title: Peptide-coated nanotube-based biosensor for the detection of disease-specific autoantibodies in human serum.
abstract: We demonstrate a label-free peptide-coated carbon nanotube-based immunosensor for the direct assay of human serum. A rheumatoid arthritis (RA)-specific (cyclic citrulline-containing) peptide, was immobilized to functionalized single-walled carbon nanotubes deposited on a quartz crystal microbalance (QCM) sensing crystal. Serum from RA patients was used to probe these nanotube-based sensors, and antibody binding was detected by QCM sensing. Specific antibody binding was also determined by comparing the assay of two serum control groups (normal and diseased sera), and the native unmodified peptide. The sensitivity of the nanotube-based sensor (detection in the femtomol range) was higher than that of the established ELISA and recently described microarray assay systems, detecting 34.4 and 37.5% more RA patients with anti-citrullinated peptide antibodies than those found by ELISA and microarray, respectively. There was also an 18.4 and 19.6% greater chance of a negative test being a true indicator of a person not having RA than by either ELISA or microarray, respectively. The performance of our label-free biosensor enables its application in the direct assay of sera in research and diagnostics.
authors.affiliation: Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA. drouvaka@cmgm.stanford.edu
authors.forename: Katerina A
authors.initials: KA
authors.lastname: Drouvalakis
authors.forename: Sarunya
authors.initials: S
authors.lastname: Bangsaruntip
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hueber
authors.forename: Leland G
authors.initials: LG
authors.lastname: Kozar
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Utz
authors.forename: Hongjie
authors.initials: H
authors.lastname: Dai
mesh_terms: D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000175:diagnosis*; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D001774:Blood Chemical Analysis / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods; D043942:Nanotubes / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry* / Q000276:immunology
chemical_list: D001323:Autoantibodies; D010455:Peptides