Massachusetts Institute of Technology

Ohio Aerospace Institute

David S Cannell

Richard J Cohen

George B Benedek

Anthony E Smart

William V Meyer

Marzio Giglio

Gustav K Von Schulthess

H Michael Cheung

J Adin Mann, Jr

Thomas W Taylor

James A Lock

Padetha Tin

Jixiang Zhu

A method and apparatus for analyzing a fluid containing light scattering components. The apparatus includes a laser adapted to direct abeam of light into the fluid such as a liquid containing particles, and at least two detectors to receive light scattered by the fluid, which received light is used to calculate a physical property of the fluid. A focusing lens may be used to focus the light beam to a focal waist in the fluid to enhance the degree of spatial coherence of the scattered light. The two detectors are aligned onto the focal waist and are adapted to send a signal to a data processor which correlates the signal received from said two detectors. The two detectors are spaced a substantially equal distance from the focal waist and are oriented at substantially the same angle with respect to the direction of propagation of the incident beam. The data processor is adapted to cross-correlate the signals received from the two detectors. A polarizer can be positioned between the focal waist and the two detectors to aid in positioning the detectors and to enhance the efficiency and speed of the measurement.

Cross-correlation method and apparatus for suppressing the effects of

Method and apparatus for determining the concentration of any of a wide range of antigen or antibody molecules with a high degree of specificity, accuracy and sensitivity. Antigen or antibody concentration is determined by effecting an agglutination reaction between carrier particles in a liquid medium, exposing the liquid medium to a beam of light, and measuring the ratio of the intensities of light scattered at two different angles as a function of antigen or antibody concentration. The unknown concentration of antibody or antigen is determined by comparison with similar measurements of the anisotropy ratio using known concentrations of the molecule being tested for. The agglutination reaction is performed using carrier particles coated with an agglutinant. The carrier particles should be fairly uniform in size and their diameter can be less than or comparable to the wavelength of light. By this invention, one may specifically ascertain the absolute concentration of the antigen or antibody in question in the sample being analyzed. In addition to detecting antigen or antibody molecules, the process of this invention can be used to determine the concentration of any substance capable of specifically promoting or inhibiting an agglutination reaction.

Immunoassay by light scattering intensity anisotropy measurements

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Santa Barbara, CA, United States of America

David S Cannell