30results about How to "Reduce detection background" patented technology

The invention provides a method used for simultaneous detection of three food-borne pathogenic bacteria based on multicolor upconversion fluorescence labeling. According to the method, three upconversion materials with differentiable fluorescence spectrums are used for forming multicolor upconversion fluorescent nanoprobes via respective connection with aptamers of staphylococcus aureus, vibrio parahaemolyticus, and salmonella, and complementary oligonucleotide single chains of the aptamers are connected with magnetic nanoparticles so as to form nano-composites. When bacteria to be tested are in a detection system, double chain unwinding is realized because of specific binding of the pathogenic bacteria with corresponding aptamers; it is possible to realize simultaneous quantitative determination of staphylococcus aureus, vibrio parahaemolyticus, and salmonella by monitoring upconversion fluorescence signal strength at 477nm, 550nm, and 660nm, detection linear range ranges from 50 to 1000000cfu/ml, and detection limits are 25cfu/ml, 10cfu/ml, and 15cfu/ml respectively. The method is used for detection of pathogenic bacteria, is high in sensitivity, is rapid and convenient, and can be used for detection of the three pathogenic bacteria in food such as milk and shrimp meat; and results are accurate and reliable.

The invention discloses a preparation method for a small-molecule microarray. The preparation method comprises the steps of bonding the hydroxyl terminal of a nonspecific adsorption resistance material modified on a chip substrate with the hydroxyl terminal of a small-molecule light crosslinking agent through an esterification reaction, and randomly fixing small molecules on the hydroxyl terminals through light crosslinking. By the adoption of a direct esterification mode, the small-molecule light crosslinking agent is quickly and efficiently coupled to the surface of the nonspecific adsorption resistance material; a chip modification process is simple and convenient and can be implemented under a normal temperature condition; therefore, the modification cost is reduced, and the modification efficiency is improved; a high detection signal is guaranteed; a non-reacted group still keeps high nonspecific adsorption resistance capacity, so that a background signal is reduced; the prepared small-molecule microarray is high in detection signal and low in background signal and can be used for mutual action between high-flux screened small-molecule medicaments and targets.

The invention discloses a nanometer-material-photothermal-effect-based cell detection method and a cell detection device. The method comprises the following detecting steps: (1) centrifuging cell solution to be detected, discharging supernatant, redissolving with PBS (Phosphate buffer solution) and centrifuging again, repeating the operations, discharging supernatant, and dissolving centrifuged precipitates with 10mul of PBS buffer solution; (2) dropwise adding the treated cell sample onto a sample adding area of an infiltration test strip, and washing for three times with PBST (Phosphate buffer solution-tween) solution; (3) adding with 5-20muL of grapheme-gold-antibody compound into the sample adding area of the infiltration test strip, washing for three times with PBST solution and airing; and (4) radiating the sample adding area of the detection device with laser with the excitation wavelength of 808nm for 10-90s, recording the temperature before and after radiation, calculating the temperature difference, and drawing a calibration curve by use of the cell number as an x-coordinate and the temperature difference as a y-coordinate, wherien when one sample is detected, the temperature difference of the sample is detected and is substituted into the calibration curve to calculate the cell number. The detection device and the detection method have the advantages that the detection method is simple, the detection time is short, the detection sensitivity is high and the like.

The invention discloses a method for detecting glucose by paper-based colorimetric assay. The method comprises the following steps: manufacturing a homemade colorimeter; designing a hydrophobic wax printing pattern; cutting a piece of filter paper; printing the hydrophobic wax printing pattern onto the filter paper; molding by dewaxing; preparing ZnFe2O4; preparing a mixed solution; dropwise adding the mixed solution into a detection pool; dropwise adding a solution to be tested; folding the paper in half; and detecting by the homemade colorimeter. The method for detecting the glucose is simple to operate, can be operated by unprofessional people, and is high in detection speed, low in cost, simple in aftertreatment and free from pollution.

The invention provides a method and a reagent kit for simultaneously detecting the resistance sites of the three nucleotide analogues of a hepatitis B virus (HBV). Based on the genotype sequence of the HBV, four nested amplification primers and twenty-seven wild resistance-detection oligonucleotides probes aiming at ten resistance sites are designed in an HBV polymerase area, digoxin-labeled oligonucleotides universal primers are used for conducting nested PRC reaction to amplify a target DNA segment, a target DNA amplification product to be labeled is used for hybridizing with specific oligonucleotide probes on matrix, and the existence of the resistance of the HBV to the three nucleotide analogues is judged through enzymatic color development reaction link-coupled by hybridization conjugates. The method improves the accuracy, the reliability and the sensitivity and can simultaneously detect the ten resistance sites of the three nucleotide analogues, thereby realizing the high-throughput, multi-site, economic and rapid detection and fitting to clinical needs in a better way. The method is of great significance to the realization of early detection and the proper guide of clinical personalized medication.

The invention discloses a cell sifting moudle for fast sifting of antineoplastic- histone precursor histone deacetylase inhibitor compound from compound storage during new drug development. The moudle makes use of speciality that the precursor histone deacetylase inhibitor can activate some starting subsequence, constructs te oexpression vector containing special starting factor and firefly luciferase reporting gene, and builds cos- 7 clone that stably expresses said vector. The cell contains starting subsequence with different degree of activity for luciferase, the starting factor can be acitvated by histone precursor histone deacetylase inhibitor and then the expression of luciferase reporting gene is intensified, and so the detection for histone precursor histone deacetylase inhibitor activity in sample through detection of luciferase activity change can be finished in a short time. The cell sifting moudle can be used for fast and high- flux sifting of new antineoplastic and histone precursor histone deacetylase inhibitor compound from compound storage during new drug development.

The present invention relates to a new type antigen detection method. Said method utilizes the direct combination of antibody Fc fragment specific oligonucleotide ligand and antibody, and converts the antibody signal into nucleic acid signal, then utilizes PCR amplification technique to detect antigen. The utilization of said method can form the detection kit or develop practical protein ship or other biological chip for detecting other various antigens.

The invention discloses a rapid detection method for nanometer fluorescent trace of specific nucleic acid fragment on the basis of CRISPR-Cas12g. The rapid detection method comprises the following steps: with the specific nucleic acid fragment in a biological sample as a research object, preparing a nucleic acid target, a quenching fluorescence probe and a Cas12g ternary complex of the biologicalsample; mixing the Cas12g ternary complex, the nucleic acid target, the quenching fluorescent probe, background RNA and an RNA enzyme inhibitor in a nuclease buffer solution for incubation, after theCas12g ternary complex is recognized and matched with the nucleic acid target, shearing the nucleic acid target in accompany with non-specific trans-shearing of the quenching fluorescent probe so as to obtain detectable fluorescence; and collecting fluorescence spectrum data, and constructing a quantitative detection model of an up-conversion nanometer fluorescence intensity change value and nucleic acid targets with different concentrations so as to realize rapid detection of the nanometer fluorescence trace of the nucleic acid target in the biological sample. The rapid detection method provided by the invention is applicable to rapid, specific and sensitive detection of the specific nucleic acid fragment in the biological sample.

The invention discloses a micro-fluidic chip capable of removing bubbles; the top of a chip body is provided with an annular gas communication pool, the inner bottom of the gas communication pool is provided with a concave gas filtering pool and a reaction pool, the inner bottom of the gas communication pool is covered with a hydrophobic filter membrane, and the gas communication pool and the gas filtering pool as well as the gas communication pool and the reaction pool are separated by the hydrophobic filter membrane; a gas hole communicated with the gas communication pool is formed in the area, corresponding to the gas communication pool, of the upper cover plate; a sample adding pool is formed in the center of the chip body; a sample adding hole communicated with the sample adding pool is formed in the position, corresponding to the sample adding pool, of the upper cover plate; the bottom of the sample adding pool is communicated with the gas filtering pool through a first channel; and the bottom of the gas filtering pool is communicated with the reaction pool through a second channel. The influence of bubbles on the detection result in the sample detection process can be avoided, so that the accuracy of the detection result is improved. The chip is small in size, does not need mechanical driving force for sample adding, is convenient to use, and is suitable for various POCT scenes.

The invention discloses a salmonella detection test strip based on quantum dot labeling and a preparation method of the salmonella detection test strip and belongs to the field of food safety detection. A ZnS:Mn quantum dot is connected with a salmonella aptamer to serve as a signal probe, and the salmonella is detected by utilizing a test strip chromatography principle. The test strip is composedof a sample pad, a nitrocellulose membrane (NC film), absorbent paper and a back plate. the aptamer complementary sequence connected with streptavidin and Poly A is sprayed and fixed on a NC film byusing a BioDot three-dimensional spray point instrument to form a detection line T line and a quality control line C line. The quantum dots and the salmonella aptamer (the aptamer contains a Poly T sequence) are coupled to serve as a signal probe, and when the signal probe and a sample solution are mixed and then dropwise added to a sample pad, due to the capillary force effect caused by absorbentpaper, the signal probe migrates from the sample pad to the absorbent paper through the NC film. The salmonella is detected according to the fluorescence intensity ratio of the T line to the C line.

The invention discloses a method for high specificity detection of target DNA in a sample. The method comprises the steps of pretreatment, preliminary treatment, a one-step reaction, post-treatment, and a color development reaction. Traditional molecular hybridization methods are substantially improved, nucleic acid hybridization and enzyme linking reactions are carried out in a combined manner, and synergistic cooperation treatment of solid sustenance surfaces before and after the hybridization reaction are carried out through pretreatment, preliminary treatment and post-treatment, so the detection efficiency of the target DNA in the sample and the solid sustenance surface DNA molecule hybridization specificity are improved, and the false positivity of a detection result is effectively avoided.

The invention relates to multispectral up-conversion nanoparticle-based immunochromatographic test paper for rapidly detecting multiple pesticide residues and a preparation method for the immunochromatographic test paper, and belongs to the technical field of chemical analysis. The pesticide test paper comprises a test paper board, a sample dropwise-addition unit, a detection unit and a sample recovery unit, wherein the sample dropwise-addition unit, the detection unit and the sample recovery unit are all connected to the test paper board; the detection unit is positioned in middle of the test paper board, and comprises an antigen coating buffer and confining liquid. The immunochromatographic test paper and the preparation method for the same have the beneficial effects that the test paper has the characteristics of rapidness, convenience, specificity, sensitivity and low cost, particularly has the characteristics of rapidness and convenience, is particularly suitable for grassroots units, field operating personnel, large-batch short-time detection and large-scale general survey and the like, has great development potential and broad application prospect, is considered as one of the most promising novel technologies for food safety detection, and becomes the main development trend of food safety detection.

The invention discloses a probe for improving antigen detection sensitivity of pathogenic microorganisms and a kit containing the probe. The probe is double-stranded DNA which contains a fluorescence label and is provided with a restriction enzyme site, and the double-stranded DNA consists of Cy5-B-CM-S and NH2-B-CM-AS; wherein the Cy5-B-CM-S is as shown in SEQ ID No. 1, and the NH2-B-CM-AS is as shown in SEQ ID No. 2. The probe is combined with a detection antibody of a to-be-detected antigen, so that the detection background can be greatly reduced, the detection sensitivity of the pathogenic microorganism antigen is improved, and a foundation is laid for research and development of a single-molecule diagnostic reagent of the pathogenic microorganism antigen. Meanwhile, the probe restriction enzyme design can realize rapid detection of antigens.