The present invention generally relates to droplet libraries and to systems and methods for the formation of libraries of droplets. The present invention also relates to methods utilizing these droplet libraries in various biological, chemical, or diagnostic assays.

The binding specificity of at least one plasma protein suspended or dissolved in a liquid medium is altered by exposing the protein to an oxidizing agent or an electric current sufficient to alter its binding specificity. A masked protein such as an autoantibody can be recovered from blood or blood products or extracts by oxidizing the protein to change its binding specificity.

A method of quantitatively determining an analyte in a fluid sample by an immunoassay comprises binding of the analyte to a ligand capable of specifically binding to the analyte, wherein at least part of the analyte is present as an analyte complex is disclosed. The method comprises the steps of: a) subjecting the sample to a first acidic pH to at least substantially dissociate any analyte complex present and provide substantially all analyte in free form, b) raising the first acidic pH to a second acidic pH where re-formation of complexes is prevented but where binding of analyte to the ligand is permitted, and c) determining the binding of analyte to the ligand to quantitatively determine the analyte in the sample.

The disclosed methods use a multi-phase system to separate samples according to the density of an analyte of interest. The method uses a multi-phase system that comprises two or more phase-separated solutions and a phase component such as a surfactant or polymer. The density of the analyte of interest differs from the densities of the rest of the sample. The density of the analyte of interest is substantially the same as one or more phases. Thus, when the sample is introduced to the multi-phase system, the analyte of interest migrates to the phase having the same density as the analyte of interest, passing through one or more phases sequentially.

This invention relates to imaging, such as by expansion microscopy, labelling, and analyzing biological samples, such as cells and tissues, as well as reagents and kits for doing so.

The disclosure provides a reagent for extracting immunosuppressant drugs from whole blood sample for immunoassay. The extraction reagent comprises protein denaturant, proteolytic enzyme, surfactant and pH buffer. The disclosure also provides a method and an immunoassay kit for detection of the immunosuppressant concentration in a whole blood sample using the extraction reagent. The extraction reagent of the present disclosure doesn't need the use of organic solvent as that in the traditional extraction method, therefore the adverse effects of the organic solvent on the antibody activity in a detection system and the other relative defects associated to its use are obviated. The drug extraction process of the present disclosure doesn't need centrifugation, the processed sample can be directly applied for immunoassay. The operation for drug extraction by the present disclosure is simple, and the detection result based on this extraction method is accurate.

The present invention provides a detection method for a monoclonal antibody in a sample, comprising: (a) a step of capturing the monoclonal antibody in the sample and immobilizing the monoclonal antibody in pores of a porous body; (b) a step of bringing the porous body in which the monoclonal antibody is immobilized with nanoparticles on which protease is immobilized to conduct selective protease digestion of the monoclonal antibody; (c) a step of detecting, by a liquid chromatography mass spectrometry (LC-MS), peptide fragments obtained by the selective protease digestion; and (a) a step of conducting a reduction reaction under an acidic condition after the step (a). By the present invention, further applicability of the detection method for the monoclonal antibodies using mass spectrometry is expected.

A kit for separating a sample comprising one or more biological analytes of interest using a multi-phase system comprising: a) two or more phase components selected from the group consisting of a polymer, a surfactant, and combinations thereof; b) optionally a tag molecule capable of binding the one or more biological analytes of interest; and c) instructions for: (i) combining the two or more phase-separated solutions with a common solvent to create a multi-phase system; (ii) optionally, combining the biological analyte of interest and tag molecule, and (iii) separating the biological analyte of interest from the sample.

A multi-phase system includes a phase-separated solution comprising at least two phases, each phase having a phase component selected from the group consisting of a polymer, a surfactant and combinations thereof, wherein at least one phase comprises a polymer, wherein the phases, taken together, represent a density gradient. Novel two-phase, three-phase, four-phase, five-phase, or six-phase systems are disclosed. Using the disclosed multi-phase polymer systems, particles, or other analyte of interest can be separated based on their different densities or affinities.

A multi-phase system includes a phase-separated solution comprising at least two phases, each phase having a phase component selected from the group consisting of a polymer, a surfactant and combinations thereof, wherein at least one phase comprises a polymer, wherein the phases, taken together, represent a density gradient. Novel two-phase, three-phase, four-phase, five-phase, or six-phase systems are disclosed. Using the disclosed multi-phase polymer systems, particles, or other analyte of interest can be separated based on their different densities or affinities.