USE OF A QUARTZ-CRYSTAL MICROBALANCE TO MONITOR IMMUNOLIPOSOME-ANTIGEN INTERACTION

We have used quartz crystal microbalance (QCM)-based real-time biospec ific interaction measurement to analyze the binding of immunoliposomes to antigen and examined the use of liposomes as signal-enhancing reag ents in competitive QCM immunoassay. For the preparation of immunolipo somes, various amounts of bacterially induced lipid-tagged single-chai n antibody against 2-phenyloxazolone were incorporated in phosphatidyl choline liposomes. The immunoliposomes bound specifically to immobiliz ed hapten, and this binding was inhibited by soluble hapten in a conce ntration-dependent manner. In this competitive assay, antigen could be measured in the concentration range from 10(-5) to 10(-8) M.