Effect of Process Parameters on Electrochemical Performance of a Glutamate Microbiosensor

Tan, Chao; Doughty, Phillip T.; Magee, Katherine; Murray, Teresa A.; Siddiqui, Shabnam; Arumugam, Prabhu U.

doi:10.1149/1945-7111/ab6b0b

Cited by 10 publications

(15 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The exposed Pt microwires were electrochemically cleaned using the cyclic voltammetry (CV) method. The CV was run in a 2-electrode setup using an Ag/AgCl reference/counter electrode in a 0.05 M H 2 SO 4 electrolyte solution, and the potential was cycled between − 0.3 V to + 1.0 V with a 20 mV/s scan rate for 15 cycles 76,78 . The rationale for cleaning the microwire is to increase hydrogen peroxide sensitivity, which is due to significant reductions in the charge transfer resistances of the Pt microelectrode grains and grain boundaries (details not shown).…”

Section: Methodsmentioning

confidence: 99%

“…The third microwire, called the sentinel channel, was constructed by applying only the enzyme matrix solution with BSA and glutaraldehyde (i.e., the matrix does not contain any enzymes). The sentinel microsensor plays an important role in measuring the presence of small electroactive molecules (interferents) present in the vicinity of the biosensor probe that can be easily oxidized at the + 0.7 V applied to all three Pt microwires 76 . Examples of common interferents are nitric oxide, dopamine and AA.…”

Section: Methodsmentioning

confidence: 99%

“…Producing these biosensors in-house offers several advantages. (1) The mPD layer can be coated on the outside for longer sensor life for in vivo applications, or on the inside for higher sensitivity, short-term use 76 . (2) Additional wires can be added and placed at different depths for recording in more than one brain area.…”

Section: Uses Of Stimulation To Treat Neurological Disordersmentioning

confidence: 99%

See 2 more Smart Citations

Novel microwire-based biosensor probe for simultaneous real-time measurement of glutamate and GABA dynamics in vitro and in vivo

Doughty

Hossain

Gong

et al. 2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

Glutamate (GLU) and γ-aminobutyric acid (GABA) are the major excitatory (E) and inhibitory (I) neurotransmitters in the brain, respectively. Dysregulation of the E/I ratio is associated with numerous neurological disorders. enzyme-based microelectrode array biosensors present the potential for improved biocompatibility, localized sample volumes, and much faster sampling rates over existing measurement methods. However, enzymes degrade over time. To overcome the time limitation of permanently implanted microbiosensors, we created a microwire-based biosensor that can be periodically inserted into a permanently implanted cannula. Biosensor coatings were based on our previously developed GLU and reagent-free GABA shank-type biosensor. In addition, the microwire biosensors were in the same geometric plane for the improved acquisition of signals in planar tissue including rodent brain slices, cultured cells, and brain regions with laminar structure. We measured real-time dynamics of GLU and GABA in rat hippocampal slices and observed a significant, nonlinear shift in the E/I ratio from excitatory to inhibitory dominance as electrical stimulation frequency increased from 10 to 140 Hz, suggesting that GABA release is a component of a homeostatic mechanism in the hippocampus to prevent excitotoxic damage. Additionally, we recorded from a freely moving rat over fourteen weeks, inserting fresh biosensors each time, thus demonstrating that the microwire biosensor overcomes the time limitation of permanently implanted biosensors and that the biosensors detect relevant changes in GLU and GABA levels that are consistent with various behaviors. Near real-time measurement of neurotransmitter levels in the brain is expected to reveal important clues to the underlying mechanisms of neurological disorders, such as epilepsy, addiction, motor control 1-3 , and secondary damage after stroke 4 and traumatic brain injury 5,6. Two important and ubiquitous neurotransmitters in the brain are l-glutamine (GLU) and γ-aminobutyric acid (GABA), which are the major excitatory and inhibitory neurotransmitters, respectively. A balance of excitatory (E) and inhibitory (I) electrical signaling in local networks (E/I ratio) is observed in awake states and in sleep, with the exception of slow-wave sleep in humans and monkeys 7. Dysregulation in E/I is closely linked to dysregulation of GLU and/or GABA dynamics 8. Prolonged, excessive GLU release often leads to excitotoxic neuronal cell death directly or through a cascade of secondary cellular injury 9,10. Furthermore, insufficient release of GABA is associated with seizures 6,11 and autism 12. Most studies so far have only looked at GLU and GABA in isolation 13,14. However, a more meaningful interpretation of the mechanisms of disease and secondary injury can be obtained by knowing the regional E/I balance 15. Furthermore,

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Uses Of Stimulation To Treat Neurological Disordersmentioning

confidence: 99%

See 1 more Smart Citation

Novel microwire-based biosensor probe for simultaneous real-time measurement of glutamate and GABA dynamics in vitro and in vivo

Doughty

Hossain

Gong

et al. 2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…Each ceramic wafer contained 56 microelectrodes. Upon diamond cutting of the wafer into discrete probes, each new probe contained eight platinized, platinum microelectrodes (100 µM × 50 µM) in four pairs shown in Figure 2 [ 25 ].…”

Section: Methodsmentioning

confidence: 99%

In Vitro Electrochemical Detection of Hydrogen Peroxide in Activated Macrophages via a Platinum Microelectrode Array

Carriere

Rodrigues

Tan

et al. 2021

Sensors

Self Cite

View full text Add to dashboard Cite

Oxidative stress, an excess of endogenous or exogenous reactive oxygen species (ROS) in the human body, is closely aligned with inflammatory responses. ROS such as hydrogen peroxide (H2O2), superoxide, and radical hydroxyl ions serve essential functions in fighting infection; however, chronic elevation of these species irreversibly damages cellular components. Given the central role of inflammation in a variety of diseases, including Alzheimer’s disease and rheumatoid arthritis, a low-cost, extracellular, non-invasive assay of H2O2 measurement is needed. This work reports the use of a platinum microelectrode array (Pt MEA)-based ceramic probe to detect time- and concentration-dependent variations in H2O2 production by activated RAW 264.7 macrophages. First, these cells were activated by lipopolysaccharide (LPS) to induce oxidative stress. Chronoamperometry was then employed to detect the quantity of H2O2 released by cells at various time intervals up to 48 h. The most stimulatory concentration of LPS was identified. Further experiments assessed the anti-inflammatory effect of dexamethasone (Dex), a commonly prescribed steroid medication. As expected, the probe detected significantly increased H2O2 production by LPS-doped macrophages, subsequently diminishing the pro-inflammatory effect in LPS-doped cells treated with Dex. These results strongly support the use of this probe as a non-invasive, robust, point-of-care test of inflammation, with a high potential for multiplexing in further studies.

show abstract

“…The temporal resolution of CA makes it possible to study neurochemical events on millisecond timescales. The simple mechanism of CA grants it the ability to continuously record for several hours [ 41 , 42 ].…”

Section: Electrochemical Sensorsmentioning

confidence: 99%

Recent Advances in In Vivo Neurochemical Monitoring

Tan

Robbins

et al. 2021

Micromachines

Self Cite

View full text Add to dashboard Cite

The brain is a complex network that accounts for only 5% of human mass but consumes 20% of our energy. Uncovering the mysteries of the brain’s functions in motion, memory, learning, behavior, and mental health remains a hot but challenging topic. Neurochemicals in the brain, such as neurotransmitters, neuromodulators, gliotransmitters, hormones, and metabolism substrates and products, play vital roles in mediating and modulating normal brain function, and their abnormal release or imbalanced concentrations can cause various diseases, such as epilepsy, Alzheimer’s disease, and Parkinson’s disease. A wide range of techniques have been used to probe the concentrations of neurochemicals under normal, stimulated, diseased, and drug-induced conditions in order to understand the neurochemistry of drug mechanisms and develop diagnostic tools or therapies. Recent advancements in detection methods, device fabrication, and new materials have resulted in the development of neurochemical sensors with improved performance. However, direct in vivo measurements require a robust sensor that is highly sensitive and selective with minimal fouling and reduced inflammatory foreign body responses. Here, we review recent advances in neurochemical sensor development for in vivo studies, with a focus on electrochemical and optical probes. Other alternative methods are also compared. We discuss in detail the in vivo challenges for these methods and provide an outlook for future directions.

show abstract

Effect of Process Parameters on Electrochemical Performance of a Glutamate Microbiosensor

Cited by 10 publications

References 51 publications

Novel microwire-based biosensor probe for simultaneous real-time measurement of glutamate and GABA dynamics in vitro and in vivo

Novel microwire-based biosensor probe for simultaneous real-time measurement of glutamate and GABA dynamics in vitro and in vivo

In Vitro Electrochemical Detection of Hydrogen Peroxide in Activated Macrophages via a Platinum Microelectrode Array

Recent Advances in In Vivo Neurochemical Monitoring

Contact Info

Product

Resources

About