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Kang X, Wu C, Alibakhshi MA, Liu X, Yu L, Walt DR, Wanunu M. Nanopore-Based Fingerprint Immunoassay Based on Rolling Circle Amplification and DNA Fragmentation. ACS Nano 2023; 17:5412-5420. [PMID: 36877993 PMCID: PMC10629239 DOI: 10.1021/acsnano.2c09889] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
In recent years, nanopore-based sequencers have become robust tools with unique advantages for genomics applications. However, progress toward applying nanopores as highly sensitive, quantitative diagnostic tools has been impeded by several challenges. One major limitation is the insufficient sensitivity of nanopores in detecting disease biomarkers, which are typically present at pM or lower concentrations in biological fluids, while a second limitation is the general absence of unique nanopore signals for different analytes. To bridge this gap, we have developed a strategy for nanopore-based biomarker detection that utilizes immunocapture, isothermal rolling circle amplification, and sequence-specific fragmentation of the product to release multiple DNA reporter molecules for nanopore detection. These DNA fragment reporters produce sets of nanopore signals that form distinctive fingerprints, or clusters. This fingerprint signature therefore allows the identification and quantification of biomarker analytes. As a proof of concept, we quantify human epididymis protein 4 (HE4) at low pM levels in a few hours. Future improvement of this method by integration with a nanopore array and microfluidics-based chemistry can further reduce the limit of detection, allow multiplexed biomarker detection, and further reduce the footprint and cost of existing laboratory and point-of-care devices.
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Affiliation(s)
- Xinqi Kang
- Departments
of Bioengineering, Physics, and Chemistry and Chemical Biology, Northeastern
University, Boston, Massachusetts 02115, United States
| | - Connie Wu
- Department
of Pathology, Brigham and Women’s Hospital, Harvard Medical School and Wyss Institute for Biologically Inspired
Engineering at Harvard University, Boston, Massachusetts 02115, United States
| | - Mohammad Amin Alibakhshi
- Departments
of Bioengineering, Physics, and Chemistry and Chemical Biology, Northeastern
University, Boston, Massachusetts 02115, United States
| | - Xingyan Liu
- Departments
of Bioengineering, Physics, and Chemistry and Chemical Biology, Northeastern
University, Boston, Massachusetts 02115, United States
| | - Luning Yu
- Departments
of Bioengineering, Physics, and Chemistry and Chemical Biology, Northeastern
University, Boston, Massachusetts 02115, United States
| | - David R. Walt
- Department
of Pathology, Brigham and Women’s Hospital, Harvard Medical School and Wyss Institute for Biologically Inspired
Engineering at Harvard University, Boston, Massachusetts 02115, United States
| | - Meni Wanunu
- Departments
of Bioengineering, Physics, and Chemistry and Chemical Biology, Northeastern
University, Boston, Massachusetts 02115, United States
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2
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Alibakhshi MA, Kang X, Clymer D, Zhang Z, Vargas A, Meunier V, Wanunu M. Scaled-Up Synthesis of Freestanding Molybdenum Disulfide Membranes for Nanopore Sensing. Adv Mater 2023; 35:e2207089. [PMID: 36580439 DOI: 10.1002/adma.202207089] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 12/08/2022] [Indexed: 06/17/2023]
Abstract
2D materials are ideal for nanopores with optimal detection sensitivity and resolution. Among these, molybdenum disulfide (MoS2 ) has gained traction as a less hydrophobic material than graphene. However, experiments using 2D nanopores remain challenging due to the lack of scalable methods for high-quality freestanding membranes. Herein, a site-directed, scaled-up synthesis of MoS2 membranes on predrilled nanoapertures on 4-inch wafer substrates with 75% yields is reported. Chemical vapor deposition (CVD), which introduces sulfur and molybdenum dioxide vapors across the sub-100 nm nanoapertures results in exclusive formation of freestanding membranes that seal the apertures. Nucleation and growth near the nanoaperture edges is followed by nanoaperture decoration with MoS2 , which proceeds until a critical flake curvature is achieved, after which fully spanning freestanding membranes form. Intentional blocking of reagent flow through the apertures inhibits MoS2 nucleation around the nanoapertures, promoting the formation of large-crystal monolayer MoS2 membranes. The in situ grown membranes along with facile membrane wetting and nanopore formation using dielectric breakdown enables the recording of dsDNA translocation events at an unprecedentedly high 1 MHz bandwidth. The methods presented here are important steps toward the development of scalable single-layer membrane manufacture for 2D nanofluidics and nanopore applications.
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Affiliation(s)
| | - Xinqi Kang
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA
| | - David Clymer
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Zhuoyu Zhang
- School of Physics, Nankai University, Tianjin, 300071, P.R. China
| | - Anthony Vargas
- Department of Physics, Northeastern University, Boston, MA, 02115, USA
| | - Vincent Meunier
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Meni Wanunu
- Department of Physics, Northeastern University, Boston, MA, 02115, USA
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA
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3
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Farhangdoust F, Alibakhshi MA, Cheng F, Liang W, Liu Y, Wanunu M. Rapid Identification of DNA Fragments through Direct Sequencing with Electro-Optical Zero-Mode Waveguides. Adv Mater 2022; 34:e2209376. [PMID: 36482018 PMCID: PMC9930659 DOI: 10.1002/adma.202209376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Affiliation(s)
| | | | - Feng Cheng
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Wentao Liang
- Department of Physics, Northeastern University, Boston, MA, 02115, USA
| | - Yongmin Liu
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - Meni Wanunu
- Department of Physics, Northeastern University, Boston, MA, 02115, USA
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
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4
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Yu L, Kang X, Alibakhshi MA, Pavlenok M, Niederweis M, Wanunu M. Stable polymer bilayers for protein channel recordings at high guanidinium chloride concentrations. Biophys J 2021; 120:1537-1541. [PMID: 33617833 DOI: 10.1016/j.bpj.2021.02.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 02/02/2021] [Accepted: 02/15/2021] [Indexed: 11/28/2022] Open
Abstract
The use of chaotropic reagents is common in biophysical characterization of biomolecules. When the study involves transmembrane protein channels, the stability of the protein channel and supporting bilayer membrane must be considered. In this letter, we show that planar bilayers composed of poly(1,2-butadiene)-b-poly(ethylene oxide) diblock copolymer are stable and leak-free at high guanidinium chloride concentrations, in contrast to diphytanoyl phosphatidylcholine bilayers, which exhibit deleterious leakage under similar conditions. Furthermore, insertion and functional analysis of channels such as α-hemolysin and MspA are straightforward in these polymer membranes. Finally, we demonstrate that α-hemolysin channels maintain their structural integrity at 2 M guanidinium chloride concentrations using blunt DNA hairpins as molecular reporters.
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Affiliation(s)
| | | | | | - Mikhail Pavlenok
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Meni Wanunu
- Department of Physics; Department of Bioengineering; Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts.
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5
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Zhong J, Alibakhshi MA, Xie Q, Riordon J, Xu Y, Duan C, Sinton D. Exploring Anomalous Fluid Behavior at the Nanoscale: Direct Visualization and Quantification via Nanofluidic Devices. Acc Chem Res 2020; 53:347-357. [PMID: 31922716 DOI: 10.1021/acs.accounts.9b00411] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Nanofluidics is the study of fluids under nanoscale confinement, where small-scale effects dictate fluid physics and continuum assumptions are no longer fully valid. At this scale, because of large surface-area-to-volume ratios, the fluid interaction with boundaries becomes more pronounced, and both short-range steric/hydration forces and long-range van der Waals forces and electrostatic forces dictate fluid behavior. These forces lead to a spectrum of anomalous transport and thermodynamic phenomena such as ultrafast water flow, enhanced ion transport, extreme phase transition temperatures, and slow biomolecule diffusion, which have been the subject of extensive computational studies. Experimental quantification of these phenomena was also enabled by the advent of nanofluidic technology, which has transformed challenging nanoscale fluid measurements into facile optical and electrical recordings. Our groups' focus is to investigate nanoscale (2 to 103 nm) fluid behaviors in the context of fluid mechanics and thermodynamics through the development of novel nanofluidic tools, to examine the applicability of classical equations at the nanoscale, to identify the source of deviations, and to explore new physics emerging at this scale. In this Account, we summarize our recent findings regarding liquid transport, vaporization, and condensation of nanoscale-confined liquids. Our study of nanoscale water transport identified an additional resistance in hydrophilic nanochannels, attributed to the reduced cross-sectional area caused by the formation of an immobile hydration layer on the surfaces. In contrast, a reduction in flow resistance was discovered in graphene-coated hydrophobic nanochannels, due to water slippage on the graphene surface. In the context of vaporization, the kinetic-limited evaporation flux was measured and found to exceed the classical theoretical prediction by an order of magnitude in hydrophilic nanochannels/nanopores as a result of the thin film evaporation outside of the apertures. This factor was eliminated by modifying the hydrophobicity of the aperture's exterior surface, enabling the identification of the true kinetic limits inside nanoconfinements and a crucial confinement-dependent evaporation coefficient. The transport-limited evaporation dynamics was also quantified, where experimental results confirmed the parallel diffusion-convection resistance model in both single nanoconduits and nanoporous systems at high accuracy. Furthermore, we have extended our studies to different aspects of condensation in nanoscale-confined spaces. The initiation of condensation for a single-component hydrocarbon was observed to follow the Kelvin equation, whereas for hydrocarbon mixtures it deviated from classical theory because of surface-selective adsorption, which has been corroborated by simulations. Moreover, the condensation dynamics deviates from the bulk and is governed by either vapor transport or liquid transport depending on the confinement scale. Overall, by using novel nanofluidic devices and measurement strategies, our work explores and further verifies the applicability of classical fluid mechanics and thermodynamic equations such as the Navier-Stokes, Kelvin, and Hertz-Knudsen equations at the nanoscale. The results not only deepen our understanding of the fundamental physical phenomena of nanoscale fluids but also have important implications for various industrial applications such as water desalination, oil extraction/recovery, and thermal management. Looking forward, we see tremendous opportunities for nanofluidic devices in probing and quantifying nanoscale fluid thermophysical properties and more broadly enabling nanoscale chemistry and materials science.
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Affiliation(s)
- Junjie Zhong
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
| | - Mohammad Amin Alibakhshi
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, United States
| | - Quan Xie
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, United States
| | - Jason Riordon
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
| | - Yi Xu
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
| | - Chuanhua Duan
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, United States
| | - David Sinton
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
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6
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Yu L, Kang X, Amin Alibakhshi M, Wanunu M. Stable Hybrid Polymer-Lipid Membrane for High Voltage Biological Nanopore Experiments. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.2623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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7
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Kang X, Amin Alibakhshi M, Wanunu M. Multiplexed Molecular Counters using a High-Voltage Transmembrane Pore Platform. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.2624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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8
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Yazbeck R, Alibakhshi MA, Von Schoppe J, Ekinci KL, Duan C. Characterization and manipulation of single nanoparticles using a nanopore-based electrokinetic tweezer. Nanoscale 2019; 11:22924-22931. [PMID: 31763666 DOI: 10.1039/c9nr08476b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Manipulation and characterization of nanoscale objects through electrokinetic techniques offer numerous advantages compared to the existing optical methods and hold great potential for both fundamental research and practical applications. Here we present a novel electrokinetic tweezer for single nanoparticle manipulation and characterization based on electrokinetic trapping near a low-aspect-ratio nanopore. We find that this nanopore-based electrokinetic tweezer share lots of similarity with optical tweezers and can be modeled as an overdamped harmonic oscillator, with the spring constant of the system being the trap stiffness. We show that different values of ionic currents through the nanopore and trap stiffnesses are achieved when trapping nanoparticles with different sizes (down to 100 nm) and/or zeta potentials. We also demonstrate that the trap stiffness and nanoparticle position can be easily tuned by changing the applied voltage and buffer concentration. We envision that further development of this electrokinetic tweezer will enable various advanced tools for nanophotonics, drug delivery, and biosensing.
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Affiliation(s)
- Rami Yazbeck
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA.
| | | | - Joseph Von Schoppe
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA.
| | - Kamil L Ekinci
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA.
| | - Chuanhua Duan
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA.
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9
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Abstract
Biological nanopores have been used as powerful platforms for label-free detection and identification of a range of biomolecules for biosensing applications and single molecule biophysics studies. Nonetheless, high limit of detection (LOD) of analytes due to inefficient biomolecular capture into biological nanopores at low voltage poses practical limits on their biosensing efficacy. Several approaches have been proposed to improve the voltage stability of the membrane, including polymerization and hydrogel coating, however, these compromise the lipid fluidity. Here, we developed a chip-based platform that can be massively produced on a wafer scale that is capable of sustaining high voltages of 350 mV with comparable membrane areas to traditional systems. Using this platform, we demonstrate sensing of DNA hairpins in α-hemolysin nanopores at the nanomolar regime under high voltage. Further, we have developed a workflow for one-pot enzymatic release of DNA hairpins with different stem lengths from magnetic microbeads, followed by multiplexed nanopore-based quantification of the hairpins within minutes, paving the way for novel nanopore-based multiplexed biosensing applications.
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10
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Abstract
Evaporation from nanopores plays an important role in various natural and industrial processes that require efficient heat and mass transfer. The ultimate performance of nanopore-evaporation-based processes is dictated by evaporation kinetics at the liquid-vapor interface, which has yet to be experimentally studied down to the single nanopore level. Here we report unambiguous measurements of kinetically limited intense evaporation from individual hydrophilic nanopores with both hydrophilic and hydrophobic top outer surfaces at 22 °C using nanochannel-connected nanopore devices. Our results show that the evaporation fluxes of nanopores with hydrophilic outer surfaces show a strong diameter dependence with an exponent of nearly -1.5, reaching up to 11-fold of the maximum theoretical predication provided by the classical Hertz-Knudsen relation at a pore diameter of 27 nm. Differently, the evaporation fluxes of nanopores with hydrophobic outer surfaces show a different diameter dependence with an exponent of -0.66, achieving 66% of the maximum theoretical predication at a pore diameter of 28 nm. We discover that the ultrafast diameter-dependent evaporation from nanopores with hydrophilic outer surfaces mainly stems from evaporating water thin films outside of the nanopores. In contrast, the diameter-dependent evaporation from nanopores with hydrophobic outer surfaces is governed by evaporation kinetics inside the nanopores, which indicates that the evaporation coefficient varies in different nanoscale confinements, possibly due to surface-charge-induced concentration changes of hydronium ions. This study enhances our understanding of evaporation at the nanoscale and demonstrates great potential of evaporation from nanopores.
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Affiliation(s)
- Yinxiao Li
- Department of Mechanical Engineering , Boston University , Boston , Massachusetts 02215 , United States
| | - Haowen Chen
- Department of Mechanical Engineering , Boston University , Boston , Massachusetts 02215 , United States
| | - Siyang Xiao
- Department of Mechanical Engineering , Boston University , Boston , Massachusetts 02215 , United States
| | - Mohammad Amin Alibakhshi
- Department of Mechanical Engineering , Boston University , Boston , Massachusetts 02215 , United States
| | - Ching-Wen Lo
- Department of Mechanical Engineering , Boston University , Boston , Massachusetts 02215 , United States
- Department of Mechanical Engineering , National Chiao Tung University , Hsinchu 300 , Taiwan
| | - Ming-Chang Lu
- Department of Mechanical Engineering , National Chiao Tung University , Hsinchu 300 , Taiwan
| | - Chuanhua Duan
- Department of Mechanical Engineering , Boston University , Boston , Massachusetts 02215 , United States
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11
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12
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Xie Q, Alibakhshi MA, Jiao S, Xu Z, Hempel M, Kong J, Park HG, Duan C. Fast water transport in graphene nanofluidic channels. Nat Nanotechnol 2018; 13:238-245. [PMID: 29292381 DOI: 10.1038/s41565-017-0031-9] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 11/17/2017] [Indexed: 06/07/2023]
Abstract
Superfast water transport discovered in graphitic nanoconduits, including carbon nanotubes and graphene nanochannels, implicates crucial applications in separation processes and energy conversion. Yet lack of complete understanding at the single-conduit level limits development of new carbon nanofluidic structures and devices with desired transport properties for practical applications. Here, we show that the hydraulic resistance and slippage of single graphene nanochannels can be accurately determined using capillary flow and a novel hybrid nanochannel design without estimating the capillary pressure. Our results reveal that the slip length of graphene in the graphene nanochannels is around 16 nm, albeit with a large variation from 0 to 200 nm regardless of the channel height. We corroborate this finding with molecular dynamics simulation results, which indicate that this wide distribution of the slip length is due to the surface charge of graphene as well as the interaction between graphene and its silica substrate.
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Affiliation(s)
- Quan Xie
- Department of Mechanical Engineering, Boston University, Boston, MA, USA
| | | | - Shuping Jiao
- Department of Engineering Mechanics and Center for Nano and Micro Mechanics, Tsinghua University, Beijing, China
| | - Zhiping Xu
- Department of Engineering Mechanics and Center for Nano and Micro Mechanics, Tsinghua University, Beijing, China
| | - Marek Hempel
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jing Kong
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Hyung Gyu Park
- Department of Mechanical and Process Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Zürich, Switzerland
| | - Chuanhua Duan
- Department of Mechanical Engineering, Boston University, Boston, MA, USA.
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13
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Amin Alibakhshi M, Halman JR, Wilson J, Aksimentiev A, Afonin KA, Wanunu M. Sensitive Detection and Identification of Nucleic Acid Nanoparticles in Solid-State Nanopores. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.1006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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14
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Alibakhshi MA, Halman JR, Wilson J, Aksimentiev A, Afonin KA, Wanunu M. Picomolar Fingerprinting of Nucleic Acid Nanoparticles Using Solid-State Nanopores. ACS Nano 2017; 11:9701-9710. [PMID: 28841287 PMCID: PMC5959297 DOI: 10.1021/acsnano.7b04923] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Nucleic acid nanoparticles (NANPs) are an emerging class of programmable structures with tunable shape and function. Their promise as tools for fundamental biophysics studies, molecular sensing, and therapeutic applications necessitates methods for their detection and characterization at the single-particle level. In this work, we study electrophoretic transport of individual ring-shaped and cube-shaped NANPs through solid-state nanopores. In the optimal nanopore size range, the particles must deform to pass through, which considerably increases their residence time within the pore. Such anomalously long residence times permit detection of picomolar amounts of NANPs when nanopore measurements are carried out at a high transmembrane bias. In the case of a NANP mixture, the type of individual particle passing through nanopores can be efficiently determined from analysis of a single electrical pulse. Molecular dynamics simulations provide insight into the mechanical barrier to transport of the NANPs and corroborate the difference in the signal amplitudes observed for the two types of particles. Our study serves as a basis for label-free analysis of soft programmable-shape nanoparticles.
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Affiliation(s)
| | - Justin R. Halman
- Nanoscale Science Program, Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
| | - James Wilson
- Department of Physics, University of Illinois at Urbana—Champaign, Urbana, Illinois 61801, United States
| | - Aleksei Aksimentiev
- Department of Physics, University of Illinois at Urbana—Champaign, Urbana, Illinois 61801, United States
| | - Kirill A. Afonin
- Nanoscale Science Program, Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
- The Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
| | - Meni Wanunu
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, United States
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
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15
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Abstract
Capillary evaporation in nanoscale conduits is an efficient heat/mass transfer strategy that has been widely utilized by both nature and mankind. Despite its broad impact, the ultimate transport limits of capillary evaporation in nanoscale conduits, governed by the evaporation/condensation kinetics at the liquid-vapor interface, have remained poorly understood. Here we report experimental study of the kinetic limits of water capillary evaporation in two dimensional nanochannels using a novel hybrid channel design. Our results show that the kinetic-limited evaporation fluxes break down the limits predicated by the classical Hertz-Knudsen equation by an order of magnitude, reaching values up to 37.5 mm/s with corresponding heat fluxes up to 8500 W/cm2. The measured evaporation flux increases with decreasing channel height and relative humidity but decreases as the channel temperature decreases. Our findings have implications for further understanding evaporation at the nanoscale and developing capillary evaporation-based technologies for both energy- and bio-related applications.
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Affiliation(s)
- Yinxiao Li
- Department of Mechanical Engineering, Boston University , Boston, Massachusetts 02215, United States
| | - Mohammad Amin Alibakhshi
- Department of Mechanical Engineering, Boston University , Boston, Massachusetts 02215, United States
| | - Yihong Zhao
- Department of Mechanical Engineering, Boston University , Boston, Massachusetts 02215, United States
| | - Chuanhua Duan
- Department of Mechanical Engineering, Boston University , Boston, Massachusetts 02215, United States
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16
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Alibakhshi MA, Liu B, Xu Z, Duan C. Geometrical control of ionic current rectification in a configurable nanofluidic diode. Biomicrofluidics 2016; 10:054102. [PMID: 27679678 PMCID: PMC5018007 DOI: 10.1063/1.4962272] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 08/24/2016] [Indexed: 06/06/2023]
Abstract
Control of ionic current in a nanofluidic system and development of the elements analogous to electrical circuits have been the subject of theoretical and experimental investigations over the past decade. Here, we theoretically and experimentally explore a new technique for rectification of ionic current using asymmetric 2D nanochannels. These nanochannels have a rectangular cross section and a stepped structure consisting of a shallow and a deep side. Control of height and length of each side enables us to obtain optimum rectification at each ionic strength. A 1D model based on the Poisson-Nernst-Planck equation is derived and validated against the full 2D numerical solution, and a nondimensional concentration is presented as a function of nanochannel dimensions, surface charge, and the electrolyte concentration that summarizes the rectification behavior of such geometries. The rectification factor reaches a maximum at certain electrolyte concentration predicted by this nondimensional number and decays away from it. This method of fabrication and control of a nanofluidic diode does not require modification of the surface charge and facilitates the integration with lab-on-a-chip fluidic circuits. Experimental results obtained from the stepped nanochannels are in good agreement with the 1D theoretical model.
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Affiliation(s)
| | - Binqi Liu
- School of Aerospace Engineering, Tsinghua University , Beijing 100084, China
| | - Zhiping Xu
- Applied Mechanics Laboratory, Department of Engineering Mechanics and Center for Nano and Micro Mechanics, Tsinghua University , Beijing 100084, China
| | - Chuanhua Duan
- Department of Mechanical Engineering, Boston University , Boston, Massachusetts 02215, USA
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17
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Abstract
We report label-free electrical detection of enzymatic reactions using 2-D nanofluidic channels and investigate reaction kinetics of enzymatic reactions on immobilized substrates in nanoscale-confined spaces. Trypsin proteolysis is chosen for demonstration of the detection scheme. When trypsin cleaves poly-l-lysine coated on the surface of silica nanochannels, the resulting change of surface charge density can be detected by monitoring the ionic conductance of the nanochannels. Our results show that detection of such surface enzymatic reactions is faster than detection of surface binding reactions in nanochannels for low-concentration analytes. Furthermore, the nanochannel sensor has a sensitivity down to 5 ng/mL, which statistically corresponds to a single enzyme per nanochannel. Our results also suggest that enzyme kinetics in nanochannels is fundamentally different from that in bulk solutions or plain surfaces. Such enzymatic reactions form two clear self-propagating reaction fronts inside the nanochannels, and the reaction fronts follow square-root time dependences at high enzyme concentrations due to significant nonspecific adsorption. However, at low enzyme concentrations when nonspecific adsorption is negligible, the reaction fronts propagate linearly with time, and the corresponding propagation speed is related to the channel geometry, enzyme concentration, catalytic reaction constant, diffusion coefficient, and substrate surface density. Optimization of this nanochannel sensor could lead to a quick-response, highly sensitive, and label-free sensor for enzyme assay and kinetic studies.
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Affiliation(s)
- Chuanhua Duan
- Department of Mechanical Engineering, Boston University , Boston, Massachusetts 02215, United States
| | - Mohammad Amin Alibakhshi
- Department of Mechanical Engineering, Boston University , Boston, Massachusetts 02215, United States
| | - Dong-Kwon Kim
- Department of Mechanical Engineering, Ajou University , Suwon 443-749, South Korea
| | - Christopher M Brown
- Department of Pharmaceutical Chemistry, University of California , San Francisco, California 94158, United States
| | - Charles S Craik
- Department of Pharmaceutical Chemistry, University of California , San Francisco, California 94158, United States
| | - Arun Majumdar
- Department of Mechanical Engineering, Stanford University , Stanford, California 94305, United States
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18
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Alibakhshi MA, Xie Q, Li Y, Duan C. Accurate measurement of liquid transport through nanoscale conduits. Sci Rep 2016; 6:24936. [PMID: 27112404 PMCID: PMC4844961 DOI: 10.1038/srep24936] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 03/30/2016] [Indexed: 11/10/2022] Open
Abstract
Nanoscale liquid transport governs the behaviour of a wide range of nanofluidic systems, yet remains poorly characterized and understood due to the enormous hydraulic resistance associated with the nanoconfinement and the resulting minuscule flow rates in such systems. To overcome this problem, here we present a new measurement technique based on capillary flow and a novel hybrid nanochannel design and use it to measure water transport through single 2-D hydrophilic silica nanochannels with heights down to 7 nm. Our results show that silica nanochannels exhibit increased mass flow resistance compared to the classical hydrodynamics prediction. This difference increases with decreasing channel height and reaches 45% in the case of 7 nm nanochannels. This resistance increase is attributed to the formation of a 7-angstrom-thick stagnant hydration layer on the hydrophilic surfaces. By avoiding use of any pressure and flow sensors or any theoretical estimations the hybrid nanochannel scheme enables facile and precise flow measurement through single nanochannels, nanotubes, or nanoporous media and opens the prospect for accurate characterization of both hydrophilic and hydrophobic nanofluidic systems.
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Affiliation(s)
- Mohammad Amin Alibakhshi
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA
| | - Quan Xie
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA
| | - Yinxiao Li
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA
| | - Chuanhua Duan
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA
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Azarpeyvand M, Alibakhshi MA, Self R. Effects of multi-scattering on the performance of a single-beam acoustic manipulation device. IEEE Trans Ultrason Ferroelectr Freq Control 2012; 59:1741-1749. [PMID: 22899120 DOI: 10.1109/tuffc.2012.2378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The effects of multiple scattering on acoustic manipulation of spherical particles using helicoidal Bessel-beams are discussed. A closed-form analytical solution is developed to calculate the acoustic radiation force resulting from a Bessel-beam on an acoustically reflective sphere, in the presence of an adjacent spherical particle, immersed in an unbounded fluid medium. The solution is based on the standard Fourier decomposition method and the effect of multi-scattering is taken into account using the addition theorem for spherical coordinates. Of particular interest here is the investigation of the effects of multiple scattering on the emergence of negative axial forces. To investigate the effects, the radiation force applied on the target particle resulting from a helicoidal Bessel-beam of different azimuthal indexes (m = 1 to 4), at different conical angles, is computed. Results are presented for soft and rigid spheres of various sizes, separated by a finite distance. Results have shown that the emergence of negative force regions is very sensitive to the level of cross-scattering between the particles. It has also been shown that in multiple scattering media, the negative axial force may occur at much smaller conical angles than previously reported for single particles, and that acoustic manipulation of soft spheres in such media may also become possible.
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