title: Signal enhancement of surface plasmon resonance based immunosensor using gold nanoparticle-antibody complex for beta-amyloid (1-40) detection.
abstract: Numerous studies have indentified that beta-amyloid (1-40) in cerebrospinal fluid as a potential biomarker for Alzheimer's disease. In order for early detection of the Alzheimer's disease, an ultrasensitive diagnostic tool is required. In this study, an ultrasensitive surface plasmon resonance (SPR) based immunosensor for beta3-amyloid (1-40) was developed and its signal enhanced (1-40) with a gold (Au) nanoparticle-antibody complex. Antibodies to beta3-amyloid (1-40) were immobilized on the Au surface leading to a highly efficient immunoreaction due to the fact the paratope of the antibody faced in the opposite direction to the solid surface. The surface morphology of the bio-surface was investigated by using scanning tunneling microscopy (STM). The binding process of antibody fragments to the Au surface, target analytes, and Au nanoparticle-antibody complexes were monitored using SPR. The plot of SPR angle difference versus beta3-amyloid (1-40) concentration shows a linear correlation over a concentration range of nine orders of magnitude, having a detetion limit up to 1 fg/ml.
authors.affiliation: Department of Chemical and Biomolecular Engineering,Sogang University, #1 Shin-su, Mapo-gu, Seoul 121-742, Republic of Korea.
authors.forename: Jin-Ho
authors.initials: JH
authors.lastname: Lee
authors.forename: Da-Yeon
authors.initials: DY
authors.lastname: Kang
authors.forename: Taek
authors.initials: T
authors.lastname: Lee
authors.forename: Sang-Uk
authors.initials: SU
authors.lastname: Kim
authors.forename: Byung-Keun
authors.initials: BK
authors.lastname: Oh
authors.forename: Jeong-Woo
authors.initials: JW
authors.lastname: Choil
mesh_terms: D016229:Amyloid beta-Peptides / Q000032:analysis*; D000911:Antibodies, Monoclonal / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D007118:Immunoassay / Q000295:instrumentation*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010446:Peptide Fragments / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D016229:Amyloid beta-Peptides; D000911:Antibodies, Monoclonal; D010446:Peptide Fragments; C078592:amyloid beta-protein (1-40); D006046:Gold