COMPARISON OF LIPOSOME AMPLIFICATION AND FLUOROPHOR DETECTION IN FLOW-INJECTION IMMUNOANALYSES

A flow-injection liposome immunoanalysis (FILIA) system was developed for the measurement of imazethapyr herbicide. The liposome is a spheri cal vesicle encapsulating many marker molecules in an aqueous interior . By incorporating analyte-phospholipid conjugates into the bilayer, t he liposome can competitively bind to anti-analyte antibody, immobiliz ed in the immunoreactor column of the FILIA system. In this study, the analyte-tagged liposome containing a fluorescent dye, ng carboxyfluor escein, was compared to a single fluorophor-tagged analyte used for th e generation of the analytical signal. The liposome enhanced sensitivi ty by 1000-fold compared to the single fluorescent molecule-tagged ana lyte. This is the first report to demonstrate directly the amplificati on of the response by liposomes in a flow-injection immunoassay. (C) 1 997 Elsevier Science B.V.