Highly Selective Artificial Cholesteryl Crown Ether K<sup>+</sup>‐Channels

Sun, Zhanhu; Barboiu, Mihail; Legrand, Yves‐Marie; Petit, Eddy; Rotaru, Alexandru

doi:10.1002/ange.201506430

Cited by 43 publications

(21 citation statements)

References 55 publications

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“…Energy barriers resulting from ion dehydration at the pore mouth have been adopted to explain selectivity between similar ions in subnanometer pores ( 9 ). Hence, it was concluded that to facilitate the permeation of specific ions, the ion-pore attraction near the pore entrance should be increased to reduce the energy barrier for the ion to enter the pore ( 21 , 56 , 57 ). However, according to our simulations and experimental results, the overall energy for ion permeation through relatively long subnanometer pores is governed by the intrapore diffusion, rather than partitioning at the pore entrance, due to the strong ion-pore wall interactions.…”

Section: Discussionmentioning

confidence: 99%

Intrapore energy barriers govern ion transport and selectivity of desalination membranes

et al. 2020

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State-of-the-art desalination membranes exhibit high water-salt selectivity, but their ability to discriminate between ions is limited. Elucidating the fundamental mechanisms underlying ion transport and selectivity in subnanometer pores is therefore imperative for the development of ion-selective membranes. Here, we compare the overall energy barrier for salt transport and energy barriers for individual ion transport, showing that cations and anions traverse the membrane pore in an independent manner. Supported by density functional theory simulations, we demonstrate that electrostatic interactions between permeating counterion and fixed charges on the membrane substantially hinder intrapore diffusion. Furthermore, using quartz crystal microbalance, we break down the contributions of partitioning at the pore mouth and intrapore diffusion to the overall energy barrier for salt transport. Overall, our results indicate that intrapore diffusion governs salt transport through subnanometer pores due to ion-pore wall interactions, providing the scientific base for the design of membranes with high ion-ion selectivity.

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Section: Discussionmentioning

confidence: 99%

Intrapore energy barriers govern ion transport and selectivity of desalination membranes

et al. 2020

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“…In contrast, biological channels can differentiate between ions of the same charge, such as potassium and sodium 3 . One can envision, however, that the ability to impart chemical selectivity at specific locations along the nanopore could also be incorporated into this platform, as recently shown through crown-ether functionalization of nanopores 37 , and crown-ether channels [38][39][40][41] . Such ion selective channels would enable a selective response of the amplifying circuits to specific ions.…”

Section: Discussionmentioning

confidence: 99%

Ionic Amplifying Circuits Inspired by Electronics and Biology

Lucas¹,

Lin²,

Baker

et al. 2020

Biophysical Journal

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Integrated circuits are present in all electronic devices, and enable signal amplification, modulation, and relay. Nature uses another type of circuits composed of channels in a cell membrane, which regulate and amplify transport of ions, not electrons and holes as is done in electronic systems. Here we show an abiotic ionic circuit that is inspired by concepts from electronics and biology. The circuit amplifies small ionic signals into ionic outputs, and its operation mimics the electronic Darlington amplifier composed of transistors. The individual transistors are pores equipped with three terminals including a gate that is able to enrich or deplete ions in the pore. The circuits we report function at gate voltages < 1 V, respond to sub-nA gate currents, and offer ion current amplification with a gain up to~300. Ionic amplifiers are a logical step toward improving chemical and biochemical sensing, separations and amplification, among others.

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“…A conventional ion-relay mechanism for ion transport requires three or more relay stations to fully span the hydrophobic membrane region, with at least one station residing around the center of the membrane where ions experience the highest energetic penalty. 18,[30][31][32][33][34][35][36][37] During the ion-relay process, where the preceding station captures and relays the ion to the next station, all stations do not move significantly. We envisioned that the number of relay stations could be reduced to two if they are customized to be capable of swinging along the membrane axis back and forth between the membrane's hydrophilic region and its center.…”

Section: Initial Statementioning

confidence: 99%

Molecular Tetrahedrons as Selective and Efficient Ion Transporters via a Two-Station Swing-Relay Mechanism

Shen

Ang

et al. 2021

CCS Chem

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The traditional approach to utilizing an ion-relay mechanism for ion transport requires three or more ion-relay stations. Herein, we describe a novel strategy, incorporating a swing action to realize a minimal ion-relay mechanism via only two relay stations. This swing-relay mechanism was achieved using a class of crown ether-appended, long-armed molecular tetrahedrons (MTs). These MTs comprise ion-relaying crown units attached to a rigid tetrahedral core via flexible alkyl linkers, which act as the mobile arms and endow the crown units with great mobility to swing. Driven by the ionic concentration gradient and supported by the mobile arms, two crown units located in the membrane's opposite hydrophilic regions swing toward each other to complete a single ion-relay step in the center of the membrane to enable fast ion conduction across. Generally, 18crown-6-containing MT6s exhibited higher activities and better K + /Na + selectivities than 15-crown-5-containing MT5s, with the most active MT6-C10 displaying an EC 50 (K + ) of 0.9 μM (i.e., 0.9 mol % relative to lipid) and the most selective MT6-C4 showing K + /Na + selectively of 6.3. Finally, five control MTs were rationally designed to establish the action of the novel unimolecular two-station swing-relay as an efficient yet unprecedented mechanism of synthetic ion transporters.

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Highly Selective Artificial Cholesteryl Crown Ether K⁺‐Channels

Cited by 43 publications

References 55 publications

Intrapore energy barriers govern ion transport and selectivity of desalination membranes

Intrapore energy barriers govern ion transport and selectivity of desalination membranes

Ionic Amplifying Circuits Inspired by Electronics and Biology

Molecular Tetrahedrons as Selective and Efficient Ion Transporters via a Two-Station Swing-Relay Mechanism

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Highly Selective Artificial Cholesteryl Crown Ether K+‐Channels

Cited by 43 publications

References 55 publications

Intrapore energy barriers govern ion transport and selectivity of desalination membranes

Intrapore energy barriers govern ion transport and selectivity of desalination membranes

Ionic Amplifying Circuits Inspired by Electronics and Biology

Molecular Tetrahedrons as Selective and Efficient Ion Transporters via a Two-Station Swing-Relay Mechanism

Contact Info

Product

Resources

About

Highly Selective Artificial Cholesteryl Crown Ether K⁺‐Channels