310results about How to "Reduce background signal" patented technology

This invention provides methods of monitoring the expression levels of a multiplicity of genes. The methods involve hybridizing a nucleic acid sample to a high density array of oligonucleotide probes where the high density array contains oligonucleotide probes complementary to subsequences of target nucleic acids in the nucleic acid sample. In one embodiment, the method involves providing a pool of target nucleic acids comprising RNA transcripts of one or more target genes, or nucleic acids derived from the RNA transcripts, hybridizing said pool of nucleic acids to an array of oligonucleotide probes immobilized on surface, where the array comprising more than 100 different oligonucleotides and each different oligonucleotide is localized in a predetermined region of the surface, the density of the different oligonucleotides is greater than about 60 different oligonucleotides per 1 cm2, and the olignucleotide probes are complementary to the RNA transcripts or nucleic acids derived from the RNA transcripts; and quantifying the hybridized nucleic acids in the array.

The devices and method are provided for detecting labeled and label-free analytes, such as nucleic acids and proteins, employing conjugated cationic, anionic and neutral polymers. The analytes can be immobilized on a solid support material. The solid support material can be disposed in the pre-fabricated patterns on a substrate. The chemical structures of the polymers employed by the various embodiments of the present invention are described herein.

The present invention relates to compositions and methods for the detection and quantification of individual target molecules in biomolecular samples. In particular, the invention relates to coded, labeled compositions comprising at least two probes hybridized to each other that are capable of binding to and identifying target molecules based on the probes' label codes. Methods of making and using such compositions are also provided. The compositions can be used in diagnostic, prognostic, quality control and screening applications.

Systems and methods employing Coherent Raman Scattering (CRS), e.g., Coherent anti-Stokes Raman Spectroscopy (CARS) and / or Stimulated Raman Scattering (SRS) are provided. Systems and methods for performing flow cytometry, imaging and sensing using low-resolution CRS are also provided.

The present invention relates to a method for detecting an analyte in a sample, said method comprising: (a) contacting said sample with at least one set of at least first and second proximity probes, wherein said probes each comprise an analyte-binding moiety and can simultaneously bind to the analyte, and wherein (i) said first proximity probe comprises a nucleic acid moiety attached at one end to the analyte-binding moiety, wherein a circular or circularizable oligonucleotide is hybridized to said nucleic acid moiety before, during or after said contacting step; and (ii) said second proximity probe comprises an enzyme moiety, attached to the analyte-binding moiety, capable of directly or indirectly enabling rolling circle amplification (RCA) of the circular or, when it is circularized, of the circularizable oligonucleotide hybridized to the nucleic acid moiety of the first proximity probe, wherein said RCA is primed by said nucleic acid moiety of said first proximity probe; (b) if necessary, circularizing said oligonucleotide, to produce a circularized template for RCA; (c) subjecting said circular or circularized template to RCA, wherein if the enzyme moiety of the second proximity probe in step (a)(ii) is a DNA polymerase, this step does not utilize a free DNA polymerase; and (d) detecting a product of said RCA.

Methods and systems for spatially resolved spin resonance detection in a sample of material are disclosed. Also disclosed are methods and systems for spatially resolved impedance measurements in a sample of material. The disclosed methods and samples can be used in screening of plurality of biological, chemical and material samples.

A simple, fast, selective and highly sensitive electrochemical method assay and disposable device for detection of viruses, bacteria, proteins, DNA, and / or organic / inorganic compounds. The sensor has a multi-layered construction, with each successive layer performing a different function. The design further allows for the packing of numerous microscopic electrode transducers onto the small footprint of a biochip device, allowing for a high-density array of sensors.

The devices and method are provided for detecting labeled and label-free analytes, such as nucleic acids and proteins, employing conjugated cationic, anionic and neutral polymers. The analytes can be immobilized on a solid support material. The solid support material can be disposed in the pre-fabricated patterns on a substrate. The chemical structures of the polymers employed by the various embodiments of the present invention are described herein.

The invention belongs to the technical field of neoplastic disease diagnosis, and discloses a kit for early diagnosis of neoplastic disease, a method and applications of the kit. The kit includes a specific capturing and detecting system for a tumor exosome and a molecular beacon fluorescent detection system. The specific capturing and detecting system for the tumor exosome includes a solution ofa magnetic gold nanosphere composite modified by a tumor exosome specific ligand and adopting ferric ferrous oxide as a core, and a gold nanocage solution modified by the exosome specific ligand. Themolecular beacon fluorescent detection system includes a molecular beacon probe provided with a fluorescent group, fluorescent amplification substrate hybrid chains provided with fluorescent groups and a buffer liquid. The kit and the method combine tumor exosome specific capturing and analysis and a molecular beacon fluorescent detection method, and greatly increases accuracy and reliability of early diagnosis of tumor.

The invention relates to a making method and an application of a mycotoxin photoelectrochemical sensor for in situ generation of CdS. The method uses cerium dioxide doped reduced graphene oxide as an antibody capture substrate, and the cerium dioxide doped reduced graphene oxide has good conductivity and large specific surface area, and can effectively reduce background signals. Na2S is directly dropped to the surface of an electrode with Cd<2+> functionalized porous TiO2 nanoparticles as a semiantigen marker carrier in order to realize in situ generation of narrow band gap CdS with a high photoelectric conversion rate, and a photoelectric current signal can be generated through irridating the CdS by an LED lamp of visible light wavelength. The carrier TiO2 can be well matched with the energy band of the CdS in order to further improve the photoelectric conversion signal of the CdS, so the competitive photoelectrochemical sensor for super sensitive detection of zearalenone, alpha-zeranol, aflatoxin B1, aflatoxin B2, ochratoxin A, ochratoxin B and other mycotoxins is made.

A method of reading an array of moieties such as polynucleotides (for example, DNA) on at least a portion of a surface of a transparent slide which is opposite a first portion on the opposing surface, which array has been previously exposed to a sample. The method may include mounting the slide on a slide holder and retaining the slide thereon in a mounted position in which the holder does not contact the previously exposed array. The holder is then inserted into an array reader and the array read. A holder and slides which can be used in the method are also provided.

The invention provides a microRNA quantitative detection analytic method by utilizing isothermal amplification to synthesize a fluorescent nano silver cluster probe. The method is as below: a DNA amplification template containing three kinds of functional sequences is designed: a sequence binding with a target microRNA, a nicking endonuclease enzyme sequence and a DNA complementary sequence for synthesis of fluorescent nano cluster; when the target microRNA and the DNA amplification template are combined, isothermal amplification reaction and specific enzyme reaction of nicking endonuclease are induced to obtain a large number of single-stranded DNA products; the DNA sequence for synthesis of fluorescent nano silver cluster and a silver nitrate solution are employed to prepare the fluorescent nano silver cluster probe under the reduction of sodium borohydride; fluorescence signal of the reaction system are determined, and a fluorescence change value is calculated; the value is compared with a standard working curve to calculate the concentration of the target microRNA. The method has the advantages of high sensitivity, strong specificity, wide linear detection range, low background signal and simple operation, and can be widely applied to microRNA detection of biological samples such as tissue, blood or cells.

Target-specific hybrid capture (TSHC) provides a nucleic acid detection method that is not only rapid and sensitive, but is also highly specific and capable of discriminating highly homologous nucleic acid target sequences. The method produces DNA-RNA hybrids which can be detected by a variety of methods.

Described herein is a particle detection system capable of spatially resolving the interaction of particles with a beam of electromagnetic radiation. Using a specific electromagnetic beam cross sectional shape and orientation, the detection sensitivity of a particle detection system can be improved. Also provided are methods for detecting and sizing particles in a manner that has low background signal and allows for spatially resolving the scattering or emission of electromagnetic radiation from particles.

Substrates are provided for use in the detection, identification and analysis of biologic or chemical samples that are labeled with a fluorescent label, in which the plane of maximum fluorescence is displaced from a reflective substrate surface so that the intensity maximum of the standing wave interference pattern of incident and reflected probe radiation is enhanced. The format of the substrates includes substantially planar surfaces as well as substrates with introduced variations to the substrate surface, e.g., depressions, wells, pedestals and the like, disposed in arrays or other similar structures such that one or more fluorophore-comprising objects can be attached thereto.

The present invention relates to protein chip based on labeling streptavidin-biotin technology. The hybridization reaction includes the following steps: dropping tested sample to sample applied chip and washing out redundant sample with elution liquid; blocking wtih blockage liquid, washing and air drying; dropping protein marked with biotin diluted by blockage liquid, washing and air drying; anddropping fluorescnet or enzyme labeled streptavidin diluted by blockage liquid, washing and air drying. The protein chip of the present invention is used in determining antigen and antibody, and detecting specific matter combined with protein. The improved method of the present invention has clear, stable and reliable test results and wide application range.

The invention relates to an ARMS fluorescent quantitative PCR-based gene mutation kit and a method thereof. Compared with present gene polymorphism detection kits and methods thereof, the enhanced ARMS fluorescent quantitative PCR-based gene polymorphism mutation kit and the method thereof have the advantages of strong specificity, high sensitivity, low cost, highly reliable result, low background, easy determination of the result, ascendant operation and use, fast and convenient fluorescent quantitative PCR, closed tube detection in the whole course, pollution reduction, and reduction of the unnecessary cost and workload. The fluorescent quantitative PCR can realize the characterization of the amplification efficiency by using a CT value, so the method can realize the detection of the nuclear gene polymorphism heterozygote genotype conditions, and makes the result accurately and reliably determined.

Methods for spatially resolved spin resonance detection in a sample of material, with a resolution as small as 0.5 μ m –1 mm. In one embodiment, a coupler having at least one pair of degenerate orthogonal modes provides an evanescent input signal along one coupler axis to the sample, to which a magnetic field is applied, and senses a spin interaction signal along another coupler axis. In another embodiment, an evanescent input signal is applied to the sample along one of two identical transmission line resonators, and a difference of the two resonator signals provides a spin interaction signal. In another embodiment, a polarized laser beam provides an evanescent input signal to the sample, and the spin interaction signal is sensed according to a second beam polarization direction. Certain ferromagnetic or ferrimagnetic molecules, such as YIG, can be used to tag selected chemical and biological molecules, using spatially resolved spin resonance detection for interrogation.

The invention is a laser-inducing-fluorescence detector. It includes: a piece of inching equipment to plant and ajdust the position of sample holder; an aided light source to adjust the light path; an observation mirror for adjusting the light path; an exciting light source as its working light source made up of the laser, the reference photoelectric diode and light-reducing board and the dichroiscope; a group of optical lenses in imagine and focus the working light source, made up of the focus lens, the imagining lens, the light-filtering piece and the light diaphragm; and a photoelectric signal converter to receive and output the detecting signal. The invention is based on the common-focus mode to get the high-efficiency imagining system and it can be used in the separating-analysis technique such as Micro-HPLC, CE, CEC and so on.

The invention provides a method for detecting mercury ions through a gold electrode modified by polythymidine DNA, which is characterized in that polythymidine DNA molecule is taken as a recognition element for mercury ions, the gold electrode modified by polythymidine DNA is prepared, then mercury ions in an aqueous solution is detected by the prepared gold electrode, wherein alkali base T in DNA molecule is capable of specifically binding with mercury ions to form a stable T-Hg<2+>-T structure. The intensity of an electrochemical signal is relative with the concentration of mercury ions in the solution, so that the concentration of mercury ions in the aqueous solution can be calculated. According to the invention, the method for detecting mercury ions has the advantages of no pollution on environment, good selectivity on mercury ions, eliminated interference of most metal ions, high sensitivity, simple required apparatus and low cost, and is suitable for being applicable to such humble situations as fields and the like.

Buffered assay solutions for performing 1) binding or 2) functional assays on GPCR arrays, along with methods for their use are described. The buffered assay solution has an underlying composition having: a buffer reagent with a pH in the range of about 6.5 to about 7.9; an inorganic salt of either a monovalent or divalent species, at a concentration from about 1 mM to about 500 mM; and optionally a combination of: c) a blocker reagent at a concentration of about 0.01 wt. % to about 2 wt. % of the composition, or d) protease-inhibitor at a concentration of about 0.001 mM to about 100 mM. In an embodiment for functional assay uses, the composition is modified to also include a GTP-analogue, a guanosine 5′-diphosphate (GDP) salt, and / or an anti-oxidant reagent.

A method for rapid in-situ detection of object surface pollutants is characterized in that a flexible and semi-transparent surface enhanced Raman substrate is used and is composed of a Raman active nanoparticle assembly body and a flexible polymer; by a way that the substrate is directly affixed to the surface of an object to be detected, or the substrate is rubbed back and forth on the surface of the object to be detected, or the substrate is coiled into a capillary, the adsorption and enrichment capacity of the substrate on the pollutants on the surface of the object to be detected is enhanced, then the on-site rapid in-situ detection of the pollutants on the surface of the object is achieved by a surface enhancing Raman technique. Compared with other detection methods, the method is simple, rapid, low in cost, and beneficial for on-site casual inspection, and has wide application prospects in the fields of environmental monitoring, food safety, medical treatment and health care and the like.

The present invention discloses a telomerase activity detection kit and a detection method thereof. According to the kit, a ternary linking structure probe is adopted to recognize a telomerase product, and a ternary linking structure triggered DNA molecule machine and a base stacking triggered DNA molecule machine are combined to achieve isothermal cascade nucleic acid amplification to convert a reverse transcription event of the telomerase in a tumor cell extract into a significantly-enlarged fluorescence detection signal so as to precisely determine telomerase activity in a trace amount of tumor cells and achieve detection on tumor cell telomerase activity inhibition by chemical drugs.

A method for performing sub-micron optical spectroscopy, using a heated SPM probe and far-field collection optics is described. The enhanced emission characteristics at a sharp heated tip constitute a highly localized wideband IR source. Thus the IR absorption and emission properties of a sample surface adjacent can be observed and measured in the farfield even though the interaction region is sub-micron in scale. . . . providing spatial resolution mapping of sample composition.

The invention relates to a method for sensitively detecting alkaline phosphatase by double-signal amplification mediated by a transcription reaction initiated by dephosphorylation. The method comprises the steps that a 5'-phosphorylated T7 promoter single chain is designed, alkaline phosphatase can catalyze 5'-phosphorylated T7 promoter to be dephosphorylated to protect the T7 promoter chain frombeing digested by Lambada exonuclease, the remaining T7 promoter can activate transcription reaction mediated by T7 RNA polymerase, and thus a large number of RNA transcripts are produced; and subsequently, the RNA transcripts complement and pair with Taqman probes to form a RNA-DNA duplex, duplex-specific nucleases is introduced to initiate circular cutting of the Taqman probes, and a significantly enhanced fluorescence signal is produced. The method is simple and convenient to operate, has high sensitivity and high specificity, and can be applied to the screening of target inhibitors in complex biological samples and the quantitative detection of targets in cervical cancer cells.

There is provided a simple, inexpensive reaction analysis kit and system capable of performing highly sensitive, quantitative measurement. A chemical luminescence reaction is employed and a sensor element is used to detect the reaction in a highly sensitive manner. That is, a reaction detection plate is used to transmit a signal detected in the sensor element via a reader coil and a reader and then analyze the reaction. The reaction detection plate has a) a membrane, b) a first antibody impregnated section that is disposed such that it faces the membrane and holds a first labeled antibody that specifically binds to a substance to be analyzed, c) a second antibody immobilized section that is provided in part of the membrane and has an immobilized second antibody, the second antibody specifically binding to the substance to be analyzed, and d) a sensor element that is disposed such that it faces the second antibody immobilized section and includes a light detector and a signal transceiver.

The invention discloses a tetrazine compound, a method for preparing the same and application of the tetrazine compound. The tetrazine compound is tetrazine phosphate ester. The tetrazine phosphate ester prepared by the aid of the method can be applied to preparing tetrazine derivatives, and the tetrazine derivatives with fluorescent groups can be used as biological orthogonal fluorescent probes. The tetrazine compound, the method and the application have the advantages that the tetrazine phosphate ester is used as an intermediate for preparing the tetrazine derivatives, accordingly, different varieties of tetrazine derivatives can be prepared from the tetrazine phosphate ester and can be applied to the biological orthogonal fluorescent probes with far infrared / near infrared emission wavelengths and long Stoke's shift, the prepared biological orthogonal fluorescent probes are high in specificity, low in background signal and sensitive and efficient in fluorescent activation, and the like.

The invention discloses a fluorescent probe and a pesticide residue detection kit based on a carboxylesterase inhibition method. The pesticide residue detection kit comprises a reagent stock solution a and a reagent stock solution b, wherein the reagent stock solution a is a buffer solution containing phosphate, and the reagent stock solution b is a solution of the fluorescent probe. Experiments find that the strength of the self fluorescence of the probe is very weak, and after carboxylesterase is added, the probe react and release an IR-780 hemicyanine skeleton fluorescent parent body, the fluorescence of the solution is remarkably strengthened, showing that the method can be used for detection of the activity of the carboxylesterase; after adding a tiny amount of pesticides in the carboxylesterase, the fluorescence of the solution is remarkably weakened, showing that a tiny amount of the pesticides can inhibit the activity of the carboxylesterase, and thus the fluorescent probe can be used for detection of pesticide residues. The fluorescent probe has the advantages of being easy to operate, low in cost, fast, efficient and sensitive, and the fluorescent probe is convenient for application and popularization, and has a huge application prospect in the fields of agriculture, food and the like.