Article
Chemistry, Multidisciplinary
Liping Guo, Yuancheng Liu, Haiou Zeng, Shengping Zhang, Ruiyang Song, Jing Yang, Xiao Han, Ying Wang, Luda Wang
Summary: This study successfully fabricates functionalized graphene nanopores through the decoupling etching and in situ covalent modification, achieving precise regulation of ion transport behaviors. The functionalized graphene nanopores exhibit asymmetric ion transport behaviors and efficient ion sieving, and also show potential applications in energy conversion.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Yanbo Xin, Qin Gao, Jiangshun Huang, Juan Gao, Xueli Geng, Hongliang Shi, Mei Wang, Zhisong Xiao, Paul K. Chu, Anping Huang
Summary: In this study, asymmetric double-layer graphene stacks with charged nanopores were constructed and the ion current rectification phenomenon was observed. The trapping behavior of cations and anions in the nanochannels was found to be optimal at a specific electric field. The underlying mechanism of the rectification effect was elucidated based on the dependence between ion current and carrier concentration.
MATERIALS TODAY CHEMISTRY
(2023)
Article
Mechanics
Yinghua Qiu, Long Ma
Summary: Continuum simulations are used to investigate the influence of electroosmotic flow (EOF) on ionic transport through nanopores. The results show that EOF has a significant impact on the ionic current, especially in nanopores of smaller diameters. This study provides important guidance for simulation conductance in nanofluidic experiments.
Review
Chemistry, Physical
Dominik Duleba, Robert P. Johnson
Summary: This review provides an update on the current state of ion rectifying solid-state nanopore sensors, presenting the recent developments and challenges in the field. It explains the phenomenon of ion current rectification in geometrically asymmetric nanopores and the principle of sensing using these systems. In addition to conventional approaches, intriguing sensing schemes that offer a more flexible sensing approach are also discussed. Furthermore, the review offers an overview of recent efforts in amplifying ion currents and rectification, and briefly discusses future perspectives for the field.
CURRENT OPINION IN ELECTROCHEMISTRY
(2022)
Article
Engineering, Chemical
Yuan Zhang, Panyu Ren, Lei Wang, Emmanuel Pamete, Samantha Husmann, Volker Presser
Summary: This study investigates the influence of electrolyte confinement inside carbon nanopores on ion electrosorption in capacitive deionization. Understanding the intricate pore size effect enhances charge storage performance and desalination, as well as ion separation.
Article
Chemistry, Multidisciplinary
Mojtaba Abdollahzadeh, Milton Chai, Ehsan Hosseini, Mohammad Zakertabrizi, Munirah Mohammad, Hadi Ahmadi, Jingwei Hou, Sean Lim, Asghar Habibnejad Korayem, Vicki Chen, Mohsen Asadnia, Amir Razmjou
Summary: This study introduces a highly tunable design concept to fabricate monovalent ion-selective membranes with asymmetric sub-nanometer pores and implanted energy barriers. The measurements show exceptional selectivity and ion rectification, which holds significance in sensing, energy storage, and separation technologies.
ADVANCED MATERIALS
(2022)
Article
Mechanics
Morteza Sadeghi, Mohammad Hassan Saidi, Martin Kroger, Mario Tagliazucchi
Summary: This study focuses on the electrokinetic energy conversion, electroviscous effect, and induced internal and external magnetic fields in a smart polyelectrolyte grafted soft nanopore with pH responsiveness. The researchers used an efficient molecular theory approach to analyze the total free energy of the system, considering the conformational entropy, electrostatic interactions, and chemical equilibrium reactions. The model predictions were found to be in agreement with analytical solutions, and the effects of various environmental and polymer brush parameters were discussed. The study concludes that the electrokinetic energy conversion efficiency is optimal at moderate pH values and low salt concentrations, and it is influenced by both the environmental and polymer brush properties. The study also highlights the potential of using magnetic field readouts for measuring streaming currents and controlling internal and external magnetic fields.
Article
Nanoscience & Nanotechnology
Wilfred S. Russell, Chih-Yuan Lin, Zuzanna S. Siwy
Summary: Multivalent ions can modify the properties of solid/liquid interfaces and invert the polarity of surface charge, affecting separation processes based on charge. The density of positive charge induced by charge inversion may depend on the pore opening diameter, salt concentration, and applied voltage. Nanoconfinement can modify the effective positive charge density, leading to different ion transport and selectivity in differently sized pores of the same porous material.
ACS APPLIED NANO MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Yoav Green
Summary: This article discusses the changes in the electrical conductance of a nanopore at different electrolyte concentrations. It has been found that, in addition to surface charge regulation, other mechanisms such as convection and slip lengths affect the conductance. The inclusion of convection does not change the slope, but considering the effects of hydrodynamic slip doubles the slope. When all effects are taken into account, the slope can take any value between 0 and 1.
Article
Chemistry, Physical
Patricio Ramirez, Javier Cervera, Jose A. Manzanares, Saima Nasir, Mubarak Ali, Wolfgang Ensinger, Salvador Mafe
Summary: Experimental study of the electrical conductance-voltage curves of charged conical nanopores in different ionic concentrations. Investigation of the effects of salt and salt mixtures on conductance, including the valency of ions, pore charge asymmetry, and pore charge inversion phenomena. Description of how multivalent ions can tune the nanopore conductance and their impact on ionic conductance and negative differential conductance phenomena.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Analytical
Haowei Mao, Qun Ma, Hongquan Xu, Lei Xu, Qiujiao Du, Pengcheng Gao, Fan Xia
Summary: This theoretical study investigates the contribution of charged species on the outer surface of nanopores to the ion current signal. Results show that under certain conditions, the contribution from outer-surface charged species can be stronger than that of the inner walls, particularly when the electrostatic effect at the tip of the nanopore is stronger. Additionally, using nanopore arrays with small openings and low pore density in a low concentration electrolyte can further enhance this effect.
Article
Biochemistry & Molecular Biology
Andrey Gorobchenko, Semyon Mareev, Victor Nikonenko
Summary: This study investigates the mechanism of permselectivity in ion-exchange membranes using a 1D model based on the Nernst-Planck-Poisson equation system. The results show that the change in permselectivity coefficient with increasing current density is mainly due to the change in the membrane/solution layer. At low current densities, divalent ions control the ion fluxes, while at higher current densities, monovalent ions become predominant. The study provides insights into the trade-off between membrane permselectivity and permeability.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Nanoscience & Nanotechnology
Joydeep Majhi, Santanu K. Maiti, Sudin Ganguly
Summary: This paper discusses the possibility of achieving rectification operation in graphene nanoribbon (GNR). Asymmetry is induced in GNR by introducing nanopores in order to make the system a rectifier. The rectification properties of differently structured nanopores are discussed, and it is found that the shape and orientation of the nanopores play a critical and sensitive role in the degree of current rectification. The dependence of Fermi energy on the degree of current rectification is also studied for a particular shape of the nanopore, as the choice of Fermi energy is crucial for obtaining significant current rectification. The role of nanopore size and different spatial distributions of the electrostatic potential profile across the GNR are explored, and the stability of the nanopores is also discussed with a proposed solution.
Article
Engineering, Chemical
G. De Luca, J. Luque Di Salvo, A. Cipollina, G. L. Luque, A. Fuoco, E. P. M. Leiva, G. Micale
Summary: The confinement effect on ion hydration in narrow pores is investigated in this study, and it is found that it can provide a membrane with high selectivity for Na+ compared to traditional ion exchange membranes. This selectivity is mainly based on thermodynamics rather than size exclusion mechanisms. However, Cl- is completely excluded within the range of investigated CNT diameters.
Article
Biophysics
Xia Qiu, Jingyi Dong, Qingshan Dai, Mimi Huang, Yongxin Li
Summary: An ultrasensitive and label-free method for detecting miRNA-21 was developed by combining nanopore ionic current rectification (ICR) technology with HCR technology. The detection strategy showed linear correlation between ICR ratio and logarithm of miRNA-21 concentration within a certain range, holding great promise in the field of cancer diagnosis.
BIOSENSORS & BIOELECTRONICS
(2023)
Article
Chemistry, Multidisciplinary
Kaikai Chen, Adnan Choudhary, Sarah E. Sandler, Christopher Maffeo, Caterina Ducati, Aleksei Aksimentiev, Ulrich F. Keyser
Summary: High-resolution analysis of biomolecules has greatly advanced biosensing, but there are limited methods available for high-resolution analysis of unlabeled single molecules in their native states. In this work, label-free electrical sensing of single molecules with nanometer resolution is demonstrated using a narrow solid-state nanopore. The super-resolution ability is attributed to the enhancement of the electric field at the tip of the nanopore induced by nanostructures. This work presents a general approach to improve the resolution of single-molecule nanopore sensing and has implications for label-free high-resolution DNA sequence mapping and digital information storage.
ADVANCED MATERIALS
(2023)
Article
Biotechnology & Applied Microbiology
Luning Yu, Xinqi Kang, Fanjun Li, Behzad Mehrafrooz, Amr Makhamreh, Ali Fallahi, Joshua C. Foster, Aleksei Aksimentiev, Min Chen, Meni Wanunu
Summary: The electrical current blockade caused by a peptide or protein passing through a nanopore can be used as a fingerprint for molecule identification in biosensor applications. This study presents an enzyme-free method for slow, unidirectional transport of full-length proteins through nanopores. By using a chemically resistant biological nanopore, alpha-hemolysin, and a high concentration guanidinium chloride buffer, protein transport can be propelled by electroosmotic effect. The translocation dynamics of proteins resemble that of single-stranded DNA, and single-translocation events contain enough information for orientation and identity determination with over 90% accuracy using a supervised machine-learning classifier.
NATURE BIOTECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Christopher Maffeo, Lauren Quednau, James Wilson, Aleksei Aksimentiev
Summary: Flowing fluid past chiral objects has been used to power rotary motion in man-made machines for centuries. In nanoscale biological or chemical systems, rotary motion is generated by biasing Brownian motion through cyclic chemical reactions. In this study, we demonstrate that a chiral biological molecule (DNA or RNA duplex) rotates unidirectionally at billions of revolutions per minute when an electric field is applied along the duplex, with the rotation direction determined by the duplex's chirality. The rotation is powered by the drag force of the electro-osmotic flow, mimicking the operating principle of a macroscopic turbine at the nanoscale.
NATURE NANOTECHNOLOGY
(2023)
Article
Automation & Control Systems
Martin Burger, Ina Humpert, Jan-Frederik Pietschmann
Summary: We study a dynamic optimal transport problem on a network, where there is an additional cost for interchanging mass between edges and vertices scaled with a parameter & kappa;. Using duality, we demonstrate the existence of minimisers and discuss the connections between the model and other metrics such as Fisher-Rao and the classical Wasserstein metric. Finally, we analyze the limiting behavior of the model in terms of the parameter & kappa;.
ESAIM-CONTROL OPTIMISATION AND CALCULUS OF VARIATIONS
(2023)
Article
Chemistry, Physical
Kumar Sarthak, David Winogradoff, Yingda Ge, Sua Myong, Aleksei Aksimentiev
Summary: Proteins with disordered regions are important for cellular signaling and biological condensates, but mutations can lead to neurodegenerative diseases. Molecular dynamics simulations were used to study the effects of different force fields on the structure and dynamics of a protein called FUS. The simulations showed that certain force fields produced conformations within the experimental range and also influenced the stability of RNA-protein complexes. The findings suggest that a combination of protein and RNA force fields can provide an optimal description of proteins with both structured and disordered regions and their interactions with RNA.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Siddharth Krishnan, Aleksei Aksimentiev, Stuart Lindsay, Dmitry Matyushov
Summary: Single-molecule measurements reveal that proteins without redox cofactors can still exhibit electrical conductance over nanometer scale distances. This is surprising considering the expected time scale for electron transport based on hopping rates and energy barriers. However, molecular dynamics simulations combined with an electron transfer theory show that the unique molecular configurations of non-redox-active proteins allow for long-range conductivity with low reorganization energies. These findings are supported by experimental current decay calculations.
ACS PHYSICAL CHEMISTRY AU
(2023)
Review
Chemistry, Multidisciplinary
Xiaojun Wei, Tadas Penkauskas, Joseph E. Reiner, Celeste Kennard, Mark J. Uline, Qian Wang, Sheng Li, Aleksei Aksimentiev, Joseph W. F. Robertson, Chang Liu
Summary: Biotechnological innovations have advanced large-scale protein studies, but current methods for identifying and quantifying individual proteins are insufficient for single-molecule protein sequencing. Nanopore-inspired systems have been developed for genome sequencing, and are now emerging as tools for protein identification and analysis, with potential for novel protein sequencing. This review summarizes recent advances in biological nanopore sensors for protein sequencing, including amino acid identification, controlled translocation of peptides and proteins, and device and algorithm development supported by simulations. The review highlights the need for collaborative efforts across multiple disciplines to enable practical implementation of nanopore-based protein sequencing.
Article
Chemistry, Multidisciplinary
Emmanuel Bourret, Xiaoyang Liu, Cora A. Noble, Kevin Cover, Tanisha P. Davidson, Rong Huang, Ryan M. Koenig, K. Shawn Reeves, Ivan V. Vlassiouk, Michel Cote, Jefferey S. Baxter, Andrew R. Lupini, David B. Geohegan, Harry C. Dorn, Steven Stevenson
Summary: This study reports the experimental isolation and characterization of the largest soluble carbon molecule in its pristine form. The [5,5] C-130-D-5h(1) fullertube has a higher aspect ratio compared to previous fullertubes and contains more nanotubular carbons than end-cap fullerenyl atoms. Through analysis of various data, a single candidate isomer and fullertube structure, [5,5] C-130-D-5h(1), were identified. The isolation of this new fullertube opens up possibilities for further studies on electron confinement, fluorescence, and metallic character.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Correction
Biotechnology & Applied Microbiology
Luning Yu, Xinqi Kang, Fanjun Li, Behzad Mehrafrooz, Amr Makhamreh, Ali Fallahi, Joshua C. Foster, Aleksei Aksimentiev, Min Chen, Meni Wanunu
NATURE BIOTECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Xin Shi, Anna-Katharina Pumm, Christopher Maffeo, Fabian Kohler, Elija Feigl, Wenxuan Zhao, Daniel Verschueren, Ramin Golestanian, Aleksei Aksimentiev, Hendrik Dietz, Cees Dekker
Summary: In this study, we experimentally demonstrate the feasibility of developing functional synthetic turbines at the nanoscale by rationally designing nanoscale DNA origami turbines. These turbines can utilize transmembrane electrochemical potentials to rotate autonomously and operate in physiological conditions. This research opens new possibilities for engineering active robotics at the nanoscale.
NATURE NANOTECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Ivan Vlassiouk, Sergei Smirnov, Alexander Puretzky, Olugbenga Olunloyo, David B. Geohegan, Ondrej Dyck, Andrew R. Lupini, Raymond R. Unocic, Harry M. Meyer III, Kai Xiao, Dayrl Briggs, Nickolay Lavrik, Jong Keum, Ercan Cakmak, Sumner B. Harris, Marti Checa, Liam Collins, John Lasseter, Reece Emery, John Rayle, Philip D. Rack, Yijing Stehle, Pavan Chaturvedi, Piran R. Kidambi, Gong Gu, Ilia Ivanov
Summary: This article reports a chemical vapor deposition process for the conformal growth of hBN on large surfaces of various alloys and steels. It demonstrates the protection of steels against corrosion and oxidation, as well as a reduction in friction coefficient. The growth mechanism is revealed and a new method using N2 gas is proposed for large-scale hBN synthesis.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Pavan Chaturvedi, Nicole K. Moehring, Thomas Knight, Rahul Shah, Ivan Vlassiouk, Piran R. Kidambi
Summary: Selective proton permeation through atomically thin graphene can be achieved by hot-pressing it with proton conducting polymer (such as Nafion). The quality and defects of graphene transfer are influenced by hot-press time, temperature, and pressure. Sandwich membranes of Nafion|graphene|Nafion, prepared under optimal transfer conditions, show reduced hydrogen crossover and comparable proton area specific resistance, making them suitable for practical PEM applications.
MATERIALS ADVANCES
(2023)
Article
Chemistry, Physical
Prabhat Tripathi, Behzad Mehrafrooz, Aleksei Aksimentiev, Sophie E. Jackson, Martin Gruebele, Meni Wanunu
Summary: This study investigates the behavior of knotted protein structures during translocation through a pore. Using single molecule nanopore experiments and all-atom MD simulations, the researchers observed an unusual behavior in which the rate of translocation plateaus or slows down as the electric potential driving the reaction increases. This study sheds light on the influence of topology on the forced translocation of knotted proteins.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Merle Scherf, Florian Scheffler, Christopher Maffeo, Ulrich Kemper, Jingjing Ye, Aleksei Aksimentiev, Ralf Seidel, Uta Reibetanz
Summary: The development of DNA origami technique has inspired the use of three-dimensional DNA cages for targeted drug delivery. This study presents a method using DNA origami nanotubes for efficient loading and retention of cargo molecules within the DNA cages.
Article
Chemistry, Multidisciplinary
Prabhat Tripathi, Morgan Chandler, Christopher Michael Maffeo, Ali Fallahi, Amr Makhamreh, Justin Halman, Aleksei Aksimentiev, Kirill A. Afonin, Meni Wanunu
Summary: This study characterizes and distinguishes RNA fiber structures with different degrees of branching using solid-state nanopore experiments and simulations. It is found that fibers with more branches produce longer and deeper ionic current blockades. Additionally, the study shows that the kissing loop interactions in the fibers are resistant to heating.