67 results about "Serum albumin protein" patented technology

The invention discloses a kit for determining glycocholic acid in human blood. The kit comprises a reagent A, a reagent B and a calibrator for glycocholic acid with known concentration, wherein the mass ratio of the reagent A to the reagent B is (1-5):1; the reagent A comprises a microorganism inhibiting agent, EDTA (Ethylene Diamine Tetraacetic Acid), glycerol, albumin bovine serum, a surface active agent, a reactive reinforcing agent, sodium chloride and a Good's buffer solution with the pH of 6-8; and the reagent B comprises the microorganism inhibiting agent, the EDTA (Ethylene Diamine Tetraacetic Acid), the glycerol, the albumin bovine serum, the surface active agent, the reactive reinforcing agent, sodium chloride, the Good's buffer solution with the pH of 6-8 and nanoparticles crosslinked with a glycocholic acid monoclonal antibody. The kit is simple, convenient and fast in detection and operation, can be used for simultaneously and quickly determining a large amount of samples and has good detection accuracy and sensitivity.

This invention is related to an adhesive composition which may be used to bond or seal tissue in vivo. The adhesive composition is readily formed from a two component mixture which includes a first part of a protein, preferably a serum albumin protein, in an aqueous buffer having a pH in the range of about 8.0-11.0 and a second part of a water-compatible or water-soluble bifunctional crosslinking agent. When the two parts of the mixture are combined, the mixture is initially a liquid which cures in vivo on the surface of tissue in less than about one minute to give a strong, flexible, pliant substantive composition which bonds to the tissue and is absorbed in about four to sixty days. The adhesive composition may be used either to bond tissue, to seal tissue or to prevent tissue adhesions caused by surgery.

This invention is related to an adhesive composition which may be used to bond or seal tissue in vivo. The adhesive composition is readily formed from a two component mixture which includes a first part of a protein, preferably a serum albumin protein, in an aqueous buffer having a pH in the range of about 8.0-11.0 and a second part of a water-compatible or water-soluble bifunctional crosslinking agent. When the two parts of the mixture are combined, the mixture is initially a liquid which cures in vivo on the surface of tissue in less than about one minute to give a strong, flexible, pliant substantive composition which bonds to the tissue and is absorbed in about four to sixty days. The adhesive composition may be used either to bond tissue, to seal tissue or to prevent tissue adhesions caused by surgery.

The invention belongs to the technical field of functional nanometer materials, in particular to a water-phase preparation method of a near-infrared luminescent silver sulfide quantum dot. The preparation method is a normal-temperature and normal-pressure water-phase preparation method and comprises the following steps of: with silver nitrate, bovine serum albumin and sodium sulfide as raw materials, regulating and controlling the nucleation and growth of a nanometer material by using protein, and eliminating unreacted ions through dialysis via a semipermeable membrane to obtain an extra-small (smaller than 10 nanometers) silver sulfide quantum dot stably existing in a water solution. In the preparation process, water is used as a solvent, conditions are mild, operability is strong, an extra-small quantum dot with good luminescent window and better biocompatibility is obtained under extremely mild reaction conditions, and the quantum dot is hopeful to achieve broad application prospect in the aspect of living organism imaging.

The invention relates to an immobilization method of bovine serum albumin taking poly-dopamine / oxidized graphene as a second-order reaction platform in a micro-fluidic chip channel and chiral separation application of the bovine serum albumin, and belongs to the technical field of micro-fluidic chips. The immobilization method comprises the following steps of: pumping a dopamine and oxidized graphene mixed solution into a micro-fluidic chip separation channel by using a vacuum pump, wherein the dopamine fixes the oxidized graphene to the surface of the micro-fluidic chip separation channel to form a poly-dopamine / oxidized graphene film in a self-polymerization process; combining the bovine serum albumin with the surface of poly-dopamine / oxidized graphene under the action of Pi-Pi, a hydrogen bond, hydrophobicity, and the like between the poly-dopamine / oxidized graphene and the bovine serum albumin to obtain a poly-dopamine / oxidized graphene / bovine serum albumin functionalized micro-fluidic chip channel. The bovine serum albumin has good stability, biocompatibility and hydrophilicity, can be used for enhancing the loading capacity of the bovine serum albumin in the micro-fluidic chip separation channel, keeping the biological activity of the bovine serum albumin and providing the universal platform for the high-efficiency separation of an amino acid antipode and a dipeptide antipode.

The invention discloses a kit capable of quantitatively detecting soluble B7-H1, which comprises a horseradish peroxidase label, tetramethylbenzidine serving as a reaction substrate, bovine serum albumin, an elisa plate, washing liquor, stop solution, a coating antibody, a standard protein and a detection antibody, wherein the coating antibody is a mouse anti-human B7-H1 monoclonal antibody and the nucleotide sequence of the heavy chain of the coating antibody is represented by a nucleotide sequence SEQ ID No.3 in the sequence list, and the nucleotide sequence of the light chain of the coating antibody is represented by a nucleotide sequence SEQ ID No.4 in the sequence table. The kit capable of quantitatively detecting soluble B7-H1 has high specificity and can be used for accurately quantitative analysis on soluble B7-H1 protein factor concentration in liquid for human cell culture supernate, serum, plasma, hydrothorax and the like.

The invention discloses a conductive and heat-conducting glass fiber composite material coated with dopamine and modified by nano-silica, which is characterized in that a buffer solution is added to the nano-silica, ultrasonically dispersed, dopamine is added, reacted in a water bath, centrifuged, Washing and drying; adding KH570 and ethanol to micron aluminum nitride, adjusting pH, ultrasonic oscillation, heating and stirring, reflux reaction, vacuum filtration after cooling, washing with water, drying, grinding and crushing to obtain modified aluminum nitride; glass fiber After calcination, soak in acetone for cleaning treatment, add hydrochloric acid solution, hydroxylation treatment, wash with distilled water, dry, add bovine serum albumin solution, stir for reaction, wash with water, and dry to obtain bovine serum albumin modified glass fiber Adding modified glass fiber to the graphite oxide dispersion, stirring, pulling, washing, drying, steam treatment, heat treatment, and then mixing with the material obtained above to obtain a conductive and thermally conductive material.

The invention discloses an amperometric DNA (deoxyribonucleic acid) electrochemical sensor based on a protein controlled assembling interface. The amperometric DNA electrochemical sensor comprises an electrode, proteins, a capture probe DNA, a signal probe DNA and horse radish peroxidases, wherein the electrode is a gold electrode, the proteins are bovine serum albumins, the capture probe DNA is a 5' terminated mercapto modified single-strand DNA, the signal probe DNA is a 3' terminated biotin labeled single-strand DNA, and the horse radish peroxidases are labeled by avidin. The amperometric DNA electrochemical sensor is characterized in that the bovine serum albumins are formed into a sequentially-assembled bovine serum albumin molecule layer on the surface of the gold electrode, and the capture probe DNA is assembled by using sequential holes among bovine serum albumin molecules in the bovine serum albumin molecule layer. The amperometric DNA electrochemical sensor is used for carrying out detection on a target DNA, and the detection limit is 0.01pmol / L. Compared with similar methods, the amperometric DNA electrochemical sensor constructed by using the method is high in sensitivity and good in repeatability.

A method for detecting and absorbing heavy metal ions in water by a bovine serum albumin sensor belongs to the technical field of biologic-inorganic hybridization. The bovine serum albumin sensor is made by automatically assembling bovine serum albumin and houghite nano-sheets, wherein a bovine serum albumin molecule contains rich fluorescence-emission groups such as tryptophan, tyrosine and phenyl alanine, the heavy metal ions cause the fluorescence of the bovine serum albumin to quench, and the fluorescence intensity change of the bovine serum albumin and the quantity of the fixed heavy metal ions are in linear relation; the fluorescence of the bovine serum albumin molecule quenches regularly along with the increase of the concentration of the heavy metal ions in water, and the fluorescence intensity change of the bovine serum albumin and the initial concentration of the heavy metal ions in water are in fine linear relation. The bovine serum albumin sensor can perform real-time and on-line detection and absorption to the heavy metal ions in water within the concentration range of 1-100ppm of the heavy metal ions.

A synthesis method of an universal artificial antigen of alkylphenol medicines belongs to the technical field of biochemical engineering. The synthesis method is as follows: nonyl phenol (NP) is used as hapten, and the active ester method is adopted to couple the hapten and the carrier protein bovine serum albumin (BSA) to obtain the universal artificial antigen of alkylphenol medicines. Polyacrylamide gel electrophoresis is adopted to detect the coupling ratio of the conjugate. By adopting the method, the universal artificial antigen of alkylphenol medicines can be synthesized successfully; the synthesis step is concise and effective; and the method can be completely used in immunoassay, provide the necessary artificial antigen for the future research of people and meet the need of the domestic research on the artificial antigen.

The present invention describes the use of a fluorescent NIR dye for various applications by simply changing the solvent conditions. Molecule of formula 1 in the monomeric state (30% ACN / 25 mM phosphate buffer) can be used for the sensitive detection of thiols and monitoring minor fluctuations in the thiol concentration inside live cells. Molecule 1 in the self-assembled state (25 mM phosphate buffer) can be used for labeling of serum albumin protein either covalently or noncovalently at specific pH. The probe 1 specifically bind with the serum albumin proteins noncovalently at lower pH gives a “turn-on” NIR emission whereas it binds covalently at higher pH gives a “turn-on” green fluorescence. Since the probe detects serum albumin proteins selectively in presence of other thiol containing small molecules, the probe can be used as an excellent sensor for serum albumin proteins. The dye-protein complex of various ratios can be used as sensors to detect the pH variations in a broad window from 4.6-11.6 with high sensitivity. Due to the high biocompatibility and water solubility the dye protein complex is useful for ratiometric detection of minor pH variations inside cellular environment.

The invention discloses a mannose functionalized protein gold nano-cluster, and a preparation method and an application thereof. The method comprises the following steps: S1, bovine serum albumin andNH2-mannose are dissolved in a buffer solution and then are mixed with EDC, and stirring, purification and concentration are carried out in sequence to obtain a mannose-bovine serum albumin conjugate,wherein the mass ratio of the bovine serum albumin to the NH2-mannose to the EDC is (9-11):3:1; and S2, the mannose-bovine serum albumin conjugate is mixed with a chloroauric acid solution in a buffer solution, the pH value is adjusted, and stirring and purifying are sequentially carried out to obtain the protein gold nano-cluster. The preparation method of the protein gold nano-cluster is convenient, simple, rapid and efficient, and the protein gold nano-cluster synthesized by the method is nontoxic, good in biocompatibility, good in dispersity, strong in fluorescence and high in detection sensitivity.

The invention discloses a bovine serum albumin nano microsphere preparation method, and provides a protein nano microsphere cross-linking method based on protein dimerization. According to the method, bovine serum albumin is used as a matrix material, and through the protein dimerization and inverse solution method, bovine serum albumin nano microsphere cross-linking can be realized to obtain a nano microsphere drug delivery material with structural stability. The method avoids the use of a toxic chemical crosslinking agent, and guarantees the use safety of the delivery system, and biological activity of the entrapped drugs is expected to retain, so that the the nano microsphere system biocompatibility can be significantly improved. The method is simple and easy in process and equipment and safe to operate, has the advantages of low preparation temperature, short processing cycle and the like, and has the application value in the fields of embedding and transfering of active drugs, proteins or gene.

The invention relates to synthesis and an application of an envelope antigen universal for pyrethriods pesticide, belonging to the technical field of biochemical engineering. The envelope antigen universal for pyrethriods pesticide is synthesized by taking 3-phenoxybenzoic acid and nitrobenzene alanine as raw material through two steps of chemical reaction, the envelope antigen and a carrier protein BSA (Bovine Serum Albumin) are coupled through diazotization, and the coupling ratio of a conjugate is identified and estimated through ultraviolet spectroscopy. The synthesized conjugate (envelope antigen) is used for enzyme linked immunoassay and preparation of a collaurum immunochromatography test strip. The enzyme linked immunoassay and the preparation of the collaurum immunochromatography test strip prove that the synthesis of the envelope antigen universal for pyrethriods pesticide is synthesized successfully, thus providing a basis for establishment of a immunoassay method of the pyrethriods pesticide, and meeting the domestic requirement of rapid detection on the pyrethriods pesticide.

The present invention teaches a marker useful for detection and measurement of free radical damage. Specifically, the invention takes advantage of alterations which occur to the N-terminus of the albumin molecule, a circulating protein in human blood, in the presence of free radicals. These alterations effect the ability of the N-terminus of the albumin molecule to bind metals. Methods for detecting and quantifying this alteration include evaluating and quantifying the cobalt binding capacity of an albumin-containing sample, analysis and measurement of the ability of albumin to bind exogenous cobalt, detection and measurement of the presence of copper in a purified albumin sample and use of an immunological assay specific to the altered form of serum albumin which occurs following free radical damage. Also taught by the present invention is the use of the peptide Asp Ala His Lys and the compound Asp-Ala-His-Lys-R, wherein R is any chemical group capable of producing a detectable signal when a metal ion capable of binding to the N-terminus of naturally-occurring albumin is bound to the compound, for detection and quantitation of the marker. Methods of the present invention also include use of the marker as a “biochemical tag,” thereby allowing for sensitive detection and measurement of the efficacy of clinical drugs and therapeutics which result in the generation of free radicals or which act to limit free radical damage. The marker also acts as a “biological tag” of a process implicated in a wide array of diseases and conditions and, accordingly, may be used to monitor and assess such diseases and conditions. Finally, the invention provides antibodies, immunoassays, and kits for use in detecting or quantitating the marker.

The invention discloses a preparation method of heavy metal cadmium artificial antigen, which applies 2-S-(4- aminobenzene)-1, 4, 7, 10 tetraazacyclo cyclononane-1, 4, 7, 10-acetate tetrahydrate(p-NH2-Bn-DOTA, DOTA for short) as cheating agent, and couples cadmium ion chelating agent composite with carrier protein bovine serum albumin BSA or egg albumin OVA; thus the artificial antigen is prepared. The method adds the sodium borohydride processing step on the basis of traditional method, and improves the coupling efficiency and antiserum titre. The invention further discloses an application ofDOTA in preparation of the heavy metal cadmium artificial antigen.

A sperm liquefying agent is an enzyme preserving fluid. Its preparing method includes adding weighed protein hydrlytic enzyme and carbodiimide into enzyme preserving fluid for reaction of 4-12 hour at 4 degree C, adding 2-aminothanol for reaction of 1-4 hour at room temperature, adding regulatig fluid concenration to be 2-10g / l. A liquefying method is also disclosed.

The invention relates to the technical field of biological chemistry, and particularly discloses a preparation method of fluoroacetamide hapten and application of a monoclonal antibody. The fluoroacetamide hapten is synthesized by taking ethyl fluoroacetate and p-aminophenylacetic acid as main raw materials; the fluoroacetamide hapten and carrier protein bovine serum albumin (BSA) or keyhole limpet hemocyanin (KLH) are coupled through an active lipid method, and thus a conjugate is prepared. Through experimental verification, it shows that the prepared conjugate enables a living body to generate the antibody against fluoroacetamide, that is to say, the prepared conjugate is fluoroacetamide artificial antigen. The prepared fluoroacetamide artificial antigen is suitable for enzyme-linked immunological analysis of fluoroacetamide.

The invention relates to an acidified albumin and a preparation method thereof, and an application of the acidified albumin in inhibiting beta-amyloid protein aggregation. According to the invention, diglycolic anhydride is modified on the amino group on the surface of serum albumin, such that a product with isoelectric point of 3.8-4.3 and with diglycolic anhydride average modification number between 3 and 14.5 is obtained. The product is the acidified albumin. Diglycolic anhydride powder is added into a solution of serum albumin dissolved in deionized water and with a concentration of 1-20mg / mL; a sodium hydroxide solution is dropped in at a same time, such that the pH value of the reaction liquid is stably maintained at 6.0-7.0; a stirring reaction is carried out for 0.5-5h under room temperature; and free diglycolic anhydride is removed, such that acidified serum albumin with a stable molecular structure is obtained. According to the acidified serum albumin provided by the invention, serum albumin surface negative charge amount is improved, such that the interaction of serum albumin and Abeta is promoted, and thus Abeta aggregation is inhibited, and beta-amyloid protein aggregate cytotoxicity is reduced. The acidified albumin is used in medicines used for treating Alzheimer's disease and beta-amyloid protein aggregation-related diseases.

The invention discloses a tin / protein nano hybrid membrane and applications thereof, wherein Sn<2+> reduces protein disulfide bonds to induce protein self-assembly so as to form a tin / protein composite nano film, ie., the hybrid membrane, and the protein is lysozyme, bovine serum albumin, insulin or beta-lactoglobulin. According to the invention, the preparation method of the hybrid membrane is simple, rapid and easy to realize large-area preparation; and the hybrid membrane has good biocompatibility, no obvious toxicity to cells, good chemical stability, mechanical stability and optical transparency, and good adhesion and flexibility, can be adhered to the surfaces of various base materials, has good inhibition effect on escherichia coli, staphylococcus aureus and candida albicans, further has good catalytic performance, can be used as a photocatalytic material for photocatalytic decomposition of water to produce hydrogen under visible light irradiation, and can also be used as an electrocatalytic material for preparation of a conductive polymer membrane.

The invention relates to a virus delivery culture medium. The virus delivery culture medium contains the following components in concentration: Hank'S equilibrium liquid, 0.2-2 g / L of amino acid, 5-50% of glycerol, 0.02-0.2% of a ProClin preservative and 2-15 g / L of bovine serum albumin. The virus delivery culture medium has the beneficial effects that the virus delivery culture medium is based on the Hank's equilibrium liquid, amino acid is added as a virus protein shell protection component, glycerol is added, the protection of the complete form of a virus in a long-term low-temperature stored virus sample is facilitated, the antigen activity of a virus shell is facilitated, and the virus delivery culture medium is suitable for antigen detection and nucleic acid detection of the virus; and meanwhile, the preservative is added, so that the virus delivery culture medium is suitable for virus transportation and long-term preservation. The virus delivery culture medium has no interference on the detection of an in-vitro diagnostic reagent, avoids the abuse of antibiotics, and reduces the drug resistance risk of pathogenic bacteria.

The present invention relates to one new kind of long-acting thymulin and its preparation and medical use, as well as DNA sequence coding the protein and host cell carrying the DNA sequence. The long-acting thymulin protein includes one first area with at least 85 % sequence homology with serum albumin, one second area connected to the C-end of serum albumin and with at least 85 % sequence homology with thymulin and one third area connected to the N-end of serum albumin and with at least 85 % sequence homology with thymulin. It may have one or several joining peptides. Experiments show that the long-acting thymulin has the bioactivity similar to that of thymulin as well as long half life, and may be used in treating various kinds of immunodeficiency diseases and various kinds of adaptive diseases.

The invention provides a preparation method of human serum albumin. The preparation method comprises the following steps: inoculating pichia pastoris for producing human serum albumin into a culture medium, performing fermenting, and obtaining the human serum albumin from fermentation liquor. The culture medium is a BSM culture medium in which the concentrations of other components are reduced to1 / 4 at most except glycerol and pichia pastoris microelements 1, and preferably, the concentrations of other components are reduced to 1 / 4-1 / 2. The invention also provides a purification method of thehuman serum albumin. The yield of the human serum albumin prepared by the preparation method and the proportion of the human serum albumin in total protein are remarkably higher than those in the prior art, cost of a culture medium used in the preparation method is remarkably reduced, and the risk of animal-derived virus pollution is avoided, so that cost of the preparation method is remarkably reduced. According to the purification method, the recovery rate of purification is remarkably increased, and the purity of a final product is remarkably and further improved.

The invention discloses a quantitative method for a dimensional electrophoresis protein sample. The method includes the steps of: preparing a dimensional electrophoresis sample; preparing a 1-2mg / mL bovine serum albumin (BSA) solution by using the a dimensional electrophoresis cell lysate, taking 8 centrifuge tubes, adding 0-200 muL of bovine serum albumin solution respectively, and supplementing ultrapure water to 1 mL to reach a final concentration of standard protein of 0-0.2mg / ml, then adding 5 mL of a 0.01% Coomassie brilliant blue G-250 or R-250 dye solution into each centrifuge tube, and fully mixing to obtain standard mixture solutions with different concentrations; preparing a dimensional electrophoresis sample mixed solution; adding the sample decrypting and framing fluorescence intensity; drawing a standard curve; and calculating the concentration of the dimensional electrophoresis protein sample. The invention has the advantages of simple operation, accuracy, fastness and cheapness.

The present invention provides a cat serum albumin recombinant protein and an efficient expression method thereof in pichia pastoris, and relates to a recombinant nucleotide sequence of the cat serumalbumin (as shown in SEQ ID NO:3), a vector containing the nucleotide sequence, and an engineered cell containing the aforementioned vector. Based on a natural sequence of a cat serum albumin gene, codons are optimized to enable the gene to be more suitable to be expressed in yeast cells, the modified encoded cat serum albumin DNA sequence is cloned into a pichia pastoris expression vector pPICK9,a pichia pastoris expression strain GS115 is transformed, and G418 pressure screening is conducted to obtain a clone train that efficiently expresses the cat serum albumin with an expression level upto 2 g / L. The protein expressed by the method is close to natural, high in expression efficiency, simple in operation process and suitable for large-scale industrial production.

The invention discloses a method for detecting ethylene in fruits by using a chemical fluorescent probe taking bovine serum albumin as a scaffold, and relates to a method for detecting ethylene in fruits. The invention aims to solve the problems of easy environmental interference, long detection time, poor selectivity and the like in the ethylene detection process. A preparation method comprises the following steps: 1, preparing 1-vinylpyrene; 2, preparing a ruthenium-based compound; and 3, preparing the chemical fluorescent probe taking bovine serum albumin as a scaffold. The use method comprises the following steps: adding ethylene gas extracted from a fruit sample into a prepared chemical fluorescent probe aqueous solution taking bovine serum albumin as a scaffold, and carrying out fluorescence detection after constant-temperature incubation. The method is simple and safe to operate, and the prepared chemical fluorescent probe taking the bovine serum albumin as the scaffold has the advantages of high selectivity, good water solubility, short detection time and the like.

The invention discloses a traditional Chinese medicine composition for treating chronic nephritis proteinuria and a preparation method and application thereof. The traditional Chinese medicine composition of the invention has both spleen tonifying and kidney reinforcing functions and both tonifying and astringency inducing effects, and is assisted by a small amount of dampness-excreting ingredients so as to exert spleen and kidney tonifying, qi benefiting, essence securing, pathogen eliminating, and body resistance strengthening effects. The traditional Chinese medicine composition is preparedfrom the following bulk drugs by weight: 30-50 parts of astragalus membranaceus, 20-30 parts of mantis egg-case, 15-20 parts of bighead atractylodes rhizome, 15-20 parts of semen cuscutae, 10-15 parts of schisandra chinensis, 10-15 parts of dogberry, 10-15 parts of poria cocos and 10-15 parts of honey-fried licorice roots. Clinical application proves that the traditional Chinese medicine composition can improve the clinical symptoms of patients with chronic nephritis; pharmacodynamic studies show that the composition can reduce 24-hour urine protein quantification of a cationized bovine serumalbumin (C-BSA) induced chronic nephritis model and reduce the content of serum urea nitrogen and creatinine in rats, is suitable for long-term administration of chronic nephritis patients with spleen-kidney qi deficiency syndromes, and has wide clinical application value and guiding significance.

The invention discloses a chromatographic method for separating and purifying recombinant human serum albumin-epidermal growth factor fusion protein from genetically engineered rice seeds. The methodcomprises the following specific steps: 1) extracting a crude extract containing recombinant human serum albumin-epidermal growth factor fusion from recombinant human serum albumin-epidermal growth factor fusion protein genetically engineered rice seeds; 2) performing cation exchange chromatography on the crude extract containing the human serum albumin-epidermal growth factor fusion protein to obtain a primary product I; and 3) carrying out anion exchange chromatography on the primary product I to obtain the purified human serum albumin-epidermal growth factor fusion protein target substance.According to the extraction and purification method disclosed by the invention, the recombinant human serum albumin-epidermal growth factor fusion protein of which the purity is greater than 95% canbe obtained, the protein activity is good, and the yield is high. The method is simple in process, economical, efficient and suitable for industrial production and application.

The invention provides a sample diluent for an ELISA detection kit. The sample diluent comprises serum albumin, animal IgG, a protein stabilizer, a metal ion exchanger, a salt buffer solution, Tween 20, Proclin300 and purified water. According to the invention, the protein stabilizer and the metal ion exchanger are added into the sample diluent, so that interference of a matrix effect can be effectively reduced, and non-specific adsorption can be removed; and healthy animal IgG is added, so that a to-be-detected sample can be protected, a serum environment can be simulated, interference of heterotropism antibodies and rheumatoid factors in a serum and plasma sample can be reduced, false positive is reduced, and the accuracy and repeatability of ELISA detection results are improved.