Abstract: What has been developed is an improved method of determining the binding constants between two molecules that requires significantly fewer materials and potentially less time (in the case of a whole cell analysis less time to grow cell cultures as fewer cells are required in the same analysis) to undertake. The method involves utilizing an NSB measurement in preferably an n-curve analysis in order to determine the Kd and/or Rt without having to complete actual measurements to determine the lower knee of the curve(s) in the n-curve analysis. Preparing the experiment utilizing the additional samples allows an experiment represented in a binding curve having an upper and a lower knee to no longer be required to run through the lower knee to a point of completion.

Abstract: The present disclosure is directed toward improved methods of conducting a competitive binding assay or experiment. The methodology includes utilizing either a positive control, a negative control, or both in order to scale experimentation results to results that can be utilized to obtain a precise measurement of the kinetic rate constant (the off rate denoted as koff) describing the dissociation of a non-covalent complex such as an antibody antigen complex, receptor ligand complex, etc.

Abstract: The present invention provides an improved system for detecting the presence or level of an analyte in a sample. In “competition-like” assays of the present invention, a sample including an analyte is mixed with a second ligand to which the analyte binds, and the mixture is exposed to a solid phase containing a first ligand that can compete with the analyte for binding to the second ligand. According to the present invention, the time of exposure of the mixture to the solid phase is limited so that substantially no dissociation of analyte/second ligand complex occurs. The competition-like assays of the present invention are preferably performed with a solid phase containing a substantial excess of first ligand. In “sandwich-type” assays of the present invention, a sample including an analyte is contacted with a solid phase including a first ligand that binds the analyte and, simultaneously or subsequently, is contacted with a second ligand that binds the analyte (or the analyte/first ligand complex).

Abstract: The invention comprises methods of detecting the presence or level of an analyte in a sample by detecting the formation of a binding complex on a solid phase.

Abstract: The present invention provides an improved system for detecting the presence or level of an analyte in a sample. In “competition-like” assays of the present invention, a sample including an analyte is mixed with a second ligand to which the analyte binds, and the mixture is exposed to a solid phase containing a first ligand that can compete with the analyte for binding to the second ligand. According to the present invention, the time of exposure of the mixture to the solid phase is limited so that substantially no dissociation of analyte/second ligand complex occurs. The competition-like assays of the present invention are preferably performed with a solid phase containing a substantial excess of first ligand.

Abstract: A system for assaying a fluid sample, typically employing a fluorescent tag, the system comprising a lens capable of focussing both excitation and fluorescent radiation, a fluid-flow conducting conduit being provided in the lens extending transversely of the optical axis of and through the focal region of the latter. One or more mechanical screens are disposed adjacent to the focal region in the conduit to arrest passage of beads as a function of bead diameter. The beads, precoated with at least a moiety of a ligand/conjugate complex, e.g. a specific-binding ligand, are preferably substantially transparent to both the excitation and fluorescent radiation.

Abstract: A system for assaying a fluid sample, typically employing a fluorescent tag, the system comprising a lens capable of focussing both excitation and fluorescent radiation, a fluid-flow conducting conduit being provided in the lens extending transversely of the optical axis of and through the focal region of the latter. One or more mechanical screens are disposed adjacent to the focal region in the conduit to arrest passage of beads as a function of bead diameter. The beads, precoated with at least a moiety of a ligand/conjugate complex, e.g. a specific-binding ligand, are preferably substantially transparent to both the excitation and fluorescent radiation.

Abstract: A system for assaying a fluid sample, typically employing a fluorescent tag, the system comprising a lens capable of focussing both excitation and fluorescent radiation, a fluid-flow conducting conduit being provided in the lens extending transversely of the optical axis of and through the focal region of the latter. One or more mechanical screens are disposed adjacent the focal region in the conduit to arrest passage of beads as a function of bead diameter. The beads, precoated with at least a moiety of a ligand/conjugate complex, e.g. a specific-binding ligand, are preferably substantially transparent to both the excitation and fluorescent radiation.

Abstract: A hand press which includes a first lever arm having adjacent one end thereof a hollow receptacle having one end opened, the other end covered by a perforated screen, and a second lever arm pivotally mounted at the one end of the first lever arm. A piston is fixededly positioned on the second arm for insertion into the open end of the receptacle, the receptacle typically being shaped as a toroidal segment having its axis of elongation conforming to an arc having a mean radius of curvature defined by the distance between the pivot point and the center of the face of the piston. The periphery of the piston face is provided with a ring to insure a tight sliding fit of the piston in the receptacle.

Abstract: An assay apparatus employing total internal reflection of excitation radiation at the interface between a replaceable optically conductive assay device and a surrounding liquid phase containing the substance being assayed. The assay device is formed of a radiation transmissive, elongated fiber having on the surface thereof a component of a complex formed in an immunological-type specific reaction. A fluorophore that can be excited into fluorescence by the excitation radiation is attached to another component of the complex. The assay device also includes a boss formed of a similarly radiation transmissive material with an index of refraction preferably matched to that of the fiber, one end of the fiber being fixedly coupled to the boss. The boss is dimensioned so that the maximum solid acceptance angle for excitation radiation introduced into the fiber end lies totally within the transmissive medium of said boss.

Abstract: An assay apparatus employing total internal reflection of excitation radiation at the interface between a replaceable 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 immunological-type specific reaction. A fluorophore that can be excited into fluorescence by the excitation radiation is attached to another component of the complex. The rod is coaxially mounted within a tube that is sized with respect to said rod so that a fluid sample may be introduced into said tube.The rod and tubing are supported in a mounting assembly that is attachable to an optical assembly for transmitting excitation radiation into the proximal end of the rod and receiving fluorescent radiation emitted from the proximal end of the rod. Included in the apparatus is a mounting assembly for centering the rod within tube and for biasing the rod in a first direction against an annular seat.