Enhancement of sensitivity and specificity by surface modification of carbon nanotubes in diagnosis of prostate cancer based on carbon nanotube field effect transistors

Jun Pyo Kim, Byung Yang Lee, Joohyung Lee, Seunghun Hong, Sang Jun Sim

Research output: Contribution to journalArticle

96 Citations (Scopus)

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 (∼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.

Original languageEnglish
Pages (from-to)3372-3378
Number of pages7
JournalBiosensors and Bioelectronics
Volume24
Issue number11
DOIs
Publication statusPublished - 2009 Jul 15

Keywords

  • Biosensor
  • Carbon nanotube
  • Field effect transistor
  • Prostate cancer
  • Spacer
  • Surface modification

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry

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