LUMINESCENT OXYGEN CHANNELING IMMUNOASSAY - MEASUREMENT OF PARTICLE BINDING-KINETICS BY CHEMILUMINESCENCE

A method for monitoring formation of latex particle pairs by chemilumi nescence is described. Molecular oxygen is excited by a photosensitize r and an antenna dye that are dissolved in one of the particles. (1) D elta(g)O(2) diffuses to the second particle and initiates a high quant um yield chemiluminescent reaction of an olefin that is dissolved in i t. The efficiency of (1) Delta(g)O(2) transfer between particles is ap proximate to 3.5%. The technique permits real-time measurement of part icle binding kinetics. Second-order rate constants increase with the n umber of receptor binding sites on the particles and approach diffusio n control. By using antibody-coated particles, a homogenous immunoassa y capable of detecting approximate to 4 amol of thyroid-stimulating ho rmone in 12 min was demonstrated. Single molecules of analyte produce particle heterodimers that are detected even when no larger aggregates are formed.