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Effect of single nanoparticle-nanopore interaction strength on ionic current modulation

Pal, S and Ramkumar, B and Jugade, S and Rao, A and Naik, A and Chakraborty, B and Varma, MM (2020) Effect of single nanoparticle-nanopore interaction strength on ionic current modulation. In: Sensors and Actuators, B: Chemical, 325 .

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Official URL: https://dx.doi.org/10.1016/j.snb.2020.128785


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. © 2020 Elsevier B.V.

Item Type: Journal Article
Publication: Sensors and Actuators, B: Chemical
Publisher: Elsevier BV
Additional Information: The copyright of this artticle belongs to Elsevier BV
Department/Centre: Division of Mechanical Sciences > Chemical Engineering
Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited: 04 Sep 2020 10:28
Last Modified: 04 Sep 2020 10:28
URI: http://eprints.iisc.ac.in/id/eprint/66469

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