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Title: Conical Nanopores for Efficient Ion Pumping and Desalination

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Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
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Journal Article: Published Article
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Related Information: CHORUS Timestamp: 2017-11-27 14:12:46; Journal ID: ISSN 1948-7185
American Chemical Society
Country of Publication:
United States

Citation Formats

Zhang, Yu, and Schatz, George C. Conical Nanopores for Efficient Ion Pumping and Desalination. United States: N. p., 2017. Web. doi:10.1021/acs.jpclett.7b01137.
Zhang, Yu, & Schatz, George C. Conical Nanopores for Efficient Ion Pumping and Desalination. United States. doi:10.1021/acs.jpclett.7b01137.
Zhang, Yu, and Schatz, George C. Mon . "Conical Nanopores for Efficient Ion Pumping and Desalination". United States. doi:10.1021/acs.jpclett.7b01137.
title = {Conical Nanopores for Efficient Ion Pumping and Desalination},
author = {Zhang, Yu and Schatz, George C.},
abstractNote = {},
doi = {10.1021/acs.jpclett.7b01137},
journal = {Journal of Physical Chemistry Letters},
number = ,
volume = ,
place = {United States},
year = {Mon Jun 12 00:00:00 EDT 2017},
month = {Mon Jun 12 00:00:00 EDT 2017}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on June 7, 2018
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Cited by: 6works
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  • Single conically shaped nanopores produce stable ion current fluctuations when in contact with weakly soluble salts, such as calcium hydrogen phosphate (CaHPO{sub 4}) and cobalt hydrogen phosphate (CoHPO{sub 4}). The pore spontaneously switches between high and low conductance states, called open and closed states, respectively. Pore opening and closing are linked to the dynamic formation of the calcium and cobalt precipitates at the small opening of the pore. The probabilities of pore opening and closing are voltage-dependent, and this characteristic of ion current signal is known for biological voltage-gated channels. We show that new types of ion current fluctuations aremore » obtained in conditions at which precipitates of CaHPO{sub 4} and CoHPO{sub 4} can form in the pore at the same time.« less
  • Surface modification will change the surface charge density (SCD) at the signal-limiting region of nanochannel devices. By fitting the measured i V curves in simulation via solving the Poisson and Nernst Planck equations, the SCD and therefore the surface coverage can be noninvasively quantified. Amine terminated organosilanes are employed to chemically modify single conical nanopores. Determined by the protonation deprotonation of the functional groups, the density and polarity of surface charges are adjusted by solution pH. The rectified current at high conductivity states is found to be proportional to the SCD near the nanopore orifice. This correlation allows the noninvasivemore » determination of SCD and surface coverage of individual conical nanopores.« less
  • Current rectification is well known in ion transport through nanoscale pores and channel devices. The measured current is affected by both the geometry and fixed interfacial charges of the nanodevices. In this article, an interesting trend is observed in steady-state current–potential measurements using single conical nanopores. A threshold low-conductivity state is observed upon the dilution of electrolyte concentration. Correspondingly, the normalized current at positive bias potentials drastically increases and contributes to different degrees of rectification. This novel trend at opposite bias polarities is employed to differentiate the ion flux affected by the fixed charges at the substrate–solution interface (surface effect),more » with respect to the constant asymmetric geometry (volume effect). The surface charge density (SCD) of individual nanopores, an important physical parameter that is challenging to measure experimentally and is known to vary from one nanopore to another, is directly quantified by solving Poisson and Nernst–Planck equations in the simulation of the experimental results. The flux distribution inside the nanopore and the SCD of individual nanopores are reported. The respective diffusion and migration translocations are found to vary at different positions inside the nanopore. This knowledge is believed to be important for resistive pulse sensing applications because the detection signal is determined by the perturbation of the ion current by the analytes.« less