title: Carbon nanotube amplification strategies for highly sensitive immunodetection of cancer biomarkers.
abstract: We describe herein the combination of electrochemical immunosensors using single-wall carbon nanotube (SWNT) forest platforms with multi-label secondary antibody-nanotube bioconjugates for highly sensitive detection of a cancer biomarker in serum and tissue lysates. Greatly amplified sensitivity was attained by using bioconjugates featuring horseradish peroxidase (HRP) labels and secondary antibodies (Ab(2)) linked to carbon nanotubes (CNT) at high HRP/Ab(2) ratio. This approach provided a detection limit of 4 pg mL(-)(1) (100 amol mL(-)(1)), for prostate specific antigen (PSA) in 10 microL of undiluted calf serum, a mass detection limit of 40 fg. Accurate detection of PSA in human serum samples was demonstrated by comparison to standard ELISA assays. PSA was quantitatively measured in prostate tissue samples for which PSA could not be differentiated by the gold standard immunohistochemical staining method. These easily fabricated SWNT immunosensors show excellent promise for clinical screening of cancer biomarkers and point-of-care diagnostics.
authors.affiliation: Department of Chemistry, 55 N. Eagleville Rd., University of Connecticut, Storrs, Connecticut 06269, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Yu
authors.forename: Bernard
authors.initials: B
authors.lastname: Munge
authors.forename: Vyomesh
authors.initials: V
authors.lastname: Patel
authors.forename: Gary
authors.initials: G
authors.lastname: Jensen
authors.forename: Ashwin
authors.initials: A
authors.lastname: Bhirde
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Gong
authors.forename: Sang N
authors.initials: SN
authors.lastname: Kim
authors.forename: John
authors.initials: J
authors.lastname: Gillespie
authors.forename: J Silvio
authors.initials: JS
authors.lastname: Gutkind
authors.forename: Fotios
authors.initials: F
authors.lastname: Papadimitrakopoulos
authors.forename: James F
authors.initials: JF
authors.lastname: Rusling
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008297:Male; D037742:Nanotubes, Carbon; D017430:Prostate-Specific Antigen / Q000097:blood; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor; D037742:Nanotubes, Carbon; D017430:Prostate-Specific Antigen