249 results about "Biotin-binding proteins" patented technology

Antimicrobial peptides enable an alternate approach to developing antimicrobial coatings due to their targeting of the membranes of the bacteria. High specific activity is achieved by orienting the peptides so that the antimicrobial ends of the peptides maximally contact the bacteria. In one embodiment, one end of the peptide is covalently attached directly to the substrate. In another embodiment, the peptides are immobilized on the substrate using a coupling agent or tether. Non-covalent methods include coating the peptide onto the substrate or physiochemically immobilizing the peptides on the substrate using highly specific interactions, such as the biotin / avidin or streptavidin system. The compositions are substantially non-leaching, antifouling, and non-hemolytic. The immobilized peptides retain sufficient flexibility and mobility to interact with and de endocytosed by the bacteria, viruses, and / or fungi upon exposure. Immobilizing the peptides to the substrate reduces concerns regarding toxicity of the peptides and the development of antimicrobial resistance, while presenting substantially all of the peptide at the site of action at the surface of the substrate.

Methods of reversal of the binding between a biotin compound and a biotin-binding compound are disclosed. A method of reversibly releasing a biotinylated moiety from a streptavidin (or avidin) coated support is shown as an example. The strong interaction between streptavidin or avidin-biotin is made much weaker by using a combination of modified streptavidin or avidin and modified biotin like desthiobiotin or a derivative thereof like DSB-X Biotin. A protein, such as an antibody may be biotinylated with the modified biotin. When this protein is isolated by binding the modified biotin to the modified streptavidin or avidin bound to an solid surface, it may be released under very gently and very rapid conditions by addition of free biotin. In contrast to proteins obtained by the prior art release methods the protein obtained using the previously available release methods, the proteins obtained using the methods disclosed herein will maintain their native conformation. Uses of the methods in various procedures including cell detachment procedures and techniques of detection, identification, determination, purification, separation and / or isolation of target proteins or nucleic acid molecules are also described.

A method for producing viral gene delivery vehicles which can be transferred to pre-selected cell types by using targeting conjugates. The gene delivery vehicles comprise: 1) the gene of interest; and 2) a viral capsid or envelope carrying a member of a specific binding pair, the counterpart of which is not directly associated with the surface of the target cell. These vehicles can be rendered unable to bind to their natural cell receptor. The targeting conjugates include the counterpart member of the specific binding pair, linked to a targeting moiety which is a cell-type specific ligand (or fragments thereof). The number of the specific binding pair present on the viral vehicles can be, for example, an immunoglobulin binding moiety (e.g., capable of binding to a Fc fragment, protein A, protein G, FcR or an anti-Ig antibody), or biotin, avidin or streptavidin. The virus' outer membrane or capsid may contain a substance which mediates entrance of the gene delivery vehicle into the target cell. Due to the specificity of the ligand, the binding pair's high affinity, and the gene delivery vehicle's inability to be targeted when used alone, the universality of the method for gene delivery, together with its high cell type selectively can be achieved by using various targeting conjugates.

The invention relates to the immune analysis field, in particular relating to a method for performing an immunological test on biomolecules by avidin / streptavidin magnetic composite particles, which takes avidin / streptavidin magnetic composite particles as carriers, and comprises the following steps:, coating biotinylated antibody or antigen, adding a specimen to be tested and enzyme labeled antibody / enzyme labeled antigen / enzyme labeled anti-antibody, adding chromogenic substrate and testing.Biotin and avidin / streptavidin has strong binding capacity, can fix the antigen / antibody labeled by the biotin through the avidin / streptavidin labeled on the surface of the magnetic composite particles so as to use the system to test specific antibody / antigen. The test system has the advantages of high sensitivity, high specificity, high stability, strong adaptability and the like.

The invention discloses a biodegradable particle-cell composition having at least one biodegradable particle, at least one receptive group covalently linked thereto, and a cell anchored thereto. The particle can be polylactide, a polylactide-lysine copolymer, polylactide-lysine-polyethylene glycol copolymer, starch, or collagen. The receptive group can be an antibody, a fragment of an antibody, an avidin, a streptavidin, or a biotin moiety. Moreover, the particle can also have extracellular matrix components other than collagen. The particle-cell compositions can be used for selection of cells from a population, for cell culture of anchorage-dependent cells, for cryopreservation of anchorage-dependent cells, and for transplantation as a cell therapy.

Methods of preparing targeting ligand bound avidin-lipid vesicles for use in preparing a targeted, therapeutic liposome composition are disclosed. Each vesicle comprises an avidin molecule coupled to the polymer-conjugated biotin which retains multiple free site biotin-binding sites such that the vesicle may be used to further couple a biotinylated-targeting ligand.

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 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 discloses a method for detecting a surviving gene based on a graphene-gold composite material electrochemical DNA (Deoxyribose Nucleic Acid) biosensor. The method comprises the following steps: a specific probe is designed according to a gene segment to be detected; a capture probe is self-assembled on the surface of G-3DAu / GCE through a gold-sulfur bond; the capture probe and a signal probe with the tail end marked by biotin are respectively combined with a target DNA to form a 'sandwich' model in the presence of the target DNA; a horse radish peroxidase marked by avidin can be combined with the biotin marked by the signal probe, so that the HRP (Horse Radish Peroxidase) can be fixed on the surface of an electrode; the electrode is placed in a base solution of 3, 3', 5, 5'-tetramethyl benzidine (TMB) and H2O2, and the H2O2 can oxidize TMB to generate a bidiazotizedbenzidine material under the catalyzing of the HRP, so that an electrochemical signal is generated. The method has the advantages of being simple, quick and green in preparation process, and high in selectivity and sensitivity.

The invention discloses a biological sample signal amplification method adopting the combination of terahertz metamaterials and nanogold particles. The method comprises the following steps: preparing a plurality of biological sample solutions with different concentrations and gold standard avidin solutions with different concentrations; dropwise adding the biological sample solutions onto the surfaces of the terahertz metamaterials, and airing at the room temperature; dropwise adding the gold standard avidin solutions on the surfaces of the terahertz metamaterials, and airing at the room temperature; collecting terahertz time-domain signals of all sample points to be measured on the surfaces of the terahertz metamaterials and reference sample points; calculating the transmissivity or the reflectivity of all the sample points to be measured and the reference sample points according to the terahertz time-domain signals; and calculating to obtain the frequency shift of transmission peaks or reflection peaks according to the frequency value corresponding to the lowest point of the transmissivity or the reflectivity. According to the method, the terahertz metamaterials and the nanogold particles are used for modifying; the sample signals are amplified by using an electric field local enhancement effect of the metamaterials; the electric field distribution effect is changed by nanogold, and the sample signals are further amplified by nanogold modifying; and the detection is high in sensitivity, the operation is convenient and fast, and fast detection requirements increased day by day are met.

Biosensor components (chips) are described based on direct biocoating processes that result in the tenacious and stable, noncovalent (believed to be chemisorptive) binding of anchor substances such as avidin(s) other proteins having specific binding partners or oligo- or poly-nucleotides onto any piezo-electrically active crystal surface. The resulting platform technology can be developed for a variety of biosensors with specific applications in biological assays. The table mono layers of the anchor substances forms reactive layers, ready to bind a capture reagent such as a biot-inylated antibody for capture and detection of analytes in biologic fluid samples. Although the processes described herein can be performed on any type of piezoelectric material in any number of configurations, some embodiments are directed to a biosensor with the foregoing biocoating onto a particular acoustic plate mode biosensor and where the interdigitated transducers (IDTs) are present on the opposite side of the crystal's biocoated film.

The invention relates to the field of immunoassay medical science, and in particular provides a chemoluminescent immunoassay kit of a hyaluronic acid and a preparation method thereof. The kit comprises: 1) calibrating products of the hyaluronic acid; 2) an avidinylation solid phase carrier; 3) a biotinylation polyclonal antibody or monoclonal antibody of the hyaluronic acid; 4) a label of a hyaluronic acid binding protein; 5) a chemoluminescent substrate; and 6) a washing solution. Furthermore, the method for preparing the kit comprises the following steps: 1) preparing the calibrating objects from hyaluronic acid pure products ; 2) dermatating the carrier by an avidin; 3) performing biotinylation on the polyclonal antibody or monoclonal antibody of the hyaluronic acid; 4) labeling the hyaluronic acid binding protein by the label; 5) preparing the chemoluminescent substrate; 6) preparing the washing solution; 7) sub-packaging the calibrating products, the label, the chemoluminescent substrate and the washing solution; and 8) assembling the substances into the finished products. The kit has the advantages of simpleness, convenience, quickness, sensitiveness, stability, and the like.

The invention relates to a nucleic acid detection method combining RNA amplification with a hybrid capture method. The nucleic acid detection method includes the following steps of extracting nucleic acid from a sample or splitting the sample to release the nucleic acid to be detected, conducting transcription and amplification on the nucleic acid to be detected to obtain an RNA product, adding the obtained RNA product together with a DNA probe marked with biotins to a solid phase so that hybridization can be conducted, forming a DNA / RNA heterozygote through hybridization, coating the solid phase with specific antibodies for recognizing the heterozygote or avidin or streptavidin, capturing the heterozygote through the solid phase, and adding avidin or streptavidin or antibodies for recognizing the DNA / RNA heterozygote to the solid phase to achieve obtaining of a nucleic acid signal, wherein the avidin or the streptavidin or the antibodies for recognizing the DNA / RNA heterozygote are marked with enzymes with the secondary amplification capacity. According to the nucleic acid detection method, the inherent pollution problem of the PCR is avoided, RNA molecules can be directly detected, inverse transcription and pre-dissociation of RNA do not need to be conducted, and the operation steps are greatly simplified.

The invention discloses combined detection test paper of influenza A virus antigen and influenza B virus antigen and a preparation method thereof. The test paper comprises a sample pad, a fiberglass membrane containing a colloidal gold particle label, a nitrocellulose membrane and water absorbing paper, wherein the nitrocellulose membrane comprises a detection area which is coated with an influenza A virus antibody, a detection area which is coated with an influenza B virus antibody and a control area which is coated with an goat anti-rabbit antibody; the colloidal gold particle label comprises a micro signal amplification system and a colloidal gold labeled rabbit IgG antibody; and the micro signal amplification system is a colloidal gold particle-avidin-biotin-influenza A / B virus antibody. According to the invention, an avidin-biotin microsignal amplification system is added in a double-antibody sandwich detection system, the signal of a target antibody is enlarged, the detection sensitivity is increased, false negative or detection omission due to weak signals can be avoided, simultaneously combined detection can be carried out on the influenza A and B virus antigens, and the detection time, sample and cost can be saved.

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.

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 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.

Peptide motifs DXaAXbPXc (SEQ ID NO: 1) or (CDXaAXbPXcCG) (SEQ ID NO: 2) that define binding to avidin or Neutravidin with high affinity, but not to streptavidin. Peptides, polypeptides and other molecules that incorporate this motif may be identified, detected, or purified by methods involving the specific binding of the motif sequence with avidin or Neutravidin. Orthogonal selection or labeling methods employing the specific binding of this peptide motif to avidin and Neutravidin, as well as utilization of the binding interaction between streptavidin and molecules that specifically bind to it.

A nanopartide and its avidin probe are disclosed. Said gene probe for detecting the mutation or non-mutation of DNA is prepared from nanoparticles or colloidal particles and avidin, streptavidin, or antibiotin through preparing colloidal gold and preparing the compound. Its advantges are high sensitivity, specificity and speed.

The invention relates to a method for sorting target cells by using avidin / streptavidin magnetic composite particles. In the method, a biotin-labeled monoclonal antibody is added into an experimental system, magnetic particles are bonded with the biotin-labeled monoclonal antibody through avidin / streptavidin, the monoclonal antibody is specifically bonded with corresponding antigen on the surfaceof the cells to make the cells captured by the magnetic particles so as to purify and separate the cells. Because the biotin-avidin and biotin-streptavidin have the characteristics of high system specificity, high stability, wide application range and low experiment cost, the obtained avidin / streptavidin magnetic composite particles have high biotin bonding property; and the labeled amount is improved in the measurement technique, and biomolecules are difficult to denature or inactivate, so that the cell sorting specificity is further improved. The high-purity target cells can be sorted by specifically bonding the biotin with the avidin or streptavidin; and the method has the advantages of no need of expensive instrument, simple operation and time saving.

An isolated protein which is structurally and functionally similar to avidin but with improved properties, such as better affinity towards biotin conjugate, useful immunological properties or faster biotin dissociation rate, compared to avidin and streptavidin.

A method for ligand-based binding of lipid encapsulated particles to molecular epitopes on a surface in vivo or in vitro comprises sequentially administering (a) a site specific ligand activated with a biotin activating agent; (b) an avidin activating agent; and (c) lipid encapsulated particles activated with a biotin activating agent, whereby the ligand is conjugated to the particles through an avidin-biotin interaction and the resulting conjugate is bound to the molecular epitopes on such surface. The conjugate is effective for imaging by x-ray, ultrasound, magnetic resonance or positron emission tomography. Compositions for use in ultrasonic imaging of natural or synthetic surfaces and for enhancing the acoustic reflectivity thereof are also disclosed.

A solid carrier of protein chip is composed of a substrate, a biotin marked enclosing substance layer on said substrate, and an avidin layer on said enclosing substance layer. Its advantages are less diffusion of sample applied point and high sensitivity. A process for preparing the solid carrier of protein chip is also disclosed.

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.

A method of forming an array of proteins selected from antigens or antibodies; said method comprising the steps of (i) expressing in a recombinant cell, a fusion protein which comprises either (a) an antigen or (b) an antibody binding protein, fused to a peptide having up to 50 amino acids, which peptide comprises amino acid sequence of SEQ ID NO 1 LX1X2IX3X4X5X6KX7X8X9X10 (SEQ ID NO 1) where X1 is a naturally occurring amino acid, X2 is any naturally occurring amino acid other than leucine, valine, isoleucine, tryptophan, phenylalanine or tyrosine, X3 is phenylalanine or leucine, X4 is glutamine or asparagine, X5 is alanine, glycine, serine or threonine, X6 is glycine or methionine, X7 is isoleucine, methionine or valine, X8 is glutamine, leucine, valine, tyrosine or isoleucine, X9 is tryptophan, tyrosine, valine, phenylalanine, leucine or isoleucine and X10 is any naturally occurring amino acid other than asparagine or glutamine; where said peptide is capable of being biotinylated by a biotin ligase at the lysine residue adjacent to X6; (ii) biotinylating said peptide of the fusion protein at the lysine residue adjacent X6; (iii) isolating the biotinylated fusion protein; (iv) applying the biotinylated fusion protein to an avidin or streptavidin coated non-porous support; (v) forming an array of at least three different proteins on the support by either (a) where the fusion protein comprises an antigen, carrying out steps (i) to (iv) the desired number of times to form an antigen array; or (b) where the fusion protein comprises an antibody binding protein, applying to said protein, either prior to or after step (iv) a plurality of different antibodies or binding fragments thereof.

The present invention provides a method of assaying for kinase activity, comprising contacting a fluorescently labeled phosphorylatable peptide substrate with an ATP analog in the presence of a kinase enzyme to yield a first product; contacting the first product with a reactant that comprises a biotin derivative to yield a second product; contacting the second product with a biotin-binding protein; and detecting a difference in a fluorescence polarization level from the second product as compared to a fluorescence polarization of the peptide substrate.

The invention relates to a magnetic immunochromatographic test strip for combined detection of HIV-1+2 antibody and P24 antigen and a preparation method thereof. The test strip is assembled by pasting a coating film, magnetic particles combined with the HIV-1+2 antibody and the P24 antigen, a sample pad and a water-absorbing pad which are mutually staggered by 2 millimeters in turn on a bottom plate and then covering an upper layer with a transparent plastic sealing film, wherein the coated film is precoated with an HIV-1+2 antibody detection line, an HIV P24 antigen detection line and a quality control line. As the test strip introduces a magnetic immunochromatography technique and a biotin-avidin system into the combined detection of the HIV-1+2 antibody and the P24 antigen, the test strip has the advantages of greatly increasing detection sensitivity result accuracy, shortening detection window period and reducing the labor intensity of operators.

In some embodiments, the present disclosure relates to an avian-free egg white composition comprising 45-63% Ovalbumin, 9-15% Ovotransferrin, 0-15% Ovomucoid, 3- 5% Ovoglobulin G2, 3-5% Ovoglobulin G3, 2.5-5% Ovomucin, 3-5% Lysozyme, 1-2% Ovoinhibitor, 0.8-1.5% Ovoglycoprotein, 0.6-1.0% Flavoprotein, 0.3-0.8% Ovomacroglobulin, 0.02-0.1% Avidin, and 0.02-0.1% Cystatin. In some embodiments, the composition comprises an edible yeast and one or more of the preceding proteins. In some embodiments, the avian-free egg white further comprises one or more of: flavor enhancers, calcium supplements, added vitamins, and a gelling agent. In some embodiments, the present disclosure pertains to a non-allergenic egg-white composition for human consumption. In some embodiments, the present disclosure pertains to methods of making the avian-free egg-white composition.

The invention discloses a probe for nucleic acid enriching capture and a design method thereof. A two-way probe consists of a positive-sense strand probe and an antisense strand probe, wherein both the positive-sense strand probe and the antisense strand probe adopt probe zero-lap designs; the lengths of the positive-sense strand probe and the antisense strand probe are 30 to 89 basic groups; the 3' or 5' position of the probe is provided with biotin labels, and can be combined with avidin on magnetic beads. The two-way probe can improve the capture specificity (i.e., the capture on the genome DNA in the non-targeted position can be reduced); the capture on the sample mutant type DNA is obviously improved. The original copy number of the capture sample nucleic acid can be increased.