Electrostatic Screening Modulates Analyte Binding and Emission of Carbon Nanotubes
Electrostatic Screening Modulates Analyte Binding and Emission of Carbon Nanotubes
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DOI：
10.1021/acs.jpcc.8b01239
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发表时间：
2018-05-17
影响因子：
3.7
通讯作者：
Heller, Daniel A.
中科院分区：
文献类型：
--
作者：
Harvey, Jackson D.;Zerze, Gul H.;Heller, Daniel A.
许多纳米材料是有前途的生物传感器元件，由于能够将生物分子相互作用转换为电信号或光信号。某些纳米材料具有固有电荷，因此容易受到静电力的影响，静电力可能会增强或减弱其响应。在这里，使用实验和计算的方法相结合，我们发现和表征的溶剂盐条件在确定由于阴离子分析物与固有响应的纳米材料，单壁碳纳米管的相互作用的光学变化的程度的关键作用。使用一个良好的特征模型阴离子分析物，我们发现，一价盐使聚阴离子结合的碳纳米管在一个高度剂量依赖性的方式，但不与中性带电的分析物的更大的光学变化。分子动力学模拟被用来从自由能的角度来定量地理解这种机制。我们还表明，盐可用于提高检测的灵敏度为聚阴离子分析物。这些结果表明，静电屏蔽是固有带电纳米颗粒传感器的一个重要参数，可以对其进行调整以控制对分析物的响应。
Many nanomaterials are promising biosensor elements due to capabilities for transduction of biomolecular interactions into an electrical or optical signal. Certain nanomaterials have intrinsic charges and are thus susceptible to electrostatic forces that may enhance or attenuate their response. Here, using a combination of experimental and computational approaches, we found and characterized a critical role of the solvent salt conditions in determining the extent of optical changes due to anionic analyte interaction with an intrinsically responsive nanomaterial, single-walled carbon nanotubes. Using a well-characterized model anionic analyte, we found that monovalent salts enabled greater optical changes of a polyanion-bound carbon nanotube in a highly dose dependent manner but not with a neutrally charged analyte. Molecular dynamics simulations were used to derive a quantitative understanding of this mechanism from a free-energy perspective. We also show that salt can be used to enhance the sensitivity of detection for a polyanionic analyte. These results suggest that electrostatic screening is an important parameter for intrinsically charged nanoparticle sensors and it may be tuned to control the response to analytes.