AN ADVANCED SOLID SUPPORT FOR IMMUNOASSAYS AND OTHER AFFINITY APPLICATIONS

A 6-mm diameter glass bead that has a hydrophilic coating containing e poxy groups has been developed for immunoassays and other affinity app lications. These QuantAffinity(TM) beads covalently bind protein in th e range of 200-400 ng per bead. Derivatization with protein in the pre sence of high concentrations of potassium phosphate (pH 7.0-8.0) gener ally gives complete coupling in 16 hours. No preactivation of the supp ort or the protein is necessary. Low nonspecific binding and high rete ntion of bound protein activity are inherent in the system due to the special surface chemistry. Several enzymatic and radioactive immunoass ays as well as a biotin-avidin-based assay are described A use of Quan tAffinity beads in small-scale purification is also presented