title: Development of fluorescence change-based, reagent-less optic immunosensor.
abstract: A reagent-less, regenerable and portable optic immunosensor was developed. A model sample, immunoglobulin G (IgG), was detected with this system based on changes in fluorescent intensity of fluorescent labeled protein A with specific reactivity to IgG depending on a reaction between the proteins. A glass plate immobilized with Qdot-labeled protein A was placed on the top of optic fibers designed for both excitation and fluorescence emission. The optic fibers with the Qdot-labeled protein A-immobilized glass plate were inserted into a solution of pH 7.4 phosphate buffered saline. After stabilization of the fluorescence intensity, IgG was added and the time-course of the fluorescence intensity was measured on a fluorometer connected with the optic fibers. Furthermore, the fluorescence response of a transient state was evaluated with the same system. When the Qdot-labeled protein A bound to IgG, fluorescence intensity decreased because of the inhibition by IgG. The degree of fluorescence decrease depends on the IgG concentration at a steady state and also in a transient state.
authors.affiliation: Department of Applied Physics, Seikei University, 3-3-1, Kichijoji-kitamachi, Musashino-shi, Tokyo 180-8633, Japan.
authors.forename: Satoka
authors.initials: S
authors.lastname: Aoyagi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kudo
mesh_terms: D000936:Antigen-Antibody Complex / Q000032:analysis / Q000276:immunology; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D016231:Fluorescence Polarization Immunoassay / Q000295:instrumentation* / Q000379:methods; D007074:Immunoglobulin G / Q000032:analysis* / Q000276:immunology; D007202:Indicators and Reagents; D045663:Quantum Dots; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013205:Staphylococcal Protein A / Q000032:analysis* / Q000276:immunology
chemical_list: D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D007202:Indicators and Reagents; D013205:Staphylococcal Protein A