An oligonucleotide-functionalized carbon nanotube chemiresistor for sensitive detection of mercury in saliva.
An oligonucleotide-functionalized carbon nanotube chemiresistor for sensitive detection of mercury in saliva.
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DOI：
10.1039/c6an00018e
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发表时间：
2016-04
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影响因子：
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通讯作者：
Dawit N. Wordofa;Pankaj Ramnani;T. Tran;A. Mulchandani
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文献类型：
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作者：
Dawit N. Wordofa;Pankaj Ramnani;T. Tran;A. Mulchandani
二价汞（Hg（2+））离子和一甲基汞（CH 3 Hg（+））是已知对人类具有高毒性的两种形式的汞。在这项工作中，我们提出了一个高选择性，灵敏和无标记的化学电阻生物传感器检测，Hg（2+）和CH 3 Hg（+）离子使用DNA功能化的单壁碳纳米管（SWNTs）。使用接头分子用捕获寡核苷酸聚T官能化SWNT。polyT与polyA杂交形成polyT：polyA双链体。暴露于汞离子后，polyT：polyA双链体去杂交，形成T-Hg（2+）-T双链体。这种结构转换导致polyA从SWNT表面释放，并且相应地观察到化学电阻式生物传感器的电阻的变化，其用于量化汞离子浓度。该生物传感器对缓冲溶液中CH 3 Hg（+）离子的检测动态范围为0.5 ~ 100 nM，灵敏度为28.34%/log（nM）。最后，通过检测掺有已知浓度的汞离子的模拟唾液样品中的Hg（2+）和CH 3 Hg（+）离子，证明了生物传感器的真实的世界应用。
Divalent mercuric (Hg(2+)) ion and monomethyl mercury (CH3Hg(+)) are two forms of mercury that are known to be highly toxic to humans. In this work, we present a highly selective, sensitive and label-free chemiresistive biosensor for the detection of both, Hg(2+) and CH3Hg(+) ions using DNA-functionalized single-walled carbon nanotubes (SWNTs). The SWNTs were functionalized with the capture oligonucleotide, polyT, using a linker molecule. The polyT was hybridized with polyA to form a polyT:polyA duplex. Upon exposure to mercury ions, the polyT:polyA duplex dehybridizes and a T-Hg(2+)-T duplex is formed. This structure switch leads to the release of polyA from the SWNT surface and correspondingly a change in the resistance of the chemiresistive biosensor is observed, which is used to quantify the mercury ion concentration. The biosensor showed a wide dynamic range of 0.5 to 100 nM for the detection of CH3Hg(+) ions in buffer solution with a sensitivity of 28.34% per log (nM) of CH3Hg(+). Finally, real world application of the biosensor was demonstrated by the detection of Hg(2+) and CH3Hg(+) ions in simulated saliva samples spiked with a known concentration of mercury ions.