26results about How to "Reduce background signal" patented technology

This invention belongs to the field of photocrosslinking probe technology, specifically relating to a GUSB photocrosslinking probe, its preparation method, and its application. The GUSB photocrosslinking probe has the general chemical formula C0. 13 H 18 N2O6-R, wherein R is any one of the oxalic group elements or peptide bonds. The R group covalently connects the glucuronic acid recognition core and the photosensitive unit in the GUSB photocrosslinking probe, and the R group contains no more than 4 atoms, resulting in a small size and low steric hindrance. The GUSB photocrosslinking probe provided by this invention uses glucuronic acid as the recognition core, combined with a small-volume diazacyclopropane photosensitive unit and a terminal alkyne group, to achieve µM-level in-situ covalent capture of active GUSB in complex systems such as cells or tissues. The probe of this invention significantly improves positioning accuracy, sensitivity, data availability, quantification, and enrichment, while also possessing advantages such as modular synthesis, mild conditions, and strong system compatibility, effectively addressing the technical shortcomings of existing technologies that struggle to accurately obtain GUSB activity in situ under low-dose conditions.

This invention belongs to the field of biosensor technology, specifically relating to an aflatoxin B1 sensor based on exchange catalysis and photocurrent polarity reversal, its preparation method, and its application. The sensor includes a reference electrode, a photosensitive substrate electrode, an AFB1-specific aptamer-trigger chain conjugate, a basement exchange catalytic nucleic acid amplification system, and an h-Zn1Cd5S-hairpin H conjugate. The sensor constructed by this invention is easy to operate, has a fast response speed, good repeatability, high detection sensitivity, and specificity. It can avoid interference from signal fluctuations, and its preparation method is simple, showing broad application prospects in aflatoxin B1 detection.

The invention belongs to the technical field of biotechnology and protein determination, and particularly relates to confining liquid as well as a preparation method and application thereof. Modified bovine serum albumin and recombinant casein polypeptide are used as core components of the confining liquid, hydroxypropyl-beta-cyclodextrin, polyglycerol fatty acid ester and other auxiliary components are added, and the confining liquid is prepared through a specific technology. The modified bovine serum albumin and the recombinant casein polypeptide have a synergistic effect, so that active sites of the detection carrier can be efficiently sealed; the stabilizing agent and other components are supplemented, so that the stability and compatibility of the confining liquid are improved. The confining liquid is simple and convenient in preparation process, controllable in cost, suitable for various detection carriers such as elisa plates and nitrocellulose membranes, capable of reducing non-specific binding and improving detection sensitivity, and suitable for various biological detection scenes such as enzyme-linked immunosorbent assay.

The invention provides a composition, a kit and a method for detecting African swine fever virus, and relates to the technical field of gene detection. The primer group and the probe provided by the invention are used for detecting the African swine fever virus, the probe is a ZIPNA probe, the ZIPNA probe comprises a 5 '-terminal fluorophore, a 3'-terminal quenching group and a spermine group, and the ZIPNA probe can provide higher detection specificity because non-specific binding and background signals can be more effectively reduced. The positive ions coupled with the ZIPNA probe can neutralize negative charges of target nucleic acid and reduce electrostatic repulsion, and meanwhile, the ZIPNA probe coupled with a certain number of positive ion groups can reach a preset Tm value. The ZIPNA probe can effectively replace a small groove conjugate and locked nucleic acid, and can be used in various application fields based on nucleic acid detection. The ZIPNA probe has the advantages of being high in detection fluorescence increment, high in detection specificity, good in repeatability, high in sensitivity and the like, and practical application is facilitated.

Described herein are 1, 2-dioxetane useful as chemiluminescent probes, diagnostic agents, and imaging agents. Compositions comprising such compounds and methods of use thereof are also described herein.

The invention provides a method for detecting allura red in food by using difunctional sulfur nanodots. According to the invention, a fluorescence detection method for quantitative detection and identification of allura red (AR) is developed by utilizing dual functions of S-dots, and the S-dots are both a fluorescence indicator and a decomposition reagent of the AR. The fluorescence of the S-dots is quenched by AR, and the mechanism is a static quenching effect. In addition, due to the synergistic decomposition effect of S-dots and an etching reagent (H2O2 solution) on AR, quenched fluorescence is gradually recovered. According to the fluorescent response of S-dots to AR, AR as low as 5 nM can be quantitatively detected, and AR in food pigments can be distinguished by observing fluorescence recovery. Detection and identification of AR in actual food samples such as soda drinks, coated chocolates and fruity milk candies are realized. A new clue is provided for the design of a chemical sensor, and the method has great application potential in the aspect of guaranteeing food safety.

The invention discloses a flow type single molecule detection probe and method based on rolling circle amplification and application in the technical field of biomolecule detection. The flow type single molecule detection probe comprises a plurality of groups of magnetic bead detection probes and antibody binding probes which are used in pairs, each magnetic bead detection probe comprises a superparamagnetic microsphere, and the surface of the superparamagnetic microsphere is covalently connected with a plurality of fixed antibody probes; each fixed antibody probe comprises a first antibody and a first fixed DNA chain; each antibody binding probe comprises a second antibody and a second fixed DNA chain; aiming at the same target antigen, the first antibody and the second antibody in the same group can be specifically combined with different epitopes of the target antigen to form a sandwich immune complex. According to the invention, the hairpin structure DNA probe is combined with the adjacent ligation and rolling circle amplification technology to form dual specific screening of immune recognition and DNA ligation, so that the signal-to-noise ratio and sensitivity of detection are remarkably improved, and the design complexity, development cost and cross reaction risk of a multi-target detection system are greatly reduced.

The invention relates to an electrochemiluminescence sensor based on an intelligent controlled release-interface capture-self-enhancement mechanism and application of the electrochemiluminescence sensor in procalcitonin detection, and belongs to the technical field of electrochemiluminescence detection. Controllable release of signal molecules is achieved by packaging terpyridyl ruthenium through ZIF-8, meanwhile, a DNA layer rich in guanine is modified on an electrode interface, and the layer can serve as a nano trap to efficiently capture the signal molecules and can also serve as a co-reactant to achieve signal amplification. A DNA strand displacement reaction is utilized to regulate and control a target response release process, and detection is realized according to a quantitative relationship between the concentration of procalcitonin and an electrochemical luminescence signal. A labeling recovery method verifies that the recovery rate of the sensor in a human serum sample reaches 100.6-103.6%, good accuracy and precision are shown, and a reliable platform is provided for clinical detection of inflammatory markers.

This invention discloses a multi-channel collimation device for neutron diffraction, belonging to the technical field of neutron scattering spectrometers. The device includes a base, separating aluminum plates, and a detector. The base has an arc-shaped structure, with two bases arranged opposite each other. Each base has multiple mounting cavities spaced circumferentially on it. Each mounting cavity contains multiple separating aluminum plates spaced vertically, with a channel for the neutron beam to pass between adjacent separating aluminum plates. The detector is configured in a one-to-one correspondence with each channel. This multi-channel collimation device can optimize the neutron signal and reduce stray background signals, thereby ensuring the accuracy of experimental results.

The present invention discloses an eddy current detection circuit, method, system, storage medium and terminal, which belong to the field of eddy current non-destructive detection technology. The invention mainly utilizes a differential bridge and a transformer conditioning circuit to form a dual-path differential probe, and utilizes the signal parameters generated by the first differential signal and the second differential signal under their respective alternating magnetic fields to analyze the relationship between the amplitude, phase parameters and lift-off respectively generated under the alternating magnetic field, and performs multi-parameter signal fusion, which can suppress lift-off. The dual-path differential output has a high detection capability for defects when the lift-off changes greatly.

This invention relates to the field of biomedical technology, and more particularly to a PD-L1-targeting polypeptide, its conjugate, and its applications. The polypeptide possesses the amino acid sequence shown in SEQ ID NO.1 or SEQ ID NO.2. This invention de novo designs a high-affinity PD-L1-targeting specific polypeptide. This polypeptide achieves extremely high affinity with the extracellular domain of the PD-L1 protein through its unique spatial conformation, exhibiting excellent targeting and recognition capabilities. The polypeptide provided by this invention can be conjugated with various modified molecules, such as radionuclides, and the constructed molecular imaging probe exhibits excellent tumor tissue targeting and enrichment capabilities, superior biocompatibility, and clear imaging contrast, enabling specific recognition of PD-L1-positive tumor lesions. It can be applied to clinical scenarios such as early precision diagnosis of tumors, screening of patients for immunotherapy, real-time monitoring of efficacy, and prognostic assessment, possessing significant translational medical value and broad application prospects.

The utility model relates to an enzyme-linked immunosorbent assay (ELISA) kit based on CHR detection. The ELISA kit comprises a kit body, an elisa plate is mounted on one side in the kit body; micropores are formed in the elisa plate; a coating liquid container, a confining liquid container, a washing liquid and a detection antibody are arranged on the other side of the combination body; a substrate developing solution; and a signal detector. The double-antibody sandwich ELISA has the advantages that the double-antibody sandwich ELISA has the advantages of high specificity and sensitivity, and is suitable for detection of macromolecular antigens which have a plurality of epitopes and can be recognized by two antibodies at the same time. Two antibodies are used, one antibody is used as a capture antibody fixed antigen, and the other antibody is used as a detection antibody to generate a signal, so that the detection accuracy and repeatability can be remarkably improved, a more accurate sepsis biomarker monitoring means can be provided by accurately monitoring the CHR level, a doctor can be helped to formulate a more effective treatment scheme, and the clinical application prospect is wide. Therefore, the treatment effect and prognosis of the sepsis patient are improved.

The invention relates to the technical field of primer marking, in particular to a primer marking method based on fluorescence quenching and application. The primer labeling method is simple, and fluorescence labeling can be carried out only by manually adding a C-base-rich region to a C-base-rich region of a common primer or at the 5'tail end. And treating the fluorescence labeled primer by using a product amplification technology to form a double-stranded DNA structure. And then dissociating the double-stranded DNA structure through a fluorescent quantitative technology, and making a dissociation curve. And finally, analyzing the inverted dissociation curve to obtain the thermodynamic characteristics of double-chain dissociation of the primer when the temperature changes. The method has the characteristics of low background signal and good PCR product quenching effect. The method can be used in combination with a fluorescent probe method or a fluorescent dye method, and effectively widens the number of targets detected by a classical fluorescent probe technology or a fluorescent dye method technology. And the high sensitivity characteristic of a fluorescent probe method or a fluorescent dye method is not influenced.

The present application relates to a kind of mitochondrial DNA single nucleotide variation heterogeneity ratio in vitro detection system, kit and method, the in vitro detection system includes FnCas12a protein, crRNA, single-stranded DNA report probe, reaction buffer, PEG8000 and acetylated bovine serum albumin;The crRNA includes FnCas12a direct repeat sequence and spacer sequence, the spacer sequence is designed as with mitochondrial DNA single nucleotide variation mutant target sequence complementary pairing, and with corresponding wild type target sequence forms single base mismatch at the single nucleotide variation site;FnCas12a protein is under the guidance of the crRNA, recognizes the mutant target sequence and activates the trans cleavage activity of single-stranded DNA report probe, to generate detectable signal for reflecting the proportion of the mutant target sequence.The in vitro detection of mitochondrial DNA single nucleotide variation mutant is realized.

The application discloses a multi-target miRNA biological detection kit based on up-conversion fluorescent coded magnetic beads and a construction method and application thereof. The kit comprises three kinds of up-conversion fluorescent coded magnetic beads with different emitting colors (yellow-green, red and blue-violet), capture probes for different target miRNAs connected respectively, and corresponding fluorescent labeled detection probes. The capture probes are specifically hybridized with the target miRNAs, and then sandwich complexes are formed with the detection probes, the characteristics of the up-conversion fluorescent coded signal and the detection signal without spectral interference under different excitation wavelengths are utilized, and the magnetic separation technology is combined, so that high-throughput, high-sensitivity and high-specificity simultaneous detection of multiple miRNAs is realized. The application effectively solves the problems of insufficient miRNA detection specificity, low throughput and spectral overlap in the prior art, and provides a new detection tool for early multi-index diagnosis of tumors and other diseases.

The invention discloses a method for preparing a biotin-labeled egg allergen F1 reagent, which comprises the following steps of: a) pretreating an egg to obtain clear egg white liquid; b) mixing 0.2 M NaHCO3 buffer solutions with the same volume as the egg white and the pH value of 9.5, centrifuging to take supernate, dialyzing the supernate at the temperature of 4 DEG C, and then centrifuging to obtain an egg white extracting solution; c) performing buffer solution replacement and filtration operation on the egg white extracting solution to obtain filtrate; d) adding a labeling reagent into the filtrate for labeling to obtain a labeled reagent; e) washing and centrifuging the marked reagent for multiple times to obtain an F1 reagent; f) adding the reagent F1 into glycerol, and then sub-packaging and storing; wherein after the egg white extracting solution is obtained through dialysis in the step b), the pH value of the egg white extracting solution is adjusted to be about 4.0, then the egg white extracting solution is heated for 15-30 min at the temperature of 60-65 DEG C, the egg white extracting solution is rapidly cooled and then centrifuged for 10 min at the temperature of 4 DEG C and the weight of 12000 g, generated precipitates are discarded, supernatant is collected, and the egg white extracting solution which is further purified is obtained.

The invention discloses an aggregation-induced fluorescence enhanced carbon quantum dot as well as a preparation method and application thereof. The carbon quantum dot is a carbon nanomaterial synthesized from a tetra (4-carboxybenzene) ethylene monomer. The invention provides the carbon quantum dot, the surface of the carbon quantum dot has abundant carboxyl groups, mercury ions can be effectively grabbed, and under the guidance of the mercury ions, the carbon quantum dot has the characteristics of generating aggregation and leading to remarkable enhancement of fluorescence intensity. The carbon quantum dot belongs to a fluorescence enhancement type probe material, only emits weak fluorescence, fluorescence is enhanced after the carbon quantum dot reacts with Hg (II), and compared with a fluorescence quenching type material, fluorescence enhancement signal change is easier to effectively detect, background signals can be reduced, and the carbon quantum dot is more suitable for being applied to a biological system. The carbon quantum dot is used for Hg (II) detection and has good specificity and selectivity, interference resistance and high sensitivity, a good linear relation can be established through the fluorescence intensity of a solution and the concentration of Hg (II), and extremely low detection is achieved.

This invention discloses an intracellular imaging system for simultaneously detecting UDG and miR-375 expression levels and its applications. The intracellular imaging system uses a tetrahedral DNA nanostructure as a carrier, loading a HAT-UDG probe with an on / off conformation, and coupling it with a split CRISPR / Cas12a detection component for recognizing miR-375. The split CRISPR / Cas12a detection component includes at least Cas12a protein, scaffold RNA, spacer RNA / equivalent split crRNA components, and a fluorescent reporter substrate. This invention is the first to perform a logical AND operation between two key indicators: UDG enzyme activity and miR-375 expression level. The system can only ultimately trigger a complete fluorescence signal when both are simultaneously highly expressed. This multi-target synergistic activation design constructs a precise molecular recognition logic gate, enabling extremely accurate differentiation between prostate cancer cells (RV-1) and normal cells (293T), as well as other cancer cells (5637) that highly express UDG, fundamentally avoiding misjudgments caused by fluctuations in a single indicator or non-specific expression, resulting in extremely high imaging specificity.

This application relates to anti-CEACAM6 nanobodies, their preparation methods, nucleic acids, vectors, host cells, applications, detection reagents, or kits. The anti-CEACAM6 nanobodies include heavy chain variable regions, specifically CDR1, CDR2, and CDR3. The amino acid sequence of CDR1 is shown in SEQ ID No:12, the amino acid sequence of CDR2 is shown in SEQ ID No:14, and the amino acid sequence of CDR3 is shown in SEQ ID No:16. This antibody exhibits higher affinity, better stability, and better specificity.

The invention discloses a red light reversible regulation gene expression system and application, the system comprises three plasmid vectors, respectively a plasmid pPA formed by fusing a PUF protein and a phytochrome PhyA, a plasmid pFE formed by fusing a shuttle protein FHY1 and eIF4E, and a downstream targeting regulation plasmid pNG formed by an NRE target and a downstream gene of interest GOI; according to the invention, the binding characteristic of RNA binding protein PUF and target NRE thereof is utilized, and the characteristic of dimerization of PhyA protein and ligand FHY1 thereof under red light is fused, so that a gene expression activation system capable of bidirectional light regulation is constructed, the PUF protein continuously and stably inhibits expression of downstream genes of interest, background leakage of the system is reduced from the source, and the expression of the downstream genes of interest is inhibited. Expression of downstream interested genes can be caused only under irradiation of red light, the expression can be rapidly closed by far-red light, and the expression of the genes can be accurately controlled through light; the system can be applied to tumor treatment.

The invention discloses an immunohistochemical antibody diluent and a preparation method thereof, and belongs to the technical field of immunization, and the immunohistochemical antibody diluent is prepared by the following steps: weighing 7.8-8.1 parts by weight of sodium chloride, 0.15-0.25 part by weight of potassium chloride, 3.5-3.6 parts by weight of sodium dihydrogen phosphate and 0.25-0.3 part by weight of dipotassium phosphate, adding into 950-1050 parts by weight of deionized water, stirring at room temperature to fully dissolve, filtering, and drying to obtain the immunohistochemical antibody diluent. Then 9.5-10.5 parts of bovine serum albumin, 4.5-5.5 parts of goat serum and 0.9-1.1 parts of ProCin 300 are added, the pH is adjusted to 7.5, the color of the solution is adjusted, and an immunohistochemical antibody diluent is obtained after filtration with a 0.22-micron filter membrane; the prepared antibody diluent can improve the storage stability of the immunohistochemical antibody, is stable in performance, safe and reliable, can reduce background signals, and remarkably improves the signal-to-noise ratio of various tissue dyeing results.

The invention relates to the technical field of canine serum GnRH antibody detection, in particular to a method and a kit for detecting a GnRH antibody in canine serum. The KLH-GnRH dimer polypeptide is obtained by coupling a KLH dimer polypeptide with a GnRH dimer polypeptide; the amino acid sequence of the GnRH dimer polypeptide is as shown in SEQ ID NO. 1. The KLH-GnRH dimer polypeptide is used as an antigen, and an indirect ELISA method is adopted to detect the GnRH antibody titer, so that the hormone state and reproductive capacity of dogs at different stages are evaluated. The method has the advantages of low cost, simplicity and convenience in operation, high sensitivity, strong specificity, good accuracy and the like, stable, rapid, accurate and convenient dog serum GnRH antibody level detection can be realized, and meanwhile, the repeatability is good.

The application belongs to the technical field of luminescent substrate liquid preparation, and particularly relates to a single-component acridinium ester luminescent substrate liquid and a preparation method thereof. The single-component acridinium ester luminescent substrate liquid comprises the following raw materials: sodium hydroxide, urea peroxide, N-methyl pyrrolidone, a surfactant, sodium percarbonate, a stabilizer, triton 405 and a catalyst, does not contain hazardous components, and is safer to use. The luminescent substrate liquid has the advantages of high luminescent intensity, low background signal, good stability and thermal stability, low cost, convenient use and the like. The preparation method of the luminescent substrate liquid is simple, and the luminescent substrate liquid can be used in all types of magnetic microparticle chemiluminescence acridinium ester projects.

The present invention provides methods and systems for detecting and / or quantifying analytes, and in particular, provides methods and systems for simultaneously detecting and / or quantifying two or more analytes in a sample. In some embodiments, a colocalization assay (CLAMP) performed on microparticles is provided, the assay comprising two sets of conjugates preloaded on a carrier so that the two sets of conjugates are colocalized before contacting the sample.

The invention relates to the field of biological detection, in particular to a monoclonal antibody combination for detecting human IL-33 protein and application. The antibody combination comprises 1B3 and 4A10, the amino acid sequence of a complementary determining region of a heavy chain variable region of the monoclonal antibody 1B3 corresponds to SEQ ID NO.1-SEQ ID NO.3, and the amino acid sequence of a light chain variable region CDR of the monoclonal antibody 1B3 corresponds to SEQ ID NO.4-SEQ ID NO.6; the amino acid sequence of a heavy chain variable region CDR of the monoclonal antibody 4A10 corresponds to SEQ ID NO.7-SEQ ID NO.9, and the amino acid sequence of a light chain variable region CDR of the monoclonal antibody 4A10 corresponds to SEQ ID NO.10-SEQ ID NO.12. The antibody combination ensures the repeatability of raw material production, provides a reliable basis for preparing in-vitro diagnostic tools such as high-sensitivity and high-stability ELISA kits and the like, and has a wide application prospect.

The invention provides a system and method for detecting breast cancer ctDNA based on ExoIII-driven target cyclic signal amplification and competitive crRNA asymmetric cascade signal amplification, belonging to the technical field of bioanalysis detection; a cyclic cutting system is constructed by ExoIII enzyme, and the target ctDNA signal is cyclically converted into a large number of ssDNA (T) signals and is specifically recognized by a complete crRNA / Cas12a complex, thereby realizing a first signal amplification; a second signal amplification is constructed by competitive crRNA-mediated CRISPR / Cas12a asymmetric cascade signal amplification; conformational resetting of the CRISPR / Cas12a enzyme caused by competition between the complete crRNA and the split-type crRNA leads to an enhanced fluorescent signal, reduces the background signal, and improves the sensitivity of detection; the operation steps are simple, the detection process is simplified, and the detection efficiency, sensitivity and specificity are high.