Ultra sensitive and flexible MEAs for chronic dopamine detection at both tonic and phasic levels

超灵敏且灵活的 MEA，用于强直和阶段性水平的慢性多巴胺检测

• 批准号: 9814422
• 负责人: XINYAN Tracy CUI
• 金额: $ 20.14万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-01 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9814422
• 关键词: Acids; Acute; Agar; Area; Autopsy; Behavior; Brain; Brain Diseases; Brain region; Carbon Nanotubes; Chronic; Clinical Research; Corpus striatum structure; Detection; Development; Disease; Dopamine; Effectiveness; Electrodes; Event; Financial compensation; Foreign Bodies; Frequencies; Goals; Gold; Grouping; Hydroxydopamines; Implant; In Vitro; Individual; Inflammatory; Length; Lesion; Light; Longevity; Measurement; Measures; Mechanics; Metals; Microelectrodes; Monitor; Nanotechnology; Nature; Neurons; Neurosciences Research; Neurotransmitters; Nomifensine; Pacemakers; Parkinson Disease; Parkinsonian Disorders; Performance; Periodicity; Pharmaceutical Preparations; Phase; Physiological; Polymers; Preparation; Protocols documentation; Rattus; Research; Resolution; Rest; Scanning; Signal Transduction; Site; Techniques; Technology; Testing; Time; Tissues; Tyrosine; Validation; brain circuitry; carbon fiber; effective therapy; experimental study; flexibility; implantation; improved; in vivo; insight; multi-electrode arrays; nanocomposite; nervous system disorder; neurochemistry; neurophysiology; novel; relating to nervous system; response; sensor; sensor technology; transmission process

The ability to quantify spatially discrete dopamine (DA) concentration over a chronic, multi-week timescale is paramount to unlocking the mechanisms underlying healthy and disease state behavior. DA signaling throughout the brain occurs over multiple timescales. Phasic signaling results from high frequency burst firing, whereas tonic DA release is maintained by low frequency “pacemaker firing”. For decades, fast scan cyclic voltammetry (FSCV) at carbon fiber microelectrodes (CFEs) has been used to record sub second phasic DA transmission, but measuring resting level, tonic DA concentrations has been a technical challenge. We have recently shown that conductive polymer nanocomposite coating consisting of poly(3,4-ethylenedioxythiophene) and acid functionalized carbon nanotubes (PEDOT/CNT) significantly increases electrode sensitivity and selectivity for DA, and when combined with a novel square wave voltammetry (SWV) protocol, is capable of measuring resting DA concentrations in vivo with high selectivity. The same coating can also record sub second DA release using FSCV. Microfabricated multielectrode arrays (MEAs) have been developed to monitor neurophysiological signals simultaneously from multiple recording sites with high spatial resolution. However, the poor sensitivity and selectivity of conventional metal electrodes have limited the use of MEAs for neurochemical sensing. By applying PEDOT/fCNT coating onto MEAs, we can increase both the sensitivity and selectivity of neurochemical detection from MEA. Furthermore, implantation of stiff MEAs inevitably causes neuronal damage and inflammatory glial response, both of which compromise sensor performance, especially for long-term applications. Recent advancement in MEA technology has revealed that flexible and subcellular sized implants significantly mitigate the foreign body response resulting in seamless integration within neural tissue. Here, we hypothesize that chronic multisite DA measurement can be enabled through combining the highly sensitive PEDOT/CNT coating with ultra-small, flexible neural recording probe technology. The first specific aim is to fabricate PEDOT/fCNT functionalized flexible MEA capable of detecting DA with sensitivities and LODs in the physiologically relevant concentration range. PEDOT/CNT coating conditions will be optimized for electrode sites on 16-channel, flexible SU-8 MEAs. DA sensing performance will be investigated using SWV and FSCV in the presence of interferents. Coating stability will be assessed via mechanical bending and agar insertion experiments. The second specific aim is to determine the efficacy of PEDOT/fCNT functionalized flexible MEAs for acute and chronic in vivo DA sensing. In the acute validation experiments, sensors will be implanted into the DS of anesthetized rats. SWV (measure basal DA) and FSCV (measure electrically evoked sub second DA) measurements will be recorded from 16 individual electrode sites spanning the entire sagittal length of the DS (4 mm) before and after the acute administration of either nomifensine (NOM, increase DA) or α-methyl-DL-tyrosine (αMPT, decrease DA). In the chronic experiments, sensors will be used to record spatially discrete tonic and electrically evoked phasic DA over 28 days in 6-OH-DA lesioned rats over a period of 28 days post lesion. Post-mortem immunohistology will be conducted after 7, 14 and 28 days of probe implantation to assess inflammatory host tissue response and to monitor lesion formation. Observation of any spatially correlated changes in resting and electrically evoked DA relating to 6-OH-DA lesion formation will reveal the effectiveness of the chronic DA sensor and provide valuable physiological insight into Parkinson's Disease. This proposal has the potential to revolutionize the state of the art of neurochemical sensing by enabling high fidelity chronic measurement of tonic and phasic DA release from multiple discrete neuron groupings. The proposed in vivo experiments could shed light on the mechanisms of Parkinsonian DA compensation. On a broader sense, this technology will find a wide spread use throughout a range of basic neuroscience and clinical research areas with the ultimate goal of understanding healthy and diseased brain as well as developing effective therapies.

在慢性、多周时间尺度上量化空间离散多巴胺（DA）浓度的能力是 这对解开健康和疾病状态行为的机制至关重要。DA信令 在不同的时间尺度上发生。时相信号是由高频爆发性放电引起的， 而紧张性DA释放由低频“起搏器放电”维持。几十年来，快速扫描循环 用碳纤维微电极（CFEs）伏安法（FSCV）记录了亚第二相DA 然而，测量静息水平、紧张性DA浓度一直是一个技术挑战。我们有 最近表明，由聚（3，4-乙撑二氧噻吩） 和酸官能化的碳纳米管（PEDOT/CNT）显著增加电极灵敏度， DA的选择性，并且当与新的方波伏安法（SWV）方案结合时，能够 以高选择性测量体内静息DA浓度。同样的涂层也可以记录子 使用FSCV的第二DA释放。微制造多电极阵列（MEA）已被开发出来， 以高空间分辨率同时监测来自多个记录部位的神经生理信号。 然而，常规金属电极的差的灵敏度和选择性限制了MEA用于电化学测量的用途。 神经化学感应通过将PEDOT/fCNT涂层施加到MEA上，我们可以提高灵敏度和灵敏度。 和MEA的神经化学检测的选择性。此外，刚性MEA的植入不可避免地导致 神经元损伤和炎性神经胶质反应，这两者都会损害传感器性能，特别是 用于长期应用。MEA技术的最新进展表明，柔性和亚细胞 尺寸的植入物显著减轻了异物反应，导致神经内的无缝整合， 组织.在这里，我们假设慢性多部位DA测量可以通过结合 高灵敏度PEDOT/CNT涂层，采用超小、灵活的神经记录探针技术。 第一个具体目标是制造能够检测DA的PEDOT/fCNT官能化柔性MEA。 在生理相关浓度范围内具有灵敏度和LOD。PEDOT/CNT涂层 将针对16通道柔性SU-8 MEA上的电极位置优化条件。DA检测性能 将在存在干扰物的情况下使用SWV和FSCV进行研究。涂层稳定性将通过 机械弯曲和琼脂插入实验。第二个具体目标是确定疗效 PEDOT/fCNT功能化的柔性MEA用于急性和慢性体内DA感测。急性 在验证实验中，将传感器植入麻醉大鼠的DS中。SWV（测量基础DA） 和FSCV（测量电诱发的亚秒DA）测量将记录16名个体 在急性给药之前和之后，跨越DS整个矢状长度（4 mm）的电极部位 诺米芬辛（NOM，增加DA）或α-甲基-DL-酪氨酸（αMPT，降低DA）。慢性 实验中，传感器将被用来记录空间离散强直和电诱发相位DA超过28 在6-OH-DA损伤的大鼠中，在损伤后28天的时间内，尸检免疫组织学将 在探针植入7、14和28天后进行，以评估炎症宿主组织反应， 监测损伤形成。观察静息和电诱发DA的任何空间相关变化 与6-OH-DA损伤形成相关的研究将揭示慢性DA传感器的有效性，并提供 对帕金森氏症有价值的生理学见解。 这一提议有可能通过实现高水平的神经化学感测来彻底改变神经化学感测技术的现状。 从多个离散的神经元群进行紧张性和阶段性DA释放的保真度慢性测量。的 提出的体内实验可以阐明帕金森病DA补偿的机制。上 从更广泛的意义上说，这项技术将在一系列基础神经科学中得到广泛的应用， 临床研究领域的最终目标是了解健康和患病的大脑， 开发有效的治疗方法。