51
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Shimizu H, Mawatari K, Kitamori T. Femtoliter-scale separation and sensitive detection of nonfluorescent samples in an extended-nano fluidic device. Analyst 2014; 139:2154-7. [DOI: 10.1039/c3an02353b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Liquid chromatography using a nanofluidic chip and DIC-TLM realized separation and detection of a 21 fL, 0.61 zmol nonfluorescent sample.
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Affiliation(s)
- Hisashi Shimizu
- Department of Applied Chemistry
- School of Engineering
- The University of Tokyo
- Bunkyo, Japan
- Core Research for Evolutional Science and Technology (CREST)
| | - Kazuma Mawatari
- Department of Applied Chemistry
- School of Engineering
- The University of Tokyo
- Bunkyo, Japan
- Core Research for Evolutional Science and Technology (CREST)
| | - Takehiko Kitamori
- Department of Applied Chemistry
- School of Engineering
- The University of Tokyo
- Bunkyo, Japan
- Core Research for Evolutional Science and Technology (CREST)
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52
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Yang X, Wang Y, Liu Y, Jiang X. A sensitive hydrogen peroxide and glucose biosensor based on gold/silver core–shell nanorods. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2013.06.017] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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53
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Ma C, Contento NM, Gibson LR, Bohn PW. Recessed Ring–Disk Nanoelectrode Arrays Integrated in Nanofluidic Structures for Selective Electrochemical Detection. Anal Chem 2013; 85:9882-8. [DOI: 10.1021/ac402417w] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Chaoxiong Ma
- Department of Chemistry and Biochemistry, and ‡Department of Chemical and Biomolecular
Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Nicholas M. Contento
- Department of Chemistry and Biochemistry, and ‡Department of Chemical and Biomolecular
Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Larry R. Gibson
- Department of Chemistry and Biochemistry, and ‡Department of Chemical and Biomolecular
Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Paul W. Bohn
- Department of Chemistry and Biochemistry, and ‡Department of Chemical and Biomolecular
Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
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54
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Ma C, Contento NM, Gibson LR, Bohn PW. Redox cycling in nanoscale-recessed ring-disk electrode arrays for enhanced electrochemical sensitivity. ACS NANO 2013; 7:5483-90. [PMID: 23691968 DOI: 10.1021/nn401542x] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
An array of nanoscale-recessed ring-disk electrodes was fabricated using layer-by-layer deposition, nanosphere lithography, and a multistep reactive ion etching process. The resulting device was operated in generator-collector mode by holding the ring electrodes at a constant potential and performing cyclic voltammetry by sweeping the disk potential in Fe(CN)6(3-/4-) solutions. Steady-state response and enhanced (~10×) limiting current were achieved by cycling the redox couple between ring and disk electrodes with high transfer/collection efficiency. The collector (ring) electrode, which is held at a constant potential, exhibits a much smaller charging current than the generator (disk), and it is relatively insensitive to scan rate. A characteristic feature of the nanoscale ring-disk geometry is that the electrochemical reaction occurring at the disk electrodes can be tuned by modulating the potential at the ring electrodes. Measured shifts in Fe(CN)6(3-/4-) concentration profiles were found to be in excellent agreement with finite element method simulations. The main performance metric, the amplification factor, was optimized for arrays containing small diameter pores (r < 250 nm) with minimum electrode spacing and high pore density. Finally, integration of the fabricated array within a nanochannel produced up to 50-fold current amplification as well as enhanced selectivity, demonstrating the compatibility of the device with lab-on-a-chip architectures.
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Affiliation(s)
- Chaoxiong Ma
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
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55
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Kätelhön E, Krause KJ, Singh PS, Lemay SG, Wolfrum B. Noise Characteristics of Nanoscaled Redox-Cycling Sensors: Investigations Based on Random Walks. J Am Chem Soc 2013; 135:8874-81. [DOI: 10.1021/ja3121313] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Enno Kätelhön
- Institute of Bioelectronics
(PGI-8/ICS-8) and JARA—Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich,
Germany
| | - Kay J. Krause
- Institute of Bioelectronics
(PGI-8/ICS-8) and JARA—Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich,
Germany
| | - Pradyumna S. Singh
- 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
| | - Bernhard Wolfrum
- Institute of Bioelectronics
(PGI-8/ICS-8) and JARA—Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich,
Germany
- Institute
of Physics, RWTH Aachen University, 52074
Aachen, Germany
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56
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WEBSTER THADDAEUSA, SISMAET HUNTERJ, GOLUCH EDGARD. AMPEROMETRIC DETECTION OF PYOCYANIN IN NANOFLUIDIC CHANNELS. ACTA ACUST UNITED AC 2013. [DOI: 10.1142/s1793984413400114] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Microfabricated nanofluidic electrode assemblies (NEAs) with integrated palladium references were used to amperometrically monitor changes in pyocyanin concentration. Pyocyanin is an electroactive molecule that is produced by the opportunistic pathogen Pseudomonas aeruginosa and is directly linked to cellular processes that increase both robustness and virulence in this bacterium. This is the first time that pyocyanin has been measured in real time using microfabricated sensors. A linear response in faradaic current (R2= 0.96) was observed over a biomedically relevant range of pyocyanin concentrations (0–100 μM) while continuously measuring the current for 2 h. Measurement of the current that results from the repeated oxidation and reduction of pyocyanin at two closely spaced electrodes inside the device nanochannel yielded a 1.07 μM limit of detection without electrical isolation of the electrochemical cell. Since a reference electrode is integrated inside the nanofluidic channel of these sensors, they can potentially be employed to detect pyocyanin and other redox-active molecules in wide range of medical and environmental settings where space is limited. NEAs were also used with an external Ag/AgCl reference electrode to determine the concentration of pyocyanin in trypticase soy broth samples. This type of analysis is completed in less than 2 min and the detection limit was determined to be 441 nM.
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Affiliation(s)
- THADDAEUS A. WEBSTER
- Department of Chemical Engineering, Northeastern University, 360 Huntington Ave., 313SN, Boston, MA 02115, USA
| | - HUNTER J. SISMAET
- Department of Chemical Engineering, Northeastern University, 360 Huntington Ave., 313SN, Boston, MA 02115, USA
| | - EDGAR D. GOLUCH
- Department of Chemical Engineering, Northeastern University, 360 Huntington Ave., 313SN, Boston, MA 02115, USA
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57
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Liu Y, Wolfrum B, Hüske M, Offenhäusser A, Wang E, Mayer D. Ein elektrochemischer Gleichrichter ermöglicht Transistorfunktionen. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201207778] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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58
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Liu Y, Wolfrum B, Hüske M, Offenhäusser A, Wang E, Mayer D. Transistor Functions Based on Electrochemical Rectification. Angew Chem Int Ed Engl 2013; 52:4029-32. [DOI: 10.1002/anie.201207778] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 12/04/2012] [Indexed: 11/08/2022]
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59
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Wang X, Wang X, Gao S, zheng Y, Tang M, Chen B. A solid-state electrochemiluminescence sensing platform for detection of catechol based on novel luminescent composite nanofibers. Talanta 2013; 107:127-32. [DOI: 10.1016/j.talanta.2013.01.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Revised: 12/31/2012] [Accepted: 01/06/2013] [Indexed: 11/15/2022]
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60
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Heo JI, Lim Y, Shin H. The effect of channel height and electrode aspect ratio on redox cycling at carbon interdigitated array nanoelectrodes confined in a microchannel. Analyst 2013; 138:6404-11. [DOI: 10.1039/c3an00905j] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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61
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Nambiar SR, Aneesh PK, Rao TP. Ultrasensitive voltammetric determination of catechol at a gold atomic cluster/poly(3,4-ethylenedioxythiophene) nanocomposite electrode. Analyst 2013; 138:5031-8. [DOI: 10.1039/c3an00518f] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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62
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Webster TA, Goluch ED. Electrochemical detection of pyocyanin in nanochannels with integrated palladium hydride reference electrodes. LAB ON A CHIP 2012; 12:5195-5201. [PMID: 23108351 DOI: 10.1039/c2lc40650k] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Miniaturized and integrated components for electrochemical detection in micro- and nano-fluidic devices are of great interest as they directly yield an electrical signal and promise sensitive, label-free, real-time detection. One of the challenges facing electrochemical sensing is the lack of reliable reference electrode options. This paper describes the fabrication and characterization of a microscale palladium hydride reference electrode in a single microfabrication step. The reference electrode was integrated inside of a nanoscale constriction along with a gold working electrode to create a complete electrochemical sensor. After charging the palladium electrode with hydrogen, the device was used to detect pyocyanin concentrations from 1-100 μM, with a 0.597 micromolar detection limit. This is the first time that a palladium hydride reference electrode has been integrated with a microfabricated electrochemical sensor in a nanofluidic setup. The device was then used over the course of 8 days to measure pyocyanin produced by four different Pseudomonas aeruginosa strains in growth media. By utilizing square wave and differential pulse voltammetry, the redox active molecule, pyocyanin, was selectively detected in a complex solution without the use of any electrode surface modification.
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Affiliation(s)
- Thaddaeus A Webster
- Department of Chemical Engineering, Northeastern University, 120 Snell Engineering Center, 360 Huntington Avenue, Boston, MA 02115, USA
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63
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64
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Ino K, Nishijo T, Arai T, Kanno Y, Takahashi Y, Shiku H, Matsue T. Local Redox-Cycling-Based Electrochemical Chip Device with Deep Microwells for Evaluation of Embryoid Bodies. Angew Chem Int Ed Engl 2012; 51:6648-52. [DOI: 10.1002/anie.201201602] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 04/26/2012] [Indexed: 11/06/2022]
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65
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Ino K, Nishijo T, Arai T, Kanno Y, Takahashi Y, Shiku H, Matsue T. Local Redox-Cycling-Based Electrochemical Chip Device with Deep Microwells for Evaluation of Embryoid Bodies. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201201602] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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66
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Straver MG, Odijk M, Olthuis W, van den Berg A. A simple method to fabricate electrochemical sensor systems with predictable high-redox cycling amplification. LAB ON A CHIP 2012; 12:1548-1553. [PMID: 22361973 DOI: 10.1039/c2lc21233a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this paper an easy to fabricate SU8/glass-based microfluidic sensor is described with two closely spaced parallel electrodes for highly selective measurements using the redox cycling effect. By varying the length of the microfluidic entrance channel, a diffusion barrier is created for non-cycling species effectively increasing selectivity for redox cycling species. Using this sensor, a redox cycling amplification of ∼6500× is measured using the ferrocyanide redox couple. Moreover, a simple, but accurate analytical expression is derived that predicts the amplification factor based on the sensor geometry.
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Affiliation(s)
- M G Straver
- BIOS/Lab-on-Chip Group, MESA+ Institute for Nanotechnology, University of Twente, P. O. Box 217, 7500 AE Enschede, The Netherlands
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67
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Dahlin AB, Zahn R, Vörös J. Nanoplasmonic sensing of metal-halide complex formation and the electric double layer capacitor. NANOSCALE 2012; 4:2339-2351. [PMID: 22374047 DOI: 10.1039/c2nr11950a] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Many nanotechnological devices are based on implementing electrochemistry with plasmonic nanostructures, but these systems are challenging to understand. We present a detailed study of the influence of electrochemical potentials on plasmon resonances, in the absence of surface coatings and redox active molecules, by synchronized voltammetry and spectroscopy. The experiments are performed on gold nanodisks and nanohole arrays in thin gold films, which are fabricated by improved methods. New insights are provided by high resolution spectroscopy and variable scan rates. Furthermore, we introduce new analytical models in order to understand the spectral changes quantitatively. In contrast to most previous literature, we find that the plasmonic signal is caused almost entirely by the formation of ionic complexes on the metal surface, most likely gold chloride in this study. The refractometric sensing effect from the ions in the electric double layer can be fully neglected, and the charging of the metal gives a surprisingly small effect for these systems. Our conclusions are consistent for both localized nanoparticle plasmons and propagating surface plasmons. We consider the results in this work especially important in the context of combined electrochemical and optical sensors.
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Affiliation(s)
- Andreas B Dahlin
- Dept. of Applied Physics, Chalmers University of Technology, Gothenburg, Sweden.
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68
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García CR, Angelé-Martínez C, Wilkes JA, Wang HC, Battin EE, Brumaghim JL. Prevention of iron- and copper-mediated DNA damage by catecholamine and amino acid neurotransmitters, l-DOPA, and curcumin: metal binding as a general antioxidant mechanism. Dalton Trans 2012; 41:6458-67. [DOI: 10.1039/c2dt30060e] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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69
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Ino K, Kanno Y, Nishijo T, Goto T, Arai T, Takahashi Y, Shiku H, Matsue T. Electrochemical detection for dynamic analyses of a redox component in droplets using a local redox cycling-based electrochemical (LRC-EC) chip device. Chem Commun (Camb) 2012; 48:8505-7. [DOI: 10.1039/c2cc34264b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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70
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Yang X, Bai J, Wang Y, Jiang X, He X. Hydrogen peroxide and glucose biosensor based on silver nanowires synthesized by polyol process. Analyst 2012; 137:4362-7. [DOI: 10.1039/c2an35407a] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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71
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Batchelor-McAuley C, Dickinson EJF, Rees NV, Toghill KE, Compton RG. New Electrochemical Methods. Anal Chem 2011; 84:669-84. [DOI: 10.1021/ac2026767] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christopher Batchelor-McAuley
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Edmund J. F. Dickinson
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Neil V. Rees
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Kathryn E. Toghill
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Richard G. Compton
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
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72
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A strategy for selective detection based on interferent depleting and redox cycling using the plane-recessed microdisk array electrodes. Electrochim Acta 2011. [DOI: 10.1016/j.electacta.2011.05.129] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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73
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Dale SEC, Vuorema A, Ashmore EMY, Kasprzyk-Horden B, Sillanpää M, Denuault G, Marken F. Gold-gold junction electrodes:the disconnection method. CHEM REC 2011; 12:143-8. [DOI: 10.1002/tcr.201100008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Indexed: 10/17/2022]
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74
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Kätelhön E, Hofmann B, Lemay SG, Zevenbergen MAG, Offenhäusser A, Wolfrum B. Nanocavity redox cycling sensors for the detection of dopamine fluctuations in microfluidic gradients. Anal Chem 2011; 82:8502-9. [PMID: 20849083 DOI: 10.1021/ac101387f] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electrochemical mapping of neurotransmitter concentrations on a chip promises to be an interesting technique for investigating synaptic release in cellular networks. In here, we present a novel chip-based device for the detection of neurotransmitter fluctuations in real-time. The chip features an array of plane-parallel nanocavity sensors, which strongly amplify the electrochemical signal. This amplification is based on efficient redox cycling via confined diffusion between two electrodes inside the nanocavity sensors. We demonstrate the capability of resolving concentration fluctuations of redox-active species in a microfluidic mixing gradient on the chip. The results are explained by a simulated concentration profile that was calculated on the basis of the coupled Navier-Stokes and convection-diffusion equations using a finite element approach.
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Affiliation(s)
- Enno Kätelhön
- Institut für Bio- und Nanosysteme (IBN), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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75
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Abstract
Lithographically fabricated nanostructures appear in an increasingly wide range of scientific fields, and electroanalytical chemistry is no exception. This article introduces lithography methods and provides an overview of the new capabilities and electrochemical phenomena that can emerge in nanostructures.
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Affiliation(s)
- Liza Rassaei
- MESA+ Institute for Nanotechnology, University of Twente, The Netherlands
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76
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Hofmann B, Kätelhön E, Schottdorf M, Offenhäusser A, Wolfrum B. Nanocavity electrode array for recording from electrogenic cells. LAB ON A CHIP 2011; 11:1054-1058. [PMID: 21286648 DOI: 10.1039/c0lc00582g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We present a new nanocavity device for highly localized on-chip recordings of action potentials from individual cells in a network. Microelectrode recordings have become the method of choice for recording extracellular action potentials from high density cultures or slices. Nevertheless, interfacing individual cells of a network with high resolution still remains challenging due to an insufficient coupling of the signal to small electrodes, exhibiting diameters below 10 µm. We show that this problem can be overcome by a new type of sensor that features an electrode, which is accessed via a small aperture and a nanosized cavity. Thus, the properties of large electrodes are combined with a high local resolution and a good seal resistance at the interface. Fabrication of the device can be performed with state-of-the-art clean room technology and sacrificial layer etching allowing integration of the devices into sensor arrays. We demonstrate the capability of such an array by recording the propagation of action potentials in a network of cardiomyocyte-like cells.
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Affiliation(s)
- Boris Hofmann
- PGI-8/ICS-8, Forschungszentrum Jülich GmbH, Jülich, Germany
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77
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A novel glucose sensor based on ordered mesoporous carbon–Au nanoparticles nanocomposites. Talanta 2011; 83:1386-91. [DOI: 10.1016/j.talanta.2010.11.022] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 11/09/2010] [Accepted: 11/11/2010] [Indexed: 11/18/2022]
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78
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Shimizu H, Mawatari K, Kitamori T. Sensitive determination of concentration of nonfluorescent species in an extended-nano channel by differential interference contrast thermal lens microscope. Anal Chem 2011; 82:7479-84. [PMID: 20698489 DOI: 10.1021/ac1017088] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A photothermal detector, named differential interference contrast thermal lens microscope (DIC-TLM), was used to determine the concentration of a nonfluorescent solution in a nanochannel. This method exploits a local change in the refractive index of a solution caused by light absorption. A solution was introduced into a 100-nm scale channel by a pressure-driven nanofluidic control system and its concentration was determined by DIC-TLM. The limit of detection (LOD) was 2.4 microM in a nanochannel that was 21 microm wide and 500 nm deep. The LOD was 3 orders of magnitude smaller than that of conventional method. Moreover, the detection volume was accurately determined to be merely 0.25 fL by using a nanochannel with an optical path length of 500 nm. Based on these results, the number of detected molecules was calculated to be 390. In addition, the concentration of a solution in a nanochannel that was 790 nm wide and 500 nm deep could be determined. Finally, the relationship between sensitivity and channel size was investigated and the sensitivity was found to decrease with decreasing nanochannel size, which indicates that the changes in the refractive indices of water and silica cancel each other out. The DIC-TLM realizes sensitive detection of nonfluorescent species in nanochannels without requiring any special fabrication techniques. Therefore, DIC-TLM is expected to be a highly useful analytical technique in nanofluidics.
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Affiliation(s)
- Hisashi Shimizu
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
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79
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Sassa F, Laghzali H, Fukuda J, Suzuki H. Coulometric Detection of Components in Liquid Plugs by Microfabricated Flow Channel and Electrode Structures. Anal Chem 2010; 82:8725-32. [DOI: 10.1021/ac102289a] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fumihiro Sassa
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan, and Department of Information Technologies for Health Care, Institute for Science and Technology, Joseph Fourier University, BP 53-38041 Grenoble Cedex 9, France
| | - Hind Laghzali
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan, and Department of Information Technologies for Health Care, Institute for Science and Technology, Joseph Fourier University, BP 53-38041 Grenoble Cedex 9, France
| | - Junji Fukuda
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan, and Department of Information Technologies for Health Care, Institute for Science and Technology, Joseph Fourier University, BP 53-38041 Grenoble Cedex 9, France
| | - Hiroaki Suzuki
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan, and Department of Information Technologies for Health Care, Institute for Science and Technology, Joseph Fourier University, BP 53-38041 Grenoble Cedex 9, France
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80
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Yalcin SE, Lee SY, Joo SW, Baysal O, Qian S. Electrodiffusiophoretic motion of a charged spherical particle in a nanopore. J Phys Chem B 2010; 114:4082-93. [PMID: 20196581 DOI: 10.1021/jp100784p] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The electrodiffusiophoretic motion of a charged spherical nanoparticle in a nanopore subjected to an axial electric field and electrolyte concentration gradient has been investigated using a continuum model, composed of the Poisson-Nernst-Planck equations for the ionic mass transport and the Navier-Stokes equations for the flow field. The charged particle experiences electrophoresis in response to the imposed electric field and diffusiophoresis caused solely by the imposed concentration gradient. The diffusiophoretic motion is induced by two different mechanisms, an electrophoresis driven by the generated electric field arising from the difference of ionic diffusivities and the double layer polarization and a chemiphoresis due to the induced osmotic pressure gradient around the charged nanoparticle. The electrodiffusiophoretic motion along the axis of a nanopore is investigated as a function of the ratio of the particle size to the thickness of the electrical double layer, the imposed concentration gradient, the ratio of the surface charge density of the nanopore to that of the particle, and the type of electrolyte. Depending on the magnitude and direction of the imposed concentration gradient, one can accelerate, decelerate, and even reverse the particle's electrophoretic motion in a nanopore by the superimposed diffusiophoresis. The induced electroosmotic flow in the vicinity of the charged nanopore wall driven by both the imposed and the generated electric fields also significantly affects the electrodiffusiophoretic motion.
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Affiliation(s)
- Sinan E Yalcin
- Department of Aerospace Engineering, Old Dominion University, Norfolk, Virginia 23529, USA
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81
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McCarty GS, Moody B, Zachek MK. Enhancing Electrochemical Detection by Scaling Solid State Nanogaps. J Electroanal Chem (Lausanne) 2010; 643:9-14. [PMID: 20454636 PMCID: PMC2863020 DOI: 10.1016/j.jelechem.2010.03.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ability to quickly and inexpensively fabricate planar solid state nanogaps has enabled research to be effectively performed on devices down to just a few nanometers. Here, nanofabricated electrode pairs with electrode-to-electrode spacings of <4, 6 and 20 nm are utilized for monitoring an electroactive molecules, dopamine, in ionic solution. The results show a several order of magnitude enhancement of the electrochemical signal, collected current, for the solid state nanogaps with 6 nm electrode-electrode spacings as compared to traditional microelectrodes. The data from the <4 nm and 20 nm solid state nanogaps verify that this enhancement is due to cycling of the redox molecules in the confined geometry of the nanogap. In addition the data collected for the <4 nm nanogap emphasizes and reinforces that scaling does have limits and that as device sizes move to the few nanometer scale, the influence of a molecule's size and other physical properties becomes increasingly important and can eventually dominate the generated signals.
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Affiliation(s)
- Gregory S. McCarty
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh NC 27695
| | - Benjamin Moody
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh NC 27695
| | - Matthew K. Zachek
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh NC 27695
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82
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Lee SY, Yalcin SE, Joo SW, Baysal O, Qian S. Diffusiophoretic Motion of a Charged Spherical Particle in a Nanopore. J Phys Chem B 2010; 114:6437-46. [DOI: 10.1021/jp9114207] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sang Yoon Lee
- School of Mechanical Engineering, Yeungnam University, Gyongsan 712-749, South Korea, and Department of Aerospace Engineering, Old Dominion University, Norfolk, Virginia 23529
| | - Sinan E. Yalcin
- School of Mechanical Engineering, Yeungnam University, Gyongsan 712-749, South Korea, and Department of Aerospace Engineering, Old Dominion University, Norfolk, Virginia 23529
| | - Sang W. Joo
- School of Mechanical Engineering, Yeungnam University, Gyongsan 712-749, South Korea, and Department of Aerospace Engineering, Old Dominion University, Norfolk, Virginia 23529
| | - Oktay Baysal
- School of Mechanical Engineering, Yeungnam University, Gyongsan 712-749, South Korea, and Department of Aerospace Engineering, Old Dominion University, Norfolk, Virginia 23529
| | - Shizhi Qian
- School of Mechanical Engineering, Yeungnam University, Gyongsan 712-749, South Korea, and Department of Aerospace Engineering, Old Dominion University, Norfolk, Virginia 23529
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83
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Lewis PM, Sheridan LB, Gawley RE, Fritsch I. Signal amplification in a microchannel from redox cycling with varied electroactive configurations of an individually addressable microband electrode array. Anal Chem 2010; 82:1659-68. [PMID: 20108925 PMCID: PMC2857402 DOI: 10.1021/ac901066p] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amperometric detection at microelectrodes in lab-on-a-chip (LOAC) devices lose advantages in signal-to-background ratio, reduced ohmic iR drop, and steady-state signal when volumes are so small that diffusion fields reach the walls before flux becomes fully radial. Redox cycling of electroactive species between multiple, closely spaced microelectrodes offsets that limitation and provides amplification capabilities. A device that integrates a microchannel with an individually addressable microband electrode array has been used to study effects of signal amplification due to redox cycling in a confined, static solution with different configurations and numbers of active generators and collectors. The microfabricated device consists of a 22 microm high, 600 microm wide microchannel containing an array of 50 microm wide, 600 microm long gold microbands, separated by 25 microm gaps, interspersed with an 800 microm wide counter electrode and 400 microm wide passive conductor, with a distant but on-chip 400 microm wide pseudoreference electrode. Investigations involve solutions of potassium chloride electrolyte containing potassium ferrocyanide. Amplification factors were as high as 7.60, even with these microelectrodes of fairly large dimensions (which are generally less expensive, easier, and more reproducible to fabricate), because of the significant role that passive and active (instrumentally induced) redox cycling plays in confined volumes of enclosed microchannels. The studies are useful in optimizing designs for LOAC devices.
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Affiliation(s)
- Penny M. Lewis
- University of Arkansas, Department of Chemistry and Biochemistry, Fayetteville, AR 72701, Tel: (479) 575-6499, Fax: (479) 575-4049,
| | - Leah Bullard Sheridan
- University of Arkansas, Department of Chemistry and Biochemistry, Fayetteville, AR 72701, Tel: (479) 575-6499, Fax: (479) 575-4049,
| | - Robert E. Gawley
- University of Arkansas, Department of Chemistry and Biochemistry, Fayetteville, AR 72701, Tel: (479) 575-6499, Fax: (479) 575-4049,
| | - Ingrid Fritsch
- University of Arkansas, Department of Chemistry and Biochemistry, Fayetteville, AR 72701, Tel: (479) 575-6499, Fax: (479) 575-4049,
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84
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Abstract
As the field of nanofluidics matures, fundamental discoveries are being applied to lab-on-a-chip analyses. The unique behavior of matter at the nanoscale is adding new functionality to devices that integrate nanopores or nanochannels. (To listen to a podcast about this feature, please go to the Analytical Chemistry website at pubs.acs.org/journal/ancham.).
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85
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Wu RG, Yang CS, Lian CK, Cheing CC, Tseng FG. Dual-asymmetry electrokinetic flow focusing for pre-concentration and analysis of catecholamines in CE electrochemical nanochannels. Electrophoresis 2009; 30:2523-31. [PMID: 19639573 DOI: 10.1002/elps.200800809] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this research, a technique incorporating dual-asymmetry electrokinetic flow (DAEKF) was applied to a nanoCE electrochemical device for the pre-concentration and detection of catecholamines. The DAEKF was constructed by first generating a zeta-potential difference between the top and bottom walls, which had been pre-treated with O2 and H2O surface plasma, respectively, yielding a 2-D gradient shear flow across the channel depth. The shear flow was then exposed to a varying zeta-potential along the downstream direction by control of the field-effect in order to cause downward rotational flow in the channel. By this mechanism, almost all of the samples were effectively brought down to the electrode surface for analysis. Simulations were carried out to reveal the mechanism of concentration caused by the DAEKF, and the results reasonably describe our experiment findings. This DAEKF technique was applied to a glass/glass CE electrochemical nanochip for the analysis of catecholamines. The optimum detection limit was determined to be 1.25 and 3.3 nM of dopamine and catechol, respectively. A detection limit at the zeptomole level for dopamine can be obtained in this device, which is close to the level released by a single neuron cell in vitro.
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Affiliation(s)
- Ren-Guei Wu
- Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan
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86
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Deng S, Jian G, Lei J, Hu Z, Ju H. A glucose biosensor based on direct electrochemistry of glucose oxidase immobilized on nitrogen-doped carbon nanotubes. Biosens Bioelectron 2009; 25:373-7. [DOI: 10.1016/j.bios.2009.07.016] [Citation(s) in RCA: 213] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2009] [Revised: 07/03/2009] [Accepted: 07/21/2009] [Indexed: 11/17/2022]
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87
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Zevenbergen MAG, Singh PS, Goluch ED, Wolfrum BL, Lemay SG. Electrochemical Correlation Spectroscopy in Nanofluidic Cavities. Anal Chem 2009; 81:8203-12. [DOI: 10.1021/ac9014885] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marcel A. G. Zevenbergen
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Pradyumna S. Singh
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Edgar D. Goluch
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Bernhard L. Wolfrum
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Serge G. Lemay
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
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88
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Zevenbergen MAG, Wolfrum BL, Goluch ED, Singh PS, Lemay SG. Fast Electron-Transfer Kinetics Probed in Nanofluidic Channels. J Am Chem Soc 2009; 131:11471-7. [DOI: 10.1021/ja902331u] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marcel A. G. Zevenbergen
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Bernhard L. Wolfrum
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Edgar D. Goluch
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Pradyumna S. Singh
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Serge G. Lemay
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
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89
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Lakshmi D, Bossi A, Whitcombe MJ, Chianella I, Fowler SA, Subrahmanyam S, Piletska EV, Piletsky SA. Electrochemical sensor for catechol and dopamine based on a catalytic molecularly imprinted polymer-conducting polymer hybrid recognition element. Anal Chem 2009; 81:3576-84. [PMID: 19354259 DOI: 10.1021/ac802536p] [Citation(s) in RCA: 319] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
One of the difficulties with using molecularly imprinted polymers (MIPs) and other electrically insulating materials as the recognition element in electrochemical sensors is the lack of a direct path for the conduction of electrons from the active sites to the electrode. We have sought to address this problem through the preparation and characterization of novel hybrid materials combining a catalytic MIP, capable of oxidizing the template, catechol, with an electrically conducting polymer. In this way a network of "molecular wires" assists in the conduction of electrons from the active sites within the MIP to the electrode surface. This was made possible by the design of a new monomer that combines orthogonal polymerizable functionality; comprising an aniline group and a methacrylamide. Conducting films were prepared on the surface of electrodes (Au on glass) by electropolymerization of the aniline moiety. A layer of MIP was photochemically grafted over the polyaniline, via N,N'-diethyldithiocarbamic acid benzyl ester (iniferter) activation of the methacrylamide groups. Detection of catechol by the hybrid-MIP sensor was found to be specific, and catechol oxidation was detected by cyclic voltammetry at the optimized operating conditions: potential range -0.6 V to +0.8 V (vs Ag/AgCl), scan rate 50 mV/s, PBS pH 7.4. The calibration curve for catechol was found to be linear to 144 microM, with a limit of detection of 228 nM. Catechol and dopamine were detected by the sensor, whereas analogues and potentially interfering compounds, including phenol, resorcinol, hydroquinone, serotonin, and ascorbic acid, had minimal effect (< or = 3%) on the detection of either analyte. Non-imprinted hybrid electrodes and bare gold electrodes failed to give any response to catechol at concentrations below 0.5 mM. Finally, the catalytic properties of the sensor were characterized by chronoamperometry and were found to be consistent with Michaelis-Menten kinetics.
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Affiliation(s)
- Dhana Lakshmi
- Cranfield Health, Vincent Building, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK
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90
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LU Y, WANG M. Fabrication of Nanostructure by Template Method in Microfluidics. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2009. [DOI: 10.1016/s1872-2040(08)60111-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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91
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Chen C, Sun C, Gao Y. Application of electrosynthesized poly(aniline-co-p-aminophenol) as a catechol sensor. Electrochim Acta 2009. [DOI: 10.1016/j.electacta.2008.10.069] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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92
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Redox cycling in nanofluidic channels using interdigitated electrodes. Anal Bioanal Chem 2009; 394:447-56. [DOI: 10.1007/s00216-008-2575-x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 12/01/2008] [Accepted: 12/08/2008] [Indexed: 11/27/2022]
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93
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Augustin MA, Sanguansri P. Nanostructured materials in the food industry. ADVANCES IN FOOD AND NUTRITION RESEARCH 2009; 58:183-213. [PMID: 19878860 DOI: 10.1016/s1043-4526(09)58005-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nanotechnology involves the application, production, and processing of materials at the nanometer scale. Biological- and physical-inspired approaches, using both conventional and innovative food processing technologies to manipulate matter at this scale, provide the food industry with materials with new functionalities. Understanding the assembly behavior of native and modified food components is essential in developing nanostructured materials. Functionalized nanostructured materials are finding applications in many sectors of the food industry, including novel nanosensors, new packaging materials with improved mechanical and barrier properties, and efficient and targeted nutrient delivery systems. An improved understanding of the benefits and the risks of the technology based on sound scientific data will help gain the acceptance of nanotechnology by the food industry. New horizons for nanotechnology in food science may be achieved by further research on nanoscale structures and methods to control interactions between single molecules.
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Affiliation(s)
- Mary Ann Augustin
- CSIRO Preventative Health National Flagship, Adelaide, South Australia 5000, Australia
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