Surface plasmon resonance immunosensor for the detection of Salmonella typhimurium.
An immunosensor based on surface plasmon resonance (SPR) using protein G was developed for the detection of Salmonella typhimurium. A protein G layer was fabricated by binding chemically to self-assembly monolayer (SAM) of 11-mercaptoundecanoic acid (MUA) on gold (Au) surface. The formation of protein G layer on Au surface modified with 11-MUA and the binding of antibody and antigen in series were confirmed by SPR spectroscopy. The effect of detergent such as Tween-20 on binding efficiency of antibody and antigen was investigated by SPR. The binding efficiency of antigen to the antibody immobilized on Au surface was improved up to about 85% and 100% by using protein G and Tween-20, respectively. The surface morphology analyses of 11-MUA monolayer on Au substrate, protein G layer on 11-MUA monolayer and antibody layer immobilized on protein G layer were performed by atomic force microscope (AFM). Consequently, an immunosensor based on SPR for the detection of S. typhimurium using protein G was developed with a detection range of 10(2) to 10(9)CFU/ml. The current fabrication technique of a SPR immunosensor for the detection of S. typhimurium could be applied to construct other immnosensors or protein chips.
Oh
Byung-Keun
BK
Department of Chemical and Biomolecular Engineering, Sogang University, 1 Shinsu-dong, Mapo-gu, Seoul 121-742, South Korea.
Kim
Young-Kee
YK
Park
Kwang Won
KW
Lee
Won Hong
WH
Choi
Jeong-Woo
JW
D006046:Gold; D018625:Microscopy, Atomic Force; D009419:Nerve Tissue Proteins; D012486:Salmonella typhimurium / Q000276:immunology / Q000302:isolation & purification*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
C029152:G-substrate; D009419:Nerve Tissue Proteins; D006046:Gold