title: Construction of electrochemical flow immunoassay system using capillary columns and ferrocene conjugated immunoglobulin G for detection of human chorionic gonadotrophin.
abstract: In this paper is reported a miniaturized flow immunoassay system. Ferrocenecarboxylic acid (Fc) conjugated with anti-HCG immunoglobulin G (IgG) antibody (Fc-IgG) was prepared, and used as a novel analytical reagent. The system consists of the immunoreaction section, the capillary column packed with cation exchange resin, and the flow cell for electrochemical detection of Fc-IgG. Antibody-antigen complexes were separated from their free conjugate on the basis of differences in isoelectric point (pI) using a cation exchange capillary column. The assay yielded a linear relationship between signal and HCG concentration in the range 0-2000 mIU/ml. This simple technique enables the assay of HCG within 2 min. The cation exchange capillary column was regenerated by occasional elution with malonate buffer (pH 6.0) containing 0.5 M NaCl, to remove free conjugate. Free conjugate recovered in this manner could be reused up to eight times without significant decreases in the sensitivity of the immunoassay. This electrochemical flow immunoassay requires only minute quantities of serum and generates highly reproducible results.
authors.affiliation: Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
authors.forename: T K
authors.initials: TK
authors.lastname: Lim
authors.forename: T
authors.initials: T
authors.lastname: Matsunaga
mesh_terms: D000936:Antigen-Antibody Complex / Q000302:isolation & purification; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods / Q000706:statistics & numerical data; D006063:Chorionic Gonadotropin / Q000032:analysis* / Q000276:immunology; D002852:Chromatography, Ion Exchange / Q000295:instrumentation / Q000379:methods; D004563:Electrochemistry; D005296:Ferrous Compounds; D017022:Flow Injection Analysis / Q000295:instrumentation / Q000379:methods; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods / Q000706:statistics & numerical data; D007074:Immunoglobulin G; D000075163:Metallocenes; D008904:Miniaturization; D012680:Sensitivity and Specificity
chemical_list: D000936:Antigen-Antibody Complex; D006063:Chorionic Gonadotropin; D005296:Ferrous Compounds; D007074:Immunoglobulin G; D000075163:Metallocenes; C004998:ferrocene