The effect of fluorescence enhancing/quenching of the water-soluble fluorescent conjugated polymer poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene] (MPS-PPV) by Hantavirus antibody-L133/antigen-EHF, the specific interaction between the antibody-L133 and its antigen—EHF and the change of fluorescence intensity of MPS-PPV before and after their interaction, a new class of highly sensitive homogenous immunoassay method was set up based on reversible fluorescence quenching in a water-soluble fluorescent conjugated polymer. Hantavirus antigen-EHF was detected with the novel rapid and sensitive method. The linear range and detection limit were 4.8×10^－9～5.0×10^－8 mol/L and 1.7×10^－9 mol/L respectively. It was found that the enhancement or quenching fluorescence intensity of the polymer was not only caused by the electrostatic interaction, but also by the change of the conformation of the polymer as a result of the biomolecules.

Key words: water-soluble fluorescent conjugated polymer, MPS-PPV, fluorescence, hantavirus, biosensor