57 results about "Scatchard plot" patented technology

The present invention relates to the technical field of molecular interaction analysis, and specifically provides a method for analyzing intermolecular interactions. The method comprises the following steps: using a rare earth material with a ligand molecule modified on its surface as an upconversion material, contacting the upconversion material with a target molecule in a solution system, irradiating the solution system with excitation light that matches the rare earth material, and continuously changing the intensity of the excitation light actually received by the upconversion material as the target molecule continuously binds and dissociates with the ligand molecule of the upconversion material in a dynamic process, thereby changing the intensity of the emitted light. By recording the curve of the emission light intensity changing with time, the molecular interaction kinetic constants, such as the binding rate constant (K on ), dissociation rate constant (K off ) and affinity (K D ), etc., which solves the technical problems of low accuracy of existing BLI technology and high cost of SPR technology. Based on the above principles, the present invention has also developed a series of experimental consumables, kits, sensors and analytical devices for molecular interaction analysis.

The invention relates to a UCNPs probe-based in-situ dynamic monitoring molecular interaction method, which comprises: S1, providing a UCNPs probe, the core layer of the UCNPs probe being a rare earth up-conversion nanocrystal, the shell layer of the UCNPs probe being an anti-quenching inert material, and the anti-quenching inert material coating the surface of the rare earth up-conversion nanocrystal; the surface of the anti-quenching inert material is modified with ligand molecules, and the ligand molecules are used for being specifically combined with target molecules in a to-be-detected sample; s2, mixing or contacting the UCNPs probe with a to-be-detected sample containing target molecules to construct a to-be-analyzed molecular interaction system; s3, irradiating the molecular interaction system by adopting near-infrared pulse laser, and collecting the change of the fluorescence lifetime tau of the UCNPs along with the time t and the change of the fluorescence intensity I along with the time t in real time to obtain a tau-t curve and an I-t curve; and S4, according to the tau-t curve and the I-t curve, realizing in-situ dynamic monitoring on the molecular interaction state. According to the method, a molecular binding / dissociation event is directly converted into a quantifiable and anti-interference optical signal, and the technical defect that in-situ dynamic monitoring of molecular interaction cannot be achieved in a traditional technology is overcome.

The invention discloses a 4E6 antibody-based oxidized low-density lipoprotein detection method, which comprises: obtaining a model constructed by a target 4E6 monoclonal antibody sequence, carrying out docking analysis on the interaction of antigen binding regions, designing a mutant prediction influence, selecting an optimal combination to construct a new sequence, and carrying out expression purification to obtain the oxidized low-density lipoprotein. The optimization effect is verified by measuring and combining kinetic parameters; a dendritic-linear polymer modified structure on the surface of a latex microsphere is designed and optimized based on a computational material science method, and the modified latex microsphere is synthesized and coupled with an optimized 4E6 monoclonal antibody to form a detection probe; and establishing an oxidized low-density lipoprotein standard curve through a plurality of groups of standard substance solutions, and determining a detection limit and a quantitation limit so as to calculate the sample concentration. According to the scheme, the antibody recognition capability and the signal amplification effect can be improved, and the detection sensitivity and accuracy are improved.

The invention relates to the technical field of molecular interaction analysis, in particular to a method for analyzing intermolecular interaction, which comprises the following steps of: adopting a rare earth material with ligand molecules modified on the surface as an up-conversion material, contacting the up-conversion material with target molecules in a solution system, and irradiating the solution system by using exciting light matched with the rare earth material to obtain the intermolecular interaction. The intensity of the emitted light is changed by continuously changing the intensity of the exciting light actually received by the up-conversion material in the dynamic process of continuously combining and dissociating target molecules with ligand molecules of the up-conversion material, and a molecular interaction dynamic constant can be calculated by recording a change curve of the intensity of the emitted light along with time. According to the present invention, the BLI technology has the binding rate constant (Kon), the dissociation rate constant (Koff), the affinity (KD) and the like, and the technical problems of low precision of the existing BLI technology, expensive SPR technology and the like are solved. Based on the principle, the invention also develops a series of experimental consumables, kits, sensors and analysis devices for molecular interaction analysis.

The invention provides an extracellular vesicle marker separation-free detection method based on nanoparticle enhancement, and belongs to the technical field of detection methods, the method comprises the following steps: preparing gold nanoparticles with the surface modified with a first antibody, the first antibody being used for specific recognition of an extracellular vesicle surface marker; determining the particle size distribution of the gold nanoparticles by adopting a dynamic light scattering method, and determining the surface potentials and surface isoelectric points of the gold nanoparticles by adopting a potentiostat; adopting a transmission electron microscope to characterize the morphology of the screened gold nanoparticles; co-modifying polyethylene glycol molecules on the surfaces of the gold nanoparticles to form an anti-interference layer; mixing the gold nanoparticles with uniform morphology with a sample to be detected; adding a second antibody into the mixed system; distinguishing signals of the binding-state second antibody and the free-state second antibody through fluorescence lifetime analysis; preparing an extracellular vesicle standard substance, and obtaining a standard curve and a system response curve; the optimal detection condition is determined by solving the detection system optimization equation set, and separation-free detection is carried out.

The present invention provides a quantitative measurement method using competitive immunochromatography, which has not been previously reported. The quantitative measurement method comprises: (1) creating a calibration curve based on the signal intensity of a test line according to the concentration of a standard material by using multiple strips, and calculating the concentration of a target analyte by using the calibration curve; (2) when the concentration of the target analyte increases to a significant level on the calibration curve of the standard material, a labeled signal of a detection ligand on a control line remains unchanged in a case where a detection ligand of a target analyte-detection ligand conjugate binds to and saturates a capture ligand on the control line, making it impossible to estimate the concentration beyond that level; however, by designing a binding site for the capture ligand on the control line to be the target analyte of the target analyte-detection ligand conjugate, a high concentration of the target analyte breaks down the triple conjugate of detection ligand-target analyte-capture ligand, leading to dissociation of the labeled detection ligand and thereby weakening the signal (hook effect); and (3) comparing the signal intensity patterns of the test line and the control line according to the calibration curve of the standard material with the signal intensity pattern of a sample target analyte, and determining how far the target analyte is from the saturation point of the detection ligand. This method is characterized in that, in cases where the target analyte is present in an excessively large amount and exceeds the maximum value of a measurement range (dynamic range) of the calibration curve, the calibration curve using multiple strips and the configurations (test line and control line) of an immunochromatographic device are designed differently to distinguish such cases.

Provided are a method and system for predicting an activation potency of agonist molecules on G Protein-Coupled Receptors (GPCRs). The method includes: blindly speculating complex structures formed by binding of a ligand to an activated receptor structure and an inactivated receptor structure, respectively, via global molecular docking; extracting an initial path enabling an inactivated complex structure to be activated to an activated complex structure based on an enhanced sampling algorithm; searching for a minimum free energy path closest to the initial path by applying an automatic path optimization algorithm; calculating a free energy distribution curve along the minimum free energy path by employing umbrella sampling and determining an energy barrier height and a free energy difference before and after activation, thereby determining the activation potency of the ligand structure on the GPCRs.

The invention belongs to the technical field of molecular biology, and particularly relates to a standard substance for detecting absolute telomere length and a preparation method and application thereof. The standard substance provided by the invention exists in the form of plasmids, and comprises a telomere standard substance and a single copy gene IFNB1 standard substance. The specific standard substance for detecting the absolute telomere length has good and stable amplification efficiency, and the standard curve stability of the standard substance is high.

The invention relates to the field of materials and physicochemistry, in particular to a method for measuring thermodynamic data between a quantum dot surface and a ligand by using solvent volatilization, which comprises the following steps: preparing a ligand modified quantum dot organic solvent solution with a certain concentration, and standing until the fluorescence intensity is stable; measuring the volatilization rate of the organic solvent at the target temperature; in the same environment, volatilizing the prepared quantum dot organic solvent solution, and detecting the fluorescence intensity of the quantum dots in real time to obtain a real-time fluorescence intensity-time curve that the fluorescence intensity changes along with time; the obtained fluorescence intensity-time curve is converted through the relation of fluorescence intensity-solvent volatilization-quantum yield to obtain the data relation between the ligand density and the quantum dot quantum yield at the t moment, and then thermodynamic data can be obtained through a corrected KSV equation according to the data relation. The method is simple, accurate and practical in operability.

The invention provides a virtual screening method based on scoring function optimization. The virtual screening method is used for efficiently screening a PAK4 inhibitor. According to the method, molecular docking, scoring function optimization, machine learning and molecular dynamics simulation are combined, and the screening efficiency and accuracy are improved through a multi-level screening strategy. The method comprises the following steps: firstly, screening candidate compounds in a database by utilizing a molecular similarity algorithm, and reserving molecules similar to target binding pocket characteristics; and then, screening and optimizing the compound by adopting rapid molecular docking and key residues. Thirdly, using scoring functions such as RF-VS and GNINA as well as a deep learning method to optimize screening, and evaluating the performance of the model through an ROC curve and an enrichment factor; and finally, verifying a screening result by utilizing high-precision docking and 150ns molecular dynamics simulation, and confirming the stability and targeted binding capacity of the candidate molecules. The method is successfully applied to PAK4 inhibitor screening, the screening efficiency is remarkably improved, and an efficient and reliable solution is provided for research and development of PAK4 targeted drugs.

This invention discloses a shark-derived single-domain antibody that binds to hemoglobin and its application. The nucleotide sequence of the single-domain antibody is labeled SEQ ID NO.1, while the corresponding amino acid sequence is recorded as SEQ ID NO.2. The shark-derived single-domain antibody is used to detect hemoglobin concentration. The detection method includes setting up a standard group and a sample group, then adding the shark-derived single-domain antibody to the immunoassay plates of the standard group and the sample group, and measuring the OD of the standard group and the sample group after color development. 450 Value, based on the OD of the standard group 450 Values, plot OD 450 The standard curve is calculated based on the OD value. 450 The standard curve was used to obtain the hemoglobin concentration of the sample group. The single-domain antibody prepared in this invention exhibits good stability, high specificity, and high affinity. The antibody screened in this invention provides a theoretical basis and technical support for the subsequent diagnosis and monitoring of hemoglobin-targeted diseases.

The embodiment of the present invention discloses a SERS quantitative working curve method based on intensity ratio, comprising: step 1, obtaining a quantitative standard curve. Prepare a first batch of SERS substrates, detect the SERS spectra of target molecules of different concentrations on the first batch of SERS substrates, and select the SERS intensity of any concentration as a reference to obtain the ratio between the characteristic peak intensity of the target molecules of different concentrations and the reference intensity, and fit the corresponding relationship between the ratio and the logarithm of the target molecule concentration as a quantitative standard curve; step 2, quantitative detection of molecular concentration. Prepare a second batch of SERS substrates, detect the SERS spectra of the target molecules of unknown concentration, and detect the SERS spectra of the target molecules of known concentration as an intensity reference, and determine the concentration value of the target molecules of unknown concentration according to the ratio between the characteristic peak intensities and the corresponding relationship obtained in step 1.

The present application discloses a method and system for quantitatively detecting oxidized low-density lipoprotein based on magnetism, the method comprising: preparing a magnetic immune probe, and converting magnetic signal excitation energy into an electrical signal to calculate coupling efficiency; constructing an immunochromatographic test strip comprising a detection area, a quality control area and a binding area, and realizing the detection of oxidized low-density lipoprotein concentration in combination with the establishment of a standard curve; applying the sample to be tested to the sample pad of the test strip, combining the magnetic particles labeled with oxidized low-density lipoprotein antibodies at the binding pad position, flowing on the nitrocellulose membrane to the site labeled with another antibody, and forming a magnetic particle enrichment area through the binding action of the antigen and antibody, and through magnetic signal acquisition and data processing, quantitative detection of oxidized low-density lipoprotein can be performed. Through the scheme of the present application, high sensitivity, high specificity and rapid detection of Ox‑LDL can be achieved.

A rapid MDA content detection method based on nanogold labeling is characterized in that nanogold rod particles with stable long diameter are prepared by using a polymerization nanogold rod seed growth method, and at the moment, the surface plasmon resonance absorption peak of a nanogold rod is scanned by ultraviolet light splitting to be about 780 nm. Adding a sulfhydrylated MDA antibody, uniformly mixing, and incubating for 2 hours at 28 DEG C by using polyethylene glycol-6000 (PEG-6000), so as to functionalize the gold nanorod. And detecting the deviation value of the red peak to confirm the binding degree of the antibody, adding an MDA antigen, uniformly mixing for 2 minutes, scanning the plasmon resonance absorption peak on the surface of the gold nanorod again to confirm the deviation value of the red peak, and comparing the deviation value of the red peak with a numerical value standard curve of the deviation value of the red peak to quickly detect the content of the MDA. The method is used for rapidly detecting the content of MDA in a solution and has the advantages of being high in sensitivity, good in stability, rapid and convenient to use, and the detection limit can reach 0.000005-300 nmoL / L.

To provide a method for selectively reducing CysL97 in a preparation of IL-17 antibody recombinantly produced by a mammalian cell or antigen binding fragment thereof (e.g., a preparation of secukinumab antibody).SOLUTION: The method comprises the steps of: a) forming a reducing mixture by contacting the preparation to a reductant in a vessel where the reductant is a thiol-containing reductant having a standard oxidation-reduction potential, E0, of -0.20 V to -0.23 V at pH 7.0, as measured by thiol-disulfide exchange, and the molar ratio of reductant to antibody in the reducing mixture is between 46:1 to 118:1; and b) incubating the reducing mixture while maintaining a volumetric oxygen mass-transfer coefficient (kLa*) in the vessel to 0.37 h-1 or lower as calculated by adapting a dissolved oxygen curve to a saturation curve.SELECTED DRAWING: None

According to the present invention, a method is provided for determining kinetic parameters of a reaction between an analyte and a ligand attached to a test surface of a flow cell, the method comprising the steps of: (a) flowing a first volume of sample fluid (V1) containing the analyte through the test surface between a first time point (t1) and a second time point (t2); (b) flowing a first volume of buffer fluid (Vb1) without the analyte through the test surface between a third time point (t3) and a fourth time point (t4); (c) flowing a sample fluid (V2) containing at least a second volume of the analyte through the test surface between a fifth time point (t5) and a sixth time point (t6); (d) flowing a buffer fluid (Vb2) without the analyte through the test surface between a seventh time point (t7) and an eighth time point (t8); (e) measuring the binding of the analyte to the ligand on the test surface using a sensor to obtain a binding curve; and (f) using only a portion of the binding curve within a predefined time interval and excluding other portions of the binding curve to determine the kinetic parameters.

According to the present invention there is provided a method for determining kinetic parameters of a reaction between analyte and ligands, the method comprising the steps of, a) flowing a first volume of sample fluid (V1), which has a concentration (co) of analytes, over a test surface (3) of a flow cell (2) which has first ligands (4) attached thereto, for a first time period (tia); b) flowing a first volume of buffer solution (X / Γ) over the test surface (3) of the flow cell (2), for a first time period (tib); c) flowing at least a second volume of sample fluid (V2), over the test surface, for a second time period (t2a); wherein the second time period (t2a) is greater than the first time period (tia) and wherein the second volume of sample fluid (V2) has the same concentration (c0) of analytes as the concentration (c0) of analytes in the first volume of sample fluid (V2); d) flowing a second volume of buffer solution (V2′) over the test surface (3) of the flow cell (2), for a second time period (t2b); e) using a sensor to measure the binding on the test surface (3) during steps (a)-(d) to obtain a single measurement binding curve; f) flowing a first volume of sample fluid (V1), which has a concentration (Co) of analytes, over a test surface (3′) of a flow cell (2′) which is without first ligands, for a first time period (tia); g) flowing a first volume of buffer solution (X / Γ) over the test surface (3′) which is without first ligands, for a first time period (fib); h) flowing at least a second volume of sample fluid (V2), over the test surface (3′) which is without first ligands, for a second time period (t2a); wherein the second time period (t2a) is greater than the first time period (t1a) and wherein the second volume of sample fluid (V2) has the same concentration (c0) of analytes as the concentration (c0) of analytes in the first volume of sample fluid (V2); i) flowing a second volume of buffer solution (V2′) over the test surface (3) which is without first ligands, for a second time period (t2b); J) using a sensor to measure the binding on the test surface (3) which is without first ligands, during steps (f)-(i), to obtain a single reference binding curve; k) Using the single measurement binding curve and the single reference binding curve to determine the kinetic parameters.

The invention relates to the technical field of blood analysis, in particular to a scatter diagram-based lipid particle identification method and a blood cell analyzer. The method comprises the following steps: extracting lipid particle characteristics in a three-dimensional scatter diagram of a blood sample to obtain sample curve characteristics and particle number characteristics, and obtaining a lipid particle identification result of the three-dimensional scatter diagram based on the sample curve characteristics and the particle number characteristics; and outputting alarm information under the condition that the lipid particle recognition result represents that the lipid particles exist in the three-dimensional scatter diagram. By adopting the method, the cell counting accuracy can be improved.

A method for determining kinetic binding parameters of a molecular binder conjugated to a fluorophore. Repeated staining of an antigen and detection of emitted radiation generates a titration series. By fitting the emitted radiation over the titration series, kinetic binding parameters can be determined. The emitted radiation is detected by a camera, and single-pixel fitting using global analysis allows for discrimination of specific binding signal from nonspecific background at each pixel.

The application discloses a specific antibody for a CTLD1 domain of PLA2R and application thereof, and belongs to the technical field of bioengineering. The application provides a CTLD1 domain antibody of PLA2R or an antigen binding fragment thereof. The CTLD1 domain antibody or the antigen binding fragment thereof provided by the application can specifically recognize a corresponding PLA2R domain and has high affinity. In addition, the application provides a standard curve established by using the CTLD1 domain antibody of PLA2R as a standard product, and provides convenience for clinical detection of the concentration of IgG of anti-PLA2R CTLD1.

The present invention relates to a method of determining the percentage of intact capsid in an adeno-associated virus (AAV) sample comprising the AAV. The invention is characterized by two basic steps. The first step involves dividing each sample into two equally divided samples. One aliquot is maintained at room temperature (RT) while the other aliquot is heated below the AAV melting point to disrupt the binding affinity of the AAV to the anti-AAV coated probe. Heating the AAV aliquot results in different binding affinity of the empty capsid and the intact capsid on the anti-AAV coated probe. The heated empty capsids retain their binding affinity for the probe, while the heated complete capsids significantly reduce their binding affinity for the probe. The second step involves measuring the wavelength shifts of the heated and RT aliquot samples due to light interference and calculating their ratios. The amount of hollow capsid and intact capsid of an unknown sample can be determined by quantifying the ratio with reference to a standard curve.

The invention discloses a specific antibody aiming at a CTLD7 structural domain of PLA2R and application of the specific antibody, and belongs to the technical field of biological engineering. The invention provides a CTLD7 structural domain antibody of PLA2R or an antigen binding fragment of the CTLD7 structural domain antibody. The CysR structural domain antibody or the antigen binding fragment thereof provided by the invention can specifically recognize the corresponding PLA2R structural domain and has relatively high affinity. Besides, the invention provides a method for establishing a standard curve by using a CTLD7 structural domain antibody of PLA2R as a standard substance, so that convenience is provided for clinical detection of concentrations of IgG resisting different epitopes of PLA2R.

The present invention discloses a diagnostic reagent for alpha-fetoprotein detection, which is prepared into an alpha-fetoprotein latex kit, and positively detected by latex enhanced immunoturbidimetry. In a homogeneous liquid system, antigen and antibody are combined. When the combination ratio is appropriate, a solid immune complex is formed and precipitated from the liquid phase, which is manifested as a change in turbidity. The turbidity change is detected by a fully automatic biochemical analyzer, and a linear curve is drawn using a standard product to obtain the content of the substance to be tested in the sample. The diagnostic reagent has the advantages of convenience, speed, time saving, automatic operation, sensitivity, accuracy, etc., and can meet the needs of clinical large sample detection.

The invention discloses a quantitative method of SCCP, and relates to the field of quantitative detection of short-chain chlorinated paraffin, and the method comprises a homologous substance quantitative method and a blank deduction method; the method comprises the following steps: drawing a standard curve by using configured chlorine content and total response, and checking the standard curve to obtain response factors of different family substances according to theoretical chlorine content of different family substances; and obtaining the concentration of the homologous substances by using the response of different homologous substances in the sample and using a response factor method, and the like. According to the invention, SCCP homologous substance quantification is realized, homologous substances which exist in a laboratory blank but do not exist in a sample are identified on the basis, the blank level is reduced, and the quantification accuracy of SCCP is improved.

The present invention discloses a lung cancer prognostic marker and its application. The present invention discloses that the higher the gene expression of the capsaicin receptor TRPV1 in the cancerous tissue of lung cancer patients, the worse the patient's prognosis. A model influencing the prognosis of lung cancer patients was constructed through multivariate COX survival analysis. The K-M plot curve, ROC curve, and patient survival time all verified the accuracy and specificity of the model. Therefore, the potential application value of this marker as a prognostic indicator in lung cancer can further provide a basis for personalized treatment selection for lung cancer patients, which is of great significance for adopting personalized treatment and reducing lung cancer mortality.

The present application relates to a molecular detection method, which uses multi-channel single molecule mechanics technology to simultaneously manipulate multiple molecular probes to detect the analyte; the two ends of the molecular probe are connected to the carrier through the labeled coupling functional groups; the carrier is used to apply pulling force to the molecular probe. The detection process includes binding force and detection force: under the binding force, the molecular probe binds to the analyte; under the detection force, the length difference or length change curve difference of the molecular probe with or without the analyte is used as the signal strength to detect whether the analyte exists, the concentration of the analyte, the binding speed and the binding strength of the analyte to the specific structure. The present application is suitable for detecting the following analytes, such as proteins, drugs, small molecules, DNA, RNA and their complexes.

A method, kit, sensor and device for analyzing intermolecular interaction. In the method for analyzing intermolecular interaction, a rare-earth material of which the surface is modified with ligand molecules is used as an up-conversion material; the up-conversion material comes into contact with target molecules in a solution system; excitation light matching the rare-earth material is used to irradiate the solution system; in a dynamic process of continuous association / dissociation between the target molecules and the ligand molecules on the up-conversion material, the intensity of excitation light actually received by the up-conversion material continuously changes, such that the intensity of emitted light changes; and by recoding a curve of the intensity of the emitted light changing with time, kinetic constants of molecular interaction, such as an association rate constant (Kon), a dissociation rate constant (Koff), and affinity (KD), are calculated. In this way, existing technical problems of low accuracy of BLI technology and high costs of SPR technology.

A method and system for predicting the GPCR activation ability of agonist molecules, wherein the method comprises: using global molecular docking to blindly guess complex structures formed by a ligand structure binding to an active-state receptor structure and an inactive-state receptor structure, respectively; on the basis of an enhanced sampling algorithm, extracting an initial path capable of activating an inactive-state complex structure into an active-state complex structure; using an automatic path optimization algorithm to find a minimum free energy path closest to the initial path; and using umbrella sampling to calculate a free energy distribution curve along the minimum free energy path, and determining an energy barrier height and a free energy difference before and after activation, so as to determine the GPCR activation ability of the ligand structure.

The invention discloses a shark source single-domain antibody combined with hemoglobin and application of the shark source single-domain antibody. The nucleotide sequence of the single-domain antibody is labeled as SEQ ID NO.1, the amino acid sequence corresponding to the single-domain antibody is recorded as SEQ ID NO.2, the shark-source single-domain antibody is used for detecting hemoglobin concentration, and the detection method comprises the following steps: setting a standard substance group and a sample group, then adding the shark-source single-domain antibody into immune pore plates of the standard substance group and the sample group, and then adding the single-domain antibody into the immune pore plates of the standard substance group and the sample group. And measuring the OD450 values of the standard substance group and the sample group after color development, drawing an OD450 value standard curve according to the OD450 value of the standard substance group, and finally obtaining the hemoglobin concentration of the sample group according to the OD450 value standard curve. The prepared single-domain antibody shows good stability, high specificity and high affinity, and the screened single-domain antibody provides theoretical basis and technical support for subsequent diagnosis and monitoring of related diseases taking hemoglobin as a target spot.