Surface plasmon resonance-based trace detection of small molecules by competitive and signal enhancement immunoreaction.
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.
Aizawa
Hidenobu
H
National Institute of Advanced Industrial Science & Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
Tozuka
Mitsuhiro
M
Kurosawa
Shigeru
S
Kobayashi
Koichi
K
Reddy
Subrayal M
SM
Higuchi
Masahiro
M
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
D000911:Antibodies, Monoclonal; D000941:Antigens; D012710:Serum Albumin, Bovine; D019297:2,4-Dinitrophenol