Simple detection of nucleic acids with a single-walled carbon-nanotube-based electrochemical biosensor

Institute of Biomedical Engineering and Health Technology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
Biosensors & Bioelectronics (Impact Factor: 6.41). 07/2011; 28(1):257-62. DOI: 10.1016/j.bios.2011.07.028
Source: PubMed


We report for the first time a simple approach to fabricate an electrochemical DNA (E-DNA) biosensor by introducing the single-walled carbon nanotubes (SWNTs). The SWNTs combine with the electrochemical label (methyl blue, MB)-modified single-stranded DNA (ssDNA) probes to generate a nanomaterial-biomolecule composite, which functions as a signal amplification platform to facilitate the electron-transfer between the electrochemical label and the electrode. This SWNT-based E-DNA biosensor produces a high square wave voltammetry (SWV) signal in the absence of target DNA. In the presence of target DNA, the MB-labeled ssDNA probes are removed from the SWNT-modified electrode due to the formation of a double-stranded DNA (dsDNA), generating a relatively low SWV signal. This signal-off SWNT-based E-DNA biosensor exhibits improved sensitivity and large linear dynamic range with low detection limit; it can even distinguish 1-base mismatched target DNA. Further experiments demonstrate that the SWNT-based E-DNA biosensor is superior to the multi-walled carbon nanotube (MWNT)-based one for DNA detection. Moreover, the introduction of aptamer into the SWNT-based biosensor might be further extended to detect small biomolecules such as adenosine.

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    • "The unique properties of carbon nanotubes (CNTs) have generated a tremendous amount of research for the development of novel technological applications. Recently, there has been a great interest in applying CNTs for the sensitive detection of biomolecules, such as glucose [1], cholesterol [2], cancer biomarkers [3], proteins [4], and DNA/RNA [5], because of their remarkable biomolecular recognition [6] [7] [8] [9] [10]. When such superior biomolecular recognition capabilities are utilized together with the unique physical properties of nanoscale CNTs, it could be developed for use as microarray biosensors, which provide an efficient biomolecule identification technique over traditional techniques, such as enzyme-linked immunosorbent assays (ELISAs) and Western blots, due to their ability of carrying out the multiplex detection of biomolecules on a single platform and minimal sample consumption [11] [12] [13]. "
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