title: Miniaturized amperometric flow immunoassay system using a glass fiber membrane modified with anion.
abstract: This paper describes a miniaturized amperometric flow immunoassay system using a glass fiber membrane modified with anion. The glass fiber membrane was functionally modified with gamma-glycidoxypropyltrimethoxysilane and sodium thiosulfate and was used for separation of protein. Anti-human chorionic gonadotrophin (HCG) immunoglobulin G (IgG) antibody conjugated with ferrocenemonocarboxylic acid (Fc), namely, Fc-conjugated IgG (Fc-IgG), was used as a novel analytical reagent. HCG and Fc-IgG complexes were separated from free Fc-IgG based on differences in isoelectric point (pI) using the glass fiber membrane modified with a thiosulfonyl acid functional group. The assay yields a linear relationship between current and HCG concentration in the range of 0-2000 mIU/mL. This simple technique enables the assay of HCG within 2 min. The modified glass fiber membrane was regenerated by occasional elution with malonate buffer (pH 6.0) containing 0.5 M NaCl, to remove free Fc-IgG. Free Fc-IgG recovered in this manner could be reused up to eight times without significant decreases in sensitivity. This miniaturized amperometric 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: Tae-Kyu
authors.initials: TK
authors.lastname: Lim
authors.forename: Satoko
authors.initials: S
authors.lastname: Imai
authors.forename: Tadashi
authors.initials: T
authors.lastname: Matsunaga
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex / Q000032:analysis; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002417:Cattle; D006063:Chorionic Gonadotropin / Q000032:analysis*; D002852:Chromatography, Ion Exchange / Q000295:instrumentation*; D004563:Electrochemistry / Q000379:methods*; D005296:Ferrous Compounds / Q000737:chemistry; D017022:Flow Injection Analysis / Q000295:instrumentation / Q000379:methods; D005898:Glass / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D007074:Immunoglobulin G / Q000737:chemistry; D007525:Isoelectric Focusing / Q000379:methods; D008566:Membranes / Q000737:chemistry*; D000075163:Metallocenes; D012710:Serum Albumin, Bovine / Q000032:analysis; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D006063:Chorionic Gonadotropin; D005296:Ferrous Compounds; D007074:Immunoglobulin G; D000075163:Metallocenes; C032949:ferrocenecarboxylic acid; D012710:Serum Albumin, Bovine