immunochromatografiset

Immunochromatography is a form of chromatography that uses antibodies to detect and quantify specific analytes. It is a rapid and simple technique, often used in point-of-care diagnostics. The principle relies on the specific binding between an antigen and its corresponding antibody.

In a typical immunochromatographic assay, a sample containing the analyte is applied to a porous membrane. This membrane is usually a nitrocellulose or related material. A liquid buffer then carries the sample along the membrane via capillary action. Labeled antibodies, often conjugated to colored nanoparticles (like gold or latex beads), are immobilized at a specific location on the membrane. If the target analyte is present in the sample, it binds to these labeled antibodies.

As the liquid continues to move, the complex of analyte and labeled antibody encounters a second line of immobilized antibodies, which are also specific for the analyte. This second antibody captures the analyte-antibody complex, forming a visible line. In some formats, a control line is also present, which contains antibodies that capture unbound labeled antibodies, ensuring the test has run correctly. The intensity of the visible line can be qualitatively or quantitatively correlated to the amount of analyte present. Immunochromatographic tests are widely used for pregnancy tests, infectious disease detection, and drug screening due to their speed, low cost, and ease of use.