Carbon nanotube amplification strategies for highly sensitive immunodetection of cancer biomarkers.
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.
Yu
Xin
X
Department of Chemistry, 55 N. Eagleville Rd., University of Connecticut, Storrs, Connecticut 06269, USA.
Munge
Bernard
B
Patel
Vyomesh
V
Jensen
Gary
G
Bhirde
Ashwin
A
Gong
Joseph D
JD
Kim
Sang N
SN
Gillespie
John
J
Gutkind
J Silvio
JS
Papadimitrakopoulos
Fotios
F
Rusling
James F
JF
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
D014408:Biomarkers, Tumor; D037742:Nanotubes, Carbon; D017430:Prostate-Specific Antigen