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Carneiro-Neto E, Li Z, Pereira E, Mathwig K, Fletcher PJ, Marken F. Understanding Transient Ionic Diode Currents and Impedance Responses for Aquivion-Coated Microholes. ACS Appl Mater Interfaces 2023; 15:39905-39914. [PMID: 37567567 PMCID: PMC10450689 DOI: 10.1021/acsami.3c08543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023]
Abstract
Ionic diode based devices or circuits can be applied, for example, in electroosmotic pumps or in desalination processes. Aquivion ionomer coated asymmetrically over a Teflon film (5 μm thickness) with a laser-drilled microhole (approximately 10 μm diameter) gives a cationic diode with a rectification ratio of typically 10-20 (measured in 0.01 M NaCl with ±0.3 V applied bias). Steady state voltammetry, chronoamperometry, and electrochemical impedance spectroscopy data are employed to characterize the ionic diode performance parameters. Next, a COMSOL 6.0 finite element model is employed to quantitatively assess/compare transient phenomena and to extract mechanistic information by comparison with experimental data. The experimental diode time constant and diode switching process associated with a distorted semicircle (with a typical diode switching frequency of 10 Hz) in the Nyquist plot are reproduced by computer simulation and rationalized in terms of microhole diffusion-migration times. Fundamental understanding and modeling of the ionic diode switching process can be exploited in the rational/optimized design of new improved devices.
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Affiliation(s)
- Evaldo
Batista Carneiro-Neto
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2
7AY, United Kingdom
- Department
of Chemistry, Federal University of São
Carlos, Rod. Washington Luiz, Km 235, CEP, São
Carlos 13565-905, São
Paulo, Brazil
| | - Zhongkai Li
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2
7AY, United Kingdom
| | - Ernesto Pereira
- Department
of Chemistry, Federal University of São
Carlos, Rod. Washington Luiz, Km 235, CEP, São
Carlos 13565-905, São
Paulo, Brazil
| | - Klaus Mathwig
- imec
within OnePlanet Research Center, Bronland 10, 6708
WH Wageningen, The
Netherlands
| | - Philip J. Fletcher
- University
of Bath, Materials &
Chemical Characterisation Facility MC, Bath BA2 7AY, United Kingdom
| | - Frank Marken
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2
7AY, United Kingdom
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2
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Goldsteen PA, Sabogal Guaqueta AM, Mulder PPMFA, Bos IST, Eggens M, Van der Koog L, Soeiro JT, Halayko AJ, Mathwig K, Kistemaker LEM, Verpoorte EMJ, Dolga AM, Gosens R. Differentiation and on axon-guidance chip culture of human pluripotent stem cell-derived peripheral cholinergic neurons for airway neurobiology studies. Front Pharmacol 2022; 13:991072. [PMID: 36386177 PMCID: PMC9651921 DOI: 10.3389/fphar.2022.991072] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [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: 07/11/2022] [Accepted: 10/12/2022] [Indexed: 11/23/2022] Open
Abstract
Airway cholinergic nerves play a key role in airway physiology and disease. In asthma and other diseases of the respiratory tract, airway cholinergic neurons undergo plasticity and contribute to airway hyperresponsiveness and mucus secretion. We currently lack human in vitro models for airway cholinergic neurons. Here, we aimed to develop a human in vitro model for peripheral cholinergic neurons using human pluripotent stem cell (hPSC) technology. hPSCs were differentiated towards vagal neural crest precursors and subsequently directed towards functional airway cholinergic neurons using the neurotrophin brain-derived neurotrophic factor (BDNF). Cholinergic neurons were characterized by ChAT and VAChT expression, and responded to chemical stimulation with changes in Ca2+ mobilization. To culture these cells, allowing axonal separation from the neuronal cell bodies, a two-compartment PDMS microfluidic chip was subsequently fabricated. The two compartments were connected via microchannels to enable axonal outgrowth. On-chip cell culture did not compromise phenotypical characteristics of the cells compared to standard culture plates. When the hPSC-derived peripheral cholinergic neurons were cultured in the chip, axonal outgrowth was visible, while the somal bodies of the neurons were confined to their compartment. Neurons formed contacts with airway smooth muscle cells cultured in the axonal compartment. The microfluidic chip developed in this study represents a human in vitro platform to model neuro-effector interactions in the airways that may be used for mechanistic studies into neuroplasticity in asthma and other lung diseases.
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Affiliation(s)
- P. A. Goldsteen
- Department of Molecular Pharmacology, University of Groningen, Groningen, Netherlands
- GRIAC, Groningen Research Institute for Asthma and COPD, University of Groningen, Groningen, Netherlands
| | | | - P. P. M. F. A. Mulder
- Department of Pharmaceutical Analysis, University of Groningen, Groningen, Netherlands
| | - I. S. T. Bos
- Department of Molecular Pharmacology, University of Groningen, Groningen, Netherlands
- GRIAC, Groningen Research Institute for Asthma and COPD, University of Groningen, Groningen, Netherlands
| | - M. Eggens
- Department of Molecular Pharmacology, University of Groningen, Groningen, Netherlands
| | - L. Van der Koog
- Department of Molecular Pharmacology, University of Groningen, Groningen, Netherlands
- GRIAC, Groningen Research Institute for Asthma and COPD, University of Groningen, Groningen, Netherlands
| | - J. T. Soeiro
- Department of Molecular Pharmacology, University of Groningen, Groningen, Netherlands
| | - A. J. Halayko
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
| | - K. Mathwig
- Department of Pharmaceutical Analysis, University of Groningen, Groningen, Netherlands
| | - L. E. M. Kistemaker
- Department of Molecular Pharmacology, University of Groningen, Groningen, Netherlands
- GRIAC, Groningen Research Institute for Asthma and COPD, University of Groningen, Groningen, Netherlands
- Aquilo BV, Groningen, Netherlands
| | - E. M. J. Verpoorte
- Department of Pharmaceutical Analysis, University of Groningen, Groningen, Netherlands
| | - A. M. Dolga
- Department of Molecular Pharmacology, University of Groningen, Groningen, Netherlands
- GRIAC, Groningen Research Institute for Asthma and COPD, University of Groningen, Groningen, Netherlands
- *Correspondence: R. Gosens, ; A. M. Dolga,
| | - R. Gosens
- Department of Molecular Pharmacology, University of Groningen, Groningen, Netherlands
- GRIAC, Groningen Research Institute for Asthma and COPD, University of Groningen, Groningen, Netherlands
- *Correspondence: R. Gosens, ; A. M. Dolga,
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3
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Li Z, Pang T, Shen J, Fletcher PJ, Mathwig K, Marken F. Ionic diode desalination: Combining cationic Nafion™ and anionic Sustainion™ rectifiers. Micro and Nano Engineering 2022. [DOI: 10.1016/j.mne.2022.100157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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4
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Fontana M, Ivanovaitė Š, Lindhoud S, van der Wijk E, Mathwig K, Berg WVD, Weijers D, Hohlbein J. Probing DNA - Transcription Factor Interactions Using Single-Molecule Fluorescence Detection in Nanofluidic Devices. Adv Biol (Weinh) 2022; 6:e2100953. [PMID: 34472724 DOI: 10.1002/adbi.202100953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/16/2021] [Indexed: 01/27/2023]
Abstract
Single-molecule fluorescence detection offers powerful ways to study biomolecules and their complex interactions. Here, nanofluidic devices and camera-based, single-molecule Förster resonance energy transfer (smFRET) detection are combined to study the interactions between plant transcription factors of the auxin response factor (ARF) family and DNA oligonucleotides that contain target DNA response elements. In particular, it is shown that the binding of the unlabeled ARF DNA binding domain (ARF-DBD) to donor and acceptor labeled DNA oligonucleotides can be detected by changes in the FRET efficiency and changes in the diffusion coefficient of the DNA. In addition, this data on fluorescently labeled ARF-DBDs suggest that, at nanomolar concentrations, ARF-DBDs are exclusively present as monomers. In general, the fluidic framework of freely diffusing molecules minimizes potential surface-induced artifacts, enables high-throughput measurements, and proved to be instrumental in shedding more light on the interactions between ARF-DBDs monomers and between ARF-DBDs and their DNA response element.
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Affiliation(s)
- Mattia Fontana
- Laboratory of Biophysics, Wageningen University and Research, Stippeneng 4, Wageningen, 6708 WE, The Netherlands.,Laboratory of Biochemistry, Wageningen University and Research, Stippeneng 4, Wageningen, 6708 WE, The Netherlands
| | - Šarunė Ivanovaitė
- Laboratory of Biophysics, Wageningen University and Research, Stippeneng 4, Wageningen, 6708 WE, The Netherlands
| | - Simon Lindhoud
- Laboratory of Biochemistry, Wageningen University and Research, Stippeneng 4, Wageningen, 6708 WE, The Netherlands
| | - Elmar van der Wijk
- Laboratory of Biophysics, Wageningen University and Research, Stippeneng 4, Wageningen, 6708 WE, The Netherlands.,Laboratory of Biochemistry, Wageningen University and Research, Stippeneng 4, Wageningen, 6708 WE, The Netherlands
| | - Klaus Mathwig
- Groningen Research Institute of Pharmacy, Pharmaceutical Analysis, University of Groningen, P.O. Box 196, 9700 AD, Groningen, The Netherlands.,Stichting Imec Nederland within OnePlanet Research Center, Bronland 10, Wageningen, 6708 WH, The Netherlands
| | - Willy van den Berg
- Laboratory of Biochemistry, Wageningen University and Research, Stippeneng 4, Wageningen, 6708 WE, The Netherlands
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University and Research, Stippeneng 4, Wageningen, 6708 WE, The Netherlands
| | - Johannes Hohlbein
- Laboratory of Biochemistry, Wageningen University and Research, Stippeneng 4, Wageningen, 6708 WE, The Netherlands.,Microspectroscopy Research Facility, Wageningen University and Research, Stippeneng 4, Wageningen, 6708 WE, The Netherlands
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5
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Mestres J, Leonardi F, Mathwig K. Amperometric Monitoring of Dissolution of pH-Responsive EUDRAGIT® Polymer Film Coatings. Micromachines 2022; 13:mi13030362. [PMID: 35334654 PMCID: PMC8949041 DOI: 10.3390/mi13030362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/23/2022] [Accepted: 02/24/2022] [Indexed: 02/04/2023]
Abstract
Electrochemical sensors are powerful tools for the detection and real-time monitoring of a wide variety of analytes. However, the long-term operation of Faradaic sensors in complex media is challenging due to fouling. The protection of the electrode surface during in vivo operation is a key element for improving the monitoring of analytes. Here, we study different EUDRAGIT® controlled release acrylate copolymers for protecting electrode surfaces. The dissolution of these polymers—namely EUDRAGIT® L 30 D-55 and EUDRAGIT® FS 30 D—is triggered by a change in pH of the environment, and it is electrochemically monitored by detecting electrode access by means of a redox probe. The full dissolution of the polymer is achieved within 30 min and the electrode response indicates a complete recovery of the original electrochemical performance. We demonstrate that amperometric sensing is a practical and straightforward technique for real-time and in situ sensing of EUDRAGIT® dissolution profiles. It will find future applications in determining the protection of polymer electrode coating in real matrices and in vivo applications.
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Affiliation(s)
- Júlia Mestres
- Stichting Imec Nederland within OnePlanet Research Center, Bronland 10, 6708 WH Wageningen, The Netherlands;
- School of Chemistry, University College Cork, Kane Building, T12 YN60 Cork, Ireland
| | - Francesca Leonardi
- Stichting Imec Nederland within OnePlanet Research Center, Bronland 10, 6708 WH Wageningen, The Netherlands;
- Correspondence: (F.L.); (K.M.)
| | - Klaus Mathwig
- Stichting Imec Nederland within OnePlanet Research Center, Bronland 10, 6708 WH Wageningen, The Netherlands;
- Correspondence: (F.L.); (K.M.)
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6
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Li Z, Malpass-Evans R, McKeown NB, Carta M, Mathwig K, Lowe JP, Marken F. Effective electroosmotic transport of water in an intrinsically microporous polyamine (PIM-EA-TB). Electrochem commun 2021. [DOI: 10.1016/j.elecom.2021.107110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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7
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Li Z, Wang L, Malpass‐Evans R, Carta M, McKeown NB, Mathwig K, Fletcher PJ, Marken F. Ionic Diode and Molecular Pump Phenomena Associated with Caffeic Acid Accumulated into an Intrinsically Microporous Polyamine (PIM‐EA‐TB). ChemElectroChem 2021. [DOI: 10.1002/celc.202100432] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Zhongkai Li
- Department of Chemistry University of Bath Claverton Down Bath BA2 7AY UK
| | - Lina Wang
- Department of Chemistry University of Bath Claverton Down Bath BA2 7AY UK
| | - Richard Malpass‐Evans
- EaStCHEM School of Chemistry University of Edinburgh, Joseph Black Building David Brewster Road Edinburgh, Scotland EH9 3JF UK
| | - Mariolino Carta
- Department of Chemistry Swansea University, College of Science, Grove Building Singleton Park Swansea SA2 8PP UK
| | - Neil B. McKeown
- EaStCHEM School of Chemistry University of Edinburgh, Joseph Black Building David Brewster Road Edinburgh, Scotland EH9 3JF UK
| | - Klaus Mathwig
- Stichting imec Nederland within OnePlanet Research Center Bronland 10 6708 WH Wageningen, The Netherlands
| | - Philip J. Fletcher
- University of Bath Materials & Chemical Characterisation Facility MC2 Bath BA2 7AY UK
| | - Frank Marken
- Department of Chemistry University of Bath Claverton Down Bath BA2 7AY UK
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8
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Riza Putra B, Tshwenya L, Buckingham MA, Chen J, Jeremiah Aoki K, Mathwig K, Arotiba OA, Thompson AK, Li Z, Marken F. Microscale Ionic Diodes: An Overview. ELECTROANAL 2021. [DOI: 10.1002/elan.202060614] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Budi Riza Putra
- Department of Chemistry University of Bath Claverton Down, Bath BA2 7AY UK
- Department of Chemistry Faculty of Mathematics and Natural Sciences Bogor Agricultural University Bogor, West Java Indonesia
| | - Luthando Tshwenya
- Department of Chemical Sciences University of Johannesburg Johannesburg, Doornfontein 2028 South Africa
| | - Mark A. Buckingham
- Department of Chemistry Britannia House King's College London London SE1 1DB UK
| | - Jingyuan Chen
- University of Fukui Department of Applied Physics 3-9-1 Bunkyo Fukui 9100017 Japan
| | - Koichi Jeremiah Aoki
- University of Fukui Department of Applied Physics 3-9-1 Bunkyo Fukui 9100017 Japan
| | - Klaus Mathwig
- Stichting imec Nederland within OnePlanet Research Center Bronland 10 6708 WH Wageningen Netherlands
| | - Omotayo A. Arotiba
- Department of Chemical Sciences University of Johannesburg Johannesburg, Doornfontein 2028 South Africa
- Centre for Nanomaterials Science Research University of Johannesburg South Africa
| | | | - Zhongkai Li
- Department of Chemistry University of Bath Claverton Down, Bath BA2 7AY UK
| | - Frank Marken
- Department of Chemistry University of Bath Claverton Down, Bath BA2 7AY UK
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9
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Voci S, Al-Kutubi H, Rassaei L, Mathwig K, Sojic N. Electrochemiluminescence reaction pathways in nanofluidic devices. Anal Bioanal Chem 2020; 412:4067-4075. [PMID: 32342130 DOI: 10.1007/s00216-020-02630-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/25/2020] [Accepted: 03/30/2020] [Indexed: 11/25/2022]
Abstract
Nanofluidic electrochemical devices confine the volume of chemical reactions to femtoliters. When employed for light generation by electrochemiluminescence (ECL), nanofluidic confinement yields enhanced intensity and robust luminescence. Here, we investigate different ECL pathways, namely coreactant and annihilation ECL in a single nanochannel and compare light emission profiles. By high-resolution imaging of electrode areas, we show that different reaction schemes produce very different emission profiles in the unique confined geometry of a nanochannel. The confrontation of experimental results with finite element simulation gives further insight into the exact reaction ECL pathways. We find that emission strongly depends on depletion, geometric exclusion, and recycling of reactants in the nanofluidic device.
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Affiliation(s)
- Silvia Voci
- Bordeaux INP, Univ. Bordeaux, CNRS, ISM, UMR 5255, Site ENSCBP, 16, Avenue Pey-Berland, 33607, Pessac, France
| | - Hanan Al-Kutubi
- Department of Radiation Science and Technology, Delft University of Technology, Mekelweg 15, 2629 JB, Delft, The Netherlands
| | | | - Klaus Mathwig
- Groningen Research Institute of Pharmacy, Pharmaceutical Analysis, University of Groningen, P.O. Box 196, 9700 AG, Groningen, The Netherlands.
| | - Neso Sojic
- Bordeaux INP, Univ. Bordeaux, CNRS, ISM, UMR 5255, Site ENSCBP, 16, Avenue Pey-Berland, 33607, Pessac, France. .,Department of Chemistry, South Ural State University, Chelyabinsk, Russian Federation, 454080.
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10
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Tshwenya L, Marken F, Mathwig K, Arotiba OA. Switching Anionic and Cationic Semipermeability in Partially Hydrolyzed Polyacrylonitrile: A pH-Tunable Ionic Rectifier. ACS Appl Mater Interfaces 2020; 12:3214-3224. [PMID: 31850740 DOI: 10.1021/acsami.9b18583] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Membrane materials with semipermeability for anions or for cations are of interest in electrochemical and nanofluidic separation and purification technologies. In this study, partially hydrolyzed polyacrylonitrile (phPAN) is investigated as a pH-switchable anion/cation conductor. When switching from anionic to cationic semipermeability, also the ionic current rectification effect switches for phPAN materials deposited asymmetrically onto a 5, 10, 20, or 40 μm diameter microhole in a 6 μm thick polyethylene-terephthalate (PET) film substrate. Therefore, ionic rectifier behavior can be tuned and used to monitor and characterize semipermeability. Effects of electrolyte type and concentration and pH (relative to the zeta potential at approximately 3.1) are investigated by voltammetry, chronoamperometry, and impedance spectroscopy. A computational model provides good qualitative agreement with the observed electrolyte concentration data. High rectification effects are observed for both cations (pH > 3.1) and anions (pH < 3.1) but only at relatively low ionic strengths.
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Affiliation(s)
- Luthando Tshwenya
- Department of Chemical Sciences Formerly known as the Department of Applied Chemistry, University of Johannesburg , Doornfontein 2028 , South Africa
| | - Frank Marken
- Department of Chemistry , University of Bath , Claverton Down , Bath BA2 7AY , U.K
| | - Klaus Mathwig
- Groningen Institute of Pharmacy, Pharmaceutical Analysis , The University of Groningen , P.O. Box 196, AD Groningen 9700 , The Netherlands
| | - Omotayo A Arotiba
- Department of Chemical Sciences Formerly known as the Department of Applied Chemistry, University of Johannesburg , Doornfontein 2028 , South Africa
- Centre for Nanomaterials Science Research , University of Johannesburg , Doornfontein 2028 , Johannesburg , South Africa
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11
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de Haan P, Ianovska MA, Mathwig K, van Lieshout GAA, Triantis V, Bouwmeester H, Verpoorte E. Digestion-on-a-chip: a continuous-flow modular microsystem recreating enzymatic digestion in the gastrointestinal tract. Lab Chip 2019; 19:1599-1609. [PMID: 30950460 DOI: 10.1039/c8lc01080c] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In vitro digestions are essential for determining the bioavailability of compounds, such as nutrients. We have developed a cell-free, miniaturized enzymatic digestive system, employing three micromixers connected in series to mimic the digestive functions of the mouth, stomach and small intestine. This system continuously processes samples, e.g. containing nutrients, to provide a constant flow of digested materials which may be presented to a subsequent gut-on-a-chip absorption module, containing living human intestinal cells. Our system incorporates three-compartment enzymatic digestion, one of the key functions of the gastrointestinal tract. In each of these compartments, we modify the chemical environment, including pH, buffer, and mineral composition, to closely mimic the local physiological environment and create optimal conditions for digestive processes to take place. It will therefore provide an excellent addition to existing gut-on-a-chip systems, providing the next step in determining the bio-availability of orally administered compounds in a fast and continuous-flow ex vivo system. In this paper, we demonstrate enzymatic digestion in each separate compartment using compounds, starch and casein, as model nutrients. The use of transparent, microfluidic micromixers based on chaotic advection, which can be probed directly with a microscope, enabled enzyme kinetics to be monitored from the very start of a reaction. Furthermore, we have digested lactoferrin in our system, demonstrating complete digestion of this milk protein in much shorter times than achievable with standard in vitro digestions using batch reactors.
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Affiliation(s)
- Pim de Haan
- University of Groningen, Groningen Research Institute of Pharmacy, Pharmaceutical Analysis, P.O. Box 196, XB20, 9700 AD Groningen, The Netherlands.
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12
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Fontana M, Fijen C, Lemay SG, Mathwig K, Hohlbein J. High-throughput, non-equilibrium studies of single biomolecules using glass-made nanofluidic devices. Lab Chip 2018; 19:79-86. [PMID: 30468446 DOI: 10.1039/c8lc01175c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Single-molecule detection schemes offer powerful means to overcome static and dynamic heterogeneity inherent to complex samples. However, probing biomolecular interactions and reactions with high throughput and time resolution remains challenging, often requiring surface-immobilized entities. Here, we introduce glass-made nanofluidic devices for the high-throughput detection of freely-diffusing single biomolecules by camera-based fluorescence microscopy. Nanochannels of 200 nm height and a width of several micrometers confine the movement of biomolecules. Using pressure-driven flow through an array of parallel nanochannels and by tracking the movement of fluorescently labelled DNA oligonucleotides, we observe conformational changes with high throughput. In a device geometry featuring a T-shaped junction of nanochannels, we drive steady-state non-equilibrium conditions by continuously mixing reactants and triggering chemical reactions. We use the device to probe the conformational equilibrium of a DNA hairpin as well as to continuously observe DNA synthesis in real time. Our platform offers a straightforward and robust method for studying reaction kinetics at the single-molecule level.
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Affiliation(s)
- Mattia Fontana
- Laboratory of Biophysics, Wageningen University and Research, Stippeneng 4, Wageningen, 6708 WE, The Netherlands
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13
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Al-Kutubi H, Voci S, Rassaei L, Sojic N, Mathwig K. Enhanced annihilation electrochemiluminescence by nanofluidic confinement. Chem Sci 2018; 9:8946-8950. [PMID: 30647886 PMCID: PMC6301198 DOI: 10.1039/c8sc03209b] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [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: 07/19/2018] [Accepted: 09/30/2018] [Indexed: 12/30/2022] Open
Abstract
The generation of stable enhanced light emission by electrochemiluminescence in microfabricated nanofluidic electrochemical devices is demonstrated for the first time by exploiting nanogap amplification.
Microfabricated nanofluidic electrochemical devices offer a highly controlled nanochannel geometry; they confine the volume of chemical reactions to the nanoscale and enable greatly amplified electrochemical detection. Here, the generation of stable light emission by electrochemiluminescence (ECL) in transparent nanofluidic devices is demonstrated for the first time by exploiting nanogap amplification. Through continuous oxidation and reduction of [Ru(bpy)3]2+ luminophores at electrodes positioned at opposite walls of a 100 nm nanochannel, we compare classic redox cycling and ECL annihilation. Enhanced ECL light emission of attomole luminophore quantities is evidenced under ambient conditions due to the spatial confinement in a 10 femtoliter volume, resulting in a short diffusion timescale and highly efficient ECL reaction pathways at the nanoscale.
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Affiliation(s)
- Hanan Al-Kutubi
- University of Groningen , Groningen Research Institute of Pharmacy , Pharmaceutical Analysis , P.O. Box 196 , 9700 AD Groningen , The Netherlands .
| | - Silvia Voci
- University of Bordeaux , Bordeaux INP , Institut des Sciences Moléculaires , UMR CNRS 5255 , 33607 Pessac , France .
| | - Liza Rassaei
- Rotterdam School of Management , Erasmus University , Burgemeester Oudlaan 50 , 3062 PA Rotterdam , The Netherlands.,Delft University of Technology , Van der Maasweg 9 , 2629 HZ Delft , The Netherlands
| | - Neso Sojic
- University of Bordeaux , Bordeaux INP , Institut des Sciences Moléculaires , UMR CNRS 5255 , 33607 Pessac , France .
| | - Klaus Mathwig
- University of Groningen , Groningen Research Institute of Pharmacy , Pharmaceutical Analysis , P.O. Box 196 , 9700 AD Groningen , The Netherlands .
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14
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Oomen PE, Zhang Y, Chiechi RC, Verpoorte E, Mathwig K. Electrochemical sensing with single nanoskived gold nanowires bisecting a microchannel. Lab Chip 2018; 18:2913-2916. [PMID: 30155534 DOI: 10.1039/c8lc00787j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We suspended a single nanoskived gold nanowire in a microfluidic channel. In this preliminary report, a 200 nm-diameter nanowire was used as an electrode to perform hydrodynamic voltammetry in the center of solution flow. Suspended nanowires exhibit superior current response due to highly efficient mass transport in the area of fastest flow.
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Affiliation(s)
- Pieter E Oomen
- University of Groningen, Groningen Research Institute of Pharmacy, Pharmaceutical Analysis, P.O. Box 196, 9700 AD Groningen, The Netherlands.
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15
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Kang S, Nieuwenhuis AF, Mathwig K, Mampallil D, Kostiuchenko ZA, Lemay SG. Single-molecule electrochemistry in nanochannels: probing the time of first passage. Faraday Discuss 2018; 193:41-50. [PMID: 27775135 DOI: 10.1039/c6fd00075d] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The diffusive mass transport of individual redox molecules was probed experimentally in microfabricated nanogap electrodes. The residence times for molecules inside a well-defined detection volume were extracted and the resulting distribution was compared with quantitative analytical predictions from random-walk theory for the time of first passage. The results suggest that a small number of strongly adsorbing sites strongly influence mass transport at trace analyte levels.
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Affiliation(s)
- Shuo Kang
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
| | - Ab F Nieuwenhuis
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
| | - Klaus Mathwig
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
| | - Dileep Mampallil
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
| | - Zinaida A Kostiuchenko
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
| | - Serge G Lemay
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
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16
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Abstract
Nanoscale channels and electrodes for electrochemical measurements exhibit extreme surface-to-volume ratios and a correspondingly high sensitivity to even weak degrees of surface interactions. Here, we exploit the potential-dependent reversible adsorption of outer-sphere redox species to modulate in space and time their concentration in a nanochannel under advective flow conditions. Induced concentration variations propagate downstream at a species-dependent velocity. This allows one to amperometrically distinguish between attomole amounts of species based on their time-of-flight. On-demand concentration pulse generation, separation, and detection are all integrated in a miniaturized platform.
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Affiliation(s)
- Jin Cui
- MESA+ Institute for Nanotechnology , University of Twente , PO Box 217, 7500 AE Enschede , The Netherlands
| | - Klaus Mathwig
- MESA+ Institute for Nanotechnology , University of Twente , PO Box 217, 7500 AE Enschede , The Netherlands
| | - Dileep Mampallil
- MESA+ Institute for Nanotechnology , University of Twente , PO Box 217, 7500 AE Enschede , The Netherlands
| | - Serge G Lemay
- MESA+ Institute for Nanotechnology , University of Twente , PO Box 217, 7500 AE Enschede , The Netherlands
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17
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Tshwenya L, Arotiba O, Putra BR, Madrid E, Mathwig K, Marken F. Cationic diodes by hot-pressing of Fumasep FKS-30 ionomer film onto a microhole in polyethylene terephthalate (PET). J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2018.03.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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18
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Affiliation(s)
- Klaus Mathwig
- University of Groningen, Groningen Institute of Pharmacy; Pharmaceutical Analysis; P.O. Box 196, 9700 AD Groningen The Netherlands
| | | | - Frank Marken
- Department of Chemistry; University of Bath; Claverton Down, Bath BA2 7AY UK
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19
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Putra BR, Aaronson BD, Madrid E, Mathwig K, Carta M, Malpass-Evans R, McKeown NB, Marken F. Ionic Diode Characteristics at a Polymer of Intrinsic Microporosity (PIM) | Nafion “Heterojunction” Deposit on a Microhole Poly(ethylene-terephthalate) Substrate. ELECTROANAL 2017. [DOI: 10.1002/elan.201700247] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Budi Riza Putra
- Department of Chemistry; University of Bath; Claverton Down BA2 7AY UK
- Department of Chemistry, Faculty of Mathematics and Natural Sciences; Bogor Agricultural University; Bogor, West Java Indonesia
| | | | - Elena Madrid
- Department of Chemistry; University of Bath; Claverton Down BA2 7AY UK
| | - Klaus Mathwig
- Groningen Research Institute of Pharmacy, Pharmaceutical Analysis; University of Groningen; P.O. Box 196 9700 AD Groningen The Netherlands
| | - Mariolino Carta
- School of Chemistry; University of Edinburgh, Joseph Black Building; West Mains Road Edinburgh Scotland EH9 3JJ, UK
| | - Richard Malpass-Evans
- School of Chemistry; University of Edinburgh, Joseph Black Building; West Mains Road Edinburgh Scotland EH9 3JJ, UK
| | - Neil B. McKeown
- School of Chemistry; University of Edinburgh, Joseph Black Building; West Mains Road Edinburgh Scotland EH9 3JJ, UK
| | - Frank Marken
- Department of Chemistry; University of Bath; Claverton Down BA2 7AY UK
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20
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Zafarani HR, Mathwig K, Sudhölter EJR, Rassaei L. Electrochemical Amplification in Side-by-Side Attoliter Nanogap Transducers. ACS Sens 2017; 2:724-728. [PMID: 28670622 PMCID: PMC5485373 DOI: 10.1021/acssensors.7b00180] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 05/16/2017] [Indexed: 11/30/2022]
Abstract
We report a strategy for the fabrication of a new type of electrochemical nanogap transducer. These nanogap devices are based on signal amplification by redox cycling. Using two steps of electron-beam lithography, vertical gold electrodes are fabricated side by side at a 70 nm distance encompassing a 20 attoliter open nanogap volume. We demonstrate a current amplification factor of 2.5 as well as the possibility to detect the signal of only 60 analyte molecules occupying the detection volume. Experimental voltammetry results are compared to calculations from finite element analysis.
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Affiliation(s)
- Hamid Reza Zafarani
- Laboratory of Organic
Materials and Interfaces, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Klaus Mathwig
- University of Groningen, Groningen Research Institute of Pharmacy, Pharmaceutical Analysis, P.O. Box 196, 9700 AD Groningen, The Netherlands
| | - Ernst J. R. Sudhölter
- Laboratory of Organic
Materials and Interfaces, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Liza Rassaei
- Laboratory of Organic
Materials and Interfaces, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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21
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Affiliation(s)
- Liza Rassaei
- Chemical Engineering; TU Delft; Julianalaan 136 Delft 2628 BL The Netherlands
| | - Guobao Xu
- The State Key Laboratory of Electroanalytical Chemistry; Changchun Institute of Applied Chemistry, Chinese Academy of Sciences; 5625 Renmin Street Changchun, Jilin China
| | - Zhifeng Ding
- Department of Chemistry; University of Western Ontario, 1151; Richmond St. London, Ontario N6A5B7 Canada
| | - Klaus Mathwig
- University of Groningen; Groningen Research Institute of Pharmacy; P.O. Box 196 9700 AD Groningen The Netherlands
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22
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He D, Madrid E, Aaronson BDB, Fan L, Doughty J, Mathwig K, Bond AM, McKeown NB, Marken F. A Cationic Diode Based on Asymmetric Nafion Film Deposits. ACS Appl Mater Interfaces 2017; 9:11272-11278. [PMID: 28287696 DOI: 10.1021/acsami.7b01774] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A thin film of Nafion, of approximately 5 μm thickness, asymmetrically deposited onto a 6 μm thick film of poly(ethylene terephthalate) (PET) fabricated with a 5, 10, 20, or 40 μm microhole, is shown to exhibit prominent ionic diode behavior involving cation charge carrier ("cationic diode"). The phenomenon is characterized via voltammetric, chronoamperometric, and impedance methods. Phenomenologically, current rectification effects are comparable to those observed in nanocone devices where space-charge layer effects dominate. However, for microhole diodes a resistive, a limiting, and an overlimiting potential domain can be identified and concentration polarization in solution is shown to dominate in the closed state.
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Affiliation(s)
- Daping He
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
| | - Elena Madrid
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
| | - Barak D B Aaronson
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
| | - Lian Fan
- Department of Biology and Biochemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
| | - James Doughty
- Department of Biology and Biochemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
| | - Klaus Mathwig
- Pharmaceutical Analysis, Groningen Research Institute of Pharmacy, University of Groningen , P.O. Box 196, 9700 AD Groningen, The Netherlands
| | - Alan M Bond
- Monash University , School of Chemistry, Clayton, Vic 3800, Australia
| | - Neil B McKeown
- EastChem School of Chemistry, University of Edinburgh , David Brewster Road, Edinburgh, EH9 3FJ, U.K
| | - Frank Marken
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
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23
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Affiliation(s)
- Hamid Reza Zafarani
- Laboratory
of Organic Materials and Interfaces, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Klaus Mathwig
- Pharmaceutical
Analysis, Groningen Research Institute of Pharmacy, University of Groningen, P.O. Box 196, 9700 AD Groningen, The Netherlands
| | - Serge G. Lemay
- MESA+
Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Ernst J. R. Sudhölter
- Laboratory
of Organic Materials and Interfaces, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Liza Rassaei
- Laboratory
of Organic Materials and Interfaces, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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24
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Al-Kutubi H, Zafarani HR, Rassaei L, Mathwig K. Electrofluorochromic systems: Molecules and materials exhibiting redox-switchable fluorescence. Eur Polym J 2016. [DOI: 10.1016/j.eurpolymj.2016.04.033] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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25
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Rong Y, Song Q, Mathwig K, Madrid E, He D, Niemann RG, Cameron PJ, Dale SE, Bending S, Carta M, Malpass-Evans R, McKeown NB, Marken F. pH-induced reversal of ionic diode polarity in 300nm thin membranes based on a polymer of intrinsic microporosity. Electrochem commun 2016. [DOI: 10.1016/j.elecom.2016.05.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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26
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Kalkman GA, Zhang Y, Monachino E, Mathwig K, Kamminga ME, Pourhossein P, Oomen PE, Stratmann SA, Zhao Z, van Oijen AM, Verpoorte E, Chiechi RC. Bisecting Microfluidic Channels with Metallic Nanowires Fabricated by Nanoskiving. ACS Nano 2016; 10:2852-2859. [PMID: 26836373 DOI: 10.1021/acsnano.5b07996] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This paper describes the fabrication of millimeter-long gold nanowires that bisect the center of microfluidic channels. We fabricated the nanowires by nanoskiving and then suspended them over a trench in a glass structure. The channel was sealed by bonding it to a complementary poly(dimethylsiloxane) structure. The resulting structures place the nanowires in the region of highest flow, as opposed to the walls, where it approaches zero, and expose their entire surface area to fluid. We demonstrate active functionality, by constructing a hot-wire anemometer to measure flow through determining the change in resistance of the nanowire as a function of heat dissipation at low voltage (<5 V). Further, passive functionality is demonstrated by visualizing individual, fluorescently labeled DNA molecules attached to the wires. We measure rates of flow and show that, compared to surface-bound DNA strands, elongation saturates at lower rates of flow and background fluorescence from nonspecific binding is reduced.
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Affiliation(s)
- Gerard A Kalkman
- Groningen Research Institute of Pharmancy , Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Yanxi Zhang
- Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Stratingh Institute for Chemistry, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Enrico Monachino
- Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Klaus Mathwig
- Groningen Research Institute of Pharmancy , Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Machteld E Kamminga
- Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Parisa Pourhossein
- Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Stratingh Institute for Chemistry, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Pieter E Oomen
- Groningen Research Institute of Pharmancy , Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Sarah A Stratmann
- Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Zhiyuan Zhao
- Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Stratingh Institute for Chemistry, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Antoine M van Oijen
- Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Elisabeth Verpoorte
- Groningen Research Institute of Pharmancy , Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Ryan C Chiechi
- Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Stratingh Institute for Chemistry, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands
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Zafarani HR, Mathwig K, Sudhölter EJ, Rassaei L. Electrochemical redox cycling in a new nanogap sensor: Design and simulation. J Electroanal Chem (Lausanne) 2016. [DOI: 10.1016/j.jelechem.2015.11.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Mathwig K, Chi Q, Lemay SG, Rassaei L. Handling and Sensing of Single Enzyme Molecules: From Fluorescence Detection towards Nanoscale Electrical Measurements. Chemphyschem 2015; 17:452-7. [DOI: 10.1002/cphc.201500686] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Klaus Mathwig
- Pharmaceutical Analysis; Groningen Research Institute of Pharmacy; University of Groningen; P.O. Box 196 9700 AD Groningen The Netherlands
| | - Qijin Chi
- Department of Chemistry; Technical University of Denmark; 2800 Kongens Lyngby Denmark
| | - Serge G. Lemay
- MESA+ Institute for Nanotechnology; University of Twente; P.O. Box 217 7500 AE Enschede The Netherlands
| | - Liza Rassaei
- Laboratory of Organic Materials and Interfaces; Department of Chemical Engineering; Delft University of Technology; Julianalaan 136 2628 BL Delft The Netherlands
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29
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Affiliation(s)
- Klaus Mathwig
- Pharmaceutical
Analysis, Groningen Research Institute of Pharmacy, University of Groningen, P.O. Box 196, 9700 AD Groningen, The Netherlands
| | - Tim Albrecht
- Department
of Chemistry, Imperial College London, Exhibition Road, South Kensington
Campus, London, SW7 2AZ, U.K
| | - Edgar D. Goluch
- Department
of Chemical Engineering, Northeastern University, 360 Huntington Avenue, 313SN, Boston, Massachusetts 02115, United States
| | - Liza Rassaei
- Department
of Chemical Engineering, Delft University of Technology, Julianalaan
136, 2628 BL Delft, The Netherlands
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Abstract
The reference electrode is a key component in electrochemical measurements, yet it remains a challenge to implement a reliable reference electrode in miniaturized electrochemical sensors. Here we explore experimentally and theoretically an alternative approach based on redox cycling which eliminates the reference electrode altogether. We show that shifts in the solution potential caused by the lack of reference can be understood quantitatively, and determine the requirements for accurate measurements in miniaturized systems in the absence of a reference electrode.
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Affiliation(s)
- Sahana Sarkar
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands, ; Fax: +31 53 489 3511; Tel : +31 53 489 2306
| | - Klaus Mathwig
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands, ; Fax: +31 53 489 3511; Tel : +31 53 489 2306
| | - Shuo Kang
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands, ; Fax: +31 53 489 3511; Tel : +31 53 489 2306
| | - Ab. F. Nieuwenhuis
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands, ; Fax: +31 53 489 3511; Tel : +31 53 489 2306
| | - Serge G. Lemay
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands, ; Fax: +31 53 489 3511; Tel : +31 53 489 2306
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Abstract
The sensing of enzymatic processes in volumes at or below the scale of single cells is challenging but highly desirable in the study of biochemical processes. Here we demonstrate a nanofluidic device that combines an enzymatic recognition element and electrochemical signal transduction within a six-femtoliter volume. Our approach is based on localized immobilization of the enzyme tyrosinase in a microfabricated nanogap electrochemical transducer. The enzymatic reaction product quinone is localized in the confined space of a nanochannel in which efficient redox cycling also takes place. Thus, the sensor allows the sensitive detection of minute amounts of product molecules generated by the enzyme in real time. This method is ideally suited for the study of ultra-small-volume systems such as the contents of individual biological cells or organelles.
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Abstract
The development of experiments capable of probing individual molecules has led to major breakthroughs in fields ranging from molecular electronics to biophysics, allowing direct tests of knowledge derived from macroscopic measurements and enabling new assays that probe population heterogeneities and internal molecular dynamics. Although still somewhat in their infancy, such methods are also being developed for probing molecular systems in solution using electrochemical transduction mechanisms. Here we outline the present status of this emerging field, concentrating in particular on optical methods, metal-molecule-metal junctions, and electrochemical nanofluidic devices.
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Affiliation(s)
- Klaus Mathwig
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, the Netherlands; ,
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Kätelhön E, Krause KJ, Mathwig K, Lemay SG, Wolfrum B. Noise phenomena caused by reversible adsorption in nanoscale electrochemical devices. ACS Nano 2014; 8:4924-4930. [PMID: 24694343 DOI: 10.1021/nn500941g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We theoretically investigate reversible adsorption in electrochemical devices on a molecular level. To this end, a computational framework is introduced, which is based on 3D random walks including probabilities for adsorption and desorption events at surfaces. We demonstrate that this approach can be used to investigate adsorption phenomena in electrochemical sensors by analyzing experimental noise spectra of a nanofluidic redox cycling device. The evaluation of simulated and experimental results reveals an upper limit for the average adsorption time of ferrocene dimethanol of ∼200 μs. We apply our model to predict current noise spectra of further electrochemical experiments based on interdigitated arrays and scanning electrochemical microscopy. Since the spectra strongly depend on the molecular adsorption characteristics of the detected analyte, we can suggest key indicators of adsorption phenomena in noise spectroscopy depending on the geometric aspect of the experimental setup.
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Affiliation(s)
- Enno Kätelhön
- Institute of Bioelectronics (PGI-8/ICS-8) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich , 52425 Jülich, Germany
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Abstract
Adsorption often dominates the response of nanofluidic systems due to their high surface-to-volume ratios. Here we harness this sensitivity to investigate the reversible adsorption of outer-sphere redox species at electrodes, a phenomenon that is easily overlooked in bulk measurements. We find that even though adsorption does not necessarily play a role in the electron-transfer process, such adsorption is nevertheless ubiquitous for the widely used outer-sphere species. We investigate the physical factors driving adsorption and find that this counterintuitive behavior is mediated by the anionic species in the supporting electrolyte, closely following the well-known Hofmeister series. Our results provide foundations both for theoretical studies of the underlying mechanisms and for contriving strategies to control adsorption in micro/nanoscale electrochemical transducers where surface effects are dominant.
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Affiliation(s)
- Dileep Mampallil
- MESA+ Institute for Nanotechnology, University of Twente, Carre 4409, Achterhorst, 7500AE Enschede, The Netherlands
| | - Klaus Mathwig
- MESA+ Institute for Nanotechnology, University of Twente, Carre 4409, Achterhorst, 7500AE Enschede, The Netherlands
| | - Shuo Kang
- MESA+ Institute for Nanotechnology, University of Twente, Carre 4409, Achterhorst, 7500AE Enschede, The Netherlands
| | - Serge G Lemay
- MESA+ Institute for Nanotechnology, University of Twente, Carre 4409, Achterhorst, 7500AE Enschede, The Netherlands
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Kang S, Nieuwenhuis AF, Mathwig K, Mampallil D, Lemay SG. Electrochemical single-molecule detection in aqueous solution using self-aligned nanogap transducers. ACS Nano 2013; 7:10931-10937. [PMID: 24279688 DOI: 10.1021/nn404440v] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Electrochemical detection of individual molecular tags in nanochannels may enable cost-effective, massively parallel analysis and diagnostics platforms. Here we demonstrate single-molecule detection of prototypical analytes in aqueous solution based on redox cycling in 40 nm nanogap transducers. These nanofluidic devices are fabricated using standard microfabrication techniques combined with a self-aligned approach that minimizes gap size and dead volume. We demonstrate the detection of three common redox mediators at physiological salt concentrations.
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Affiliation(s)
- Shuo Kang
- MESA+ Institute for Nanotechnology, University of Twente , PO Box 217, 7500 AE Enschede, The Netherlands
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37
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Affiliation(s)
- Dileep Mampallil
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Klaus Mathwig
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Shuo Kang
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Serge G. Lemay
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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38
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Abstract
The development of methods for detecting and manipulating matter at the level of individual macromolecules represents one of the key scientific advancements of recent decades. These techniques allow us to get information that is largely unobtainable otherwise, such as the magnitudes of microscopic forces, mechanistic details of catalytic processes, macromolecular population heterogeneities, and time-resolved, step-by-step observation of complex kinetics. Methods based on optical, mechanical, and ionic-conductance signal transduction are particularly developed. However, there is scope for new approaches that can broaden the range of molecular systems that we can study at this ultimate level of sensitivity and for developing new analytical methods relying on single-molecule detection. Approaches based on purely electrical detection are particularly appealing in the latter context, since they can be easily combined with microelectronics or fluidic devices on a single microchip to create large parallel assays at relatively low cost. A form of electrical signal transduction that has so far remained relatively underdeveloped at the single-molecule level is the direct detection of the charge transferred in electrochemical processes. The reason for this is simple: only a few electrons are transferred per molecule in a typical faradaic reaction, a heterogeneous charge-transfer reaction that occurs at the electrode's surface. Detecting this tiny amount of charge is impossible using conventional electrochemical instrumentation. A workaround is to use redox cycling, in which the charge transferred is amplified by repeatedly reducing and oxidizing analyte molecules as they randomly diffuse between a pair of electrodes. For this process to be sufficiently efficient, the electrodes must be positioned within less than 100 nm of each other, and the analyte must remain between the electrodes long enough for the measurement to take place. Early efforts focused on tip-based nanoelectrodes, descended from scanning electrochemical microscopy, to create suitable geometries. However, it has been challenging to apply these technologies broadly. In this Account, we describe our alternative approach based on electrodes embedded in microfabricated nanochannels, so-called nanogap transducers. Microfabrication techniques grant a high level of reproducibility and control over the geometry of the devices, permitting systematic development and characterization. We have employed these devices to demonstrate single-molecule sensitivity. This method shows good agreement with theoretical analysis based on the Brownian motion of discrete molecules, but only once the finite time resolution of the experimental apparatus is taken into account. These results highlight both the random nature of single-molecule signals and the complications that it can introduce in data interpretation. We conclude this Account with a discussion on how scientists can overcome this limitation in the future to create a new experimental platform that can be generally useful for both fundamental studies and analytical applications.
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Affiliation(s)
- Serge G. Lemay
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Shuo Kang
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Klaus Mathwig
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Pradyumna S. Singh
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
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Singh PS, Kätelhön E, Mathwig K, Wolfrum B, Lemay SG. Stochasticity in single-molecule nanoelectrochemistry: origins, consequences, and solutions. ACS Nano 2012; 6:9662-9671. [PMID: 23106647 DOI: 10.1021/nn3031029] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Electrochemical detection of single molecules is being actively pursued as an enabler of new fundamental experiments and sensitive analytical capabilities. Most attempts to date have relied on redox cycling in a nanogap, which consists of two parallel electrodes separated by a nanoscale distance. While these initial experiments have demonstrated single-molecule detection at the proof-of-concept level, several fundamental obstacles need to be overcome to transform the technique into a realistic detection tool suitable for use in more complex settings (e.g., studying enzyme dynamics at single catalytic event level, probing neuronal exocytosis, etc.). In particular, it has become clearer that stochasticity--the hallmark of most single-molecule measurements--can become the key limiting factor on the quality of the information that can be obtained from single-molecule electrochemical assays. Here we employ random-walk simulations to show that this stochasticity is a universal feature of all single-molecule experiments in the diffusively coupled regime and emerges due to the inherent properties of brownian motion. We further investigate the intrinsic coupling between stochasticity and detection capability, paying particular attention to the role of the geometry of the detection device and the finite time resolution of measurement systems. We suggest concrete, realizable experimental modifications and approaches to mitigate these limitations. Overall, our theoretical analyses offer a roadmap for optimizing single-molecule electrochemical experiments, which is not only desirable but also indispensable for their wider employment as experimental tools for electrochemical research and as realistic sensing or detection systems.
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Affiliation(s)
- Pradyumna S Singh
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
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Mathwig K, Mampallil D, Kang S, Lemay SG. Electrical cross-correlation spectroscopy: measuring picoliter-per-minute flows in nanochannels. Phys Rev Lett 2012; 109:118302. [PMID: 23005685 DOI: 10.1103/physrevlett.109.118302] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 06/27/2012] [Indexed: 06/01/2023]
Abstract
We introduce all-electrical cross-correlation spectroscopy of molecular number fluctuations in nanofluidic channels. Our approach is based on a pair of nanogap electrochemical transducers located downstream from each other in the channel. When liquid is driven through this device, mesoscopic fluctuations in the local density of molecules are transported along the channel. We perform a time-of-flight measurement of these fluctuations by cross-correlating current-time traces obtained at the two detectors. Thereby we are able to detect ultralow liquid flow rates below 10 pL/min. This method constitutes the electrical equivalent of fluorescence cross-correlation spectroscopy.
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Affiliation(s)
- Klaus Mathwig
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
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Abstract
Nanofluidic thin-layer cells count among the most sensitive electrochemical sensors built to date. Here we study both experimentally and theoretically the factors that limit the response time of these sensors. We find that the key limiting factor is reversible adsorption of the analyte molecules to the surfaces of the nanofluidic system, a direct consequence of its high surface-to-volume ratio. Our results suggest several means of improving the response time of the sensor, including optimizing the device geometry and tuning the electrode biasing scheme so as to minimize adsorption.
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Affiliation(s)
- Shuo Kang
- MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
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Qin Y, Kim Y, Zhang L, Lee SM, Yang RB, Pan A, Mathwig K, Alexe M, Gösele U, Knez M. Preparation and elastic properties of helical nanotubes obtained by atomic layer deposition with carbon nanocoils as templates. Small 2010; 6:910-914. [PMID: 20397206 DOI: 10.1002/smll.200902159] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Affiliation(s)
- Yong Qin
- Max Planck Institute of Microstructure Physics Weinberg 2, 06120 Halle, Germany.
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Grimm S, Martín J, Rodriguez G, Fernández-Gutierrez M, Mathwig K, Wehrspohn RB, Gösele U, San Roman J, Mijangos C, Steinhart M. Cellular interactions of biodegradable nanorod arrays prepared by nondestructive extraction from nanoporous alumina. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/b926432a] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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