. Under control of the internal structure of the key nano-diamond material, through fluorescence produced by the nano-diamond material containing nitrogen-vacancy center NV<-> in a negatively charged state under excitation light at the wavelength of 400 nm to 600 nm, the anti-counterfeiting effects are effectively achieved.

Belonging to the field of material chemistry, the invention relates to a synthesis method of carbon nanodot with fluorescence, photoacoustic and photothermal effects. The method includes: using an FDAapproved safety excipient F-127, carrying out simple and convenient solid-phase synthesis reaction, removing the residual impurities of the reaction, and then conducting drying to obtain the carbon nanodot with fluorescence, photoacoustic and photothermal effects. The invention provides the new method for preparation of the carbon nanodot with fluorescence, photoacoustic and photothermal effects,and the prepared carbon nanodot has the characteristics of uniform size, stable and adjustable fluorescence emission, good photoacoustic-photothermal effect, high water dispersibility and good biocompatibility, and can be prepared into preparations widely applicable to photothermal therapy or combined therapy under the guidance of precise dual-mode imaging of tumors.

The invention discloses a near-infrared fluorescent magnetic Fe NCs dual-mode probe as well as a synthesis method and an application thereof. The valence state of an iron element in the magnetic Fe NCs dual-mode probe is zero, the particle size of the iron element is 5 nm, an iron nano-cluster prepared from glutathione serving as a stabilizer and iron ions in a molar ratio of 1: 0.3073 has excellent near-infrared fluorescence emission capacity, interference of biological autofluorescence in a sample can be effectively avoided, and the product can be used for high-sensitivity detection of the drug molecule tiopronin in a complex detection system. Besides, the probe also has relatively strong paramagnetic properties, can generate bright T1 weighted image signals under the action of an external magnetic field, is gradually enhanced along with the increase of the concentration of the probe, and also has a wide application prospect in the aspect of magnetic resonance imaging.

The present invention discloses a thrombin detection method based on a graphene quantum dot / erbium ion fluorescent nano probe. Rare earth ions Er<3+> are combined with carboxylic acid groups on the surface of GQDs (graphene quantum dots) for assembly onto the surface of the GQDs to form a GQDs / Er<3+> complex to cause fluorescence quenching of the GQDs, when thrombin isadded, the GQDs / Er<3+> complex is decomposed to recover fluorescence of the GQDs, the fluorescence recovery degree of the GQDs is positively-proportional to the concentration of the thrombin, and the thrombin can be detected. The detection of the sensitivity and selectivity of the thrombin can be achieved only by fluorescence switch converting of the GQDs without functional modification of the surface of the GQDs and use of a thrombin aptamer.

The invention provides a tumor-targeted fluorescent probe, and application of the fluorescent probe in tumor NO detection, which belongs to the biotechnology field. The invention in particular relates to a fluorescent probe which can be targeted to a tumor tissue based on specificity. The fluorescent probe can form a complex with double-charge copper ions, and can be applied for the fluorescent imaging detection of the level of NO in the tumor. The fluorescent probe is the Top10 bacterial strain of colibacillus modified with N-(3-(2- phenyl imidazolyl)-4-hydroxy phenyl) maleimide. The fluorescent probe can be targeted to the tumor tissue quickly in a mammal body. In addition, the complex formed by the fluorescent probe and the double-charge copper ions can react with NO released in the tumor tissue, thus significantly improving the fluorescence intensity. In this way, the fluorescent probe can be used for the fluoroscopic detection of NO in the tumor tissue of a living body and the fluorescent imaging of the living body.

A preparation method of a CeCl3:Eu<3+> fluorescent probe array comprises the following four steps: 1, preparing a Eu(NO3)3 solution by using EuO to obtain an activator solution; 2, preparing a substrate solution by using Ce(NO3)3; 3, adjusting the pH value of a mixed solution formed by Eu(NO3)3, Ce(NO3)3, NaCl and citric acid to 6.0, and performing a reaction to obtain a CeCl3:Eu<3+> fluorescent probe; and 4, and performing silicon chip treatment and ion etching to obtain the fluorescent probe array. The emission spectrum band is red, and the negatively charged carboxyl group on the surface ofthe CeCl3:Eu<3+> fluorescent probe and a positively charged paraquat molecule spatially get close to each other due to anion and cation interaction, so fluorescence resonance energy transfer occurs,the fluorescence intensity of the fluorescent probe array is reduced, selective identification and detection of the paraquat molecule are realized, and the detection limit is 10<-9> mol.L<-1>.

The invention discloses a ratiometric fluorescent probe for detecting drugs and a preparation method thereof. The ratiometric fluorescent probe is of a three-layer wrapping structure, the inner layeris a copper cluster I, the middle layer is a metal organic framework material containing amino, the outer layer is a copper cluster II containing carboxyl, and the copper cluster I and the copper cluster II emit fluorescence of different colors under single exciting light. The surface of the copper cluster II is modified with an antibody which can be specifically combined with a drug to be detected; and the metal organic framework material is connected with the copper cluster II through carboxyl and amino. The ratiometric fluorescent probe is high in detection sensitivity, high in reliability, high in signal-to-noise ratio, high in detection flux, simple to operate and capable of effectively detecting the drug content.