479 results about "Avidin" patented technology

Cyanine and related dyes, such as merocyanine, styryl and oxonol dyes, are strongly light-absorbing and highly luminescent. Cyanine and related dyes having functional groups make them reactive with amine, hydroxy and sulfhydryl groups are covalently attached to proteins, nucleic acids, carbohydrates, sugars, cells and combinations thereof, and other biological and nonbiological materials, to make these materials fluorescent so that they can be detected. The labeled materials can then be used in assays employing excitation light sources and luminescence detectors. For example, fluorescent cyanine and related dyes can be attached to amine, hydroxy or sulfhydryl groups of avidin and to antibodies and to lectins. Thereupon, avidin labeled with cyanine type dyes can be used to quantify biotinylated materials and antibodies conjugated with cyanine-type dyes can be used to detect and measure antigens and haptens. In addition, cyanine-conjugated lectins can be used to detect specific carbohydrate groups. Also, cyanine-conjugated fragments of DNA or RNA can be used to identify the presence of complementary nucleotide sequences in DNA or RNA.

Cyanine and related dyes, such as merocyanine, styryl and oxonol dyes, are strongly light-absorbing and highly luminescent. Cyanine and related dyes having functional groups make them reactive with amine, hydroxy and sulfhydryl groups are covalently attached to proteins, nucleic acids, carbohydrates, sugars, cells and combinations thereof, and other biological and nonbiological materials, to make these materials fluorescent so that they can be detected. The labeled materials can then be used in assays employing excitation light sources and luminescence detectors. For example, fluorescent cyanine and related dyes can be attached to amine, hydroxy or sulfhydryl groups of avidin and to antibodies and to lectins. Thereupon, avidin labeled with cyanine type dyes can be used to quantify biotinvlated materials and antibodies conjugated with cyanine-type dyes can be used to detect and measure antigens and haptens. In addition, cyanine-conjugated lectins can be used to detect specific carbohydrate groups. Also, cyanine-conjugated fragments of DNA or RNA can be used to identify the presence of complementary nucleotide sequences in DNA or RNA.

Aggregation is a major cause of the misbehavior of proteins. A system for modifying a protein to create a more stable variant is provided. The method involves identifying non-conserved hydrophobic amino acid residues on the surface of a protein, suitable for mutating to more hydrophilic residues (e.g., charged amino acids). Any number of residues on the surface may be changed to create a variant that is more soluble, resistant to aggregation, has a greater ability to re-fold, and / or is more stable under a variety of conditions. The invention also provides GFP, streptavidin, and GST variants with an increased theoretical net charge created by the inventive technology. Kits are also provided for carrying out such modifications on any protein of interest.

The invention relates to the field of analyzing immunological determination, in particular to a method for immunological detection by combining an acridinium ester labeling technology with general magnetic particles and an immunological determination (quantitative / qualitative) kit which is prepared by utilizing the method. According to the method disclosed by the invention, substances, such as acridinium ester or acridine sulfonamide are used for labeling and detecting an antigen or an antibody, biotin is used for labeling and capturing the antigen or the antibody, and the immunological determination of biomolecules is carried out by combining the general (chain enzyme) avidin labeled magnetic particles. The method disclosed by the invention has the advantages of high sensitivity, wide detection range and capabilities of realizing the automation easily and having a wide application prospect in the field of the immunological detection.

A humanized murine antibody is provided that binds to the human insulin receptor (HIR). The humanized murine antibody is suitable for use as a Trojan horse to deliver pharmaceutical agents to human organs and tissue that express the HIR. The humanized munne antibody is especially well suited for delivering neuropharmaceutical agents from the blood stream to the brain across the blood brain barrier (BBB). The humanized murine antibody may be genetically fused to the pharmaceutical agent or it may be linked to the pharmaceutical agent using an avidin-biotin conjugation system.

Oligonucleotides and other biomolecules are immobilized in high density on solid substrates through covalent forces using either a permanent thioether bond, or a chemoselectively reversible disulfide bond to a surface thiol. Substrates which have hydroxyl groups on their surfaces can be first silanized with a trichlorosilane containing 2-20 carbon atoms in its hydrocarbon backbone, terminating in a protected thiol group. The oligonucleotides or other biomolecules are first connected to a tether consisting of a hydrocarbon or polyether chain of 2-20 units in length which terminates in a thiol group. This thiol may be further modified with a halobenzylic-bifunctional water soluble reagent which allows the conjugate to be immobilized onto the surface thiol group by a permanent thioether bond. Alternatively, the oligonucleotide-tether-thiol group can be converted to a pyridyldisulfide functionality which attaches to the surface thiol by a chemoselectively reversible disulfide bond. The permanently bound oligonucleotides are immobilized in high density compared to other types of thiol functionalized silane surface and to the avidin-biotin method.

A humanized murine antibody is provided that binds to the human insulin receptor (HIR). The humanized murine antibody is suitable for use as a Trojan horse to deliver pharmaceutical agents to human organs and tissue that express the HIR. The humanized murine antibody is especially well suited for delivering neuropharmaceutical agents from the blood stream to the brain across the blood brain barrier (BBB). The humanized murine antibody may be genetically fused to the pharmaceutical agent or it may be linked to the pharmaceutical agent using an avidin-biotin conjugation system.

Devices and methods for performing assays to determine the presence or quantity of a specific analyte of interest in a fluid sample. In devices according to this invention two separate flow paths are established sequentially in the device with a single user activation step. The first flow path delivers the analyte of interest (if present in the sample) and conjugate soluble binding reagents to the solid phase. If analyte is present, an analyte:conjugate complex is formed and immobilized. The volume of sample delivered by this first path is determined by the absorbent capacity of the solid phase, and not by the amount of sample added to the device, relieving the user from the necessity of measuring the sample. The sample / conjugate mixture is prevented from entering the second flow path because the capillarity and the surface energy of the second flow path prevent it from being wetted by this mixture. The second flow path allows a wash reagent to remove unbound conjugate and sample from the solid phase to the absorbant, and optionally to deliver detection reagents. The invention may be adapted to many assay formats including, sandwich immunoassays, colloidal gold, or sol particle assays, heterogeneous generic capture assays and competitive assays. In one embodiment, sandwich assays can be performed by immobilizing an analyte binding reagent on the solid phase, and drying a labeled analyte binding reagent in the first flow path. In a competitive assay embodiment, the first flow path would contain labeled analyte that is dissolved by the sample, and the analyte binding reagent is immobilized on the solid phase. In each of these embodiments, the assay can be further modified to run in a "generic capture" format, where the solid phase binding reagent is instead conjugated to a generic ligand such as biotin, and dried in the first flow path (either together or separately from the other assay reagents), and a generic ligand binding reagent (such as avidin) is immobilized on the solid phase. Another aspect of the present invention includes a subassembly for the immunoassay device that is comprised of a plastic housing and a means for delivering fluid and / or wash solution. This subassembly comprises a structure formed from a hydrophobic polymer selectively treated with a water insoluble surface active agent that has been applied as a solution in an organic solvent rendering portions of the surface hydrophilic. When the surface is contacted with an aqueous liquid, it flows only along the treated areas, creating a defined fluid flow path, thereby delivering sample / conjugate solutions to said solid phase.

A fusion protein for delivery of a wide variety of agents to a cell via antibody-receptor-mediated endocytosis comprises a first segment and a second segment: the first segment comprising a variable region of an antibody that recognizes an antigen on the surface of a cell that after binding to the variable region of the antibody undergoes antibody-receptor-mediated endocytosis, and, optionally, further comprises at least one domain of a constant region of an antibody; and the second segment comprising a protein domain selected from the group consisting of avidin, an avidin mutein, a chemically modified avidin derivative, streptavidin, a streptavidin mutein, and a chemically modified streptavidin derivative. Typically, the antigen is a protein. Typically, the protein antigen on the surface of the cell is a receptor such as a transferrin receptor-or an insulin receptor. The invention also includes an antibody construct incorporating the fusion protein that is either a heavy chain or a light chain together with a complementary light chain or heavy chain to form an intact antibody molecule. The invention further includes targeting methods and screening methods.

The invention provides a chemoluminescence immunoassay measuring kit and a preparation method thereof for quantificationally detect triiodothyronine (T3) magnetic particles. The kit mainly comprises a triiodothyronine serial calibration sample, magnetic particle solution coated by an anti-fluorescein isothiocyanate (FITC) monoclonal antibody, a T3 antigen marked by biotin, T3 monoclonal antibody marked by FITC, streptavidin marked by alkaline phosphatase, chemoluminescence substrate solution and 20-time concentrated washing solution. The invention adopts a competitive-method reaction mode, effectively utilizes the chemoluminescence technology combined with magnetic particles and biotin-avidin immunity magnifying technology principle to quantificationally detect the content of T3 in blood serum and blood plasma samples of human bodies and ensure the sensitivity of the detection. The kit is simple, convenient, fast, sensitive and stable to use, and provides a very valuable detection method for clinic diagnosis and scientific research works.

The invention discloses a high-flux typed analyzing technique, material and agent box of nucleic acid based on stream-oriented cell tool-microcarrier gene chip, which is characterized by the following: augmentating promoter starting target to connect biotin; connecting magnet microparticle and fluorescent material on the nucleic acid probe; crossing with single-chain of target nucleic acid; separating and purifying target nucleic acid single-chain-probe; adopting high-polymolecule microparticle of clad biotin-proof protein as microcarrier; connecting target nucleic acid single-chain-probe; adopting double probe-sandwich method to test nucleic acid single-chain.

The invention relates to the field of detection in clinical immunology, in particular to a fluorescent immune chromatographic test strip for quantitively detecting troponin I and a preparation method thereof. The test strip provided by the invention comprises a bottom plate, sample absorbing pads attached to the bottom plate and staggered to each other sequentially, a labeled antibody pad, a coating film and a water absorbing pad. The labeled antibody pad is a troponin monoclonal antibody pad I coated with a fluorescent micro-spherical label and a troponin monoclonal antibody pad II coated with a biotin label for identifying different epitopes. The coating film is provided with a detection strip and a quality control strip. Avidin is fixedly arranged on the detection strip. A rabbit antimouse IgG antibody is fixedly arranged on a quality control line. By improving the test strip, a biotin-avidin amplifying system and a fluorescent immune chromatographic technology are introduced into detection of troponin I. Combined with a fluorescent detector, individual quantitive detection of troponin I is realized, therefore, extreme convenience is provided for clinical use.

The invention discloses a test strip for detecting aflatoxin B1 or M1 by utilizing an aptamer. The test strip for detecting the aflatoxin B1 or M1 by utilizing the aptamer, provided by the invention, comprises a sample absorption pad, a marker pad, a reaction film and a water absorption pad, wherein the marker pad is coated with a detection probe; the detection probe is an aflatoxin B1 aptamer marked by fluorescein; the nucleotide sequence of the aflatoxin B1 aptamer is sequence 1; the reaction film comprises a detection region and a quality control region; the detection region is coated with a conjugate formed by an aflatoxin B1 hapten and a carrier protein; and the quality control region is coated with a quality control probe, and the quality control probe is a conjugate formed by avidin conjugation probe marked aflatoxin B1 complementary single strand DNA (Deoxyribose Nucleic Acid)) molecules. The test strip for detecting the aflatoxin B1 or M1, provided by the invention, has the advantages of high sensitivity, accuracy in quantifying, strong specificity, simplicity and convenience, and short detection time.

The invention relates to a preparation method and application of an electrochemical sensor for detection of heavy metal lead contaminants and belongs to the technical field of electrochemical detection. The preparation method is characterized by including; performing synthesis to obtain a Fe-MOFs nano material, reducing palladium-platinum bimetallic nanoparticles onto the Fe-MOFs nano material, and mixing a hairpin type DNA signal probe with the composite material to obtain a biological signal probe; performing layer-by-layer self-assembly through rGO-TEPA and avidin for fixing of '8-17'DNAzyme to obtain the electrochemical sensor for detection of the heavy metal lead contaminants. The sensor is successfully applied to detection of lead contaminants in the environment. The preparation method and application has the advantages of high flexibility, high specificity and rapid and convenient detection; experimental evidence is provided for research of lead contamination detection technology, and new concepts and new technology platforms are provided for monitoring the lead contaminants in the environment are provided.

The invention discloses a test strip for detecting HIV antibodies in spittle and a preparation method thereof. The test strip comprises a sample pad, a fiberglass film, a nitrocellulose film and absorbent paper, wherein the fiberglass film is tightly connected with one end of the sample pad and contains colloidal gold particle markers; the nitrocellulose film is tightly connected with the other end of the fiberglass film; the absorbent paper is tightly connected with the other end of the nitrocellulose film; the sample pad, the fiberglass film, the nitrocellulose film and the absorbent paper are all arranged on a base plate; the nitrocellulose film comprises a detection area coated with HIV recombinant antigens and a control area coated with goat anti rabbit antibodies; and the colloidal gold particle marker comprises a colloidal gold particle-avidin-biotin-antihuman IgG antibody composite micro-signal amplification system, and colloidal gold marking rabbie IgG antibodies. Due to the adoption of the avidin-biotin micro-signal amplification system, the test strip amplifies signals of the target antibodies, improves detection sensitivity and avoids false negative or detection omission caused by too weak signals.

Labeled nucleotide analogs comprising at least one avidin protein, at least one dye-labeled compound, and at least one nucleotide compound are provided. The analogs are useful in various fluorescence-based analytical methods, including the analysis of highly multiplexed optical reactions in large numbers at high densities, such as single molecule real time nucleic acid sequencing reactions. The analogs are detectable with high sensitivity at desirable wavelengths. They contain structural components that modulate the interactions of the analogs with DNA polymerase, thus decreasing photodamage and improving the kinetic and other properties of the analogs in sequencing reactions. Also provided are nucleotide and dye-labeled compounds of the subject analogs, as well as intermediates useful in the preparation of the compounds and analogs. Compositions comprising the compounds, methods of synthesis of the intermediates, compounds, and analogs, and mutant DNA polymerases are also provided.

Methods for delivering a biologically active molecule into a cell by linking a molecule to the cell surface, wherein the molecule can act as a surface receptor, then complexing the biologically active molecule with a ligand for the surface receptor, and finally contacting the biologically active molecule-ligand complex with the cell surface are disclosed. Delivery of any biologically active molecule, e.g. proteins, enzymes, nucleic acids, hormones, nucleic acids, and oligonucleotides, is contemplated. The use of biotin or biotinylated antibodies as the surface receptor is disclosed. The use of PEI and PEI-avidin conjugates complexed with oligonucleotides for delivery into a directly or indirectly biotinylated cell surface, along with the PEI-avidin-nucleic acid compositions, are disclosed. Primary and cultured cells with a covalently linked surface receptor molecule, such as biotin, on their surfaces are also disclosed.

The present invention relates to magnetic fine particles having a lower critical solution temperature to which at least one substance selected from biotin and avidin is immobilized, and a method of converting a substance, a method of separating or concentrating a microorganism, a method of modifying a denatured protein, a method of detecting a nucleic acid, a separating agent, and a method of separating a biological substance using the same.

The invention relates to novel streptavidin binding peptides.

The invention relates to immunoconjugates of formula: A-B-(C)n where B may be present or absent, A is a specific binding protein such as an antibody or an antibody binding fragment, or a ligand binding to a receptor present on target cells B comprises at least one molecule to which "A" and "C" bind, such as an avidin / streptavidin complex, "C" is an MHC molecule, and "n" is a whole number ranging from 1 to 10. The conjugates provide the exquisite binding specificity of antibodies, combined with an ability to stimulate cytotoxic T cells to identify and to destroy cells on which the conjugate is bound and oligomerized. The conjugates are useful both therapeutically and diagnostically.

The present invention is directed to immunoassays for detecting one or more target analytes in a fluid sample wherein the detection reaction occurs on a solid support and involves an amplification system. In particular, the invention is directed to making and using a test device having at least one site for detecting the presence of at least one target analyte, wherein a conjugate comprising dextran-polystreptavidin is immobilized at the test site(s) as a capture reagent for a complex containing the target analyte.

The invention provides for polynucleotides and vectors comprising at least two tag sequences. The invention also provides for polynucleotides and vectors comprising a streptavidin binding peptide sequence and a calmodulin binding peptide sequence. The invention also provides for polynucleotides and vectors wherein a gene of interest is fused in frame to at least two tag sequences, for example, a streptavidin binding peptide sequence and a calmodulin binding peptide sequence. The invention also provides for the chimeric proteins encoded by these polynucleotides. The invention also provides for methods of using the polynucleotides of the invention for detecting and / isolating protein complexes or identifying a binding partner for a protein of interest.

Magnets and magnetic particle-labeled reagents are used to capture and / or release magnetic particle-tagged entities for immunohematology diagnostic testing purposes, especially tests performed in blood banking. The magnetic tagged entities may be tagged antibodies, tagged blood cells, tagged universal binding partners, especially tagged lectins and tagged Coombs reagent, and other binding agents such as biotin-avidin, Protein A or G, ligands and their receptors and the like. Separation of unbound material from bound material is effected through the use of one or both the magnetic field effect on the magnetic labeled reactants and the density gradients of layers of an assay construct. Constructs such as chromatographic strip lateral flow format, and liquid phase reactions in suitable vessels with end point determinations that do not require centrifugation to detect reacted entities. Readable labels such as enzymes, fluorophors, chemiluminescent materials, radioactive isotopes, and other labels may be attached to Coombs reagent to provide a readable product of the Coombs reagent with any antibody participating in the assay.

The present invention provides a drug delivery system wherein a "parachute" structure is coupled to a therapeutic compound. The "parachute" structure comprises hydrophilic branched molecules with a defined action diameter. The complex (a parachute structure coupled with a therapeutic compound) is either fixed at a cell membrane or delivered to a defined distance from the membrane within the cell. The membrane-anchoring / localizing effect of the parachute is achieved by hydrophilic structures linked with a branching unit of desired therapeutic compounds. Furthermore, the parachute structures can be connected by a spacer (e.g. beta-amino acids, gamma-amino butyric acid, or poly-amino acids) instead of directly binding to the therapeutic compound, so that the therapeutic compounds can be localized within the cells at a defined distance from the cell membrane. A spacer containing a breaking point can determine the time span, during which the drug exhibits its therapeutic activity. The hydrophilic residues can also carry signals for targeting the parachute-therapeutic complex to a defined tissue type. This can be mediated by an antibody which is specific for a tumor marker. Alternatively, a Biotin can be attached at C6 position of the sugar and then react with an Avidin-labeled tumor-specific antibody. The parachute function may also be achieved by other, more bulky hydrophilic structures such as oligosaccharides connected to the branching unit. Such sugar oligomers have specific attachment points to cell selectins, and therefore do not need additional molecular structures to target a specific tumor tissue. The use of the parachute structure gives the advantages of being able to localize a photosensitizer or chemotherapeutic drug at the site within a cell where it can destroy the tumor cell most effectively. This reduces the level of necessary systemic doses of the drugs, promotes drug excretion, and therefore considerably reduces side effects of the therapy.

The invention provides a broad-spectrum nucleic acid aptamer capable of identifying lipopolysaccharides of different Gram-negative bacterium sources. The broad-spectrum nucleic acid aptamer is obtained by directed screening on the basis of the capture-SELEX technology of label-free target molecules and immobilized nucleic acid libraries. A directed screening method of the broad-spectrum nucleic acid aptamer includes: using mouse salmonella typhi lipopolysaccharides as the unique target, using a biotin-avidin effect to fix random oligonucleotide libraries to Fe3O4 magnetic nano particles wrapped by avidin through biotinylated short complementary chains, performing incubation, separation, amplification, digestion single chain preparation, cloning sequencing and the like, adding complete active bacteria of salmonella and escherichia coli to serve as directed molecules to perform directed screening when the libraries are enriched to a certain degree, and one broad-spectrum nucleic acid aptamer capable of identifying four kinds of lipopolysaccharides is obtained through 15 rounds of repeated screening. The nucleic acid aptamer is applicable to the analysis and detection, separation and enriching, toxicity neutralizing and the like of the lipopolysaccharides in aspects of drinking water, food or clinical medicine and the like.

The invention discloses a quantitative detection kit for exon mutation of epidermal growth factor receptor (EGFR) relevant to lung cancers, which comprises a primer for amplifying exons of EGFR genes 18, 19, 20, 21, a sequencing primer and a magnetic bead marked by avidin. The invention also discloses a preparation method and a using method of the kit. The detection method in the invention not only has high sensitivity so that 1% of mutation can be detected, but also has visual result and simple, accurate and rapid interpretation, greatly reduces the false negative rate of the detection result and avoids invalid targeted medicine selections of clinical patients, thereby saving valuable treating time for the patients and improving the life quality of the patients.

The invention discloses an adenosine detecting method based on a micro-fluidic chip and a nucleic adapter technology. Biotin-modified adenosine nucleotide adapter and biotin-modified casein are fixed on the surface of an avidin-modified microsphere to form a functional microsphere through a biotin-avidin combining method; capture probes modified with horseradish peroxidase and sulfydryl are modified on nanometer particles as signal marks; functional nanometer particles flow to a micro-fluidic microsphere array to detect a detection area of a chip and hybrid with a microsphere array; after elution, an adenosine solution flows to be incubated with hybridized microspheres; a peroxidase substrate solution flows in; biotinylated tyramine is combined with the casein on the surface of the microsphere; the avidin-marked quantum dot flows in after elution; qualification and quantification are carried out on the adenosine by calculating a ratio of a fluorescence amount of the microsphere surface after adenosine inflows and a fluorescence amount of the microsphere surface before the adenosine inflows. The adenosine detecting method provided by the invention can be used for detecting and analyzing a target at high sensitivity, so that the specific and accurate quantitative analysis of the adenosine in a serum sample is realized.

The invention discloses a sepsis early diagnosis liquid chip which mainly includes the following components: microsphere coated with PCT capturing antibody, microsphere coated with CRP capturing antibody, microsphere coated with IL-6 capturing antibody, microsphere coated with Neopterin capturing antibody, these microspheres have codes with different colors; biotin-labeled test antibody; avidin-linked phycoerythrin. The invention sepsis early diagnosis liquid chip has advantages of high detection efficiency, a small amount of sample, high specificity and high sensitivity. And at the same time, the invention can test four kinds of specific markers of sepsis simultaneously, improve sensitivity and specificity of sepsis early diagnosis, distinguish sepsis caused by bacterial and viral, judge severity and poor prognosis of sepsis and monitor continuously for judging reflection of patient to certain kind of treatment.

The invention discloses a method for detecting a Miltenberger blood group antibody. The method comprises the steps of coupling nano magnetic beads with avidin to form avidin magnetic beads; coupling the avidin magnetic beads with a multipeptide antigen with a biotin-modified tail end, and closing non-coupled sites to obtain immune magnetic beads; uniformly mixing the immune magnetic beads with a detection sample, then performing incubation and washing, adding fluorescence labeled second antibody or enzyme-labeled second antibody, performing incubation and washing, and measuring a result. In the mode, the method for detecting the Miltenberger blood group antibody based on nano magnetic bead immunoassay is low in operation difficulty and is simple and convenient to operate, can be used for simultaneously detecting complete antibodies and incomplete antibodies; the detection process is short in time, and the result is easy to judge; automation is easily realized, and the detection result is accurate; in combination with a detector, semi-quantitative or quantitative detection can be realized; clinical safe, effective and scientific blood transfusion can be guaranteed.

Labeled nucleotide analogs comprising at least one avidin protein, at least one dye-labeled compound, and at least one nucleotide compound are provided. The analogs are useful in various fluorescence-based analytical methods, including the analysis of highly multiplexed optical reactions in large numbers at high densities, such as single molecule real time nucleic acid sequencing reactions. The analogs are detectable with high sensitivity at desirable wavelengths. They contain structural components that modulate the interactions of the analogs with DNA polymerase, thus decreasing photodamage and improving the kinetic and other properties of the analogs in sequencing reactions. Also provided are nucleotide and dye-labeled compounds of the subject analogs, as well as intermediates useful in the preparation of the compounds and analogs. Compositions comprising the compounds, methods of synthesis of the intermediates, compounds, and analogs, and mutant DNA polymerases are also provided.