109 results about "Fluorescent quenching" patented technology

The invention relates to the technical field of fluorescent hydrogel, in particular to high-strength and high-stability fluorescent hydrogel as well as a preparation method and application thereof, the fluorescent hydrogel is formed by physical crosslinking of a hydrogel matrix, a rare earth fluorescent complex and a stabilizer, the hydrogel matrix is of a double-network structure formed by physical crosslinking of polyvinyl alcohol and carboxymethyl cellulose; the rare earth fluorescent complex is formed by connecting rare earth metal ions and an organic antenna material through coordination; the stabilizer is trisodium citrate. Compared with other fluorescent hydrogel, the fluorescent hydrogel with high strength and high stability provided by the invention has the advantages that the phenomena of fluorescence decay and fluorescence quenching caused by metal ions and saturated salt solution are avoided, and the fluorescence is kept stable in a wide pH range. Because the fluorescence characteristic is not influenced by environmental corrosion factors, the information can be stably displayed for a long time, and the method can be used for information encryption and anti-counterfeiting in an extreme environment.

The application belongs to the technical field of fluorescent probe detection, and discloses a bimetallic nanocluster fluorescent probe compound and application thereof in preparation of a product for rapidly detecting acetylene. The fluorescent probe compound is a gold-copper bimetallic nanocluster solution modified by adamantane thiol, which is used as a fluorescent probe for acetylene detection. The solution has a clear and controllable preparation process. Through specific proportioning and reaction conditions of cuprous chloride, adamantane thiol, tetrachloroauric acid, sodium borohydride and other reagents, a probe solution with stable fluorescence characteristics can be prepared. The bimetallic nanocluster fluorescent probe compound is applied in preparation of a product for rapidly detecting acetylene. Through specific combination of fluorescent molecules and acetylene gas to trigger the secondary effect of fluorescence quenching, detection is realized, and other substances cannot trigger quenching. At a wavelength of 700 nm, the linear relationship (R 2 >0.99) between the fluorescence intensity and the acetylene concentration realizes accurate quantification of the acetylene concentration, and the minimum detection limit is 0.026 muL / L.

The invention belongs to the technical field of chrysin detection, and particularly relates to a dual-emission fluorescent molecularly imprinted polymer as well as a preparation method and application thereof. The method comprises the following steps: preparing carbon dots with different emission wavelengths; carrying out amination modification on the carbon dots; and preparing the dual-emission fluorescent molecularly imprinted polymer. The method also comprises the following steps: respectively adding the dual-emission fluorescent molecularly imprinted polymer into chrysin solutions with different known concentrations, carrying out fluorescence quenching reaction, and establishing a standard curve according to the linear relationship between the detected fluorescence intensity and the corresponding concentration of the chrysin solution; adding the dual-emission fluorescent molecularly imprinted polymer into a solution of a to-be-detected product, and carrying out fluorescence quenching reaction to obtain fluorescence intensity; and calculating the concentration of chrysin in the solution to be detected according to the standard curve. The preparation method is used for solving the technical problems that in the prior art, a single-emission fluorescent molecularly imprinted polymer has defects in the aspects of sensitivity, background fluorescence interference resistance in a complex environment and the like in the detection process.

This invention provides a method for screening β-galactosidase inhibitors, belonging to the field of pharmaceutical technology. The first step of this method uses fluorescence sensing technology to rapidly identify natural products with β-Gal inhibitory activity. The principle is based on the fluorescence quenching property of p-nitrophenol (PNP) on sulfur quantum dots (SQDs); β-Gal catalyzes the hydrolysis of p-nitrophenyl-β-D-galactopyranoside (PNPG) to generate the specific product PNP; in the presence of β-Gal, PNPG can be enzymatically catalyzed to generate PNP, quenching the fluorescence of SQDs; when screened for β-Gal inhibitory activity, the fluorescence of SQDs can be restored. The second step uses affinity chromatography to capture components in samples with β-Gal inhibitory activity. This method involves immobilizing β-Gal on a support material, eluting with a solvent to obtain components that can bind to β-Gal, and then using liquid chromatography-mass spectrometry (LC-MS) to identify the components. This method can rapidly and accurately screen β-Gal inhibitors from natural products.

The invention relates to a method for specifically detecting tetrahydrocannabinol and hydride thereof by utilizing bridged beta-cyclodextrin, and belongs to the technical field of analysis and detection of supramolecular materials. The method comprises the following steps: firstly, combining 1, 6-hexamethylenediamine bridged bis-beta-cyclodextrin with an indicator to form a supramolecular probe; in a buffer system with a pH value of 9-11, tetrahydrocannabinol or a hydride thereof specifically competes to be combined with a cavity and displaces an indicator by utilizing a synergistic inclusion effect of a bridging subject and dissociation difference of guest molecules, so that the system is subjected to fluorescence quenching or color change, and a structural analogue cannabidiol does not generate obvious interference. The method solves the problems that the sensitivity is low and cannabidiol cannot be effectively distinguished in the prior art through cooperation of specific main body construction and environment regulation, has the advantages of being rapid in detection, high in specificity, high in accuracy and the like, and is suitable for environment monitoring and field screening.

The invention relates to the technical field of photovoltaic modules, and particularly discloses a tetraphenyl ethylene-benzotriazole derivative compound and application thereof in the photovoltaic field. The absorption spectrum of the tetraphenyl ethylene-benzotriazole derivative compound disclosed by the invention can be subjected to red shift to 420 nm, so that high-energy ultraviolet light can be completely absorbed; the maximum emission wavelength of a fluorescence emission spectrum is more than 440nm and even can reach 500nm, so that the light utilization level of the crystalline silicon solar cell is improved; the absolute light-emitting quantum efficiency is very high, and the converted wavelength can be better utilized by a photovoltaic device. The substituted tetraphenyl ethylene part contained in the derivative compound has AIE performance, and the fluorescence quenching effect of traditional small organic molecules in high concentration, solid state and aggregation state is avoided. The light conversion film can overcome the problem that the fluorescence quantum yield is remarkably reduced in the laminating process, the performance of the film is not affected when the phenomena of precipitation, agglomeration and the like of auxiliaries in the film occur, and the light conversion film is used for preparing a photovoltaic module.

The application discloses a fluorescence enhancement anchor agent based on a fluoroboron dipyrrin-tetrazine dye for inflation microscopy technology, and belongs to the technical field of biochemical analysis. The fluorophore of the fluorescence enhancement anchor agent is shown in formula (I), formula (II) or formula (III): the tetrazine group carried by the fluorescence enhancement anchor agent is removed from fluorescence quenching through a biological orthogonal reaction with a drug probe, and the drug probe is shown in formula (IV): the fluorescence enhancement anchor agent can covalently and non-covalently anchor small molecules in a hydrogel network based on a tetrazine biological orthogonal reaction, and realizes inflation microscopic fluorescence imaging of a double fluorescence enhancement mechanism. In addition, the drug probe selects a non-covalent drug, gefitinib, as a probe core, is modified with a BCN click handle, and successfully realizes in-situ fluorescence inflation microscopic imaging of an EGFR drug-target, thereby providing a new tool for research and clinical research on non-covalent drug target co-localization information of exosomes.

The invention provides a light-emitting auxiliary material and a preparation method and application thereof, and belongs to the technical field of light-emitting materials, the structural formula of the light-emitting auxiliary material is shown in the general formula I. The light-emitting auxiliary material takes 9, 9-phenylalkyl fluorene as a parent nucleus, aryl and arylamine groups are connected to the two sides of fluorene of the 9, 9-phenylalkyl fluorene respectively, 9-phenylalkyl fluorene has relatively high glass transition temperature and quantum fluorescence efficiency, the stability and luminous efficiency of the compound can be effectively improved, the energy levels of the highest occupied molecular orbital and the lowest unoccupied molecular orbital can be flexibly adjusted by introducing an electron-donating group arylamine, and the energy barrier of hole injection can be effectively reduced; meanwhile, the other side is connected with an aryl group, so that a conjugated system can be effectively extended, a fluorescence quenching phenomenon caused by intermolecular pi-pi accumulation and excessive molecular aggregation is reduced, the service life of an OLED (Organic Light Emitting Diode) device can be effectively prolonged, the luminous efficiency of the OLED device can be effectively improved, and the driving voltage can be reduced by utilizing the light-emitting auxiliary material.

The application belongs to the technical field of functional polyurethane materials, and more particularly relates to a polyurethane fluorescent material applicable to bacterial detection and a preparation method thereof. The polyurethane pre-polymer is obtained by pre-polymerization of a hydrophobic polyether monomer, isocyanate, a catalyst and a hydrophilic solvent; a chain extender is added to the pre-polymer for chain extension reaction, and then a capping agent is added for capping reaction, and after curing, a polyurethane elastomer is obtained; the polyurethane elastomer is mixed with an ethanol solution, curcumin is added, and stirred uniformly to obtain a fluorescent polyurethane solution, and curing obtains a polyurethane-based fluorescent material. The polyurethane fluorescent material applicable to bacterial detection is designed through a polyurethane segment, ensures solid-state light emission of curcumin, does not cause fluorescence quenching, ensures activity of a heat-sensitive base material at room temperature, and the fluorescent color is different under different bacterial concentrations, and the response is sensitive.

The invention discloses a CPN-Y2-Cl cation framework material as well as a preparation method and application thereof. The CPN-Y2-Cl cation framework material is constructed by carrying out quaternization reaction on tetra (1-imidazole phenyl) ethylene and 5, 5 '-bromomethyl-2, 2'-dipyridyl, and is obtained by carrying out anion exchange. The material has rapid and efficient adsorption performance on I3 <-> in a water phase, and still shows good selectivity in the presence of various competitive anions. Meanwhile, the material has obvious fluorescence quenching in the process of acting with I3 <->, and rapid detection of I3 <-> in water can be realized. The material designed by the invention is stable in performance, the preparation process is simple and convenient, and the prepared organic cation framework material has dual functions of adsorption and fluorescence recognition, and has a wide application prospect in the fields of treatment and real-time monitoring of radioactive iodine polluted water.

The invention belongs to the technical field of fluorescent dyes, and particularly relates to a phenanthroline-based double-BODIPY fluorescent dye with an asymmetric structure as well as a preparation method and application of the phenanthroline-based double-BODIPY fluorescent dye. The preparation method comprises the following steps: mixing a chlorinated BODIPY derivative with 1, 10-phenanthroline-5-amino, adding palladium acetate, tri-tert-butylphosphine, potassium tert-butoxide and toluene, and carrying out a heating reflux reaction; and after the reaction is finished, cooling, reducing pressure to remove toluene, dissolving the obtained product with dichloromethane, washing, drying, concentrating, and separating and purifying through silica gel column chromatography to obtain the target dye. The unique asymmetric structure in the prepared target dye destroys the planarity and symmetry of molecules, effectively weakens the fluorescence quenching effect caused by molecular self-absorption and pi... pi accumulation, and further has relatively large Stokes shift and high solid-state luminous efficiency; good application potentials are shown in a plurality of fields such as high-performance solid-state light-emitting devices and biological probes.

This invention discloses a polycyclic compound and an organic electroluminescent device containing the same. The invention introduces a bridged ring structure to reduce the electron-donating ability of nitrogen atoms, and further weakens this ability through a bridged ring and benzene ring structure, avoiding a redshift in the material's emission. Compared to the benzene ring, the twisted structure of the bridged ring weakens the intermolecular interactions caused by this planar configuration, which is more conducive to the dispersion of dopants in the host material, effectively avoiding fluorescence quenching and improving luminescence efficiency. Simultaneously, the use of a double boron framework allows the material to maintain a narrow half-width at half-maximum (WHM), resulting in devices fabricated using the compound of this invention exhibiting excellent performance in terms of efficiency and lifetime.

The invention discloses a fluorescent probe based on an ESIPT principle and application of the fluorescent probe in detection of total iron, ferrous iron and ferric iron. The probe OHNH contains a phenolic hydroxyl group, generates strong fluorescence through ESIPT, and has the advantages of good light stability, high fluorescence quantum yield, good water solubility, difficult hydrolysis, simple synthesis and the like. Fe and OHNH can generate specific complexation, the ESIPT process is influenced, and fluorescence quenching is caused. Fe is easily oxidized into Fe under the heating condition of a drying oven, and then fluorescence quenching is also triggered. Based on the principle, high-selectivity and high-sensitivity detection of total iron, ferrous iron and ferric iron can be realized. The method is low in cost, easy and convenient to operate, high in specificity and high in accuracy, and visual detection can be achieved. Furthermore, the method can be used for valence state distinguishing and content determination of iron in complex matrixes such as medicines, foods and water bodies, and has important practical application value.

The application discloses a kind of photoactivation manganese ion bridging type deoxyribozyme probe preparation and its application in Cistanche inhibiting acetylcholinesterase activity.The probe is pSD@MnO2 Composite structure, which is composed of manganese dioxide nanosheet and functional nucleic acid assembly adsorbed on its surface, the assembly includes S chain labeled with fluorescence / quenching group and containing deoxyribozyme cleavage site, and pD chain partially hybridized with S chain and containing photocleavage site.Its preparation includes nucleic acid probe assembly, MnO2 Nanosheet complexing and purification steps.When applied, AChE catalytic product decomposes MnO2, releases Mn 2+ And nucleic acid chain; after centrifugation, pD chain is cut by ultraviolet light activation trigger, and released DNAzyme is cut under the assistance of Mn 2+ It produces amplified fluorescence signal; by comparing signal change before and after adding inhibitor, inhibition activity can be quantitatively evaluated.The application combines photocontrol activation with enzyme cascade amplification, realizes high sensitivity and operation synchronism of detection process, and is especially suitable for high-throughput rapid screening of AChE inhibitor in Cistanche and other natural products.

The invention discloses a dual-response type near-infrared two-region quantum dot nanoprobe as well as preparation and application thereof, and belongs to the technical field of biomedical nanomaterials and molecular imaging. The quantum dot nanoprobe comprises an inner core and a shell, wherein the shell is coated outside the inner core; the inner core comprises a near-infrared emission quantum dot core, and the surface of an NIR-II quantum dot is connected with a response peptide and a quencher; the shell is prepared from a polylactic acid-glycolic acid copolymer, polylactic acid, polycaprolactone, a polylactide-polyethylene glycol copolymer, a polylactide-polycaprolactone copolymer, a polysulfide block copolymer and the like. According to the NIR-II quantum dot nanoprobe disclosed by the invention, a response peptide chain and a fluorescence quencher are introduced through chemical modification, and a signal off-on function is realized, so that an activated fluorescent probe with high specificity and high contrast is constructed; the nano-composite particle with controllable particle size, adjustable fluorescence and stable structure is formed, has targeting property, responsiveness and biocompatibility, and is suitable for accurate real-time imaging in a complex in-vivo environment.

The invention belongs to the technical field of antibacterial materials, and particularly relates to a zwitterionic photosensitizer material, nanoparticles and a preparation method and application of the zwitterionic photosensitizer material and the nanoparticles. The structural formula of the zwitterionic photosensitizer material is shown in the specification, wherein x is any integer between 3 and 5; r1 and R2 groups are shown in the specification. The zwitterionic photosensitizer material based on sulfonation has excellent hydrophilicity and biological activity, can achieve an efficient sterilization effect at a low dosage, and has efficient curability on mouse living body wound infection, so that the zwitterionic photosensitizer material can be used for preparing a medicine for treating wound infection, and the problems that in the prior art, aggregation causes a fluorescence quenching effect, and the toxicity is poor are solved. And the problem of poor antibacterial treatment effect caused by reduction of ROS yield due to aggregation is solved.

The invention discloses a cell single-molecule mechanical force sensor for single-molecule mechanical force detection in a cell phagocytosis process as well as a preparation method and application of the cell single-molecule mechanical force sensor. The sensor comprises a microsphere substrate and a plurality of double-stranded DNA mechanical probes modified on the surface of the microsphere substrate, the probe is composed of a first single-stranded DNA and a partially complementary second single-stranded DNA and forms an FRET or fluorescence quenching pair, when a pulling force applied to the probe by a receptor-ligand effect exceeds a preset melting threshold value in a process of swallowing or wrapping microspheres by a cell, the double-stranded DNA generates melting or conformational change and generates fluorescence signal change, and the fluorescence signal change is detected by the first single-stranded DNA and the partially complementary second single-stranded DNA. Therefore, the detection of the monomolecular mechanical force of the phagocytic interface is realized. By adjusting the geometric conformation and sequence design of the probe, a probe library with different melting force thresholds can be constructed, and quantitative analysis and spatial distribution characterization of mechanical force in the phagocytosis process are realized. According to the application, a three-dimensional phagocytic interface can be truly simulated, and an effective tool is provided for revealing a mechanism for regulating and controlling endothelial cell phagocytic behaviors through blood flow mechanics and screening related disease drugs.

The invention relates to the technical field of analytical chemistry and nano sensing materials, and discloses a quantum dot microsphere fluorescent probe for trace quaternary ammonium salt detection and a preparation method thereof, and the probe is prepared from porous CdSe quantum dot microspheres, fluorescein isothiocyanate and a buffer solution. The FITC is used as an energy donor, the porous microspheres are used as an energy receptor, the FITC and the porous microspheres close the distance through electrostatic adsorption, a fluorescence resonance energy transfer system with an open initial state is constructed, and fluorescence quenching of the FITC and fluorescence enhancement of the quantum dots are shown. When quaternary ammonium salt is detected, the FITC is separated from the surface of the microsphere by utilizing a hydrophobic competitive replacement mechanism, the FRET process is blocked, the fluorescence of the FITC is recovered, and the fluorescence of the quantum dots is reduced, so that the detection is realized through the change of a ratio fluorescence signal. The method has the advantages of high detection sensitivity, good selectivity, high response speed, strong anti-interference capability and the like, and realizes rapid quantitative detection of trace long alkyl quaternary ammonium salt in a complex environment.

The application discloses a polyarylbutene and a preparation method and application thereof. The polyarylbutene is obtained by polymerizing a multi-propargyl compound and a methylene compound in an organic solvent under the protection of inert gas. The method has mild conditions, the polymerized monomers are simple and easy to obtain, the polymer has high yield, high molecular weight, high atomic economy, and excellent regioselectivity and stereoselectivity. The polyarylbutene has excellent processability and high thermal stability, high refractive index, metal ion fluorescence quenching, and cell imaging, and can be applied to the fields of optics, detection, biology, medicine and environment.

The application discloses a kind of preparation and application of N, P doped titanium carbide nano quantum dot fluorescent probe, belong to fluorescence sensing technical field.The application uses ethylenediamine, diammonium hydrogen phosphate as nitrogen source and phosphorus source respectively to synthesize the N, P doped Ti3C2MXene quantum dot of blue light emission, and the N, P doped Ti3C2MXene quantum dot has good stability and high quantum yield.Based on the fact that tetracycline (TC) can quench the fluorescence of N, P doped Ti3C2MXene quantum dot fluorescent probe, the N, P doped Ti3C2MXene quantum dot fluorescent probe is used for tetracycline detection.The fluorescent probe has high selectivity, wide linear range and high sensitivity, providing a new method for tetracycline detection in milk.

The invention discloses an AIE fluorescent sensor. The AIE fluorescent sensor is identified by a compound of a quinolinic acid derivative functionalized by a host molecule 2-hydroxy-1-naphthaldehyde and Eu < 3 + > in a DMF-H2O solution. The sensor shows yellow fluorescence in a solvent DMF-60% H2O, aqueous solutions of Fe < 3 + >, Cu < 2 + >, Sr < 2 + >, Al < 3 + >, Ag < + >, Ca < 2 + >, Hg < 2 + >, Fe < 2 + >, Co < 2 + >, Ni < 2 + >, Cd < 2 + >, Pb < 2 + >, Zn < 2 + >, Cr < 3 + >, Mg < 2 + > and Ba < 2 + > are respectively added into the solution, and only the addition of Cu < 2 + > can quench the fluorescence of the sensor. In addition, an aqueous solution of ATP, ADP, AMP, H2PO4 <->, HPO4 < 2-> and Cl <-> is added into the sensor containing the copper ions and the europium ions, and only the ATP is added, so that fluorescence of the sensor can be turned on. The recognition performance of Cu < 2 + > fluorescence quenching and ATP fluorescence opening can be used for circularly recognizing Cu < 2 + > and ATP for more than four times. Therefore, the AIE sensor can be used for fluorescent cycle recognition of copper ions and ATP (adenosine triphosphate). Meanwhile, the test paper prepared by the fluorescence sensor can also be used for detecting Cu < 2 + > and ATP. The fluorescence recognition performance has important application value in the field of ion and molecular recognition.

The invention discloses a novel nanogold sensing method for continuously detecting various heavy metals by fluorescence'on-off-on 'based on a gradual detection strategy. Gold nanoclusters (GSH-AuNCs) taking glutathione (GSH) as a reducing agent and a stabilizing agent respond to various heavy metals to cause fluorescence quenching, and a novel GSH-AuNCs visual sensing platform is designed according to the remarkable difference of fluorescence intensity before and after coordination / redox competition, so that four heavy metal ions of Fe (III), Cu (II), Hg (II) and Cr (VI) are successfully and rapidly detected step by step. The method is simple in operation steps, high in detection speed (Fe (III): 3 min, Cu (II): 30 s, Hg (II): 3 min and Cr (VI): 3 min), wide in quantitative range (0.1-200 [mu] M), high in sensitivity (LDDFe (III): 87 nM, LODCu (II): 36 nM, LODHg (II): 32 nM and LODCr (VI): 75 nM) and high in anti-interference capability, and is successfully applied to gradual detection of four heavy metals in actual water and biological fluid (urine and serum).

This invention provides a sensor and its preparation method for detecting aflatoxin B1, belonging to the fields of analytical chemistry and food safety detection technology. The sensor includes a fluorescence quenching unit and a molecular recognition and signaling unit. The fluorescence quenching unit is an amino-functionalized zirconium-based metal-organic framework material UiO-66-NH2. The molecular recognition and signaling unit is a specific nucleic acid aptamer for aflatoxin B1, one end of which is covalently modified with a fluorescent dye. The nucleic acid aptamer binds to the surface of UiO-66-NH2 through adsorption. In the absence of aflatoxin B1, the fluorescence is quenched; in the presence of aflatoxin B1, the nucleic acid aptamer binds to the target analyte and dissociates from the UiO-66-NH2 surface, restoring fluorescence. This invention constructs a fluorescence "turn-on" sensor based on the UiO-66-NH2 / TAMRA aptamer, possessing both high sensitivity and specificity. Through visualization hydrogel technology, it achieves low-cost, rapid, and on-site detection of aflatoxin B1 in complex matrices.

The invention discloses an MOFs material, a preparation method thereof and application of the MOFs material to adsorption and detection of PFOS, and belongs to the technical field of functional materials. An organic ligand of the MOFs material is 2-aminoterephthalic acid, and an inorganic metal center is Ce < 3 + >. The MOFs material has the characteristics of a specific crystal structure, rich amino functional groups, Ce < 3 + > active sites and a mesoporous structure, high-sensitivity detection of PFOS can be achieved through a fluorescence quenching effect, the detection limit is as low as 16 ppb, meanwhile, PFOS can be efficiently removed through a chemical adsorption effect, and the maximum adsorption capacity reaches 724.6 mg / g. The material has the advantages of being high in selectivity, good in stability, high in applicability and the like, synchronous detection and pollution remediation of PFOS can be achieved, and the material has good application prospects in the field monitoring and pollution control aspects of short-chain perfluorinated and polyfluoroalkyl substances (PFAS) in the environment.

The present application relates to the technical field of gene sequencing, in particular to an imaging reagent and a kit for a multi-cycle nucleic acid sequencing reaction based on fluorescence. In the imaging reagent, the synergistic effect of the combination of ethyl 3,4-dihydroxybenzoate, 4-hydroxy-3-methoxyacetophenone and sodium ascorbate reduces the generation of free radicals, inhibits nucleic acid damage during the imaging process, reduces phasing and pre-phasing, and ultimately improves the accuracy of long read sequencing. In order to improve the sequencing read length, three functional components, namely antioxidants, fluorescence quenching inhibitors and free radical scavengers, are added to the traditional imaging reagent. Compared with the existing imaging protectants, the present application creatively selects three antioxidants, namely ethyl 3,4-dihydroxybenzoate, 4-hydroxy 3-methoxy acetophenone and sodium ascorbate, for compounding, so as to exert a synergistic effect and eliminate the need for adding fluorescence quenching inhibitors and free radical scavengers.

The application discloses a tumor tissue culture and extracellular vesicle typing analysis method in a microfluidic chip, which comprises the following steps: step one, providing two aptamer probes, including an aptamer PD-L1-L (modified second fluorescent group) combined with a PD-L1 protein, an aptamer EpCAM-L combined with an EpCAM protein, and a connecting arm (containing a fluorescent quenching group and a first fluorescent group); step two, culturing tumor tissues in the chip, and capturing extracellular vesicles secreted by the tumor tissues through the modified antibodies on the chip; and step three, incubating the tumor tissues and the two aptamer probes, and then incubating the connecting arm, so that a first fluorescence recovery and a second fluorescence quenching double-switch mode are generated, so that the extracellular vesicles from tumor cells are identified; the second fluorescence of the immune cell PD-L1-L is kept, and the first fluorescence of the connecting arm is quenched, so that the extracellular vesicle typing analysis of the tumor tissues is performed.

The application relates to the field of nanomaterials and ion detection, in particular to nitrogen-sulfur co-doped carbon quantum dots with high quantum yield and a preparation method and application thereof. The preparation method of the nitrogen-sulfur co-doped carbon quantum dots with high fluorescence quantum yield comprises the following steps: S1, citric acid and L-cysteine are dissolved in deionized water, and ultrasonic stirring is carried out until the solution is clear; S2, the solution obtained in step S1 is transferred into a reaction kettle, and hydrothermal reaction is carried out for 4-10 hours; S3, the reaction product of step S2 is cooled to room temperature, the supernatant is collected by centrifugation, and the solution in the dialysis bag is collected by suction filtration and dialysis, so that the nitrogen-sulfur co-doped carbon quantum dots are obtained. The carbon quantum dots prepared by the application have the characteristics of high quantum yield, and Fe 3+ can produce a significant fluorescence quenching effect. The carbon quantum dots exhibit high selectivity, excellent anti-interference ability and high sensitivity, and have important practical application value in the field of metal ion detection. 3+ ​

The application discloses taraxacum-derived carbon dots with tunable fluorescence and application thereof, and two kinds of carbon dots R-CDs and B-CDs with fluorescent colors can be obtained by high-temperature tuning with taraxacum as a carbon source, thereby creating conditions for double-channel fluorescence detection. The R-CDs can detect the percentage content of water in various organic solvents, and the test paper prepared can be repeatedly used for multiple times. The B-CDs are a multi-mode probe with fluorescence / colorimetric / absorption / RGB identification, and can simultaneously analyze and detect DNP in multiple ways. When a certain concentration of DNP is added into the B-CDs probe solution, a relatively significant fluorescence quenching phenomenon occurs, and the color of the solution becomes yellow. The specific detection of DNP is distinguished from other interfering components (metal ions, biological molecules and aromatic nitro compounds), and the detection method can be verified with each other, thereby improving the accuracy of detection. Meanwhile, the double-channel and multi-modal target detection is realized.

This invention belongs to the field of nucleic acid aptamer technology. This invention provides a high-affinity and specific phalloidin nucleic acid aptamer and its applications. The base sequence of the high-affinity and specific phalloidin nucleic acid aptamer is shown in SEQ.ID.NO.1. The nucleic acid aptamer obtained by this invention exhibits strong specificity for phalloidin; after detection by graphene oxide fluorescence quenching, the measured fluorescence intensity reaches 867.6 (au), while its effects on other toxins and blank controls are not significant. Furthermore, it has high affinity for phalloidin, with a Kd value of 240 nM (0.203 ng / Kg). After 5' end FAM fluorescent labeling, the nucleic acid aptamer obtained by this invention can achieve visual detection of phalloidin under ultraviolet transmission irradiation.

This invention discloses an organic fluorescent probe for detecting tricyclazole, its preparation method, and its application, belonging to the field of organic synthesis and analytical chemistry. The organic fluorescent probe uses cyanostilbene as the chromophore and is modified with (1R,2R)-1,2-cyclohexanediamine and a crown ether chain to obtain a fluorescent macrocyclic structure, i.e., the organic fluorescent probe, chemically named (1R,2R)-cyclo-tris(ethoxy)-bridged-di(4-phenyl(Z-1-cyanovinyl)phenyl)-4-oxoacetylcyclohexanediamine. The organic fluorescent probe of this invention exhibits good sensing ability for tricyclazole, strong anti-interference ability, and can achieve real-time, visual, and selective detection of tricyclazole. When tricyclazole is present in the environment, the organic fluorescent probe undergoes significant fluorescence quenching. The concentration of tricyclazole in the sample can be determined based on the good linear relationship between fluorescence intensity and the equivalent concentration of tricyclazole. Furthermore, the construction method of this organic fluorescent probe is efficient, and the detection steps are simple, making it an important reference in the field of agricultural detection.