36results about How to "Achieve high sensitivity" patented technology

The invention discloses a preparation method and application of a three-dimensional graphene electrode for an electrochemical biosensor. The preparation method comprises the following steps of: fixing spongy graphene in which industrially produced foam nickel is taken as a substrate and which has a three-dimensional structure and is synthesized through chemical vapor deposition on a glass or quartz sheet; connecting the spongy graphene with the three-dimensional structure and a wire by using a silver conductive adhesive; and coating organic silica gel on a connection point of the metal wire and the graphene for insulation to obtain a spongy graphene electrochemical electrode with the three-dimensional structure. The three-dimensional spongy graphene electrode has the outstanding characteristics of high conductivity, high specific surface area, high electrochemical stability and the like, is easily subjected to surface functional modification, and has high detection sensitivity to dopamine and nicotinamide adenine dinucleotide; and a highly sensitive electrochemical biosensor for non-enzymatically and selectively detecting glucose can be obtained after the surface of the electrode is modified by Co3O4.

The invention discloses a portable multi-component online monitor of gas dissolved in transformer oil. A plurality of semiconductor lasers are arranged in a main chassis, each semiconductor laser is connected with a semiconductor laser controller, each semiconductor laser is jointly connected with a signal generating circuit and a 1*N photoswitch, the 1*N photoswitch is connected with an output optical fiber connector on the main chassis, the output optical fiber connector is connected into a long-optical distance gas absorption cell through an output optical fiber, the long-optical distance gas absorption cell is connected with an input optical fiber, the other end of the input optical fiber is connected with an input optical fiber connector on the main chassis, the input optical fiber connector is connected with a calibration absorption cell in the main chassis, and a focusing lens, an infrared photoelectric detector, a connecting lock-in amplifier and a data acquisition control module are sequentially arranged at a front-end light exit of the calibration absorption cell. According to the portable multi-component online monitor, the demand on safe monitoring of a transformer is met, and the high-sensitivity and real-time online monitoring of a failure of the transformer is actually realized.

The invention discloses a preparation method and a Cu<2+> detection application of a rare earth ratiometric fluorescent probe, and belongs to the technical field of environmental detection. The preparation method of the luminol-Tb-GMP fluorescent probe is established through the self-polymerization coordination effect among luminol, GMP and Tb<3+> by using luminol and guanosine monophosphate (GMP)as dual ligands and using a rare earth ion Tb<3+> as a luminescent center ion. The luminol-Tb-GMP fluorescent probe combines the dual fluorescent signals of luminol and Tb<3+>, and simultaneously emits dual fluorescent signals of the luminol and Tb<3+> under the same excitation wavelength. When Cu<2+> exists, the luminol and GMP have a strong coordination effect on the Cu<2+> in order to preventelectrons from being transferred from the amino group of the GMP to Tb<3+>, so fluorescence quenching of the Tb<3+> is caused, and the fluorescence intensity of the luminol is unchanged, thereby a Cu<2+> detection method based on the fluorescence signal ratio of the luminol and Tb<3+> is established. Additionally, the green fluorescence of the Tb<3+> gradually weakens and the blue fluorescence ofthe luminol gradually appears with the increase of the Cu<2+> concentration, so the visual detection of the Cu<2+> can be achieved. The luminol-Tb-GMP fluorescent probe also can be applied to the sensitive detection of the Cu<2+> in an environmental water samples and a biological sample.

The invention discloses a field effect transistor gas sensor and an array preparation method thereof. The field effect transistor (FET) gas sensor is a gate-sensitive FET gas sensor with a gate electrode modified by quantum dots, and a gate-sensitive electrode layer (5) of the FET gas sensor is of a two-layer composite structure or of a single-layer structure made of a composite material. The two-layer composite structure comprises a metal film layer and a quantum dot layer deposited on the surface of the metal film layer. The single-layer structure made of a composite material is specificallya single-layer structure made of a composite material formed by combining quantum dots and a metal or metalloid material. According to the invention, improvement is made on the internal composition and structure of the gate-sensitive FET, the corresponding preparation method and the like, quantum dots are used as a gate electrode and a gas sensitive layer at the same time, and the bias voltage ofthe gate electrode and the channel modulation effect are regulated and controlled by utilizing the adsorption characteristic of a quantum dot gate-sensitive electrode to different gases. A room-temperature gas sensor with high sensitivity, low power consumption and high selectivity can be obtained, and low-concentration target gases (such as H2) can be detected.

A viscosity detecting fluorescence probe has the structure shown in Formula (1), wherein R is -H or is represented by Formula (2). The invention further discloses application of the viscosity detecting fluorescence probe in detections of solution viscosity and intracellular viscosity. The viscosity detecting fluorescence probe is simple and convenient to synthetize, simple in post-processing process and capable of realizing high sensitivity in viscosity detection. Being a simple, quick and sensitive viscosity specificity detection reagent, the viscosity detecting fluorescence probe has a broadapplication prospect in the biomolecular detection field.

The invention discloses a polydopamine coated magnetic Fe3O4 molecularly imprinted polymer, a preparation method thereof and application of the polydopamine coated magnetic Fe3O4 molecularly imprintedpolymer. The invention also discloses an electrochemical sensor based on the polydopamine-coated magnetic Fe3O4 molecularly imprinted polymer, a preparation method of the electrochemical sensor and application of the electrochemical sensor. According to the polydopamine coated magnetic Fe3O4 molecularly imprinted polymer, the preparation method thereof, the application of the polydopamine coatedmagnetic Fe3O4 molecularly imprinted polymer, the electrochemical sensor based on the polydopamine-coated magnetic Fe3O4 molecularly imprinted polymer, the preparation method of the electrochemical sensor and the application of the electrochemical sensor of the invention, Fe3O4 is used as a carrier, molecular imprinting is directly carried out on the surface of the Fe3O4, and therefore, a complexsurface modification process is simplified. DDT recognition, extraction and separation performed a target compound have the advantages of specificity, simple steps, high efficiency and the like; a surface molecular imprinting technology is combined with electrochemical impedance spectroscopy (EIS), so that the constructed electrochemical impedance sensor integrates the advantage of selectivity ofthe molecular imprinting and the advantage of high sensitivity of the EIS.

The invention discloses a method for photoelectrochemically detecting an organophosphorus pesticide based on a BiOBr/Bi2S3 semiconductor heterojunction generated by biological induction. The method comprises the following steps: mixing malathion with avidin-modified magnetic beads, biotin-modified auxiliary DNA and a malathion aptamer, incubating, removing part of the malathion aptamer by using malathion to recover the single strand of the auxiliary DNA, triggering by using the auxiliary DNA to form G-rich dsDNA, and embedding the dsDNA into Hemin and MnTMPyP to catalyze a Na2S2O3 and H2O2 mixed solution to generate H2S. H2S reacts with BiOBr modified on an electrode to generate a BiOBr/Bi2S3 compound, so that the photocurrent is greatly increased, the change of the photocurrent and the concentration of a target object are in a linear relationship in a certain range, HCR signal amplification is designed on the basis of specific recognition of malathion and an aptamer thereof, biocatalysis is utilized to induce a BiOBr/Bi2S3 semiconductor heterojunction to amplify a signal, therefore, high-sensitivity and high-selectivity photoelectric method detection of malathion is realized.

The invention relates to a prostate-specific antigen detection reagent and a kit. The detection reagent comprises PSA first antigen, PSA second antigen and a magnetic bead commonly marked with shear enzymes, a signal amplification reaction liquid reacted with the shear enzymes. The signal amplification reaction liquid contains fluorescein/quenching agent marked block DNA chain; when the block DNA chain is cut off by the shear enzymes highly distributed on the magnetic bead, the fluorescein is separated from the quenching agent, thus the fluorescence signal can be released, thereby amplifying the detection signal of the PSA. The reagent and the kit are simple in operation, high in sensitivity, good in specificity, and applicable to rapid detection of PSA in seminal fluid and serum of a human body.

The invention relates to an electrochemical method for detecting microcystic toxins based on a nano material and Au@Pt marked antibody signal amplification technology and belongs to the technical field of analytical chemistry or water environment monitoring. The electrochemical method comprises the following steps: fixing an MoS2/AuNCs nano composite to the surface of a gold electrode through an Au-S bond, and then modifying an MC-LR antibody to the surface of the nano composite by utilizing the adsorption action; specifically combining the MC-LR antibody and an antigen, and then by combining an antibody marked by an Au@Pt core-shell material, realizing amplification of an electrochemical response signal by catalyzing H2O2; and realizing trace determination of MC-LR in a water sample according to the amplified electrochemical signal. The electrochemical method has the characteristics of high sensitivity, high specificity, simpleness, rapidness and the like. A detection method provided by the invention can also be used for detecting molecules and small molecules of algae toxins of other species in water and provides a rapid and convenient detection way for pollutants in the water.

The invention discloses a production method and application of a needle-point graphene electrochemical electrode. The production method includes the steps of transferring a graphene film synthesized by chemical vapor deposition to the surface of a micro-nano glass needle point, and using liquid conductive silver glue to connect the graphene and a lead to obtain a needle-point graphene electrode; using cobalt nitrate aqueous solution as electrolyte to deposit cobalt hydroxide on the surface of the needle-point graphene electrode by electrochemical deposition, and heating in a muffle furnace at 300-500 DEG C for 2-4 hours to obtain the needle-point graphene electrochemical electrode functionally modified by tricobalt tetroxide. The needle-point graphene electrochemical electrode can be used to detect micro-droplet samples. After surface modification by tricobalt tetroxide, a high-sensitivity electrochemical biosensor available for enzyme-free detection of glucose is obtained. In addition, the needle-point graphene electrochemical electrode can be used to puncture an active cell to detect intracellular metabolic process in real time.

The present invention addresses the problem of providing an assay method for GAD antibody, in particular, a method for assaying GAD antibody at a higher sensitivity than the conventional ELIZA method. To solve this problem, provided is an assay method for GAD antibody in the blood, said assay method being constructed by using the immune complex transfer enzyme immunoassay (ICT-EIA) method, whereby a sensitivity 33 times or greater as high as in the conventional ELIZA method can be established. As a result, type 1 diabetes mellitus can be detected at the early onset stage so that an appropriate interventional treatment can be carried out.

The invention discloses a surface enhance Raman scattering based acetylcholine detection method. According to the method, the competition between acetylcholine and organic molecules on a metal nano substrate is utilized, under the assistance of SERS, corresponding relationship between surface enhanced Raman strength of organic molecules and acetylcholine concentration is established, and highly sensitive, low cost, simple, and rapid acetylcholine detection is realized.

The invention relates to a microcystic toxin-LR electrochemical detection method with amplified graphene signals. The method comprises the following steps: (1) dropwise adding a mixed solution with a ratio of an endonuclease reaction buffer solution: a graphene-aptamer compound: a microcystic toxin-LR solution to be detected: an endonuclease solution of (9-11):(4-6):(2-4):(1-3) on the surface of an MCH/Au NPs/Au electrode; (2) culturing the MCH/Au NPs/Au electrode for 1 to 2 hours at a temperature of 25 to 35 DEG C, slightly washing the electrode surface by ethanol and ultrapure water to remove weakly combined graphene, drying the electrode in nitrogen gas, taking the electrode out, carrying out electrochemical detection to measure the concentration of the microcystic toxin-LR solution. According to the provided method, a high sensitive electrochemical analysis technology and an aptamer with a high specific recognition performance are effectively combined to detect trace microcystic toxin-LR in the environment, the detection is highly sensitive and highly specific, moreover, the instruments are cheap and portable, the method is simple and easy to perform, and the results can be obtained quickly.

The invention provides a micro-fluidic immunoassay combined detection device. The micro-fluidic immunoassay combined detection device comprises a base, a micro-fluidic reactor, a washing assembly and an upper cover, the base is provided with a groove; the micro-fluidic reactor is arranged in the groove; the washing assembly is arranged in the groove; the upper cover is covered on the base; the micro-fluidic reactor comprises a plurality of micro-fluidic pipelines which are arranged side by side; the washing assembly comprises a washing liquid storage frame, a sliding guide rail and a waste liquid storage cavity, and a soft washing liquid bag is placed in the washing liquid storage frame; a pricking needle is fixedly arranged in the groove, one end of the sliding guide rail is connected to the washing liquid storage frame, the other end of the sliding guide rail is connected to the waste liquid storage cavity, and the sliding guide rail is tightly attached to the outer side of the fixing edge and can slide along the fixing edge; the sliding guide rail slides to drive the washing liquid storage frame and the waste liquid storage cavity to integrally slide in the groove. The device has the advantages of high cleaning efficiency, high detection sensitivity and high flux.

The invention discloses a temperature type biosensor and a method for detecting a target aptamer by using the temperature type biosensor. The temperature type biosensor comprises an oxygen production bottle and a heat production bottle which are communicated through a conduit, aptamer response type DNA hydrogel is arranged at the bottom of the oxygen production bottle, and a liquid feeder is arranged at the top of the oxygen production bottle; an oxidized heating material is arranged at the bottom of the heat production bottle, and a thermometer is inserted into the top of the heat production bottle; the aptamer response type DNA hydrogel is formed by wrapping catalase with aptamer cross-linked type DNA hydrogel. The temperature type biosensor utilizes specific recognition between an aptamer and a target aptamer, adopts a DNA hydrogel amplification mechanism and utilizes aptamer response type DNA hydrogel to release CAT under stimulation of the target aptamer so as to catalyze H2O2 to generate O2, O2 and an oxidation heating material are subjected to an oxidation reduction reaction to release a large amount of heat, so that temperature change is caused, therefore, the temperature type biosensor is constructed to achieve high-sensitivity and high-selectivity temperature detection of the target aptamer.

The invention discloses a local biochemistry molecular layer decorating method for a micro-sensor part. The method is characterized in that a micro ink spraying method is used for printing same or different biochemistry molecules to a specific area, local area biochemistry functionalized decorating is carried out on the surface of the sensor part, and thus the sensor part can meet the requirementof biochemistry detection. A device for the local biochemistry molecular layer decorating method comprises a piezoelectric micro spraying head, two cameras, an XY moving table, a closed container, a closed container pneumatic control unit, an XY moving table data collecting and controlling system, a micro spraying head control unit and an environment control and measurement unit, wherein the sizeof printing drops of the piezoelectric micro spraying head can be controlled through voltage, the two cameras are used for observing the position of the micro spraying head and a device in a three-dimensional manner, the device is arranged on the XY moving table and can move in the horizontal plane along with the XY moving table, the closed container is used for containing printed biochemistry molecules, the closed container pneumatic control unit is used for adjusting the size of gas pressure in the closed container, the XY moving table data collecting and controlling system can precisely control the moving displacement of the moving table in the XY direction, the micro spraying head control unit is used for adjusting and controlling the size, the number and the state of the printing drops, and the environment control and measurement unit is used for measuring the surrounding environment condition. According to the local biochemistry molecule decorating method carried out through themicro ink spraying device, high-sensitivity, high-stability and high-throughput real-time detection to biochemistry molecules to be detected can be achieved effectively.