Fluorescent immunoassay employing optical fiber in capillary tube

Claim 1

Apparatus for performing immunoassays using an antigen-antibody complex incorporating a fluorescent tag capable of emitting fluorescent radiation when excited by exciting radiation, said apparatus comprising in combination: an optical fiber transmissive to both said exciting radiation and said fluorescent radiation; a coating on at least a portion of said fiber, said coating having a plurality of sites, each being capable of having attached thereto a selected moiety of said antigen-antibody complex so as to leave substantially unaffected the activity of said selected moiety for forming said antigen-antibody complex; and means for controlling a volume of capillary dimensions bounded by said portion of said fiber.

Claim 17

A method for immunoassay employing an optical element transmissive to excitation radiation which can excite fluorescence of a fluorescent tag included as a constituent of an antigen-antibody complex, said element being also transmissive to said fluorescence, said optical element having selected moieties of said antibody-antigen complex attached to a pre-determined area of its surface, said method comprising the steps of: immersing said optical element in a fluid sample to be assayed so that the portion of said sample immunologically reactive with said selected moieties can react therewith to form said complex; controlling the immersion of said optical element in said fluid sample so as to insure that said predetermined area is completely covered with a layer of known thickness of said fluid sample; incubating said optical element in said layer of fluid sample for a time in excess of the time required for diffusional processes to scavenge the volume of sample defined by said known area and said known thickness; illuminating said optical element with an evanescent electromagnetic wave of said excitation radiation so as to excite fluorescence of said tag in said complex attached to said optical element; and measuring the intensity of said fluorescence.

Claim 18

A method for immunoassay employing an optical element transmissive to excitation radiation which can excite fluorescence of a fluorescent tag included as a constituent of an antigen-antibody complex, said element being also transmissive to said fluorescence, said optical element having selected moieties of said antibody-antigen complex attached to a pre-determined area of its surface, said method comprising the steps of: immersing said optical element in a fluid sample to be assayed so that the portion of said sample immunologically reactive with said selected moieties can react therewith to form said complex; controlling the immersion of said optical element in said fluid sample so as to insure that said predetermined area is completely covered with a layer of known thickness of said fluid sample; incubating said optical element in said layer of fluid sample for a time in excess of the time required for diffusional processes to scavenge the volume of sample defined by said known area and said known thickness; illuminating said optical element with an evanescent electromagnetic wave of said excitation radiation so as to excite fluorescence of said tag in said complex attached to said optical element; and measuring the intensity of said fluorescence.