Polyvinylamine-streptavidin complexes labeled with a europium chelator: A universal detection reagent for solid-phase time resolved fluorometric applications

Objectives: To describe the synthesis and characteristics of a new streptav idin-based universal detection reagent which is multiply labeled with the e uropium chelate of 4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicar boxylic-acid (BCPDA). Methods and results: Polyvinylamine (PVA) was first labeled with biotin(b) and then with BGPDA to create (b)(x)-PVA-(BCCDA)(y). By mixing controlled a mounts of this complex with streptavidin (SA) and a fixed amount of Eu3+, W e were able to produce the conjugate (SA)(z)-(b)(x)-PVA(BCPDA)(y)-Eu3+. Thi s conjugate is reactive, highly fluorescent, and stable for at least 12 mon ths. It was used to develop model solid-phase time-resolved fluoroimmunoass ays for biotinylated mouse IgG and prostate spesific antigen (PSA). Detecti on limits achieved were around 1 to 2 ng/L (similar to 3x10(-18) moles/assa y). Conclusions: A new universal detection reagent was synthesized, which can b e used in combination with biotinylated reagents (e.g., antibodies, DNA pro bes, etc.) for the development of highly sensitive solid-phase time-resolve d fluorescence-based assays. Copyright (C) 2000 The Canadian Society of Cli nical Chemists.