In a method for immunologically quantifying a steroid, it is possible to exclude a steroid from cyclodextrin when a standard solution containing the steroid included in cyclodextrin is treated with a surfactant, which thereby suppresses the deviation in behavior of the antigen-antibody reaction between the specimen (test sample) and the standard solution, and then significantly improves the accuracy of steroid quantification.

A bio-substance analysis method using a sensing substrate having a fluid channel is disclosed. The method includes mixing retroreflective particles with a detection solution containing a target bio-substance, wherein a first bio-recognition substance selectively reacting with the target bio-substance is modified on the retroreflective particles; placing the sensing substrate so that a bottom is located under a cover in a direction of gravity; injecting the detection solution containing therein the retroreflective particles into a fluid channel and maintaining the solution in the channel for a first time duration; turning the sensing substrate upside down so that the bottom is located above the cover in the direction of gravity and maintaining the sensing substrate in the turned state for a second time duration; irradiating light into the fluid channel through the bottom; and generating and analyzing an image based on light retroreflected from the retroreflective particles.

A system and method for electrical label-free detection of single protein molecules via a nanoscale electrode based on detecting the transient potential change of the floating nanoelectrode, which works for both large and small molecules. The system can also be applied to study the interactions of molecules with molecular receptors on the surface of the nanoscale electrode. The motion and dynamics of the protein near the nanoscale electrode can be detected with high precision in real time based on their intrinsic charges by the potentiometric method using a differential amplifier. The nanoelectrode can be integrated into a microfluidic device for biosensing applications.

A method of determining the effect of non-specific interactions in simulated in vivo conditions is presently disclosed. The method includes (a) contacting a solution comprising a biologically relevant molecular crowding agent and a target molecule with a biosensor, wherein the surface of the biosensor comprises a capture molecule that specifically binds the target molecule; (b) allowing the target molecule to bind to the capture molecule; and (c) determining an amount of the target molecule bound to capture molecule using biolayer interferometry.

Articles (e.g., lateral flow assays) and methods for the detection of an analyte are generally described. The assays may involve the use of a network which blocks or restricts flow in the assay, e.g., due to formation of an interconnect network or lattice.

Methods and reagents are disclosed for minimizing a false result in an assay measurement for determining a concentration of an analyte in a sample suspected of containing the analyte. The method comprises pretreating both an antibody and a sample to be subjected to a non-agglutination immunoassay. In the method the antibody and the sample are combined with a pretreatment agent selected from the group consisting of hydroxyphenyl-substituted C1-C5 carboxylic acids and metallic salts thereof and halogen-substituted C1-C5 carboxylic acids and metallic salts thereof in an amount effective to enhance the accuracy of the non-agglutination immunoassay.

Provided herein is a biosensor suitable for use in measuring membrane fluidity or membrane permeability. The biosensor is formed of a solid substrate having a lipid bilayer compatible surface and a multi-lamellar lipid membrane structure localized on the lipid bilayer compatible surface. The multi-lamellar lipid membrane structure can be derived from a biological cell further comprising one or more synthetic lipids. An electrode forming all or part of the lipid bilayer compatible surface may be used to detect disruptions in the lipid membrane structure and hemolytic activity in a test sample.

Disclosed are an immunoassay method capable of highly sensitively measuring amyloid β in a blood sample, and a kit therefor. The immunoassay method for amyloid β is a method of immunoassay of amyloid β in a blood sample, wherein the immunoassay is carried out in the presence of an anionic polymer such as a dextran sulfate salt or a polystyrene sulfonic acid salt. The kit for immunoassay of amyloid β in a blood sample comprises: an anti-amyloid β antibody or an antigen-binding fragment thereof; and an anionic polymer.

Provided, inter alia, are methods and compositions for treating cancer.

A conjugate includes a binding substance having an activity to bind to a target substance and a label causing a detectable phenomenon. A molecular weight of the binding substance is less than a molecular weight of an immunoglobulin.