A Liposome Immunoassay Based on a Chemiluminescense Reaction

Abstract

A new, sensitive immunoassay involving the combination of a liposome immunoassay with chemilluminescence detection is reported. Lysis of the liposomes with cytolysin-hapten conjugates released entrapped glucose oxidase. Chemiluminescence produced by reaction of the enzymatically formed hydrogen peroxide and isoluminol was monitored via an optical fiber and photomultiplier. Without a bound/free separation procedure, this chemical amplification of the immune reaction by liposome lysis and enzymatic reaction allowed detection of 1.7 ng/assay tube of digoxin, the model analyte. When liposome-coated microplates were used to separate intact liposomes from released enzyme, the sensitivity of detection was improved to 165 pg/assay tube.