Effect of single nanoparticle-nanopore interaction strength on ionic current modulation.
Effect of single nanoparticle-nanopore interaction strength on ionic current modulation.
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DOI：
10.1016/j.snb.2020.128785
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发表时间：
2020-12
期刊：
影响因子：
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通讯作者：
Sohini Pal;Ramkumar B.;S. Jugade;A. Rao;A. Naik;B. Chakraborty;M. Varma
中科院分区：
文献类型：
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作者：
Sohini Pal;Ramkumar B.;S. Jugade;A. Rao;A. Naik;B. Chakraborty;M. Varma
固态纳米孔正在迅速崛起，成为开发各种单分子传感应用的有前途的平台。由于靶分子的移位，离子电流通过孔道的调制已经成为纳米孔传感器的主要测量方式。在这里，我们主要关注驻留时间，这是目标分子或粒子穿过孔洞所花费的时间，并使用单个金纳米颗粒(NPs)作为靶子与氮化硅(SiN)纳米孔相互作用的靶子来研究其对靶孔相互作用强度的依赖关系。在我们的例子中，相互作用的强度本质上是静电的，可以通过在纳米颗粒上覆盖带电聚合物来控制。我们报道了这种纳米孔传感器的工作状态，其特征是纳米粒子和孔之间具有吸引力的相互作用，其中驻留时间对靶-孔相互作用指数敏感。我们使用带负电荷和带正电荷的金纳米颗粒来控制它们与带负电荷的氮化硅气孔相互作用的强度。我们的实验揭示了静电力的这种调制如何极大地影响驻留时间。带正电荷的纳米粒子与孔之间具有很强的吸引力，导致驻留时间增加2-3个数量级，从0.4ms增加到75.3ms。这种驻留时间对目标和纳米孔之间相互作用强度的极端敏感性可以在新兴的纳米孔传感器应用中加以利用。
Solid-state nanopores are rapidly emerging as promising platforms for developing various single molecule sensing applications. The modulation of ionic current through the pore due to translocation of the target molecule has been the dominant measurement modality in nanopore sensors. Here, we focus on the dwell time, which is the duration taken by the target molecule or particle to traverse the pore and study its dependence on the strength of interaction of the target with the pore using single gold nanoparticles (NPs) as targets interacting with a silicon nitride (SiN) nanopore. The strength of interaction, which in our case is electrostatic in nature, can be controlled by coating the nanoparticles with charged polymers. We report on an operating regime of this nanopore sensor, characterized by attractive interactions between the nanoparticle and the pore, where the dwell time is exponentially sensitive to the target-pore interaction. We used negatively and positively charged gold nanoparticles to control the strength of their interaction with the Silicon Nitride pore which is negatively charged. Our experiments revealed how this modulation of the electrostatic force greatly affects the dwell time. Positively charged NPs with strong attractive interactions with the pore resulted in increase of dwell times by 2–3 orders of magnitude, from 0.4 ms to 75.3 ms. This extreme sensitivity of the dwell time on the strength of interaction between a target and nanopore can be exploited in emerging nanopore sensor applications.