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Ultrasensitive Label-free Electronic Chip for DNA Analysis Using Carbon Nanotube Nanoelectrode ArraysThere is a strong need for faster, cheaper, and simpler methods for nucleic acid analysis in today s clinical tests. Nanotechnologies can potentially provide solutions to these requirements by integrating nanomaterials with biofunctionalities. Dramatic improvement in the sensitivity and multiplexing can be achieved through the high-degree miniaturization. Here, we present our study in the development of an ultrasensitive label-free electronic chip for DNA/RNA analysis based on carbon nanotube nanoelectrode arrays. A reliable nanoelectrode array based on vertically aligned multi-walled carbon nanotubes (MWNTs) embedded in a SiO2 matrix is fabricated using a bottom-up approach. Characteristic nanoelectrode behavior is observed with a low-density MWNT nanoelectrode array in measuring both the bulk and surface immobilized redox species. The open-end of MWNTs are found to present similar properties as graphite edge-plane electrodes, with a wide potential window, flexible chemical functionalities, and good biocompatibility. A BRCA1 related oligonucleotide probe with 18 bases is covalently functionalized at the open ends of the MWNTs and specifically hybridized with an oligonucleotide target as well as a PCR amplicon. The guanine bases in the target molecules are employed as the signal moieties for the electrochemical measurements. Ru(bpy)3(2+) mediator is used to further amplify the guanine oxidation signal. This technique has been employed for direct electrochemical detection of label-free PCR amplicon through specific hybridization with the BRCAl probe. The detection limit is estimated to be less than approximately 1000 DNA molecules, approaching the limit of the sensitivity by laser-based fluorescence techniques in DNA microarray. This system provides a general electronic platform for rapid molecular diagnostics in applications requiring ultrahigh sensitivity, high-degree of miniaturization, simple sample preparation, and low- cost operation.
Document ID
20040081231
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)
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
July 1, 2004
Subject Category
Electronics And Electrical Engineering
Meeting Information
Meeting: Oak Ridge Conference of AACC
Location: San Jose, CA
Country: United States
Start Date: April 29, 2004
End Date: April 30, 2004
Funding Number(s)
CONTRACT_GRANT: NAS2-99092
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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