Label-free immunosensor for prostate-specific antigen based on single-walled carbon nanotube array-modified microelectrodes.
We have fabricated a label-free electrochemical immunosensor using microelectrode arrays modified with single-walled carbon nanotubes (SWNTs). Label-free detection of a cancer marker, total prostate-specific antigen (T-PSA), was carried out using differential pulse voltammetry (DPV). The current signals, derived from the oxidation of tyrosine (Tyr), and tryptophan (Trp) residues, increased with the interaction between T-PSA on T-PSA-mAb covalently immobilized on SWNTs. The selectivity of our biosensor was challenged using bovine serum albumin (BSA) as the target protein. The detection limit for T-PSA was determined as 0.25 ng/mL. Since the cut-off limit of T-PSA between prostate hyperplasia and cancer is 4 ng/mL, the performance of our label-free electrochemical immunosensor seems promising for further clinical applications.
Okuno
Jun
J
Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
Maehashi
Kenzo
K
Kerman
Kagan
K
Takamura
Yuzuru
Y
Matsumoto
Kazuhiko
K
Tamiya
Eiichi
E
D015374:Biosensing Techniques / Q000295:instrumentation*; D007118:Immunoassay; D008839:Microelectrodes; D037742:Nanotubes, Carbon; D017430:Prostate-Specific Antigen / Q000032:analysis* / Q000276:immunology
D037742:Nanotubes, Carbon; D017430:Prostate-Specific Antigen