KINETIC MODELING AND ANALYSIS OF A VESICLE SYSTEM FOR IMMUNOSENSOR DEVELOPMENT

A novel mechanism is presented for immunosensor development that uses an immunological competition reaction in a vesicle system. This system consists of a suspension of reconstituted vesicles, channel agonist, protein linker to block the channels, voltage sensitive dye and analyt e to be detected. In the proposed mechanism analyte serves a catalytic role as individual analytes competitively displace multiple channel l inkers through association with one channel, dissociation and new asso ciations with other channels. When one channel opens on a vesicle a pe rmanent Nernst potential develops for that vesicle leading to fluoresc ence of voltage sensitive dyes. The time constant of the redistributio n from linker-channel form to analyte-channel form is 0.92/k(4) (k(4) is the off-rate constant for the analyte-channel association) in the r egion of analyte concentrations less than 10(-9) M. Kinetic analyses s how that several factors, including concentration of analyte or linker , number of channels per vesicle, on-rate or off-rate constant of the linker-channel and on-rate constant of analyte-channel complexes have significant effects on the minimum signal response time. (C) 1996 Else vier Science Limited