The present invention relates to a composition for target substance detection using a magnetic nanoparticle having a Curie temperature which is within a biocompatible temperature range, a target substance detection system, and a method for obtaining an image of a living body or specimen. As the magnetic nanoparticle of the present invention has a Curie temperature within the temperature range of 0 C. to 41 C., the ferromagnetic and paramagnetic properties of the magnetic nanoparticle may be controlled within a biocompatible temperature range at a temperature at which a biological control agent is not destroyed, and the temperature of the magnetic nanoparticle is adjusted to control the magnetic properties thereof such that the properties of the magnetic nanoparticle may be used only when ferromagnetic properties are required, such as in the case of signal amplification in detecting, separating, and delivering biological control agents. Accordingly, the present invention can provide a biological substance detection system which satisfies both a decrease in non-specific binding and signal amplification using a magnetic nanoparticle having a Curie temperature which is within a biocompatible temperature range, and can be reused after detection.

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 protein suspended or dissolved in a liquid medium is reversibly altered by exposing the protein to an oxidizing agent or an electric current. A masked protein such as an autoantibody can be detected, isolated and recovered from a biological fluid by subjecting the biological fluid to an oxidizing agent or an electric current to change the binding specificity of masked proteins contained therein.

Herein is reported a method for determining the binding affinity of the binding sites of a bivalent full length antibody of the human IgG1 subclass to a homo-multimeric antigen comprising the steps of i) incubating a mixture comprising the antibody and a polypeptide that is derived from lysine-gingipain of Porphyromonas gingivalis at a pH of from pH 7.5 to pH 8.5, in the presence of a reducing agent, at a temperature of from 30 C. to 42 C., for time of from 10 min. to 240 min. to cleave the antibody into Fabs and Fc-region, and ii) determining the binding affinity of the Fabs of the antibody for its antigen using a surface plasmon resonance method by directly applying the incubated reaction mixture obtained in the previous step in the surface plasmon resonance method and therewith determining the binding affinity of the binding sites of the bivalent full length antibody of the human IgG1 subclass.

Described herein are methods, compositions, kits, and systems for detecting free and bound PlGF, and using detection of such species to distinguish between pregnant women with or without preeclampsia or related conditions.