Sienna Biotech, Inc.

Manish S Kochar

W Peter Hansen

Glen M Ford

Michael Cennerazzo

Carl Theodore Edens

James S Steel

John P Huff

Anne J Bodner

Disclosed are an optical flow particle apparatus and method for conducting a particle light scatter-based immunoassay for simultaneously measuring the presence or amount of one or more analytes in a fluid sample which involves the use of a reagent set for each analyte including first binding molecule-coated monodisperse microspheres and second binding molecule-coated colloidal particles in which at least one of the first or second binding molecules specifically binds a respective one of the analytes. In the case where more than one analytes are detected, each monodisperse microperse microsphere of a particular reagent set has a light scatter signal resolvable from that of microspheres of any other reagent set. Changes determined in the distributions of the measured light scatter signals for individual microspheres of each of the particular reagent sets are indicative of the presence or amount of the respective analyte(s) in the sample.

Light scatter-based immunoassay

Disclosed is an assay for determining the presence of at least one analyte in a sample, which involves the steps of: (a) mixing the sample and predetermined amounts of first test microparticles having disposed thereon a binding molecule which binds a first analyte, and inert reference microparticles to form a reaction mixture, and to allow for the first binding molecule to bind the first analyte; b) counting the numbers of the non-reacted first test microparticles and the reference microparticles; and (c) comparing the number of non-reacted first test microparticles to the reference microparticles to thereby establish a first test value so that the presence of the first analyte in the sample may be determined. In a preferred embodiment, the first test value is compared to a control value for a non-reactive sample, and a change value is calculated therefrom. The presence of additional analytes may be determined by adding second test microparticles having disposed thereon a second binding molecule which binds a second analyte, wherein the second test microparticles are resolvable against the first test microparticles and the reference microparticles in the given counting method, and comparing the number of non-reacted second test microparticles to the reference microparticles to establish a second test value. Also disclosed are compositions and kits containing the microparticles.

Assays using reference microparticles

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Columbia, MD, United States of America

Manish S Kochar