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Carbon Nanotube Nanoelectrode Array as an Electronic Chip for Ultrasensitive Label-free DNA DetectionA reliable nanoelectrode array based on vertically aligned multi-walled carbon nanotubes (MWNTs) embedded in SiO2 is used for ultrasensitive DNA detection. Characteristic nanoelectrode behavior is observed using low-density MWNT arrays for measuring both bulk and surface immobilized redox species such as K4Fe(CN)6 and ferrocene derivatives. The open-end of MWNTs are found to present similar properties as graphite edge-plane electrodes with wide potential window, flexible chemical functionalities, and good biocompatibility. BRCA1 related oligonucleotide probes with 18 bp are selectively functionalized at the open ends of the nanotube array and specifically hybridized with oligonucleotide targets incorporated with a polyG tag. The guanine groups are employed as the signal moieties in the electrochemical measurements. R(bpy)(sup 2+, sub 3) mediator is used to further amplify the guanine oxidation signal. The hybridization of sub-attomoles of DNA targets is detected electrochemically by combining the MWNT nanoelectrode array with the R(bpy)(sup 2+, sub 3) amplification mechanism. This technique was employed for direct electrochemical detection of label-free PCR amplicon from a healthy donor through specific hybridization with the BRCA1 probe. The detection limit is estimated to be less than 1000 DNA molecules since abundant guanine bases in the PCR amplicon provides a large signal. This system provides a general platform for rapid molecular diagnostics in applications requiring ultrahigh sensitivity, high-degree of miniaturization, and simple sample preparation, and low-cost operation.
Document ID
20040015134
Acquisition Source
Ames Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Li, Jun
(NASA Ames Research Center Moffett Field, CA, United States)
Koehne, Jessica
(NASA Ames Research Center Moffett Field, CA, United States)
Chen, Hua
(NASA Ames Research Center Moffett Field, CA, United States)
Cassell, Alan
(NASA Ames Research Center Moffett Field, CA, United States)
Ng, Hou Tee
(NASA Ames Research Center Moffett Field, CA, United States)
Fan, Wendy
(NASA Ames Research Center Moffett Field, CA, United States)
Ye, Qi
(NASA Ames Research Center Moffett Field, CA, United States)
Han, Jie
(NASA Ames Research Center Moffett Field, CA, United States)
Meyyappan, M.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Subject Category
Life Sciences (General)
Meeting Information
Meeting: Frontier Issues in NBI Technologies
Location: Taejong
Country: Korea, Republic of
Start Date: October 27, 2003
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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