title: Enhancement of sensitivity and specificity by surface modification of carbon nanotubes in diagnosis of prostate cancer based on carbon nanotube field effect transistors.
abstract: This paper presents a simple and sensitive method for the real-time detection of a prostate cancer marker (PSA-ACT complex) through label-free protein biosensors based on a carbon nanotube field effect transistor (CNT-FET). Herein, the CNT-FET was functionalized with a solution containing various linker-to-spacer ratios, the binding event of the target PSA-ACT complex onto the receptor detected by monitoring the gating effect caused by charges in the target PSA-ACT complex. Since the biosensors were used in a buffer solution, it was crucial to control the distance between the receptors through introduction of linkers and spacers so that the charged target PSA-ACT complex could easily approach the CNT surface within the Debye length to give a large gating effect. The results show that CNT-FET biosensors modified with only linkers could not detect target proteins unless a very high concentration of the PSA-ACT complex solution (approximately 500 ng/ml) was injected, while those modified with a 1:3 ratio of linker-to-spacer could detect 1.0 ng/ml without any pretreatment. Moreover, our linker and spacer-modified CNT-FET could successfully block non-target proteins and selectively detect the target protein in human serum. Significantly, this strategy can be applied to general antibody-based detection schemes and enables production of very simple and sensitive electronic biosensors to detect clinically important biomarkers for disease diagnosis.
authors.affiliation: Department of Chemical Engineering, Sungkyunkwan University, Changan-gu, Suwon 440-746, South Korea.
authors.forename: Jun Pyo
authors.initials: JP
authors.lastname: Kim
authors.forename: Byung Yang
authors.initials: BY
authors.lastname: Lee
authors.forename: Joohyung
authors.initials: J
authors.lastname: Lee
authors.forename: Seunghun
authors.initials: S
authors.lastname: Hong
authors.forename: Sang Jun
authors.initials: SJ
authors.lastname: Sim
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D015374:Biosensing Techniques / Q000295:instrumentation*; D001774:Blood Chemical Analysis / Q000295:instrumentation*; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D008297:Male; D037742:Nanotubes, Carbon / Q000737:chemistry*; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014173:Transistors, Electronic; D014407:Tumor Cells, Cultured
chemical_list: D014408:Biomarkers, Tumor; D037742:Nanotubes, Carbon; D017430:Prostate-Specific Antigen