Biological and Mechanical Limitations for Chronic Fast‐Scan Cyclic Voltammetry Sensor Design

Advanced Materials Technologies, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 8, 2025

Abstract Fast‐scan cyclic voltammetry (FSCV) is a popular approach for real‐time neurochemical sensing. Using carbon‐fiber microelectrode (CFME), sensitive sensing can be achieved in the acute setting with sub‐second resolution monoamine neurotransmitters. However, to study neuropsychiatric conditions and neurological functions, it often of interest perform longitudinal monitoring neurotransmitters over chronic timepoints. Despite notable successes, there remains substantial room improvement performance. Electrode fouling cellular encapsulation that occur following surgical implantation lead diminished sensor performance time. Additionally, working reference electrodes suffer from etching polarization hinder their longevity stability. Here, this work reviews current challenges facing sensors discusses state‐of‐the‐art advancements electrode material device design choices. This covers how biological environment negatively affect mitigate these effects. also provides examples technologies have been developed improve Improvements FSCV as tool neurotransmitter will open new opportunities neurodegenerative diseases, develop feedback systems neuromodulation, explore underpinnings normal brain function behavior.

Language: Английский

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Recent Progress in Flexible Microelectrode Arrays for Combined Electrophysiological and Electrochemical Sensing

Biosensors, Journal Year: 2025, Volume and Issue: 15(2), P. 100 - 100

Published: Feb. 10, 2025

Understanding brain function requires advanced neural probes to monitor electrical and chemical signaling across multiple timescales regions. Microelectrode arrays (MEAs) are widely used record neurophysiological activity various depths regions, providing single-unit resolution for extended periods. Recent advancements in flexible MEAs, built on micrometer-thick polymer substrates, have improved integration with tissue by mimicking the brain's soft nature, reducing mechanical trauma inflammation. These flexible, subcellular-scale MEAs can stable signals months, making them ideal long-term studies. In addition recording, been functionalized electrochemical neurotransmitter detection. Electroactive neurotransmitters, such as dopamine, serotonin, adenosine, be directly measured via methods, particularly carbon-based surfaces. For non-electroactive neurotransmitters like acetylcholine, glutamate, γ-aminobutyric acid, alternative strategies, enzyme immobilization aptamer-based recognition, employed generate signals. This review highlights recent developments MEA fabrication functionalization achieve both electrophysiological recordings, minimizing sensor fowling damage when implanted long-term. It covers multi-time scale detection, development of conducting nanomaterial composite coatings enhance sensitivity, incorporation recognition carbon electrodes MEAs. Finally, it summarizes strategies acquire measurements from same device.

Language: Английский

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PEDOT/CNT Flexible MEAs Reveal New Insights into the Clock Gene's Role in Dopamine Dynamics

Advanced Science, Journal Year: 2024, Volume and Issue: 11(27)

Published: March 2, 2024

Substantial evidence has shown that the Circadian Locomotor Output Cycles Kaput (Clock) gene is a core transcription factor of circadian rhythms regulates dopamine (DA) synthesis. To shed light on mechanism this interaction, flexible multielectrode arrays (MEAs) are developed can measure both DA concentrations and electrophysiology chronically. The dual functionality enabled by conducting polymer PEDOT doped with acid-functionalized carbon nanotubes (CNT). PEDOT/CNT microelectrode coating maintained stable electrochemical impedance detection square wave voltammetry for 4 weeks in vitro. When implanted wild-type (WT) Clock mutation (MU) mice, MEAs measured tonic concentration extracellular neural activity high spatial temporal resolution weeks. A diurnal change WT observed, but not MU, higher basal stronger cocaine-induced increase MU. Meanwhile, striatal neuronal firing rate found to be positively correlated animal groups. These findings offer new insights into dynamics context rhythm regulation, chronically reliable performance measurement capability technology hold great potential broad range neuroscience research.

Language: Английский

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Long‐Term Neural Recording Performance of PEDOT/CNT/Dexamethasone‐Coated Electrode Array Implanted in Visual Cortex of Rats

Advanced NanoBiomed Research, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 25, 2025

Implantable neural electrode arrays can be inserted in the brain to provide single‐cell electrophysiology recording for neuroscience research and brain–machine interface applications. However, maintaining signal quality over time is complicated by inflammatory tissue responses degradation of materials. Organic coatings offer a solution enhancing stimulation capabilities, including reduced impedance, increased charge injection capacity, ability incorporate release anti‐inflammatory drugs. Herein, acid‐functionalized multiwalled carbon nanotubes (CNTs) loaded with dexamethasone (Dex) are incorporated into poly(3,4‐ethylendioxythiophene) (PEDOT) as coatings. The electrochemical stability performance PEDOT/CNT/Dex coating an extended period ≈18 months investigated. Cyclic voltammetry (CV) used Dex half sites during first 11 days implantation reduce acute inflammation. PEDOT/CNT/Dex‐coated floating microelectrode demonstrate stable vivo impedance successful detection visually evoked activity from rat visual cortex even at chronic points. Additionally, CV‐stimulated exhibit higher single‐unit (SU) yield, amplitudes, signal‐to‐noise ratio compared unstimulated sites. These results highlight potential treatments improve longevity recordings.

Language: Английский

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Investigation of a chondroitin sulfate-based bioactive coating for neural interface applications

Journal of Materials Chemistry B, Journal Year: 2024, Volume and Issue: 12(22), P. 5535 - 5550

Published: Jan. 1, 2024

Invasive neural implants allow for high-resolution bidirectional communication with the nervous tissue and have demonstrated ability to record activity, stimulate neurons, sense neurochemical species high spatial selectivity resolution. However, upon implantation, they are exposed a foreign body response which can disrupt seamless integration of device native lead deterioration in functionality chronic implantation. Modifying surface by incorporating bioactive coatings has been promising approach camouflage improve while maintaining performance. In this work, we explored novel application chondroitin sulfate (CS) based hydrophilic coating, anti-fouling neurite-growth promoting properties recording electrodes. CS-coated samples exhibited significantly reduced protein-fouling vitro was maintained up 4-weeks. Cell culture studies revealed significant increase neurite attachment outgrowth decrease microglia activation CS group as compared control. After 1-week vivo implantation mouse cortex, coated probes lower biofouling uncoated controls. Like results, increased neuronal population (neuronal nuclei neurofilament) decreased microglial were observed. To assess coating's effect on performance silicon microelectrodes, implanted electrodes striatum 1 week performed impedance measurements. We observed group, likely due wettability surface. The peak-to-peak amplitude noise floor levels both controls, led comparable signal-to-noise ratio between two groups. overall single unit yield (% channels unit) 74% 67% control day 1. Taken together, study demonstrates effectiveness polysaccharide-based coating reducing improving biocompatibility electrode devices.

Language: Английский

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Ultraflexible Neural Electrodes Enabled Synchronized Long-Term Dopamine Detection and Wideband Chronic Recording Deep in Brain

ACS Nano, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 4, 2024

Ultraflexible neural electrodes have shown superior stability compared with rigid in long-term vivo recordings, owing to their low mechanical mismatch brain tissue. It is desirable detect neurotransmitters as well electrophysiological signals for months science. This work proposes a stable electronic interface that can simultaneously electrical activity and dopamine concentration deep the brain. ultraflexible electrode modified by nanocomposite of reduced graphene oxide (rGO) poly(3,4-ethylenedioxythiophene):poly(sodium 4-styrenesulfonate) (rGO/PEDOT:PSS), enhancing coating increasing its specific surface area, thereby improving sensitivity response 15 pA/μM. fluctuations conduct long-term, recordings local field potentials (LFPs), spiking activities, amplitudes high spatial temporal resolution across multiple regions, especially areas. The were implanted into brains rodent models monitor changes electrochemical different regions during administration nomifensine. Ten minutes after drug injection, enhanced neuronal firing increased LFP power detected motor cortex deeper cortical layers, accompanied gradual rise levels 192 ± 29 nM. recording consistently demonstrates chronic high-quality signal monitoring up 6 weeks. These findings highlight quality our electrophysiological/electrochemical codetection electrodes, underscoring tremendous potential applications neuroscience research brain–machine interfaces.

Language: Английский

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Enhanced Electrochemiluminescence Detection of Dopamine Using Antifouling PEDOT-Modified SPEs for Complex Biological Samples

ACS Measurement Science Au, Journal Year: 2024, Volume and Issue: 4(6), P. 712 - 720

Published: Oct. 4, 2024

Detecting medically important biomarkers in complex biological samples without prior treatment or extraction poses a major challenge biomedical analysis. Electrochemical methods, specifically electrochemiluminescence (ECL), show potential due to their high sensitivity, minimal background noise, and straightforward operation. This study investigates the ECL performance of screen-printed electrodes (SPEs) modified with conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) its derivatives for dopamine (DA) detection. PEDOT modification significantly enhances intensity, improves expands linear range DA Functionalizing ethylene glycol (EG) further stability, specificity, resistance interferences These SPEs demonstrate 1-200 μM detection limit as low 0.887 nM (

Language: Английский

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