1
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Zhao M, Cao Y, Huang IW, Monbouquette HG. Microcontact printing of choline oxidase using a polycation-functionalized zwitterionic polymer as enzyme immobilization matrix. Analyst 2023; 148:5949-5956. [PMID: 37855743 PMCID: PMC10842005 DOI: 10.1039/d3an01263h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
Highly sensitive and selective choline microbiosensors were constructed by microcontact printing (μCP) of choline oxidase (ChOx) in a crosslinked, polyamine-functionalized zwitterionic polymer matrix on microelectrode arrays (MEAs). μCP has emerged as a potential means to create implantable, multiplexed sensor microprobes, which requires the targeted deposition of different sensor materials to specific microelectrode sites on a MEA. However, the less than sufficient enzyme loading and inadequate spatial resolution achieved with current μCP approaches has limited adoption of the method for electroenzymatic microsensors. A novel polymer, poly(2-methacryloyloxyethyl phosphorylcholine)-g-poly(allylamine hydrochloride) (PMPC-g-PAH), has been developed to address this challenge. PMPC-g-PAH contributes to a higher viscosity "ink" that enables thicker immobilized ChOx deposits of high spatial resolution while also providing a hydrophilic, biocompatible microenvironment for the enzyme. Electroenzymatic choline microbiosensors with sensitivity of 639 ± 96 nA μM-1 cm-2 (pH 7.4; n = 4) were constructed that also are selective against both ascorbic acid and dopamine, which are potential electroactive interfering compounds in the mammalian brain. The high sensitivities achieved can lead to smaller MEA microprobes that minimize tissue damage and make possible the monitoring of multiple neurochemicals simultaneously in vivo with high spatial resolution.
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Affiliation(s)
- Ming Zhao
- Chemical and Biomolecular Engineering Department, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Yan Cao
- Chemical and Biomolecular Engineering Department, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - I-Wen Huang
- Chemical and Biomolecular Engineering Department, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Harold G Monbouquette
- Chemical and Biomolecular Engineering Department, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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2
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Design optimisation and characterisation of an amperometric glutamate oxidase-based composite biosensor for neurotransmitter l-glutamic acid. Anal Chim Acta 2022; 1224:340205. [DOI: 10.1016/j.aca.2022.340205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 07/15/2022] [Accepted: 07/24/2022] [Indexed: 11/22/2022]
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3
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Wang B, Wen X, Cao Y, Huang S, Lam HA, Liu TL, Chung PS, Monbouquette HG, Chiou PY, Maidment NT. An implantable multifunctional neural microprobe for simultaneous multi-analyte sensing and chemical delivery. LAB ON A CHIP 2020; 20:1390-1397. [PMID: 32211718 PMCID: PMC7192313 DOI: 10.1039/d0lc00021c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
A multifunctional chemical neural probe fabrication process exploiting PDMS thin-film transfer to incorporate a microfluidic channel onto a silicon-based microelectrode array (MEA) platform, and enzyme microstamping to provide multi-analyte detection is described. The Si/PDMS hybrid chemtrode, modified with a nano-based on-probe IrOx reference electrode, was validated in brain phantoms and in rat brain.
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Affiliation(s)
- Bo Wang
- Department of Psychiatry & Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, California 90095, USA.
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4
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Huang IW, Clay M, Wang S, Guo Y, Nie J, Monbouquette HG. Electroenzymatic glutamate sensing at near the theoretical performance limit. Analyst 2020; 145:2602-2611. [PMID: 31998887 PMCID: PMC7117983 DOI: 10.1039/c9an01969c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The sensitivity and response time of glutamate sensors based on glutamate oxidase immobilized on planar platinum microelectrodes have been improved to near the theoretical performance limits predicted by a detailed mathematical model. Microprobes with an array of electroenzymatic sensing sites have emerged as useful tools for the monitoring of glutamate and other neurotransmitters in vivo; and implemented as such, they can be used to study many complex neurological diseases and disorders including Parkinson's disease and drug addiction. However, less than optimal sensitivity and response time has limited the spatiotemporal resolution of these promising research tools. A mathematical model has guided systematic improvement of an electroenzymatic glutamate microsensor constructed with a 1-2 μm-thick crosslinked glutamate oxidase layer and underlying permselective coating of polyphenylenediamine and Nafion reduced to less than 200 nm thick. These design modifications led to a nearly 6-fold improvement in sensitivity to 320 ± 20 nA μM-1 cm-2 at 37 °C and a ∼10-fold reduction in response time to 80 ± 10 ms. Importantly, the sensitivity and response times were attained while maintaining a low detection limit and excellent selectivity. Direct measurement of the transport properties of the enzyme and polymer layers used to create the biosensors enabled improvement of the mathematical model as well. Subsequent model simulations indicated that the performance characteristics achieved with the optimized biosensors approach the theoretical limits predicted for devices of this construction. Such high-performance glutamate biosensors will be more effective in vivo at a size closer to cellular dimension and will enable better correlation of glutamate signaling events with electrical recordings.
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Affiliation(s)
- I-Wen Huang
- Chemical and Biomolecular Engineering Department University of California, Los Angeles, Los Angeles, CA 90095, USA.
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5
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Wen X, Wang B, Huang S, Liu TL, Lee MS, Chung PS, Chow YT, Huang IW, Monbouquette HG, Maidment NT, Chiou PY. Flexible, multifunctional neural probe with liquid metal enabled, ultra-large tunable stiffness for deep-brain chemical sensing and agent delivery. Biosens Bioelectron 2019; 131:37-45. [PMID: 30818131 PMCID: PMC6602555 DOI: 10.1016/j.bios.2019.01.060] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/21/2019] [Accepted: 01/24/2019] [Indexed: 10/27/2022]
Abstract
Flexible neural probes have been pursued previously to minimize the mechanical mismatch between soft neural tissues and implants and thereby improve long-term performance. However, difficulties with insertion of such probes deep into the brain severely restricts their utility. We describe a solution to this problem using gallium (Ga) in probe construction, taking advantage of the solid-to-liquid phase change of the metal at body temperature and probe shape deformation to provide temperature-dependent control of stiffness over 5 orders of magnitude. Probes in the stiff state were successfully inserted 2 cm-deep into agarose gel "brain phantoms" and into rat brains under cooled conditions where, upon Ga melting, they became ultra soft, flexible, and stretchable in all directions. The current 30 μm-thick probes incorporated multilayer, deformable microfluidic channels for chemical agent delivery, electrical interconnects through Ga wires, and high-performance electrochemical glutamate sensing. These PDMS-based microprobes of ultra-large tunable stiffness (ULTS) should serve as an attractive platform for multifunctional chronic neural implants.
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Affiliation(s)
- Ximiao Wen
- Department of Mechanical and Aerospace Engineering, University of California at Los Angeles, Los Angeles, CA, USA
| | - Bo Wang
- Department of Psychiatry & Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, CA, USA
| | - Shan Huang
- Department of Biological Chemistry, University of California at Los Angeles, CA, USA
| | - Tingyi Leo Liu
- Department of Mechanical and Industrial Engineering, University of Massachusetts Amherst, MA, USA
| | - Meng-Shiue Lee
- Department of Mechanical Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Pei-Shan Chung
- Department of Bioengineering, University of California at Los Angeles, CA, USA
| | - Yu Ting Chow
- Department of Mechanical and Aerospace Engineering, University of California at Los Angeles, Los Angeles, CA, USA
| | - I-Wen Huang
- Department of Chemical and Biomolecular Engineering, University of California at Los Angeles, CA, USA
| | - Harold G Monbouquette
- Department of Chemical and Biomolecular Engineering, University of California at Los Angeles, CA, USA
| | - Nigel T Maidment
- Department of Psychiatry & Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, CA, USA.
| | - Pei-Yu Chiou
- Department of Mechanical and Aerospace Engineering, University of California at Los Angeles, Los Angeles, CA, USA; Department of Bioengineering, University of California at Los Angeles, CA, USA.
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6
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Wang B, Feng L, Koo B, Monbouquette HG. A Complete Electroenzymatic Choline Microprobe Based on Nanostructured Platinum Microelectrodes and an IrOx On‐probe Reference Electrode. ELECTROANAL 2019. [DOI: 10.1002/elan.201900039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Bo Wang
- Chemical and Biomolecular Engineering DepartmentUniversity of California Los Angeles CA 90095 USA
| | - Lili Feng
- Chemical and Biomolecular Engineering DepartmentUniversity of California Los Angeles CA 90095 USA
| | - Bonhye Koo
- Chemical and Biomolecular Engineering DepartmentUniversity of California Los Angeles CA 90095 USA
| | - Harold G. Monbouquette
- Chemical and Biomolecular Engineering DepartmentUniversity of California Los Angeles CA 90095 USA
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7
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Clay M, Monbouquette HG. A Detailed Model of Electroenzymatic Glutamate Biosensors To Aid in Sensor Optimization and in Applications in Vivo. ACS Chem Neurosci 2018; 9:241-251. [PMID: 29076724 DOI: 10.1021/acschemneuro.7b00262] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Simulations conducted with a detailed model of glutamate biosensor performance describe the observed sensor performance well, illustrate the limits of sensor performance, and suggest a path toward sensor optimization. Glutamate is the most important excitatory neurotransmitter in the brain, and electroenzymatic sensors have emerged as a useful tool for the monitoring of glutamate signaling in vivo. However, the utility of these sensors currently is limited by their sensitivity and response time. A mathematical model of a typical glutamate biosensor consisting of a Pt electrode coated with a permselective polymer film and a top layer of cross-linked glutamate oxidase has been constructed in terms of differential material balances on glutamate, H2O2, and O2 in one spatial dimension. Simulations suggest that reducing thicknesses of the permselective polymer and enzyme layers can increase sensitivity ∼6-fold and reduce response time ∼7-fold, and thereby improve resolution of transient glutamate signals. At currently employed enzyme layer thicknesses, both intrinsic enzyme kinetics and enzyme deactivation likely are masked by mass transfer. However, O2-dependence studies show essentially no reduction in signal at the lowest anticipated O2 concentrations for expected glutamate concentrations in the brain and that O2 transport limitations in vitro are anticipated only at glutamate concentrations in the mM range. Finally, the limitations of current biosensors in monitoring glutamate transients is simulated and used to illustrate the need for optimized biosensors to report glutamate signaling accurately on a subsecond time scale. This work demonstrates how a detailed model can be used to guide optimization of electroenzymatic sensors similar to that for glutamate and to ensure appropriate interpretation of data gathered using such biosensors.
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Affiliation(s)
- Mackenzie Clay
- Chemical and Biomolecular
Engineering Department, University of California, Los Angeles, Los Angeles, California 90095-1592, United States
| | - Harold G. Monbouquette
- Chemical and Biomolecular
Engineering Department, University of California, Los Angeles, Los Angeles, California 90095-1592, United States
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8
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Soldatkina OV, Soldatkin OO, Kasap BO, Kucherenko DY, Kucherenko IS, Kurc BA, Dzyadevych SV. A Novel Amperometric Glutamate Biosensor Based on Glutamate Oxidase Adsorbed on Silicalite. NANOSCALE RESEARCH LETTERS 2017; 12:260. [PMID: 28395478 PMCID: PMC5383914 DOI: 10.1186/s11671-017-2026-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 03/29/2017] [Indexed: 05/13/2023]
Abstract
In this work, we developed a new amperometric biosensor for glutamate detection using a typical method of glutamate oxidase (GlOx) immobilization via adsorption on silicalite particles. The disc platinum electrode (d = 0.4 mm) was used as the amperometric sensor. The procedure of biosensor preparation was optimized. The main parameters of modifying amperometric transducers with a silicalite layer were determined along with the procedure of GlOx adsorption on this layer. The biosensors based on GlOx adsorbed on silicalite demonstrated high sensitivity to glutamate. The linear range of detection was from 2.5 to 450 μM, and the limit of glutamate detection was 1 μM. It was shown that the proposed biosensors were characterized by good response reproducibility during hours of continuous work and operational stability for several days. The developed biosensors could be applied for determination of glutamate in real samples.
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Affiliation(s)
- O. V. Soldatkina
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Volodymyrska Street 64, Kyiv, 01003 Ukraine
| | - O. O. Soldatkin
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Volodymyrska Street 64, Kyiv, 01003 Ukraine
- Institute of Molecular Biology and Genetics of NAS of Ukraine, Zabolotnogo Street 150, Kyiv, 03143 Ukraine
| | - B. Ozansoy Kasap
- Micro and Nanotechnology Department, Middle East Technical University, 06531 Ankara, Turkey
| | - D. Yu. Kucherenko
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Volodymyrska Street 64, Kyiv, 01003 Ukraine
| | - I. S. Kucherenko
- Institute of Molecular Biology and Genetics of NAS of Ukraine, Zabolotnogo Street 150, Kyiv, 03143 Ukraine
| | - B. Akata Kurc
- Micro and Nanotechnology Department, Middle East Technical University, 06531 Ankara, Turkey
- Central Laboratory, Middle East Technical University, 06531 Ankara, Turkey
| | - S. V. Dzyadevych
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Volodymyrska Street 64, Kyiv, 01003 Ukraine
- Institute of Molecular Biology and Genetics of NAS of Ukraine, Zabolotnogo Street 150, Kyiv, 03143 Ukraine
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9
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Electrochemical detection of neurotransmitters: Toward synapse-based neural interfaces. Biomed Eng Lett 2017. [DOI: 10.1007/s13534-016-0230-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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10
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Wang B, Koo B, Monbouquette HG. Enzyme Deposition by Polydimethylsiloxane Stamping for Biosensor Fabrication. ELECTROANAL 2017; 29:2300-2306. [PMID: 29628750 DOI: 10.1002/elan.201700302] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
High-performance biosensors were fabricated by efficiently transferring enzyme onto Pt electrode surfaces using a polydimethylsiloxane (PDMS) stamp. Polypyrrole and Nafion were coated first on the electrode surface to act as permselective films for exclusion of both anionic and cationic electrooxidizable interfering compounds. A chitosan film then was electrochemically deposited to serve as an adhesive layer for enzyme immobilization. Glucose oxidase (GOx) was selected as a model enzyme for construction of a glucose biosensor, and a mixture of GOx and bovine serum albumin was stamped onto the chitosan-coated surface and subsequently crosslinked using glutaraldehyde vapor. For the optimized fabrication process, the biosensor exhibited excellent performance characteristics including a linear range up to 2 mM with sensitivity of 29.4 ± 1.3 μA mM-1 cm-2 and detection limit of 4.3 ± 1.7 μM (S/N = 3) as well as a rapid response time of ~2 s. In comparison to those previously described, this glucose biosensor exhibits an excellent combination of high sensitivity, low detection limit, rapid response time, and good selectivity. Thus, these results support the use of PDMS stamping as an effective enzyme deposition method for electroenzymatic biosensor fabrication, which may prove especially useful for the deposition of enzyme at selected sites on microelectrode array microprobes of the kind used for neuroscience research in vivo.
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Affiliation(s)
- Bo Wang
- Chemical and Biomolecular Engineering Department, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Bonhye Koo
- Chemical and Biomolecular Engineering Department, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Harold G Monbouquette
- Chemical and Biomolecular Engineering Department, University of California, Los Angeles, Los Angeles, CA 90095, USA
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11
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Newton AJH, Wall MJ, Richardson MJE. Modeling microelectrode biosensors: free-flow calibration can substantially underestimate tissue concentrations. J Neurophysiol 2016; 117:937-949. [PMID: 27927788 PMCID: PMC5338626 DOI: 10.1152/jn.00788.2016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 12/05/2016] [Indexed: 12/11/2022] Open
Abstract
Microelectrode biosensors are typically calibrated in a free-flow environment where the concentrations at the biosensor surface are constant. However, when in tissue, the analyte reaches the biosensor via diffusion and so analyte breakdown by the biosensor results in a concentration gradient and consequently a lower concentration around the biosensor. This effect means that naive free-flow calibration will underestimate tissue concentration. We develop mathematical models to better quantify the discrepancy between the calibration and tissue environment and experimentally verify our key predictions. Microelectrode amperometric biosensors are widely used to measure concentrations of analytes in solution and tissue including acetylcholine, adenosine, glucose, and glutamate. A great deal of experimental and modeling effort has been directed at quantifying the response of the biosensors themselves; however, the influence that the macroscopic tissue environment has on biosensor response has not been subjected to the same level of scrutiny. Here we identify an important issue in the way microelectrode biosensors are calibrated that is likely to have led to underestimations of analyte tissue concentrations. Concentration in tissue is typically determined by comparing the biosensor signal to that measured in free-flow calibration conditions. In a free-flow environment the concentration of the analyte at the outer surface of the biosensor can be considered constant. However, in tissue the analyte reaches the biosensor surface by diffusion through the extracellular space. Because the enzymes in the biosensor break down the analyte, a density gradient is set up resulting in a significantly lower concentration of analyte near the biosensor surface. This effect is compounded by the diminished volume fraction (porosity) and reduction in the diffusion coefficient due to obstructions (tortuosity) in tissue. We demonstrate this effect through modeling and experimentally verify our predictions in diffusive environments. NEW & NOTEWORTHY Microelectrode biosensors are typically calibrated in a free-flow environment where the concentrations at the biosensor surface are constant. However, when in tissue, the analyte reaches the biosensor via diffusion and so analyte breakdown by the biosensor results in a concentration gradient and consequently a lower concentration around the biosensor. This effect means that naive free-flow calibration will underestimate tissue concentration. We develop mathematical models to better quantify the discrepancy between the calibration and tissue environment and experimentally verify our key predictions.
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Affiliation(s)
- Adam J H Newton
- Warwick Mathematics Institute, University of Warwick, Coventry, United Kingdom; and
| | - Mark J Wall
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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12
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Malvaez M, Greenfield VY, Wang AS, Yorita AM, Feng L, Linker KE, Monbouquette HG, Wassum KM. Basolateral amygdala rapid glutamate release encodes an outcome-specific representation vital for reward-predictive cues to selectively invigorate reward-seeking actions. Sci Rep 2015; 5:12511. [PMID: 26212790 PMCID: PMC4648450 DOI: 10.1038/srep12511] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 06/17/2015] [Indexed: 11/09/2022] Open
Abstract
Environmental stimuli have the ability to generate specific representations of the rewards they predict and in so doing alter the selection and performance of reward-seeking actions. The basolateral amygdala participates in this process, but precisely how is unknown. To rectify this, we monitored, in near-real time, basolateral amygdala glutamate concentration changes during a test of the ability of reward-predictive cues to influence reward-seeking actions (Pavlovian-instrumental transfer). Glutamate concentration was found to be transiently elevated around instrumental reward seeking. During the Pavlovian-instrumental transfer test these glutamate transients were time-locked to and correlated with only those actions invigorated by outcome-specific motivational information provided by the reward-predictive stimulus (i.e., actions earning the same specific outcome as predicted by the presented CS). In addition, basolateral amygdala AMPA, but not NMDA glutamate receptor inactivation abolished the selective excitatory influence of reward-predictive cues over reward seeking. These data support [corrected] the hypothesis that transient glutamate release in the BLA can encode the outcome-specific motivational information provided by reward-predictive stimuli.
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Affiliation(s)
| | | | - Alice S. Wang
- Dept. of Psychology, UCLA, Los Angeles, CA 90095, USA
| | | | - Lili Feng
- Dept. of Chemical Engineering, UCLA, Los Angeles, CA 90095, USA
| | - Kay E. Linker
- Dept. of Psychology, UCLA, Los Angeles, CA 90095, USA
| | | | - Kate M. Wassum
- Dept. of Psychology, UCLA, Los Angeles, CA 90095, USA
- Brain Research Institute, UCLA, Los Angeles, CA 90095, USA
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13
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Özel RE, Hayat A, Andreescu S. RECENT DEVELOPMENTS IN ELECTROCHEMICAL SENSORS FOR THE DETECTION OF NEUROTRANSMITTERS FOR APPLICATIONS IN BIOMEDICINE. ANAL LETT 2015; 48:1044-1069. [PMID: 26973348 PMCID: PMC4787221 DOI: 10.1080/00032719.2014.976867] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neurotransmitters are important biological molecules that are essential to many neurophysiological processes including memory, cognition, and behavioral states. The development of analytical methodologies to accurately detect neurotransmitters is of great importance in neurological and biological research. Specifically designed microelectrodes or microbiosensors have demonstrated potential for rapid, real-time measurements with high spatial resolution. Such devices can facilitate study of the role and mechanism of action of neurotransmitters and can find potential uses in biomedicine. This paper reviews the current status and recent advances in the development and application of electrochemical sensors for the detection of small-molecule neurotransmitters. Measurement challenges and opportunities of electroanalytical methods to advance study and understanding of neurotransmitters in various biological models and disease conditions are discussed.
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Affiliation(s)
- Rıfat Emrah Özel
- Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, NY, USA. Fax: 3152686610; Tel: 3152682394
| | - Akhtar Hayat
- Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, NY, USA. Fax: 3152686610; Tel: 3152682394
- Interdisciplinary Research Centre in Biomedical Materials (IRCBM), COMSATS Institute of Information Technology (CIIT), Lahore, Pakistan
| | - Silvana Andreescu
- Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, NY, USA. Fax: 3152686610; Tel: 3152682394
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14
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Li J, Xie J, Gao L, Li CM. Au nanoparticles-3D graphene hydrogel nanocomposite to boost synergistically in situ detection sensitivity toward cell-released nitric oxide. ACS APPLIED MATERIALS & INTERFACES 2015; 7:2726-2734. [PMID: 25580718 DOI: 10.1021/am5077777] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In situ detection of nitric oxide (NO) released from living cells has become very important in studies of some critical physiological and pathological processes, but it is still very challenging due to the low concentration and fast decay of NO. A nanocomposite of Au nanoparticles deposited on three-dimensional graphene hydrogel (Au NPs-3DGH) was prepared through a facile one-step approach by in situ reduction of Au(3+) on 3DGH to build a unique sensing film for a strong synergistic effect, in which the highly porous 3DGH offers a large surface area while Au NPs uniformly deposited on 3DGH efficiently catalyze the electrochemical oxidation of NO for sensitive detection of NO with excellent selectivity, fast response, and low detection limit. The sensor was further used to in situ detect NO released from living cells under drug stimulation, showing significant difference between normal and tumor cells under drug stimulation.
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Affiliation(s)
- Jialin Li
- Institute for Clean Energy & Advanced Materials and ‡Faculty of Materials and Energy, Southwest University , Chongqing 400715, China
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15
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Liu X, Dumitrescu E, Andreescu S. Electrochemical Biosensors for Real-Time Monitoring of Reactive Oxygen and Nitrogen Species. ACS SYMPOSIUM SERIES 2015. [DOI: 10.1021/bk-2015-1200.ch013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Xiaobo Liu
- Department of Chemistry & Biomolecular Science, Clarkson University, 8 Clarkson Avenue, Potsdam, New York 13699-5810
| | - Eduard Dumitrescu
- Department of Chemistry & Biomolecular Science, Clarkson University, 8 Clarkson Avenue, Potsdam, New York 13699-5810
| | - Silvana Andreescu
- Department of Chemistry & Biomolecular Science, Clarkson University, 8 Clarkson Avenue, Potsdam, New York 13699-5810
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16
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Moon BU, de Vries MG, Cordeiro CA, Westerink BHC, Verpoorte E. Microdialysis-coupled enzymatic microreactor for in vivo glucose monitoring in rats. Anal Chem 2013; 85:10949-55. [PMID: 24199633 DOI: 10.1021/ac402414m] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Continuous glucose monitoring (CGM) is an important aid for diabetic patients to optimize glycemic control and to prevent long-term complications. However, current CGM devices need further miniaturization and improved functional performance. We have coupled a previously described microfluidic chip with enzymatic microreactor (EMR) to a microdialysis probe and evaluated the performance of this system for monitoring subcutaneous glucose concentration in rats. Nanoliter volumes of microdialysis sample are efficiently reacted with continuously supplied glucose oxidase (GOx) solution in the EMR. The hydrogen peroxide produced is amperometrically detected at a (polypyrrole (PPy)-protected) thin-film Pt electrode. Subcutaneous glucose concentration was continuously monitored in anesthetized rats in response to intravenous injections of 20% glucose (w/v), 5 U/kg insulin, or saline as a control. In vitro evaluation showed a linear range of 2.1-20.6 mM and a sensitivity of 7.8 ± 1.0 nA/mM (n = 6). The physical lag time between microdialysis and the analytical signal was approximately 18 min. The baseline concentration of blood glucose was 10.2 ± 2.3 mM. After administering glucose to the rats, glucose levels increased by about 2 mM to 12.1 ± 2.3 mM in blood and 11.9 ± 1.5 mM in subcutaneous interstitial fluid (ISF). After insulin administration, glucose levels decreased by about 8 mM relative to baseline to 2.1 ± 0.6 mM in blood and 2.1 ± 0.9 mM in ISF. A microfluidic device with integrated chaotic mixer and EMR has been successfully combined with subcutaneous microdialysis to continuously monitor glucose in rats. This proof-of-principle demonstrates the feasibility of improved miniaturization in CGM based on microfluidics.
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Affiliation(s)
- Byeong-Ui Moon
- Biomonitoring and Sensoring, Groningen Research Institute of Pharmacy, University of Groningen , Antonius Deusinglaan 1, P.O. Box 196, 9700 AD Groningen, The Netherlands
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17
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Özel RE, Ispas C, Ganesana M, Leiter JC, Andreescu S. Glutamate oxidase biosensor based on mixed ceria and titania nanoparticles for the detection of glutamate in hypoxic environments. Biosens Bioelectron 2013; 52:397-402. [PMID: 24090755 DOI: 10.1016/j.bios.2013.08.054] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 08/26/2013] [Accepted: 08/28/2013] [Indexed: 11/26/2022]
Abstract
We report on the design and development of a glutamate oxidase (GmOx) microelectrode for measuring l-glutamic acid (GluA) in oxygen-depleted conditions, which is based on the oxygen storage and release capacity of cerium oxides. To fabricate the biosensor, a nanocomposite of oxygen-rich ceria and titania nanoparticles dispersed within a semi-permeable chitosan membrane was co-immobilized with the enzyme GmOx on the surface of a Pt microelectrode. The oxygen delivery capacity of the ceria nanoparticles embedded in a biocompatible chitosan matrix facilitated enzyme stabilization and operation in oxygen free conditions. GluA was measured by amperometry at a working potential of 0.6 V vs Ag/AgCl. Detection limits of 0.594 µM and 0.493 µM and a sensitivity of 793 pA/µM (RSD 3.49%, n=5) and 395 pA/µM (RSD 2.48%, n=5) were recorded in oxygenated and deoxygenated conditions, with response times of 2s and 5s, respectively. The biosensor had good operational stability and selectivity against common interfering substances. Operation of the biosensor was tested in cerebrospinal fluid. Preliminary in vivo recording in Sprague-Dawley rats to monitor GluA in the cortex during cerebral ischemia and reperfusion demonstrate a potential application of the biosensor in hypoxic conditions. This method provides a solution to ensure functionality of oxidoreductase enzymes in oxygen-free environments.
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Affiliation(s)
- Rıfat Emrah Özel
- Department of Chemistry and Biomolecular Science, Potsdam, NY 13699-5810, USA
| | - Cristina Ispas
- Department of Chemistry and Biomolecular Science, Potsdam, NY 13699-5810, USA
| | | | - J C Leiter
- Department of Physiology, Dartmouth Medical School, Lebanon, NH 03756
| | - Silvana Andreescu
- Department of Chemistry and Biomolecular Science, Potsdam, NY 13699-5810, USA
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18
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Selective enzyme immobilization on arrayed microelectrodes for the application of sensing neurotransmitters. Biochem Eng J 2013. [DOI: 10.1016/j.bej.2013.04.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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19
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Electrochemically deposited iridium oxide reference electrode integrated with an electroenzymatic glutamate sensor on a multi-electrode array microprobe. Biosens Bioelectron 2012. [PMID: 23208095 DOI: 10.1016/j.bios.2012.10.061] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
An implantable micromachined multi-electrode array (MEA) microprobe modified for utilization as a complete electrochemical biosensor for rapid glutamate detection is described. A post-fabrication method for electrochemical deposition of an iridium oxide (IrOx) film onto a designated microelectrode enabled incorporation of an IrOx reference electrode (RE) on the microprobe. The on-probe IrOx RE provides an alternative to the commonly utilized Ag/AgCl wire RE, which has been shown to be unstable and to cause an inflammatory response in living tissue. The IrOx film electrodeposited onto a platinum site was tested as part of a complete chemical sensing system that included a platinum counter electrode and enzymatic glutamate sensing electrodes all on a single silicon-based MEA platform. The thin film IrOx was mechanically robust enough to endure conditions of repeated heating and wetting during the MEA fabrication process. The pH dependence of the IrOx open circuit potential (OCP) was measured at -77±0.4 mV/pH and remained stable over a two-week period. The on-probe IrOx RE was tested in a two- and three-electrode system with glutamate biosensors. The biosensors were shown to detect a physiologically relevant range of glutamate concentrations and to reject the interferents, dopamine and ascorbic acid. By incorporating all of the electrodes onto a single device, baseline noise was reduced by an average of ∼61% in vitro and ∼71% in vivo with reduced tissue damage, since only a single probe needed to be implanted.
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20
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Tseng TTC, Monbouquette HG. Implantable Microprobe with Arrayed Microsensors for Combined Amperometric Monitoring of the Neurotransmitters, Glutamate and Dopamine. J Electroanal Chem (Lausanne) 2012; 682:141-146. [PMID: 23139647 PMCID: PMC3489491 DOI: 10.1016/j.jelechem.2012.07.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An implantable, micromachined microprobe with a microsensor array for combined monitoring of the neurotransmitters, glutamate (Glut) and dopamine (DA), by constant potential amperometry has been created and characterized. Microprobe studies in vitro revealed Glut and DA microsensor sensitivities of 126±5 nA·μM(-1)·cm(-2) and 3250±50 nA·μM(-1)·cm(-2), respectively, with corresponding detection limits of 2.1±0.2 μM and 62±8 nM, both at comparable ~1 sec response times. No diffusional interaction of H(2)O(2) among arrayed microelectrodes was observed. Also, no responses from the electroactive interferents, ascorbic acid (AA), uric acid (UA), DOPA (a DA catabolite) or DOPAC (a DA precursor), over their respective physiological concentration ranges, were detected. The dual sensing microbe attributes of size, detection limit, sensitivity, response time and selectivity make it attractive for combined sensing of Glut and DA in vivo.
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Affiliation(s)
| | - Harold G. Monbouquette
- Department of Chemical and Biomolecular Engineering Department, University of California, Los Angeles, CA 90095, USA, Tel: (310) 825-8946, Fax: (310) 206-4107
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21
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Wahono N, Qin S, Oomen P, Cremers TIF, de Vries MG, Westerink BHC. Evaluation of permselective membranes for optimization of intracerebral amperometric glutamate biosensors. Biosens Bioelectron 2012; 33:260-6. [PMID: 22326702 DOI: 10.1016/j.bios.2012.01.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 01/16/2012] [Accepted: 01/17/2012] [Indexed: 01/01/2023]
Abstract
Monitoring of extracellular brain glutamate concentrations by intracerebral biosensors is a promising approach to further investigate the role of this important neurotransmitter. However, amperometric biosensors are typically hampered by Faradaic interference caused by the presence of other electroactive species in the brain, such as ascorbic acid, dopamine, and uric acid. Various permselective membranes are often used on biosensors to prevent this. In this study we evaluated the most commonly used membranes, i.e. nafion, polyphenylenediamine, polypyrrole, polyaniline, and polynaphthol using a novel silica-based platinum electrode. First we selected the membranes with the highest sensitivity for hydrogen peroxide in vitro and an optimal selectivity against electrochemical interferents. Then we evaluated the performances of these membranes in a short lasting (3-4h) in vivo experiment. We found that best in vitro performance was accomplished with biosensors that were protected by a poly(m-phenylenediamine) membrane deposited onto the platinum electrode by cyclic voltammetry. However, post-implantation evaluation of these membranes showed poor selectivity against dopamine. Combination with a previously applied nafion layer did not protect the sensors against acute biofouling; indeed it was even counter effective. Finally, we investigated the ability of our biosensors to monitor the effect of glutamate transport blocker DL-TBOA on modulating glutamate concentrations in the prefrontal cortex of anaesthetized rats. The optimized biosensors recorded a rapid 35-fold increase in extracellular glutamate, and are considered suitable for further exploration in vivo.
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Affiliation(s)
- N Wahono
- Biomonitoring and Sensoring Group, Groningen University, The Netherlands.
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22
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Singh YS, Sawarynski LE, Michael HM, Ferrell RE, Murphey-Corb MA, Swain GM, Patel BA, Andrews AM. Boron-Doped Diamond Microelectrodes Reveal Reduced Serotonin Uptake Rates in Lymphocytes from Adult Rhesus Monkeys Carrying the Short Allele of the 5-HTTLPR. ACS Chem Neurosci 2010; 1:49-64. [PMID: 20352073 DOI: 10.1021/cn900012y] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Uptake resolved by high-speed chronoamperometry on a second-by-second basis has revealed important differences in brain serotonin transporter function associated with genetic variability. Here, we use chronoamperometry to investigate variations in serotonin transport in primary lymphocytes associated with the rhesus serotonin transporter gene-linked polymorphism (rh5-HTTLPR), a promoter polymorphism whose orthologs occur only in higher order primates including humans. Serotonin clearance by lymphocytes is Na(+)-dependent and inhibited by the serotonin-selective reuptake inhibitor paroxetine (Paxil®), indicative of active uptake by serotonin transporters. Moreover, reductions in serotonin uptake rates are evident in lymphocytes from monkeys with one or two copies of the short 's' allele of the rh5-HTTLPR (s/s<s/l<l/l). These findings illustrate that rh5-HTTLPR-related alterations in serotonin uptake are present during adulthood in peripheral blood cells natively expressing serotonin transporters. Moreover, they suggest that lymphocytes can be used as peripheral biomarkers for investigating genetic or pharmacologic alterations in serotonin transporter function. Use of boron-doped diamond microelectrodes for measuring serotonin uptake, in contrast to carbon fiber microelectrodes used previously in the brain, enabled these high-sensitivity and high-resolution measurements. Boron-doped diamond microelectrodes show excellent signal-to-noise and signal-to-background ratios due mainly to low background currents and are highly resistant to fouling when exposed to lymphocytes or high concentrations of serotonin.
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Affiliation(s)
| | | | | | | | | | - Greg M. Swain
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824
| | - Bhavik A. Patel
- Department of Bioengineering, Imperial College London, London, U.K. SE7 2AZ
| | - Anne M. Andrews
- Departments of Chemistry,
- Veterinary and Biomedical Sciences,
- Huck Institutes of Life Sciences
- Department of Psychiatry & Biobehavioral Sciences and California NanoSystems Institute, University of California, Los Angeles, California 90024
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Perry M, Li Q, Kennedy RT. Review of recent advances in analytical techniques for the determination of neurotransmitters. Anal Chim Acta 2009; 653:1-22. [PMID: 19800472 PMCID: PMC2759352 DOI: 10.1016/j.aca.2009.08.038] [Citation(s) in RCA: 248] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 08/25/2009] [Accepted: 08/27/2009] [Indexed: 12/18/2022]
Abstract
Methods and advances for monitoring neurotransmitters in vivo or for tissue analysis of neurotransmitters over the last five years are reviewed. The review is organized primarily by neurotransmitter type. Transmitter and related compounds may be monitored by either in vivo sampling coupled to analytical methods or implanted sensors. Sampling is primarily performed using microdialysis, but low-flow push-pull perfusion may offer advantages of spatial resolution while minimizing the tissue disruption associated with higher flow rates. Analytical techniques coupled to these sampling methods include liquid chromatography, capillary electrophoresis, enzyme assays, sensors, and mass spectrometry. Methods for the detection of amino acid, monoamine, neuropeptide, acetylcholine, nucleoside, and soluble gas neurotransmitters have been developed and improved upon. Advances in the speed and sensitivity of these methods have enabled improvements in temporal resolution and increased the number of compounds detectable. Similar advances have enabled improved detection at tissue samples, with a substantial emphasis on single cell and other small samples. Sensors provide excellent temporal and spatial resolution for in vivo monitoring. Advances in application to catecholamines, indoleamines, and amino acids have been prominent. Improvements in stability, sensitivity, and selectivity of the sensors have been of paramount interest.
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Affiliation(s)
- Maura Perry
- University of Michigan, Department of Chemistry, 930 N. University, Ann Arbor, MI 48109-1055, USA
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24
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Wassum KM, Tolosa VM, Wang J, Walker E, Monbouquette HG, Maidment NT. Silicon Wafer-Based Platinum Microelectrode Array Biosensor for Near Real-Time Measurement of Glutamate in Vivo. SENSORS 2008; 8:5023-5036. [PMID: 19543440 PMCID: PMC2699285 DOI: 10.3390/s8085023] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Using Micro-Electro-Mechanical-Systems (MEMS) technologies, we have developed silicon wafer-based platinum microelectrode arrays (MEAs) modified with glutamate oxidase (GluOx) for electroenzymatic detection of glutamate in vivo. These MEAs were designed to have optimal spatial resolution for in vivo recordings. Selective detection of glutamate in the presence of the electroactive interferents, dopamine and ascorbic acid, was attained by deposition of polypyrrole and Nafion. The sensors responded to glutamate with a limit of detection under 1muM and a sub-1-second response time in solution. In addition to extensive in vitro characterization, the utility of these MEA glutamate biosensors was also established in vivo. In the anesthetized rat, these MEA glutamate biosensors were used for detection of cortically-evoked glutamate release in the ventral striatum. The MEA biosensors also were applied to the detection of stress-induced glutamate release in the dorsal striatum of the freely-moving rat.
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Affiliation(s)
- Kate M. Wassum
- Dept. Psychiatry & Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, CA, USA; E-mails: (K.M.W.); (E.W.)
- Authors to whom correspondence should be addressed; E-mails: (H.G.M.); (N.T.M); Tel.: +1-310-206-7767; Fax: +1-310-825-7067
| | - Vanessa M. Tolosa
- Dept. Psychiatry & Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, CA, USA; E-mails: (K.M.W.); (E.W.)
| | - Jianjun Wang
- Chemical and Biomolecular Engineering Dept., UCLA, Los Angeles, CA, USA; E-Mails: (V.M.T.); (J.W.)
| | - Eric Walker
- Dept. Psychiatry & Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, CA, USA; E-mails: (K.M.W.); (E.W.)
| | - Harold G. Monbouquette
- Chemical and Biomolecular Engineering Dept., UCLA, Los Angeles, CA, USA; E-Mails: (V.M.T.); (J.W.)
- Authors to whom correspondence should be addressed; E-mails: (H.G.M.); (N.T.M); Tel.: +1-310-206-7767; Fax: +1-310-825-7067
| | - Nigel T. Maidment
- Dept. Psychiatry & Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, CA, USA; E-mails: (K.M.W.); (E.W.)
- Authors to whom correspondence should be addressed; E-mails: (H.G.M.); (N.T.M); Tel.: +1-310-206-7767; Fax: +1-310-825-7067
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25
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Barbosa RM, Lourenço CF, Santos RM, Pomerleau F, Huettl P, Gerhardt GA, Laranjinha J. In Vivo Real‐Time Measurement of Nitric Oxide in Anesthetized Rat Brain. Methods Enzymol 2008; 441:351-67. [DOI: 10.1016/s0076-6879(08)01220-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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