Kinetic modeling and analysis of a vesicle system for immunosensor development

• Published in: Biosensors & bioelectronics 1997, Vol.12 (2), p.135-144
• Main Authors: Yu, Yong-Yi, Van Wie, Bernard J., Koch, Alan R., Moffett, David F., Davis, William C.
• Format: Article
• Language: English
• Subjects: antibody-antigen binding kinetics; Antigen-Antibody Reactions; Biological and medical sciences; Biosensing Techniques; Biosensors; Biotechnology; Fundamental and applied biological sciences. Psychology; Humans; immunosensors; Kinetics; Methods. Procedures. Technologies; Models, Biological; off-rate constants; on-rate constants; protein linker; receptor channels; reconstituted vesicles; Various methods and equipments
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/S0956-5663(97)87059-5

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 analyte to be detected. In the proposed mechanism analyte serves a catalytic role as individual analytes competitively displace multiple channel linkers through association with one channel, dissociation and new associations with other channels. When one channel opens on a vesicle a permanent Nernst potential develops for that vesicle leading to fluorescence of voltage sensitive dyes. The time constant of the redistribution 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 region of analyte concentrations less than 10 −9 M. Kinetic analyses show 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.