Planar waveguide immunosensor with fluorescent liposome amplification

Medium binding antibodies may be recycled to extend the utility of planar waveguide immunosensor for theophylline. Regeneration is done by flowing antigen-free buffer over the antigen-antibody complex for more than 10 half-lives of the dissociation rate constant. One sensor may be used for more than 15 cycles without serious degradation. The use of theophylline-tagged liposomes further enhances the utility of the immunoassay technique by amplifying its signals.