title: A quantitative diffraction-based sandwich immunoassay.
abstract: It is shown that diffraction-based sensing can be enhanced for diagnostic purposes through the use of a secondary label. The limit of detection for anti-rabbit IgG was reduced more than 40-fold by using a gold-conjugated secondary antibody. The response to secondary antibody binding was linear for concentrations from 25 to 500 ng/ml of anti-rabbit IgG, suggesting that quantitative determinations can be readily done. Moreover, the binding of the secondary antibody was observed as soon as 1 min after its introduction to the surface-bound primary complex.
authors.affiliation: Axela Biosensors, Inc., 8th Floor, 1 Richmond Street West, Toronto, Canada M5H 3W4.
authors.forename: Jane B
authors.initials: JB
authors.lastname: Goh
authors.forename: Pui L
authors.initials: PL
authors.lastname: Tam
authors.forename: Richard W
authors.initials: RW
authors.lastname: Loo
authors.forename: M
authors.initials: M
authors.lastname: Cynthia Goh
mesh_terms: D000818:Animals; D000906:Antibodies / Q000378:metabolism; D000918:Antibody Specificity; D006046:Gold / Q000737:chemistry; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods*; D007074:Immunoglobulin G / Q000032:analysis*; D016014:Linear Models; D051379:Mice; D055095:Optics and Photonics; D011485:Protein Binding; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000906:Antibodies; D007074:Immunoglobulin G; D006046:Gold