| 摘要 |
<p>An assay apparatus employing total internal reflection of excitation radiation at the interface between an optically conductive rod or fiber and a surrounding liquid phase of lower index of refraction. Immobilized on the surface of the fiber is a component of a complex formed in an immunochemical-type reaction; a fluorophore that can be excited into fluorescence by the excitation radiation is attached to another component of the complex. The fiber is coaxially mounted in cantilevered position within a length of tubing, so that the excitation radiation can be launched into the unsupported end of the fiber and the fluorescent radiation tunneling back into the fiber may be observed at the same fiber end. To insure that the portion of the fiber surface between the unsupported fiber end and the mounted end is in contact with only surrounding liquid phase, one end of the tubing is provided with a covering having an aperture therein through which at least the unsupported end of the fiber extends, the clearance between the internal periphery of the aperture and the fiber being of capillary dimensions so that the meniscus formed at such clearance will retain fluid in the interspace between the fiber and tube.</p> |
