Particle-based immunoassay using a pegylated analyte-specific binding agent

Abstract

Disclosed is a method for measurement of an analyte in a microparticle-based analyte-specific binding assay, wherein the microparticles are coated with the first partner of a binding pair, the method involving mixing the coated microparticles, an analyte-specific binding agent conjugated to the second partner of the binding pair, and a sample suspected of containing or containing the analyte, wherein the second partner of the binding pair is bound to the analyte-specific binding agent via a linker having from 12 to 30 ethylene glycol units (PEG 12 to 30), thereby binding the analyte via the conjugated analyte-specific binding agent to the coated microparticles, separating the microparticles having the analyte bound via the binding pair and the analyte-specific binding agent from the mixture and measuring the analyte bound to the microparticles.

1 - 12 . (canceled) 
     
     
         13 . A kit comprising in separate containers or in separated compartments of a single container unit at least microparticles coated with a first partner of a binding pair and an analyte-specific binding agent bound to the second partner of said binding pair, wherein said second partner of the binding pair is bound to said analyte-specific binding agent via a linker comprising from 12 to 30 ethylene glycol units. 
     
     
         14 . The kit of  claim 13 , wherein said first partner of a binding pair is selected from the group consisting of avidin and streptavidin, and wherein said second partner of said binding pair is selected from the group consisting of biotin and biotin analogues. 
     
     
         15 . The kit of  claim 13 , further comprising in a separate container or in a separated compartment of a single container unit a second analyte-specific binding agent which is detectably labeled. 
     
     
         16 . The kit of  claim 13 , wherein said microparticles are from 50 nm to 20 μm in diameter. 
     
     
         17 . The kit of  claim 13 , wherein said microparticles are paramagnetic. 
     
     
         18 . The kit of  claim 13 , wherein said analyte-specific binding agent is a polypeptide of at least 50 amino acids. 
     
     
         19 . The kit of  claim 13 , wherein said analyte-specific binding agent is a polypeptide of at most 10,000 amino acids. 
     
     
         20 . The kit of  claim 13 , wherein said analyte-specific binding agent is an antibody or an antigen-binding fragment thereof.