title: Surface plasmon resonance-based trace detection of small molecules by competitive and signal enhancement immunoreaction.
abstract: A surface plasmon resonance (SPR)-immunosensor for detection of the low molecular weight compound 2,4-dinitorophenol (DNP) at ultra-low concentration has been developed. The sensor strategy is based on a competitive immunoreaction between DNP and a DNP-protein conjugate, namely DNP-bovine serum albumin conjugate (DNP-BSA). Anti-DNP monoclonal antibody was immobilized on a gold thin-film coated SPR-sensor chip by means of a chemical coupling process. DNP-BSA, on contact with the anti-DNP antibody immobilized SPR-immunosensor chip causes an increase in the resonance angle of the sensor chip. The optimum concentration of immobilized antibody on the SPR-sensor chip is 100 microg mL(-1). The SPR-immunosensor response for free DNP determination using the competitive immunoreaction had a response time of ca. 15 min. Using this method, DNP could be determined in the concentration range 1 ppt to 1 ppb. The SPR signal for ppt levels of DNP was enhanced by a factor of three by subsequently treating immuno-bound DNP-BSA with a secondary anti-DNP antibody.
authors.affiliation: National Institute of Advanced Industrial Science & Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Aizawa
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Tozuka
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kurosawa
authors.forename: Koichi
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Subrayal M
authors.initials: SM
authors.lastname: Reddy
authors.forename: Masahiro
authors.initials: M
authors.lastname: Higuchi
mesh_terms: D019297:2,4-Dinitrophenol / Q000032:analysis* / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D000941:Antigens / Q000276:immunology; D007118:Immunoassay; D012710:Serum Albumin, Bovine / Q000276:immunology; D020349:Surface Plasmon Resonance / Q000379:methods
chemical_list: D000911:Antibodies, Monoclonal; D000941:Antigens; D012710:Serum Albumin, Bovine; D019297:2,4-Dinitrophenol