Liposome immunoassay by long-lived fluorescence detection.
Immunoassay by fluorescence energy transfer from a europium chelate in liposome to allophycocyanin (APC) was demonstrated. Streptavidin or antibody to biotin was bonded to the liposome containing the europium chelate of 2-naphthoyltrifluoroacetone in the bilayer. When the biotin bonded to APC (APC-BT) was added to the prepared liposomes and the long-lived fluorescence (lambda ex 336 nm, lambda em 665 nm, delay time 0.05 ms, gate time 3.9 ms) was measured by a flow system, the fluorescence energy of the europium chelate was found to be transferred to APC-BT and the long-lived fluorescence intensity to increase linearly as the concentration of APC-BT (1-10 micrograms ml-1) increased. Further, the intensity decreased competitively with the concentration of biotin (0.1-100 microM) when biotin was added to the liposome solution containing a constant concentration of APC-BT.
Okabayashi
Y
Y
Shionogi Research Laboratories, Shionogi & Company, Ltd., Fukushima-ku, Osaka, Japan.
Ikeuchi
I
I
D000818:Animals; D000906:Antibodies; D001710:Biotin / Q000032:analysis / Q000276:immunology; D004735:Energy Transfer; D005063:Europium; D005470:Fluorometry; D007118:Immunoassay / Q000379:methods*; D008081:Liposomes; D010798:Phycocyanin
D000906:Antibodies; D008081:Liposomes; C002497:allophycocyanin; D010798:Phycocyanin; D005063:Europium; D001710:Biotin