35 results about "Isoelectric focusing" patented technology

Provided herein are bispecific antibodies having modifications that enable greater developability and manufacturability. In certain instances, such bispecific antibodies comprise common light chain bispecific antibodies that bind CD38 and CD19, having reduced isoelectric focusing, improved hydrophobic interaction chromatography retention, and effective targeting of cells expressing CD19 and CD38. Also provided are methods of reducing an experimental isoelectric point of bispecific antibodies that bind CD19 and CD38.

The invention provides a preparation method of a mineralized collagen scaffold material with a bionic structure, and belongs to the field of biomedical engineering.The preparation method comprises the steps that an amorphous calcium phosphate solution stabilized by polyacrylic acid is prepared, and the molar ratio of Ca to P in the amorphous calcium phosphate solution is 1.67: 1; preparing a collagen solution containing noradrenaline; carrying out isoelectric focusing treatment on the collagen solution under a constant voltage to form a dense membrane, and stretching the dense membrane to generate 120-200% deformation, so as to obtain a collagen membrane with a bionic structure; and soaking the collagen membrane in the amorphous calcium phosphate solution, and then performing freeze drying to obtain the noradrenaline-mineralized collagen scaffold material. The mineralized collagen scaffold material prepared by the method has excellent biocompatibility, osteogenesis inductivity and sufficient mechanical strength, can effectively promote bone tissue defect repair, and has a good application prospect in the field of bone tissue engineering. The invention further provides the mineralized collagen scaffold material with the bionic structure and application of the mineralized collagen scaffold material.

The invention discloses a method for detecting a charge variant of a monoclonal antibody. The method comprises the following steps: preparing a monoclonal antibody to be detected into a test solution; the test solution comprises a monoclonal antibody to be detected, a methylcellulose solution, urea, amino acid, an ampholyte carrier and an isoelectric point marker; detecting the test solution by adopting a full-column imaging capillary isoelectric focusing method, and determining the content percentage of the charge variant of the monoclonal antibody to be detected according to an isoelectric focusing map; wherein the isoelectric point of the amino acid is similar to the boundary isoelectric point of a main peak and an alkali peak in an isoelectric focusing map of the monoclonal antibody to be detected. According to the method, the separation degree between the main peak and the alkali peak of the to-be-detected sample can be remarkably improved. The sensitivity is good, the precision is high, and while the separation degree of a main peak and an alkali peak is improved in a targeted manner, the separation degree and proportion of an acid peak and the main peak, the isoelectric point of a sample and the like are basically not influenced.

Multispecific antibodies with reduced isoelectric focusing points are described herein.

To provide systems that are configured to perform multiple types of analysis, such as electrophoretic mobility and isoelectric electrophoresis within a single device, and that are automated so that multiple samples are analyzed simultaneously or in rapid succession with ease and robustness while consuming minimal volumes of expensive reagents and disposables.SOLUTION: A system includes: a housing; a cartridge retainer disposed within the housing; a detection assembly disposed within the housing; and a reagent tray holder movably disposed within the housing. The detection assembly is configured to transition between a first configuration, in which a first detector detects a first output of at least one emitter, and a second configuration, in which a second detector detects a second output of the at least one emitter. The reagent tray holder is configured to move relative to the cartridge retainer to place the capillary of a capillary cartridge in fluid communication with a reagent volume.SELECTED DRAWING: Figure 6

This paper provides a method for detecting low concentrations of amphoteric compounds in a sample, comprising: (a) preparing an analytical sample mixture for capillary isoelectric focusing (CIEF) detection using the sample; and (b) detecting the analytical sample mixture using a fluorescence detector via a CIEF system; wherein the concentration of the low concentration amphoteric compound in the analytical sample mixture is less than 0.5 μg / μL. This method is more resistant to background noise interference and can sensitively detect and accurately quantify low concentrations of amphoteric compounds present in the sample.

The present disclosure provides icIEF sample matrices that enable icIEF analysis of PEGylated proteins in their real conjugated states. The sample matrices of the present disclosure can include glycine, which enables the separation of co-migrated PEGylated protein charge variants. The sample matrices can also include taurine, which further improves icIEF assay by depleting matrix induced baseline interferences. Accordingly, a sample matrix of the present disclosure including a combination of glycine and taurine enables icIEF separation of acidic and basic species from the main peak for PEGylated proteins, allowing the identification / separation, characterization and quantification of discrete PEGylated protein species. By using the sample matrices of the present disclosure to characterize PEGylated proteins by icIEF, repeatability, linearity, accuracy, sample stability, and method robustness are achieved.

The utility model discloses an isoelectric focusing capillary electrophoresis apparatus for antibody drug analysis, which belongs to the technical field of capillary electrophoresis apparatuses and comprises a shell, a high-voltage direct-current power supply, a capillary part and a fluorescence detector, the high-voltage direct-current power supply is mounted in the shell, and the capillary part is positioned in the shell and positioned at the upper part of the high-voltage direct-current power supply; the positive output end and the negative output end of the high-voltage direct-current power source are communicated with the two ends of the capillary tube part respectively, the fluorescence detector is located in the shell and located above the capillary tube part, a discharging box is arranged in the shell, a feeding pipe capable of achieving movable feeding is arranged in the shell, a feeding opening is formed in the feeding pipe, and a piston is arranged in the feeding pipe in a sliding mode; an extraction assembly for controlling the piston to move is arranged outside the feeding pipe, and a feeding assembly for moving the feeding pipe so as to feed the capillary tube part is arranged in the shell, so that the suction and release amount of the sample solution can be conveniently adjusted according to requirements, and the problem of insufficient sampling of the sample solution is avoided.

The invention relates to a method for detecting interleukin 4 variants and application of the method. The method comprises the following steps: diluting an interleukin 4 sample with an amphoteric electrolyte solution to obtain a sample solution to be detected; performing capillary electrophoresis-mass spectrometry online combined detection on the to-be-detected sample solution; the volume fraction of the amphoteric electrolyte solution is 0.2-5%; the conditions of capillary electrophoresis separation comprise that a capillary isoelectric focusing electrophoresis mode is adopted; the capillary tube is a neutral coating capillary tube; and the separation voltage is 1-100 kV. The detection method has the advantages of high separation efficiency and accurate analysis result, and can comprehensively obtain the information of the heteroplasmon in the interleukin 4 sample. In addition, the isoelectric point data of each interleukin 4 heteroplasmon can be accurately obtained by the method, so that accurate characterization of the sample is realized. The method disclosed by the invention can be applied to detection of interleukin drugs so as to meet the requirements on quality control of interleukin 4 in the market.

The present disclosure relates to fluidic systems and devices for processing, extracting, or purifying one or more analytes. These systems and devices can be used to process samples and extract nucleic acids, for example, by isoelectric focusing. In particular, the systems and related methods can allow for the extraction of nucleic acids, including non-crosslinked nucleic acids, from samples such as tissues or cells. The systems and devices can also be used for multiplexed parallel sample processing.

The invention discloses a method for separating and enriching exosomes by using paper-based isoelectric focusing equipment and adopting paper-based isoelectric focusing. The method comprises the following steps: carrying out step-by-step centrifugation and ultrafiltration on an exosome solution to obtain a purified exosome solution, incubating the purified exosome solution and carbon quantum dots at a certain temperature to obtain a fluorescent exosome solution adsorbed with the carbon quantum dots, and respectively taking a glycine-hydrochloric acid solution and a glycine-sodium hydroxide solution as positive and negative electrode solutions of paper-based isoelectric focusing equipment, so as to obtain the fluorescent exosome. And performing isoelectric focusing on the paper-based material fully soaked with the fluorescent exosome solution, and finally recovering different focused exosomes. The invention provides a carrier-free ampholyte focusing platform which is convenient, easy to obtain, environment-friendly, low in cost, small in sample loading amount, low in detection limit, easy for sample enrichment and recovery, and compatible with other subsequent detection methods.

The presently claimed and described technology is directed to an acidic high polymer composition comprising about 1.0% (w / v) polymer and about 4% (v / v) carboxylic acid. The acid high polymer composition may be used as a neutral capillary storage or conditioning solution or in a method of improving capillary isoelectric focusing (cIEF) robustness or performance. The technology is also directed to a kit comprising an acidic high polymer composition, at least one stabilizer, an anolyte, and a catholyte.

The disclosure relates to methods of characterizing ampholyte compositions suitable for downstream applications such as capillary isoelectric focusing using liquid-chromatography-mass spectrometry.

To provide systems that are configured to perform multiple types of analysis, such as electrophoretic mobility and isoelectric electrophoresis within a single device, and that are automated so that multiple samples are analyzed simultaneously or in rapid succession with ease and robustness while consuming minimal volumes of expensive reagents and disposables.SOLUTION: A system includes: a housing; a cartridge retainer disposed within the housing; a detection assembly disposed within the housing; and a reagent tray holder movably disposed within the housing. The detection assembly is configured to transition between a first configuration, in which a first detector detects a first output of at least one emitter, and a second configuration, in which a second detector detects a second output of the at least one emitter. The reagent tray holder is configured to move relative to the cartridge retainer to place the capillary of a capillary cartridge in fluid communication with a reagent volume.SELECTED DRAWING: Figure 6

Systems and methods for calibrating compound markers in mass spectrometry (MS) detection are disclosed. The systems and methods automatically identify a plurality of isoelectric point (pI) markers in a sample, generate a calibration curve correlating pI with time, and convert the time scale to a pI scale. Based on the established correlation between time and pI, the system further associates pI with intensity values, enabling presentation to an operator for analysis.

The invention relates to a quantitative method for whey protein in milk and dairy products, which comprises the following steps: preparing samples including liquid dairy products and solid dairy products; quantitative detection is carried out, and analysis is carried out by combining a capillary electrophoresis system CEInfinite with an acrylamide derivative AD coating capillary column; according to the method verification, reproducibility on the same batch of AD and different batches of AD coating capillaries is compared, and then repeatability summary of isoelectric points and peak areas is obtained; and obtaining a result. According to the method disclosed by the invention, high-efficiency separation and simultaneous quantitative analysis of alpha-lactalbumin, beta-lactoglobulin A and beta-lactoglobulin B in whey protein in dairy products are rapidly realized by using full-column imaging capillary isoelectric focusing electrophoresis (icIEF) and acrylamide derivative AD coating capillary; the method has important significance in promoting scientific research, new product development and the like while guaranteeing the product quality, protecting the health of consumers and optimizing the production process.

The invention relates to the field of collagen isoelectric point detection, in particular to a collagen isoelectric point detection method. The collagen isoelectric point detection method provided by the invention comprises the following seven steps: S1, solution preparation; S2, gel preparation; S3, sample pretreatment; S4, sample application; wherein in the step of sample pretreatment in the step S3, centrifugation is segmented, and a urea solution is added before each segment of centrifugation, so that the collagen sample is not easy to gather, and formation of a normal strip by subsequent isoelectric focusing is facilitated. The electrophoresis condition is controlled in the step S5 of isoelectric focusing electrophoresis, so that the formed strip is clear, condensed and not loose, and the isoelectric point of the collagen sample can be accurately measured by utilizing a trace amount of the collagen sample.

The invention relates to a method for determining isoelectric points of proteins and polypeptides, which is characterized in that a capillary isoelectric focusing electrophoresis method or a full-column imaging capillary isoelectric focusing electrophoresis method is used for determining according to a 214nm absorption peak. The method provided by the invention solves the problem that the isoelectric point of the protein or polypeptide which does not contain a benzene ring structure cannot be measured by a capillary isoelectric focusing electrophoresis method because the protein or polypeptide does not have ultraviolet absorption under the wavelength of 280 nm.

The invention relates to a method for detecting interleukin 2 variants and application of the method. The method comprises the following steps: diluting an interleukin 2 sample with an amphoteric electrolyte solution to obtain a sample solution to be detected; performing capillary electrophoresis-mass spectrometry online combined detection on the to-be-detected sample solution; the volume fraction of the amphoteric electrolyte solution is 0.2-5%; the conditions of capillary electrophoresis separation comprise that a capillary isoelectric focusing electrophoresis mode is adopted; the capillary tube is a neutral coating capillary tube; and the separation voltage is 1-100 kV. The detection method is high in separation efficiency and accurate in analysis result, and in addition, isoelectric point data of each interleukin 2 variant can be accurately obtained by the method, so that accurate characterization of a sample is realized. The method disclosed by the invention can be applied to detection of interleukin drugs so as to meet the requirements on quality control of interleukin 2 in the market.

A method for detecting a by-product in a sample of a target asymmetric bispecific antibody (AsBsAb) is provided, comprising subjecting the sample to capillary isoelectric focusing to separate the by-product from the target AsBsAb based on a difference in their pi. In particular, the AsBsAb comprises two half antibodies, and the pi of the first half antibody is different from the pi of the second half antibody.

A method for detecting byproducts in a sample of a target asymmetric bispecific antibody (AsBsAb), comprising subjecting the sample to capillary isoelectric focusing to separate the byproducts from the target AsBsAb based on their pI differences. Specifically, the AsBsAb comprises two half-antibodies, and the pI of the first half-antibody is different from that of the second half-antibody.

The disclosure relates to methods of characterizing ampholyte compositions suitable for downstream applications such as capillary isoelectric focusing using liquid-chromatography-mass spectrometry.

The invention relates to the technical field of protein separation and preparation, and particularly discloses a method for preparing bovine serum albumin. The preparation method disclosed by the invention comprises the following steps: (1) acidifying and aging bovine whey with citric acid under the condition that the pH value is 3.0-3.4; (2) performing microfiltration on the whey protein solution, and taking permeate as first feed liquid; (3) the first feed liquid with the pH value adjusted to 6.7-7.0 is percolated with water through an ultrafiltration membrane, trapped fluid serves as second feed liquid, the protein concentration of the second feed liquid is 4%-7%, and the conductivity of the second feed liquid is smaller than 250 microseconds per centimeter; the pore diameter of the ultrafiltration membrane is 3000 to 10000 Da; and (4) separating the second feed liquid by isoelectric focusing-free flow electrophoresis, and adopting glycine-hydrochloric acid as an ampholyte system. The preparation of the BSA can be realized by utilizing the cow milk / whey which is wide in raw material source and low in cost, the obtained BSA is high in purity, and the high-purity beta-lactoglobulin can be obtained at the same time.

Disclosed and claims are a method for analyzing at least one analyte, the method including introducing a composition into a separation channel, wherein the composition includes at least one pH gradient compound, an amine buffer, and at least one analyte of interest; applying an electric field across the separation channel to create a pH gradient using the at least one pH gradient compound and separate the composition via isoelectric focusing, generating at least one focused analyte peak; mobilizing the at least one focused analyte peak; and wherein the amine buffer is configured to modify the pH gradient.

The present invention generally pertains to methods of characterizing charge variants of a protein of interest. In particular, the present invention pertains to the use of desalting size exclusion chromatography-reduced peptide mapping mass spectrometry to identify charge variants separated by capillary isolectric focusing.

The invention discloses a circulating type free flow isoelectric focusing electrophoresis device and method.The circulating type free flow isoelectric focusing electrophoresis device is mainly composed of a gas-liquid buffer chamber, liquid storage pipes, a separation chamber, a collecting pipe, a cooling device and a driving pump, liquid inlets of the separation chambers are connected with liquid storage pipes in the gas-liquid buffer chambers in a one-to-one correspondence manner through switches, liquid outlets of the separation chambers are connected with a collecting pipe through a three-way valve, another outlet of the three-way valve corresponds to the liquid storage pipes in the gas-liquid buffer chambers in a one-to-one correspondence manner, and a switch is connected between the three-way valve and the liquid storage pipes. According to the device and the method, required reagents are low in price, a constant flow pump is adopted to replace a multi-channel driving pump, the effect of infinite plate length can be achieved under continuous circulation, heat dissipation is facilitated, and a solution without a sample can be recycled in a pipeline with the corresponding pH value.

The application provides a preparation method of a mineralized collagen scaffold material with a biomimetic structure, and belongs to the field of biomedical engineering.The preparation method comprises the following steps: preparing a polyacrylic acid-stabilized amorphous calcium phosphate solution, wherein the molar ratio of Ca element to P element in the amorphous calcium phosphate solution is 1.67:1; preparing a collagen solution containing norepinephrine; performing isoelectric focusing treatment on the collagen solution under a constant voltage to form a dense film, then stretching the dense film to produce a deformation of 120% to 200%, and obtaining a collagen film with a biomimetic structure; soaking the collagen film in the amorphous calcium phosphate solution, and then performing freeze-drying to obtain a norepinephrine-mineralized collagen scaffold material.The mineralized collagen scaffold material prepared by the method has excellent biocompatibility, osteogenic induction and sufficient mechanical strength, can effectively promote bone tissue defect repair, and has a good application prospect in the field of bone tissue engineering.The application further provides a mineralized collagen scaffold material with a biomimetic structure and an application thereof.

The invention relates to imaging capillary isoelectric focusing for analyzing protein variants in a sample matrix. Embodiments of the present disclosure relate to methods, systems, devices, and kits corresponding to a method for analyzing a charge variant of a protein, such as vascular endothelial growth factor (VEGF-Trap).

This application discloses a method for detecting charge variants of monoclonal antibodies. The method includes preparing a test solution of the monoclonal antibody to be tested; the test solution includes the monoclonal antibody to be tested, methylcellulose solution, urea, amino acids, an amphoteric electrolyte carrier, and an isoelectric point marker; the test solution is detected using whole-column imaging capillary isoelectric focusing, and the percentage of charge variants of the monoclonal antibody to be tested is determined based on the isoelectric focusing spectrum; wherein the isoelectric point of the amino acid is similar to the isoelectric point of the boundary between the main peak and the base peak in the isoelectric focusing spectrum of the monoclonal antibody to be tested. This method can significantly improve the separation between the main peak and the base peak of the sample. It also exhibits good sensitivity and high precision, while specifically improving the separation between the main peak and the base peak, with minimal impact on the separation and ratio of the acid peak and the main peak, as well as the isoelectric point of the sample.