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

The invention discloses a thio probe for detecting nuclease with 3'-5' exo activity. The thio modified oligonucleotide fluorescent probe has a stem-loop structure, wherein the loop part is a single-chain structure which consists of 4-8 nucleotide residues and the stem part consists of 8-15 pairs of nucleotide residues; the phosphodiester bond between every two basic groups of the probe undergoes sulfur acylation; the phosphate group connected between the basic group at the tail end of 3' and the fluorescent group marked on the basic group does not undergo sulfur acylation; the quenching group is marked on the fourth basic group from 3' to 5'. The thio probe can be used for detecting the exo activity of the nuclease in real time, is strong in selectivity, high in sensitivity, rapid in speed, low in cost, correct and reliable, and is capable of overcoming the limits in the prior art.

The present invention provides a method for detecting fumonisin B1 based on fluorescence resonance energy transfer. The method comprises that: NaYF4:Yb,Ho upconversion fluorescence nanoparticles and gold nanoparticles are respectively and covalently bound to both ends of the stem-like part of the specific molecular beacon, wherein the fluorescence resonance energy transfer upconversion fluorescence can be quenched by the gold nanoparticles; and a fumonisin B1 aptamer and a complementary strand thereof are subjected to hybridization immobilization on the surface of magnetic nanoparticles, an analyte fumonisin B1 is added and is specifically bound with the aptamer so as to make the complementary strand be separated from the magnetic nanoparticles, and the separated complementary strand and the molecular beacon are subjected to hybridization so as to open the ring-like part of the molecular beacon, such that the fluorescence resonance energy transfer system is broken, the fluorescence signal is restored, and the fumonisin B1 content can be determined by detecting the fluorescence signal intensity, wherein the detection limitation of the method achieves 0.01 ng.mL<-1>. According to the present invention, the fumonisin B1 content in the food sample can be rapidly, accurately e and sensitively detected.

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 method for detecting glucose by paper-based colorimetry, which comprises the following steps: making a self-made colorimeter; designing a hydrophobic wax printing pattern; cutting filter paper; printing the hydrophobic wax printing pattern on the filter paper; melting wax into shape; preparing ZnFe 2 o 4 ; Prepare mixed solution; Add the mixed solution dropwise to the detection pool; Add the measured solution dropwise; The method for detecting glucose of the present invention is simple to operate, can be operated without professional technicians, has high detection speed, low cost, and simple post-treatment without pollution.

The invention relates to the field of analytical instrument research, and particularly relates to a detection method of a high-sensitivity laser-induced fluorescence detection device suitable for detection on a capillary column. The high-sensitivity laser-induced fluorescence detection device is characterized in that laser light is emitted from a laser, is filtered by a laser light filter, reflected by a dichroscope placed at a 45-degree angle relative to a horizontal plane and focused by an objective lens and finally enters a channel of a circular capillary tube from a position horizontally deviating from the center of the capillary tube by a certain distance so as to excite a component to be tested in the channel to generate fluorescence, and the fluorescence generated by excitation is collected by the objective lens, passes through the dichroscope, a focusing lens, a spatial filtering micropore and a fluorescence light filter respectively and finally enters a photoelectric detection device. The detection method not only is suitable for micro-column separation systems of capillary electrophoresis, capillary chromatography, capillary electrochromatography and the like, but also can be applied to analytic systems for flow injection analysis, sequence injection analysis, microfluidic liquid drop analysis, flow cytometry and the like based on circular capillary flow cells.

The invention discloses a cleaning head for a porous plate and relates to cleaning equipment for a porous plate and a porous biological chip. It includes a row of water suction pipes, a row of water injection pipes, water injection interface, water outlet interface, main part, side plate, side plate rubber pad, porous partition, and the main part, side plate rubber pad and porous partition. The formed water injection chamber, water outlet chamber, water injection buffer chamber and water outlet buffer chamber. The water injection interface is connected to the water injection pipe through the water injection buffer chamber, the holes in the porous partition and the water injection chamber, and the water outlet interface is connected to the water suction pipe through the water outlet buffer chamber, the holes in the porous partition and the water outlet chamber. The side plate and the side plate rubber pad are fixed on the main part in a detachable manner by screws or slots on both sides of the main part, so as to facilitate cleaning and maintenance of the chambers, partitions and pipelines. The invention has the advantages of good uniformity, convenient cleaning, maintenance and use, flexible cleaning methods, suitable for experiments of various scales, and good operability.

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.