56results about How to "Low fluorescent background" patented technology

The invention comprises novel methods and strategies to detect and / or quantify nucleic acid analytes. The methods involve nucleic acid probes with covalently conjugated dyes, which are attached either at adjacent nucleotides or at the same nucleotide of the probe and novel linker molecules to attach the dyes to the probes. The nucleic acid probes generate a fluorescent signal upon hybridization to complementary nucleic acids based on the interaction of one of the attached dyes, which is either an intercalator or a DNA groove binder, with the formed double stranded DNA. The methods can be applied to a variety of applications including homogeneous assays, real-time PCR monitoring, transcription assays, expression analysis on nucleic acid microarrays and other microarray applications such as genotyping (SNP analysis). The methods further include pH-sensitive nucleic acid probes that provide switchable fluorescence signals that are triggered by a change in the pH of the medium.

The invention discloses a two-photon formaldehyde fluorescent probe and preparation and application thereof. The probe is a novel formaldehyde probe taking 1,8-naphthalimide as a two-photon fluorogen on the basis of an intramolecular charge transfer mechanism. Probe molecules have good light stability and a large Stoke's shift, the probe can well detect the formaldehyde concentration in a neutral buffer solution, and meanwhile compared with other aldehyde compounds, the probe has good specificity on formaldehyde. It is well proved through two-photon confocal fluorescence microscopic imaging experiments that the probe can permeate through a cell membrane to enter cells and can detect a change of the formaldehyde concentration in the cells, and an effective research tool for researching the physiological action of formaldehyde in the cells is provided.

The invention discloses a method for monitoring beta amyloid protein aggregation process by aggregation-induced emission, belonging to the technical field of biomedical research and clinical detection. With the method, the high affinity between sulfydryl on cysteine and maleimide is utilized to specially combine the beta amyloid protein on an aggregation-induced emission probe. The beta amyloid protein aggregation process is monitored on the basis of aggregation-induced emission enhancement phenomenon. The method has the advantages of high sensitivity, high selectivity, good stability, low manufacture cost and the like and is easy to control. The A beta42 and A beta40 contents can be monitored in a micromole, even a nano-mole level, the detection speed of the method is improved by 15 times if being compared with that of the detection method which utilizes probes, such as ANS (8-aniline-1-naphthalene sulfonic acid) and the like. The beta amyloid protein aggregation process can be qualitatively and quantitatively monitored, the method has a good application prospect if being applied to the pathologic diagnosis of latent patients suffering from senile dementia.

The invention discloses a primer pair for specific amplification of EGFR gene 20 exon T790M and C797S loci. The sequence of the primer pair is shown in SEQ ID No:1-2. The invention further discloses a probe set for specific detection of the T790M and C797S loci. The probe set comprises a wild type probe and a mutant type probe, and the sequences are shown in SEQ ID No:3-7. The invention further discloses a reagent kit comprising the primer pair and the probe set, and a method for adopting the primer pair and the detection set for detecting EGFR gene 20 exon T790M and C797S mutation. By designing the specific primers and probes, the 3' end of the probes is connected with a minor groove binder and a non-fluorescent quenching group, the interference of background signals is lowered, hybridization of the probes and a template is stabilized, a Tm value of the probes is increased, and therefore the mutation detection sensitivity is improved.

The invention discloses a fluorescent probe, a preparation method thereof and an application of the fluorescent probe for detecting a nucleic acid G-quadruplex structure. The probe is provided with a structure in a general formula (I) is simple and stable in structure and easy to prepare. The probe can be used for specific detection of a nucleic acid G-quadruplex secondary structure, and the G-quadruplex secondary structure in solution can be rapidly detected by a fluorescence spectrometer or direct visual inspection under irradiation of a fluorescent lamp. The probe can be used for detecting the nucleic acid G-quadruplex structure in agarose gel or polyacrylamide gel and can also be used for detecting, marking or displaying existence or distribution of the G-quadruplex structure in living cells. Fluorescent materials have efficient and specific recognition capability for the nucleic acid G-quadruplex structure, have the advantages of excellent cell membrane permeability, low photo-induced toxicity, biological toxicity and photo-bleaching performance and the like, and overcome the shortcomings of high cost, high equipment requirement, complicated technical operation and the like in other detection methods.

Disclosed are a preparation method of low-fluorescent-background assembled gold magnetic composite nanometer particles and application thereof. The preparation method includes steps of preparing magnetic nanometer Fe3O4; preparing Fe3O4@SiO2 particles, decorating the surfaces of the Fe3O4@SiO2 particles with amino perssad; preparing small-diameter nanometer particles by utilizing sodium borohydride to reduce chloroauric acid; mixing the F33O4@SiO2 particle injectable suspension and the nanometer injectable suspension according to the volume proportion of 1:3, stirring the same ultrasonically, and obtaining assembled Fe3O4@SiO2@Au gold magnetic composite nanometer particles by coordinate bond of nanometer gold particles and the amino perssad on the surface of the Fe3O4@SiO2 particles. The Fe3O4@SiO2@Au gold magnetic composite nanometer particles are prepared by self-assembled technology, and are controllable in size, uniform in distribution, excellent in dispersion, stability and biocompatibility and lower in preparation cost. The preparation process is simple, requires mild reaction conditions, and has the advantages of low cost and convenience in operation.

The invention discloses a glyphosate detection micro-fluidic chip, which comprises a substrate located on the bottom part and a cover plate covered above the substrate in a sealing manner, wherein a micro-fluidic circuit is arranged on the substrate and comprises a derivatization channel and an immune response detection channel connected with the derivatization channel; a glyphosate antigen is fixed on the inner surface of the immune response detection channel; a water sample inlet and a derivative reagent inlet are arranged at an inlet of the derivatization channel; a waste liquid outlet is formed at an outlet of the immune response detection channel; a phosphate buffer solution inlet, a glyphosate antibody solution inlet, a Cy3 fluorescent dye labeled second antibody solution inlet and a sodium dodecyl sulfonate solution inlet are arranged close to the joint of the derivatization channel and the immune response detection channel. The invention also discloses a glyphosate antigen fixation method and a glyphosate detection method. The glyphosate detection micro-fluidic chip provided by the invention has the advantages of capability of simply, conveniently, quickly and accurately detecting glyphosate in water and the like.

The invention relates to application of fluorescent probes to the detecting of the enzymatic activity and sieving of an inhibitor. The invention applies a series of water-soluble conjugated polymers, conjugated oligomers and non-conjugated polymers or oligomers provided with chromophores as the fluorescent probes. By utilization of the polymers or the oligomers with high fluorescent quantum yield as the fluorescent probes which then perform single labeling on substrates of enzymes, the invention has the advantages of high efficiency, sensitivity, quantification, directness, simplicity, convenience, quickness, universality and so on when applied to the detecting of the enzymatic activity and sieving of the inhibitor.

The invention discloses a bisphenol A detecting method and detecting kit based on the dual-quenching-group nucleic acid self-assembling technology. Two DNAs of stem loop structures are designed, wherein one DNA of the stem loop structure is used for modifying a fluorophore, and the other DNA of the stem loop structure is used for modifying two quenching groups; and under the condition that bisphenol A exists, loop opening hybridization can be continuously carried out on the two DNAs of the stem loop structures, so that the fluorophore and the quenching groups get close to each other, fluorescence energy transferring happens, and fluorescence is accordingly quenched. According to the detecting method, signal amplification is sourced from continuous loop opening complementation of the two DNAs of the stem loop structures, and no protease is needed to be used, so that operation is easy, a reaction can be completed at the room temperature, the sensitivity is high, and the selectively is good. The two quenching groups exist on one DNA of the stem loop structure at the same time, and the fluorophore on the other DNA of the stem loop structure can be quenched more effectively, so that the fluorescence background is effectively reduced, the detection sensitivity is greatly improved, and the detection limit is 0.4 pM.

The invention provides a detection probe for an SNP (Single Nucleotide Polymorphism) of a human CYP2C19 gene. A detection primer consists of a specific upstream and downstream primer pair of the gene and a specific Taqman double fluorescent probe which are respectively used for correspondingly detecting SNPs at CYP2C19*2, CYP2C19*3 and CYP2C19*17 sites. The detection probe has the characteristics of quick detection and high specificity; furthermore, the detection method is simple; positive contrast and negative contrast which are necessary to conventional fluorescent quantitation PCR are eliminated, so that the operation steps and the experimental cost are reduced; the subsequent clinical treatment strategy can be guided more quickly and better.

The invention relates to the field of gene detection, in particular to a nucleic acid membrane strip and a kit for hereditary hearing loss gene detection. The kit comprises a PCR reaction liquid, wherein the PCR reaction liquid comprises a PCR reaction liquid A, a PCR reaction liquid B, a PCR reaction liquid C, a PCR reaction liquid D and a PCR reaction liquid E and also comprises corresponding primers and probes. According to the kit, the specific amplification LATE-PCR special primers are designed by use of the sequence of various mutation sites, reported by in literature, and the locked nucleic acid modified ZNATM probes are adopted, so that the least tubes of the reaction liquid can detect the most sites. The PCR reaction liquids A, B, C, D and E in the kit can be tested on the same fluorescent PCR instrument by use of the same amplification program, and the clinical requirement for quick and convenient hearing loss detection is satisfied.

The invention relates to a near infrared fluorescence probe adopting nile blue as a parent, a preparation method thereof and applications thereof. The fluorescence probe has a structure shown as the general formula I as the attached drawing 1. The fluorescence probe can effectively improve deficiencies of tumor labeling fluorescence probes at present, can sensitively and accurately response to target cells COX-2 expression amount of which is abnormal, and is suitable for effective specific near infrared fluorescence probes labeling living tumor cells. The fluorescence probe provided by the invention is simple in synthesis and products are easy to obtain. The fluorescence probe provided by the invention has a very low fluorescence background in non-tumor cells and high fluorescence signals in tumor cells, and has strong specific labeling function for tumor cells. In addition, compounds of the type have good cell membrane permeability, low biotoxicity, low phototoxicity and low photobleaching capability and can locate a special organelle of a certain kind tumor cell.

An immobilized nucleic acid detecting probe is a non-labeling oligonucleotide probe fixed to a solid substrate. The fluorescence quenching material is fixed to said solid substrate via arm moleculae. The oligonucleotide probe composed of fluorescent group, and the stem and ring of the probe is prepared on the surface of said fluorescence quenching material. The one end of said probe is fixed to the surface of said fluorescence quenching material and its another end is near the base labeled by fluorescence group.

The invention discloses a method for observing dynamic distribution of tumor cell exosome and exosome internal miRNA in recipient cells. The method comprises the following steps: after extracting thetumor cell exosome, conducting fluorescence labeling on a tumor cell exosome membrane and the exosome internal miRNA through an exosome membrane stain and a molecular beacon which is complementary with the exosome internal miRNA, and meanwhile, staining the recipient cells via a cell membrane stain; and implementing co-culture on the tumor cell exosome obtained from the fluorescence labeling and the stained recipient cells, adding an imaging buffer solution after an interaction of the tumor cell exosome and the recipient cells, and implementing dynamic tracing of exosome and miRNA in living cells through a super-resolution optical microscope. According to the method provided by the invention, the problem in the prior art that exosome cannot be carefully observed due to diffraction limit can be solved; and a novel technological means can be provided for researches on an exosome-mediated cancer metastasis mechanism and cancer metastasis and spread treatment.

The invention provides an aptamer molecular pair for detecting aflatoxin B1, a kit and a detection method thereof. The aptamer molecular pair is a molecular pair composed of molecules obtained from a 5' terminal of a molecule as shown in SEQ ID NO.1 through FAM marking and a 3' terminal of a molecule as shown in SEQ ID NO.4 or SEQ ID NO.5 through BHQ-1 marking, or a molecular pair composed of molecules obtained from a 5' terminal of a molecule as shown in SEQ ID NO.2 through FAM marking and a 3' terminal of a molecule as shown in SEQ ID NO.6 or SEQ ID NO.7 through BHQ-1 marking, or a molecular pair composed of molecules obtained from a 5' terminal of a molecule as shown in SEQ ID NO.3 through FAM marking and a 3' terminal of a molecule as shown in SEQ ID NO.8 through BHQ-1 marking. The product and method provided by the invention have low cost, high stability and a detection limit of 0.2nM.

A fungus fluorescence staining liquid is disclosed and comprises an A staining liquid and a B staining liquid. The A staining liquid includes 0.03-0.1 part by weight of fluorescein, 1-5 parts by weight of a cleaning agent and 80-150 parts by weight of water. The B staining liquid includes 0.3-1 part by weight of dye and 80-150 parts by weight of water. The A staining liquid can combine cell wall beta-polysaccharides of various funguses, thus labeling and fluorescing for detection. The B staining liquid is adopted as a counterstaining liquid and used for reducing the fluorescence background. The fungus fluorescence staining liquid comprising the A staining liquid and the B staining liquid is a rapid fungal infection detection product and can combine various funguses to emit fluorescence, thus detecting whether various suspected fungal infection diseases are fungal infection or not.

The invention discloses a fluorescent probe with the characteristic of charge transfer, and a preparation method and an application thereof, belonging to the fields of chemical synthesis, chemical analysis and biological analysis. According to the invention, the structure of the probe comprises the parts of electron-donating triphenylamine and electron-deficient quinoline salt, so the probe has the property of intramolecular charge transfer. The fluorescent probe has the following advantages: the synthetic route has high operability; the purification method is simple; the preparation cost is low; and good market competitiveness is obtained. The fluorescent probe has stable structure and low fluorescence background, wherein the fluorescence enhancement exceeds one hundred times after specific binding of the fluorescent probe with a G-quadruplex. Through fluorescence spectrum, a secondary structure of a DNA sample can be rapidly detected, and the disadvantages like high price, long cycle and complicated technical operation in the prior art are overcome.

The invention relates to a multiple nucleic acid detection method, combination and kit. The method comprises the following steps of mixing a combination containing a first primer group and a first probe with a sample from a subject; amplifying a target sequence possibly existing in the sample; carrying out melting curve analysis on an amplified product in a corresponding detection channel; and judging whether one or more targets exist or not according to a result of the melting curve analysis.

The invention relates to primer and probe sequences and a method for detecting Bacillus anthracis, Yersinia pestis and legionella pneumophilia through multiple real-time fluorescence polymerase chain reaction (PCR). The primer and probe sequences comprise a set of sequences of primers and probes for the Bacillus anthracis, Yersinia pestis and legionella pneumophilia; and the method comprises the following steps of: selecting primer pairs and probes; preparing a plasmid standard of a target gene; establishing a reaction system; and selecting a fluorescent detection channel. The primer pairs and probes have good specificity and performance, and a multiple real-time fluorescence PCR method for detecting the Bacillus anthracis, Yersinia pestis and legionella pneumophilia can be established, and has the advantages of reliable and accurate results, sensitivity, simple operation, time and labor conservation, low cost, high efficiency and the like.

The invention discloses a fluorescent probe and a preparation method thereof and an application of the fluorescent probe in detection of a nucleic-acid G-quadruplex structure. The structure of the probe is as shown in the formula (I), and the probe is simple and stable in structure and easy to prepare. The invention further discloses the fact that the probe can be used in specific detection of a nucleic-acid G-quadruplex secondary structure, and the G-quadruplex secondary structure in a solution can be detected through a fluorospectro photometer; the probe can be used in detection of the nucleic-acid G-quadruplex structure in sepharose gel or polyacrylamide gel; the probe can also be used in detecting, marking or displaying existence and distribution of the G-quadruplex structure in living cells. The fluorescent material has efficient and exclusive recognition capability on the nucleic-acid G-quadruplex structure and has the advantages of good cell membrane permeability, low photoinduced toxicity, biotoxicity and light bleaching property and the like, and shortcomings that other detection methods are high in cost, high in equipment requirement, relative complex in technical operation and the like are overcome.

The invention discloses a fluorescent probe for detecting tyrosinase as well as a preparation method and application of the fluorescent probe, and belongs to the technical field of chemical analysis and detection. The fluorescent probe for detecting tyrosinase has the following structural formula: the fluorescent probe prepared by the invention has the advantages of low fluorescent background, good chemical stability, good water solubility, high selectivity, large Stokes shift, strong anti-interference capability, high sensitivity, good detection effect and the like; the prepared fluorescent probe is in a fluorescence quenching state, and shows strong fluorescence after being combined with tyrosinase for recognition, and the fluorescence is enhanced by about 178 times; the fluorescent probe prepared by the invention not only can be used for in-vitro detection of tyrosinase activity, but also can be applied to screening of tyrosinase inhibitors, and has important significance on treatment of tyrosinase-related diseases; the fluorescent probe prepared by the invention can be used for detection and imaging of endogenous tyrosinase in cells and zebra fish, and is successfully used for detection and imaging of tyrosinase at cellular level and biological level.

Embodiment of the invention provides a cell fluorescence in situ hybridization method based on a microfluidic chip. The method includes the following steps: providing a microfluidic chip; passing an appropriate amount of cell suspension into the microfluidic chip after the microfluidic chip being coated to capture cells in the cell suspension on the surface of the microfluidic chip; passing a hypotonic solution and a fixing solution into the microfluidic chip sequentially to perform hypotonic treatment and fixation on the cells, and then adding fluorescent probes to perform fluorescence in situ hybridization on the cells; conducting storing or reading step after washing. The cell fluorescence in situ hybridization method has the advantages of simple operation steps, low reagent consumption, low cost and low fluorescence background. The invention also provides application of the cell fluorescence in situ hybridization method based on the microfluidic chip.

The invention discloses a fluorescent dye compound, the structural formula of which is shown as the formula I described in the specification, wherein X is C(CH3)2, S or O; n is 3 or 4; m is 2 or 3. The invention further discloses a method of preparing the fluorescent dye compound. The invention further discloses an application of the fluorescent dye compound. Aiming at the deficiencies in the prior art, by improvement on the basis, the invention provides novel compounds which are simple in structure, high in sensitivity and long in wavelength and have good membrane permeability. The fluorescent dye compound disclosed by the invention mainly reflects very good water solubility, and is simple in structure, easy to get raw materials and low in toxicity. A target molecule can be synthesized by 4-5 steps ordinarily, so that the fluorescent dye compound is easy to industrialize.