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Yang L, Hu J, Li MC, Xu M, Gu ZY. Solid-state nanopore: chemical modifications, interactions, and functionalities. Chem Asian J 2022; 17:e202200775. [PMID: 36071031 DOI: 10.1002/asia.202200775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/06/2022] [Indexed: 11/08/2022]
Abstract
Nanopore technology is a burgeoning detection technology for single-molecular sensing and ion rectification. Solid-state nanopores have attracted more and more attention because of their higher stability and tunability than biological nanopores. However, solid-state nanopores still suffer the drawbacks of low signal-to-noise ratio and low resolution, which hinders their practical applications. Thus, developing operatical and useful methods to overcome the shortages of solid-state nanopores is urgently needed. Here, we summarize the recent research on nanopore modification to achieve this goal. Modifying solid-state nanopores with different coating molecules can improve the selectivity, sensitivity, and stability of nanopores. The modified molecules can introduce different functions into the nanopores, greatly expanding the applications of this novel detection technology. We hope that this review of nanopore modification will provide new ideas for this field.
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Affiliation(s)
- Lei Yang
- Nanjing Normal University, College of Chemistry and Materials Science, CHINA
| | - Jun Hu
- Nanjing Normal University, College of Chemistry and Materials Science, CHINA
| | - Min-Chao Li
- Nanjing Normal University, College of Chemistry and Materials Science, CHINA
| | - Ming Xu
- Nanjing Normal University, College of Chemistry and Materials Science, CHINA
| | - Zhi-Yuan Gu
- Nanjing Normal University, College of Chemistry and Materials Science, 1 Wenyuan Rd, 210023, Nanjing, CHINA
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2
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Xia P, Zuo J, Paudel P, Choi S, Chen X, Rahman Laskar MA, Bai J, Song W, Im J, Wang C. Sapphire-supported nanopores for low-noise DNA sensing. Biosens Bioelectron 2021; 174:112829. [PMID: 33308962 DOI: 10.1016/j.bios.2020.112829] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/24/2020] [Accepted: 11/16/2020] [Indexed: 10/22/2022]
Abstract
Solid-state nanopores have broad applications from single-molecule biosensing to diagnostics and sequencing. The high capacitive noise from conventionally used conductive silicon substrates, however, has seriously limited both their sensing accuracy and recording speed. A new approach is proposed here for forming nanopore membranes on insulating sapphire wafers to promote low-noise nanopore sensing. Anisotropic wet etching of sapphire through micro-patterned triangular masks is used to demonstrate the feasibility of scalable formation of small (<25 μm) membranes with a size deviation of less than 7 μm over two 2-inch wafers. For validation, a sapphire-supported (SaS) nanopore chip with a 100 times larger membrane area than conventional nanopores was tested, which showed 130 times smaller capacitance (10 pF) and 2.6 times smaller root-mean-square (RMS) noise current (18-21 pA over 100 kHz bandwidth, with 50-150 mV bias) when compared to a silicon-supported (SiS) nanopore (~1.3 nF, and 46-51 pA RMS noise). Tested with 1k base-pair double-stranded DNA, the SaS nanopore enabled sensing at microsecond speed with a signal-to-noise ratio of 21, compared to 11 from a SiS nanopore. This SaS nanopore presents a manufacturable nanoelectronic platform feasible for high-speed and low-noise sensing of a variety of biomolecules.
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Affiliation(s)
- Pengkun Xia
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, USA; Center for Photonics Innovation, Arizona State University, Tempe, AZ, USA; Biodesign Center for Molecular Design & Biomimetics, Arizona State University, Tempe, AZ, USA
| | - Jiawei Zuo
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, USA; Center for Photonics Innovation, Arizona State University, Tempe, AZ, USA; Biodesign Center for Molecular Design & Biomimetics, Arizona State University, Tempe, AZ, USA
| | - Pravin Paudel
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, USA; Center for Photonics Innovation, Arizona State University, Tempe, AZ, USA
| | - Shinhyuk Choi
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, USA; Center for Photonics Innovation, Arizona State University, Tempe, AZ, USA; Biodesign Center for Molecular Design & Biomimetics, Arizona State University, Tempe, AZ, USA
| | - Xiahui Chen
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, USA; Center for Photonics Innovation, Arizona State University, Tempe, AZ, USA; Biodesign Center for Molecular Design & Biomimetics, Arizona State University, Tempe, AZ, USA
| | - Md Ashiqur Rahman Laskar
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, USA; Center for Photonics Innovation, Arizona State University, Tempe, AZ, USA; Biodesign Center for Molecular Design & Biomimetics, Arizona State University, Tempe, AZ, USA
| | - Jing Bai
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, USA; Center for Photonics Innovation, Arizona State University, Tempe, AZ, USA
| | - Weisi Song
- Biodesign Center for Single Molecule Biophysics, Arizona State University, Tempe, AZ, USA
| | - JongOne Im
- Biodesign Center for Single Molecule Biophysics, Arizona State University, Tempe, AZ, USA; Curent Address: INanoBio Inc, Scottsdale, AZ, USA
| | - Chao Wang
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, USA; Center for Photonics Innovation, Arizona State University, Tempe, AZ, USA; Biodesign Center for Molecular Design & Biomimetics, Arizona State University, Tempe, AZ, USA.
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3
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Lenhart B, Wei X, Zhang Z, Wang X, Wang Q, Liu C. Nanopore Fabrication and Application as Biosensors in Neurodegenerative Diseases. Crit Rev Biomed Eng 2020; 48:29-62. [PMID: 32749118 PMCID: PMC8020784 DOI: 10.1615/critrevbiomedeng.2020033151] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Since its conception as an applied biomedical technology nearly 30 years ago, nanopore is emerging as a promising, high-throughput, biomarker-targeted diagnostic tool for clinicians. The attraction of a nanopore-based detection system is its simple, inexpensive, robust, user-friendly, high-throughput blueprint with minimal sample preparation needed prior to analysis. The goal of clinical-based nanopore biosensing is to go from sample acquisition to a meaningful readout quickly. The most extensive work in nanopore applications has been targeted at DNA, RNA, and peptide identification. Although, biosensing of pathological biomarkers, which is covered in this review, is on the rise. This review is broken into two major sections: (i) the current state of existing biological, solid state, and hybrid nanopore systems and (ii) the applications of nanopore biosensors toward detecting neurodegenerative biomarkers.
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Affiliation(s)
- Brian Lenhart
- Department of Chemical Engineering, University of South Carolina, Columbia, SC
| | - Xiaojun Wei
- Department of Chemical Engineering, University of South Carolina, Columbia, SC
- Biomedical Engineering Program, University of South Carolina, Columbia, SC
| | - Zehui Zhang
- Biomedical Engineering Program, University of South Carolina, Columbia, SC
| | - Xiaoqin Wang
- Department of Chemical Engineering, University of South Carolina, Columbia, SC
| | - Qian Wang
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC
| | - Chang Liu
- Department of Chemical Engineering, University of South Carolina, Columbia, SC
- Biomedical Engineering Program, University of South Carolina, Columbia, SC
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4
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Eggenberger OM, Ying C, Mayer M. Surface coatings for solid-state nanopores. NANOSCALE 2019; 11:19636-19657. [PMID: 31603455 DOI: 10.1039/c9nr05367k] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Since their introduction in 2001, solid-state nanopores have been increasingly exploited for the detection and characterization of biomolecules ranging from single DNA strands to protein complexes. A major factor that enables the application of nanopores to the analysis and characterization of a broad range of macromolecules is the preparation of coatings on the pore wall to either prevent non-specific adhesion of molecules or to facilitate specific interactions of molecules of interest within the pore. Surface coatings can therefore be useful to minimize clogging of nanopores or to increase the residence time of target analytes in the pore. This review article describes various coatings and their utility for changing pore diameters, increasing the stability of nanopores, reducing non-specific interactions, manipulating surface charges, enabling interactions with specific target molecules, and reducing the noise of current recordings through nanopores. We compare the coating methods with respect to the ease of preparing the coating, the stability of the coating and the requirement for specialized equipment to prepare the coating.
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Affiliation(s)
- Olivia M Eggenberger
- Adolphe Merkle Institute, Chemin des Verdiers 4, University of Fribourg, Fribourg, Switzerland.
| | - Cuifeng Ying
- Adolphe Merkle Institute, Chemin des Verdiers 4, University of Fribourg, Fribourg, Switzerland.
| | - Michael Mayer
- Adolphe Merkle Institute, Chemin des Verdiers 4, University of Fribourg, Fribourg, Switzerland.
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5
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de Vreede LJ, Ying C, Houghtaling J, Figueiredo Da Silva J, Hall AR, Lovera A, Mayer M. Wafer-scale fabrication of fused silica chips for low-noise recording of resistive pulses through nanopores. NANOTECHNOLOGY 2019; 30:265301. [PMID: 30849769 DOI: 10.1088/1361-6528/ab0e2a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This paper presents a maskless method to manufacture fused silica chips for low-noise resistive-pulse sensing. The fabrication includes wafer-scale density modification of fused silica with a femtosecond-pulsed laser, low-pressure chemical vapor deposition (LPVCD) of silicon nitride (SiN x ) and accelerated chemical wet etching of the laser-exposed regions. This procedure leads to a freestanding SiN x window, which is permanently attached to a fused silica support chip and the resulting chips are robust towards Piranha cleaning at ∼80 °C. After parallel chip manufacturing, we created a single nanopore in each chip by focused helium-ion beam or by controlled breakdown. Compared to silicon chips, the resulting fused silica nanopore chips resulted in a four-fold improvement of both the signal-to-noise ratio and the capture rate for signals from the translocation of IgG1 proteins at a recording bandwidth of 50 kHz. At a bandwidth of ∼1 MHz, the noise from the fused silica nanopore chips was three- to six-fold reduced compared to silicon chips. In contrast to silicon chips, fused silica chips showed no laser-induced current noise-a significant benefit for experiments that strive to combine nanopore-based electrical and optical measurements.
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Affiliation(s)
- Lennart J de Vreede
- Biophysics group, Adolphe Merkle Institute, University of Fribourg, Fribourg, Switzerland
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6
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Houghtaling J, List J, Mayer M. Nanopore-Based, Rapid Characterization of Individual Amyloid Particles in Solution: Concepts, Challenges, and Prospects. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1802412. [PMID: 30225962 DOI: 10.1002/smll.201802412] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 08/15/2018] [Indexed: 06/08/2023]
Abstract
Aggregates of misfolded proteins are associated with several devastating neurodegenerative diseases. These so-called amyloids are therefore explored as biomarkers for the diagnosis of dementia and other disorders, as well as for monitoring disease progression and assessment of the efficacy of therapeutic interventions. Quantification and characterization of amyloids as biomarkers is particularly demanding because the same amyloid-forming protein can exist in different states of assembly, ranging from nanometer-sized monomers to micrometer-long fibrils that interchange dynamically both in vivo and in samples from body fluids ex vivo. Soluble oligomeric amyloid aggregates, in particular, are associated with neurotoxic effects, and their molecular organization, size, and shape appear to determine their toxicity. This concept article proposes that the emerging field of nanopore-based analytics on a single molecule and single aggregate level holds the potential to account for the heterogeneity of amyloid samples and to characterize these particles-rapidly, label-free, and in aqueous solution-with regard to their size, shape, and abundance. The article describes the concept of nanopore-based resistive pulse sensing, reviews previous work in amyloid analysis, and discusses limitations and challenges that will need to be overcome to realize the full potential of amyloid characterization on a single-particle level.
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Affiliation(s)
- Jared Houghtaling
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700, Fribourg, Switzerland
| | - Jonathan List
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700, Fribourg, Switzerland
| | - Michael Mayer
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700, Fribourg, Switzerland
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7
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Gangotra A, Willmott GR. Scanning ion conductance microscopy mapping of tunable nanopore membranes. BIOMICROFLUIDICS 2017; 11:054102. [PMID: 28966699 PMCID: PMC5599259 DOI: 10.1063/1.4999488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 09/06/2017] [Indexed: 06/07/2023]
Abstract
We report on the use of scanning ion conductance microscopy (SICM) for in-situ topographical mapping of single tunable nanopores, which are used for tunable resistive pulse sensing. A customised SICM system was used to map the elastomeric pore membranes repeatedly, using pipettes with tip opening diameters of approximately 50 nm and 1000 nm. The effect of variations on current threshold, scanning step size, and stretching has been studied. Lowering the current threshold increased the sensitivity of the pipette while scanning, up to the point where the tip contacted the surface. An increase in the pore area was observed as the step size was decreased, and with increased stretching. SICM reveals details of the electric field near the pore entrance, which is important for understanding measurements of submicron particles using resistive pulse sensing.
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8
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Weatherall E, Hauer P, Vogel R, Willmott GR. Pulse Size Distributions in Tunable Resistive Pulse Sensing. Anal Chem 2016; 88:8648-56. [DOI: 10.1021/acs.analchem.6b01818] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
| | | | - Robert Vogel
- Izon Science Limited, 8C Homersham Place, P.O. Box 39168,
Burnside, Christchurch 8053, New Zealand
- School
of Mathematics and Physics, The University of Queensland, Brisbane 4072, Australia
| | - Geoff R. Willmott
- The
Departments of Physics and Chemistry, The University of Auckland, Auckland 1142, New Zealand
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9
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Abstract
This Review focusses on the recent surge in applied research using tunable resistive pulse sensing, a technique used to analyse submicron colloids in aqueous solutions on a particle-by-particle basis.
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Affiliation(s)
- Eva Weatherall
- The MacDiarmid Institute for Advanced Materials and Nanotechnology
- School of Chemical and Physical Sciences
- Victoria University of Wellington
- New Zealand
- Callaghan Innovation
| | - Geoff R. Willmott
- The MacDiarmid Institute for Advanced Materials and Nanotechnology
- School of Chemical and Physical Sciences
- Victoria University of Wellington
- New Zealand
- The Departments of Physics and Chemistry
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10
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Willmott GR, Fisk MG, Eldridge J. Magnetic microbead transport during resistive pulse sensing. BIOMICROFLUIDICS 2013; 7:64106. [PMID: 24396540 PMCID: PMC3855170 DOI: 10.1063/1.4833075] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 11/11/2013] [Indexed: 05/24/2023]
Abstract
Tunable resistive pulse sensing (TRPS) experiments have been used to quantitatively study the motion of 1 μm superparamagnetic beads in a variable magnetic field. Closed-form theory has been developed to interpret the experiments, incorporating six particle transport mechanisms which depend on particle position in and near a conical pore. For our experiments, calculations indicate that pressure-driven flow dominates electrophoresis and magnetism by a factor of ∼100 in the narrowest part of the pore, but that magnetic force should dominate further than ∼1 mm from the membrane. As expected, the observed resistive pulse rate falls as the magnet is moved closer to the pore, while the increase in pulse duration suggests that trajectories in the half space adjacent to the pore opening are important. Aggregation was not observed, consistent with the high hydrodynamic shear near the pore constriction and the high magnetization of aggregates. The theoretical approach is also used to calculate the relative importance of transport mechanisms over a range of geometries and experimental conditions extending well beyond our own experiments. TRPS is emerging as a versatile form of resistive pulse sensing, while magnetic beads are widely used in biotechnology and sensing applications.
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Affiliation(s)
- Geoff R Willmott
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, Wellington, New Zealand ; Callaghan Innovation, 69 Gracefield Rd., Lower Hutt, New Zealand
| | - Matthew G Fisk
- Callaghan Innovation, 69 Gracefield Rd., Lower Hutt, New Zealand ; School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - James Eldridge
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, Wellington, New Zealand ; Callaghan Innovation, 69 Gracefield Rd., Lower Hutt, New Zealand ; School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
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11
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Platt M, Willmott GR, Lee GU. Resistive pulse sensing of analyte-induced multicomponent rod aggregation using tunable pores. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:2436-44. [PMID: 22570187 DOI: 10.1002/smll.201200058] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 03/07/2012] [Indexed: 05/09/2023]
Abstract
Resistive pulse sensing is used to monitor individual and aggregated rod-shaped nanoparticles as they move through tunable pores in elastomeric membranes. By comparing particles of similar dimensions, it is demonstrated that the resistive pulse signal of a rod is fundamentally different from that of a sphere. Rods can be distinguished using two measurements: the blockade event magnitude (Δi(p) ), which reveals the particle's size, and the full width at half maximum (FWHM) duration, which relates to the particle's speed and length. While the observed Δi(p) values agree well with simulations, the measured FWHM times are much larger than expected. This increase in dwell time, caused by rods moving through the pore in various orientations, is not observed for spherical particles. These differences are exploited in a new agglutination assay using rod-shaped particles. By controlling the surface chemistry and location of the capture ligand, rods are made to form either long "end-on-end" or wide "side-on" aggregates upon the addition of an analyte. This observation will facilitate multiplexed detection in agglutination assays, as particles with a particular aspect ratio can be distinguished by two measurements. This is first demonstrated with a biotinylated target and avidin capture probe, followed by the detection of platelet-derived growth factor (PDGF-BB) using an aptamer capture probe, with limits of detection down to femtomolar levels.
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Affiliation(s)
- Mark Platt
- Centre for Nanomedicine, School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.
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12
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Yusko EC, Prangkio P, Sept D, Rollings RC, Li J, Mayer M. Single-particle characterization of Aβ oligomers in solution. ACS NANO 2012; 6:5909-5919. [PMID: 22686709 PMCID: PMC3418869 DOI: 10.1021/nn300542q] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Determining the pathological role of amyloids in amyloid-associated diseases will require a method for characterizing the dynamic distributions in size and shape of amyloid oligomers with high resolution. Here, we explored the potential of resistive-pulse sensing through lipid bilayer-coated nanopores to measure the size of individual amyloid-β oligomers directly in solution and without chemical modification. This method classified individual amyloid-β aggregates as spherical oligomers, protofibrils, or mature fibers and made it possible to account for the large heterogeneity of amyloid-β aggregate sizes. The approach revealed the distribution of protofibrillar lengths (12- to 155 -mer) as well as the average cross-sectional area of protofibrils and fibers.
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Affiliation(s)
- Erik C. Yusko
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Panchika Prangkio
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - David Sept
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Center for Computational Medicine and Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Ryan C. Rollings
- Department of Physics, University of Arkansas, Fayetteville, Arkansas, 72701, USA
| | - Jiali Li
- Department of Physics, University of Arkansas, Fayetteville, Arkansas, 72701, USA
| | - Michael Mayer
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
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13
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Wang HW, Cheng CW, Li CW, Chang HW, Wu PH, Wang GJ. Fabrication of pillared PLGA microvessel scaffold using femtosecond laser ablation. Int J Nanomedicine 2012; 7:1865-73. [PMID: 22605935 PMCID: PMC3352691 DOI: 10.2147/ijn.s29969] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
One of the persistent challenges confronting tissue engineering is the lack of intrinsic microvessels for the transportation of nutrients and metabolites. An artificial microvascular system could be a feasible solution to this problem. In this study, the femtosecond laser ablation technique was implemented for the fabrication of pillared microvessel scaffolds of polylactic-co-glycolic acid (PLGA). This novel scaffold facilitates implementation of the conventional cell seeding process. The progress of cell growth can be observed in vitro by optical microscopy. The problems of becoming milky or completely opaque with the conventional PLGA scaffold after cell seeding can be resolved. In this study, PLGA microvessel scaffolds consisting of 47 μm × 80 μm pillared branches were produced. Results of cell culturing of bovine endothelial cells demonstrate that the cells adhere well and grow to surround each branch of the proposed pillared microvessel networks.
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Affiliation(s)
- Hsiao-Wei Wang
- Graduate Institute of Biomedical Engineering, National Chung Hsing University, Taichung, Taiwan
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14
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Vogel R, Anderson W, Eldridge J, Glossop B, Willmott G. A variable pressure method for characterizing nanoparticle surface charge using pore sensors. Anal Chem 2012; 84:3125-31. [PMID: 22369672 DOI: 10.1021/ac2030915] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel method using resistive pulse sensors for electrokinetic surface charge measurements of nanoparticles is presented. This method involves recording the particle blockade rate while the pressure applied across a pore sensor is varied. This applied pressure acts in a direction which opposes transport due to the combination of electro-osmosis, electrophoresis, and inherent pressure. The blockade rate reaches a minimum when the velocity of nanoparticles in the vicinity of the pore approaches zero, and the forces on typical nanoparticles are in equilibrium. The pressure applied at this minimum rate can be used to calculate the zeta potential of the nanoparticles. The efficacy of this variable pressure method was demonstrated for a range of carboxylated 200 nm polystyrene nanoparticles with different surface charge densities. Results were of the same order as phase analysis light scattering (PALS) measurements. Unlike PALS results, the sequence of increasing zeta potential for different particle types agreed with conductometric titration.
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Affiliation(s)
- Robert Vogel
- School of Mathematics and Physics, The University of Queensland, St. Lucia, QLD 4072, Australia.
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15
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Willmott GR, Platt M, Lee GU. Resistive pulse sensing of magnetic beads and supraparticle structures using tunable pores. BIOMICROFLUIDICS 2012; 6:14103-1410315. [PMID: 22662090 PMCID: PMC3365342 DOI: 10.1063/1.3673596] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 12/09/2011] [Indexed: 05/14/2023]
Abstract
Tunable pores (TPs) have been used for resistive pulse sensing of 1 μm superparamagnetic beads, both dispersed and within a magnetic field. Upon application of this field, magnetic supraparticle structures (SPSs) were observed. Onset of aggregation was most effectively indicated by an increase in the mean event magnitude, with data collected using an automated thresholding method. Simulations enabled discrimination between resistive pulses caused by dimers and individual particles. Distinct but time-correlated peaks were often observed, suggesting that SPSs became separated in pressure-driven flow focused at the pore constriction. The distinct properties of magnetophoretic and pressure-driven transport mechanisms can explain variations in the event rate when particles move through an asymmetric pore in either direction, with or without a magnetic field applied. Use of TPs for resistive pulse sensing holds potential for efficient, versatile analysis and measurement of nano- and microparticles, while magnetic beads and particle aggregation play important roles in many prospective biosensing applications.
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16
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Costa L, Terekhov A, Rajput D, Hofmeister W, Jowhar D, Wright G, Janetopoulos C. Femtosecond laser machined microfluidic devices for imaging of cells during chemotaxis. JOURNAL OF LASER APPLICATIONS 2011; 23:1.3614405. [PMID: 24532962 PMCID: PMC3922128 DOI: 10.2351/1.3614405] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Microfluidic devices designed for chemotaxis assays were fabricated on fused silica substrates using femtosecond laser micromachining. These devices have built-in chemical concentration gradient forming structures and are ideally suited for establishing passive diffusion gradients over extended periods of time. Multiple gradient forming structures, with identical or distinct gradient forming characteristics, can be integrated into a single device, and migrating cells can be directly observed using an inverted microscope. In this paper, the design, fabrication, and operation of these devices are discussed. Devices with minimal structure sizes ranging from 3 to 7 lm are presented. The use of these devices to investigate the migration of Dictyostelium discoideum cells toward the chemoattractant folic acid is presented as an example of the devices' utility.
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Affiliation(s)
- L Costa
- Center for Laser Applications, University of Tennessee Space Institute, Tullahoma, Tennessee 37388
| | - A Terekhov
- Center for Laser Applications, University of Tennessee Space Institute, Tullahoma, Tennessee 37388
| | - D Rajput
- Center for Laser Applications, University of Tennessee Space Institute, Tullahoma, Tennessee 37388
| | - W Hofmeister
- Center for Laser Applications, University of Tennessee Space Institute, Tullahoma, Tennessee 37388
| | - D Jowhar
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37240
| | - G Wright
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37240
| | - C Janetopoulos
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37240 and Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee 37240
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17
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Vogel R, Willmott G, Kozak D, Roberts GS, Anderson W, Groenewegen L, Glossop B, Barnett A, Turner A, Trau M. Quantitative sizing of nano/microparticles with a tunable elastomeric pore sensor. Anal Chem 2011; 83:3499-506. [PMID: 21434639 DOI: 10.1021/ac200195n] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The use of a "size-tunable" polyurethane resistive pulse sensor for quantitative sizing of nano- and microparticles is presented. A linear relationship, as first suggested by Maxwell, between particle volume and change in electric resistance across the pore was observed. Particle sizes were quantified for a given size-tunable membrane, by first creating a linear calibration curve to a series of monodisperse carboxylated polystyrene particles of various diameters and then applying this curve to calculate the size of "unknown" nanoparticles. The diameters of a selection of synthetic and biological particles, being PMMA and nonfunctionalized polystyrene particles, along with biological nanoparticles (adenovirus) were calculated using this methodology. Calculated particle diameters and coefficients of variation were shown to be in good agreement with both transmission electron microscopy and dynamic light scattering results.
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Affiliation(s)
- Robert Vogel
- School of Mathematics and Physics, The University of Queensland, St. Lucia QLD, Australia.
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Yusko EC, Billeh YN, Mayer M. Current oscillations generated by precipitate formation in the mixing zone between two solutions inside a nanopore. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:454127. [PMID: 21339613 DOI: 10.1088/0953-8984/22/45/454127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Unlike biological protein pores in lipid membranes, nanopores fabricated in synthetic materials can withstand a wide range of environmental conditions including the presence of organic solvents. This capability expands the potential of synthetic nanopores to monitor chemical reactions occurring at the interface between solutions of organic and aqueous character. In this work, nanopores fabricated in borosilicate glass or silicon nitride connected a predominantly organic solvent to an aqueous solvent, thereby generating a mixing zone between these solutions inside the pore. This configuration was exploited to precipitate small organic molecules with low aqueous solubility inside the nanopores, and concomitantly, to monitor this precipitation by the decrease of the ionic conductance through the nanopores over time. Hence, this method provides a means to induce and investigate the formation of nanoprecipitates or nanoparticles. Interestingly, precipitates with a slight electric charge were cleared from the pore, causing the conductance of the pore to return to its original value. This process repeated, resulting in stable oscillations of the ionic current. Although such oscillations might be useful in fluidic logic circuits, few conditions capable of generating oscillations in ionic currents have been reported. The frequency and amplitude of oscillations could be tuned by changing the concentration of the precipitating molecule, the pH of the electrolyte, and the applied potential bias. In addition to generating oscillations, nanopores that separate two different solutions may be useful for monitoring and mediating chemical reactions in the mixing zone between two solutions.
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Affiliation(s)
- Erik C Yusko
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Lurie Biomedical Engineering Building, Room 2174, Ann Arbor, MI 48109-2110, USA
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Yusko EC, An R, Mayer M. Electroosmotic flow can generate ion current rectification in nano- and micropores. ACS NANO 2010; 4:477-487. [PMID: 20028119 DOI: 10.1021/nn9013438] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This paper introduces a strategy for generating ion current rectification through nano- and micropores. This method generates ion current rectification by electroosmotic-driven flow of liquids of varying viscosity (and hence varying conductance) into or out of the narrowest constriction of a pore. The magnitude of current rectification was described by a rectification factor, R(f), which is defined by the ratio of the current measured at a positive voltage divided by the current measured at a negative voltage. This method achieved rectification factors in the range of 5-15 using pores with diameters ranging from 10 nm to 2.2 microm. These R(f) values are similar to the rectification factors reported in other nanopore-based methods that did not employ segmented surface charges. Interestingly, this work showed that in cylindrical nanopores with diameters of 10 nm and a length of at least 275 nm, electroosmotic flow was present and could generate ion current rectification. Unlike previous methods for generating ion current rectification that require nanopores with diameters comparable to the Debye length, this work demonstrated ion current rectification in micropores with diameters 500 times larger than the Debye length. Thus this method extends the concept of fluidic diodes to the micropore range. Several experiments designed to alter or remove electroosmotic flow through the pore demonstrated that electroosmotic flow was required for the mode of ion current rectification reported here. Consequently, the magnitude of current rectification could be used to indicate the presence of electroosmotic flow and the breakdown of electroosmotic flow with decreasing ionic strength and hence increasing electric double layer overlap inside nanopores.
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Affiliation(s)
- Erik C Yusko
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, 48109-2110, USA
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Yang K, Zhou Y, Ren Q, Ye JY, Deng CX. Dynamics of microbubble generation and trapping by self-focused femtosecond laser pulses. APPLIED PHYSICS LETTERS 2009; 95:051107. [PMID: 24958933 PMCID: PMC4056747 DOI: 10.1063/1.3187535] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 07/01/2009] [Indexed: 05/25/2023]
Abstract
Different from conventional optical tweezers used for trapping high refractive index micron-sized particles, bubble generation and trapping by femtosecond laser offer a unique strategy to manipulate microbubbles. Using high frequency ultrasound imaging and fast-frame optical video microscopy, we obtained results revealing the spatiotemporal characteristics of bubble generation and trapping by self-focused femtosecond laser pulses at multiple locations along the laser beam. We detected distinct acoustic signals associated with the laser focus and measured the trapping force by using acoustic radiation force to detrap the bubble from the laser beam.
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Affiliation(s)
- Kun Yang
- Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, Michigan 48109, USA ; Department of Biomedical Engineering, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China
| | - Yun Zhou
- Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, Michigan 48109, USA
| | - Qiushi Ren
- Department of Biomedical Engineering, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China
| | - Jing Yong Ye
- Center for Ultrafast Optical Science and Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, Michigan 48109, USA
| | - Cheri X Deng
- Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, Michigan 48109, USA
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An R, Hoffman MD, Donoghue MA, Hunt AJ, Jacobson SC. Water-assisted femtosecond laser machining of electrospray nozzles on glass microfluidic devices. OPTICS EXPRESS 2008; 16:15206-15211. [PMID: 18795059 DOI: 10.1364/oe.16.015206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Using water-assisted femtosecond laser machining, we fabricated electrospray nozzles on glass coverslips and on assembled microfluidic devices. Machining the nozzles after device assembly facilitated alignment of the nozzles over the microchannels. The basic nozzle design is a through-hole in the coverslip to pass liquids and a trough machined around the through-hole to confine the electrospray and prevent liquid from wicking across the glass surface. Electrospray from the nozzles was stable with and without pressure-driven flow applied and was evaluated using mass spectra of the peptide bradykinin.
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Affiliation(s)
- Ran An
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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Blake S, Capone R, Mayer M, Yang J. Chemically Reactive Derivatives of Gramicidin A for Developing Ion Channel-Based Nanoprobes. Bioconjug Chem 2008; 19:1614-24. [DOI: 10.1021/bc800180z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Steven Blake
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California 92093-0358, and Department of Biomedical Engineering and Department of Chemical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, Michigan 48109
| | - Ricardo Capone
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California 92093-0358, and Department of Biomedical Engineering and Department of Chemical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, Michigan 48109
| | - Michael Mayer
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California 92093-0358, and Department of Biomedical Engineering and Department of Chemical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, Michigan 48109
| | - Jerry Yang
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California 92093-0358, and Department of Biomedical Engineering and Department of Chemical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, Michigan 48109
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