ASSAY TECHNIQUE AND EQUIPMENT

摘要

An article and a technique for the assay of biochemical, biological or chemical species. In essence, the article is a substrate (10) carrying a surface relief profile (12) such as a regular sinusoidal grating. There is usually a metal layer (13) e.g. of silver or aluminium conforming to the relief profile. An inorganic oxide layer (14) may coat the metal layer (13). A further layer of a dye-tagged material (17) which is capable of binding the species undergoing assay is bonded to the structure. In use, the grating interacts with the fluorochrome by increasing absorption sensitivity and by regulating fluorescent emission into a narrow cone of angles instead of there being uniform emission in all directions. The presence of bound molecules e.g. antibodies (18) on a layer of dye-tagged antigen (17) affects the fluorescent behaviour of the system, which can be arranged to act as fluorescent activating on binding, or fluorescent inhibiting on binding of assayed species. The fluorescent intensity or the lifetime of the fluorescent state may be measured before and after binding in order to monittor or measure the species undergoing assay. In the preferred case, fluorescence is either quenched before binding of said species and activated after binding thereof, or vice versa. Also, the analyte may be dye-tagged (by conventional techniques) rather than the layer of binding material (17). The technique is well-suited to liquid phase fluorescent immuno-assay.