Nanobiosensing Neural Probes for Traumatic Brain Injury Applications

用于创伤性脑损伤应用的纳米生物传感神经探针

• 批准号: 8984835
• 负责人: Allison Hess Dunning
• 金额: --
• 依托单位: LOUIS STOKES CLEVELAND VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8984835
• 关键词: Acute; Behavior; Biochemical; Biosensing Techniques; Biosensor; Boron; Brain; Brain Injuries; Calibration; Carbon; Carbon Nanotubes; Clinical; Cognitive; Development; Diamond; Disease; Electrodes; Electronics; Electrophysiology (science); Ensure; Environment; Enzymes; Feedback; Film; Functional disorder; Glutamates; Goals; Gold; Growth; Health; Hospitals; Hydrogen Peroxide; Immobilization; Implant; In Vitro; Inflammatory Response; Injury; Intensive Care Units; Intervention; Liquid substance; Long-Term Effects; Measures; Mechanics; Metals; Methods; Microfabrication; Monitor; Motor; Needles; Nervous System Trauma; Neurologic; Oxidases; Pharmacotherapy; Physiological; Polymers; Population; Process; Property; Quality of life; Regulation; Rehabilitation Outcome; Rehabilitation therapy; Research; Resolution; Rodent Model; Role; Site; Stimulus; Stroke; Symptoms; System; Techniques; Technology; Temperature; Testing; Time; Tissues; Translations; Traumatic Brain Injury; Treatment outcome; Veterans; Wireless Technology; Work; absorption; base; brain tissue; clinical application; combat; data exchange; disability; drug rehabilitation; enzyme immobilization; extracellular; implantation; improved; in vivo; injured; meetings; microsystems; nanocomposite; nanodevice; nanoelectromechanical system; nanoscale; nanostructured; nanosystems; nanowire; nervous system disorder; neurochemistry; neurodevelopment; neurotransmission; novel; operation; oxidation; polypyrrole; programs; psychologic; public health relevance; relating to nervous system; research study; sensor; spatiotemporal; temporal measurement; tool; treatment strategy; vinyl acetate

DESCRIPTION The primary goal of the proposed work is to take the first steps toward an independent research program that focuses on the development and application of biomedical micro/nanosystems based on independently optimized materials for the study, monitoring, and treatment of neurological conditions, including traumatic brain injury (TBI) and stroke. Specifically, this project concerns the development of a platform technology involving the integration of optimal electrode, enzyme immobilization, and substrate materials for an electrochemical sensor to continuously monitor extracellular glutamate levels with high spatiotemporal resolution, sensitivity, selectivity, stability, and wide linear range. This multi-scale materials system will incorporate a bio-adaptive polymer nanocomposite substrate, gold and graphene electrodes, and polymer nanowires for enzyme immobilization. This combination of materials will provide a sensor with the requisite properties for long-term implantation for neurochemical monitoring during normal activity. Though glutamate is the focus of this work, the methods to develop this sensor can be applied to many different bioanalytes, which will be integrated in later implementations of this biosensor. A means to continuously monitor the neurochemical state outside of the hospital environment will 1) provide enhanced understanding regarding the pathophysiology associated with the long-term effects of TBI at the site of the injury 2) delineate the relationship between neurochemistry and clinical dysfunction, 3) allow for long term monitoring of rehabilitation and drug interventions and 4) allow for the novel drug therapies to be developed with highly controlled delivery. The first aim toward the overall goal is to provide a stable neural interface with high-sensitivity (>500 nA.¿M-1.cm-2) to changes in in vivo glutamate concentration through efficient glutamate oxidase immobilization. This with be achieved using microfabrication processes customized for the unique materials set proposed to achieve this goal. A novel stimuli-responsive polymer nanocomposite, poly (vinyl acetate) (PVAc-NC), substrate will be implemented to minimize the inflammatory response to the implant, thus maximizing the stability of the biotic/abiotic interface. PVAc-NC has a high elastic modulus (Edry ~ 4 GPa) in its dry state, permitting needle- like insertion into brain tissue, but displays a three order-of-magnitude reduction in elastic modulus (Ewet ~ 12 MPa) after absorption of physiological fluids, greatly reducing mechanical mismatch with cortical tissue (Ecortex ~ 10 kPa). High glutamate sensitivity and selectivity will be established by coating the gold electrode site with a nanostructured conductive polymer nanowire layer, such as polypyrrole, which will serve to immobilize glutamate oxidase, an enzyme that selectively reacts with glutamate to form several products, including hydrogen peroxide. The hydrogen peroxide will then by oxidized by a potential applied to the electrode via external electronics and the oxidation current will be measured. The magnitude of this current is linearly-related to the concentration of glutamate near the electrode. The second aim is to expand the dynamic linear range of the glutamate sensor to ensure linearity between measured current and actual glutamate concentration is maintained through the entire range expected in normal and injured brains. Toward this end, thin-film gold electrodes will be replaced with a carbon-based graphene electrode site. A transfer process will be required to integrate graphene onto PVAc-NC, as PVAc-NC is incompatible with graphene growth temperatures. These electrodes will then be functionalized with glutamate oxidase using methods comparable to those developed toward the first objective, but adapted for use on a graphene-based electrode. The two types of electrochemical sensors will be characterized and calibrated in vitro, then tested in vivo in a rodent model of TBI to assess electrode stability and the correspondence of in vivo behavior with the determined in vitro calibration parameters. PUBLIC HEALTH RELEVANCE: Traumatic brain injury (TBI) and other neurological disorders are important concerns with regard to veterans' health, especially for those veterans involved with recent combat operations. Many of the symptoms and effects of severe neurotrauma persist and progress for years beyond the initial injury, causing permanent severe disability. These sequelae are related to alterations in neurochemical regulation, but are not well understood due to the lack of tools available to monitor neurochemical levels continuously outside of the realm of an intensive care unit in a hospital. The proposed biosensor will continuously monitor neurochemical levels during normal activity with very high spatial and temporal resolution. By augmenting the functionality of well-established sensors for detecting and interpreting electrical neural signals, we will gain new understanding of the long-term effects of neurotrauma, the relationship between behavior and neurochemistry, and develop new ways to treat neurotrauma and regulate neurochemistry.

描述 拟议工作的主要目标是迈出第一步，迈向了一个独立的研究计划，该计划的重点是基于独立优化的研究，监测和治疗神经系统疾病的生物医学微/纳米系统的开发和应用，包括创伤性脑损伤（TBI）和中风。具体而言，该项目涉及平台技术的开发，涉及将电化学传感器的最佳电极，酶固定和底物材料整合在一起，以连续监测具有较高空间时间分辨率，敏感性，选择性，稳定性，稳定性和广泛线性线性范围的细胞外谷氨酸水平。该多尺度材料系统将结合生物自适应聚合物纳米复合底物，金和石墨烯电极以及聚合物纳米线，以固定酶。这种材料的组合将提供一个传感器，具有正常活动期间神经化学监测的长期植入必要特性。尽管谷氨酸是这项工作的重点，但开发该传感器的方法可以应用于许多不同的生物分析物，这些生物分析将集成到以后的生物传感器的后期实现中。一种在医院环境外连续监测神经化学状态的方法1）对与TBI在伤害部位的长期影响相关的病理生理学提供了增强的理解。 神经化学与临床功能障碍之间的关系，3）允许长期监测康复和药物干预措施，4）允许新型药物疗法为 以高度控制的交付开发。实现总体目标的第一个目的是通过高敏感性（> 500 na.m-1.cm-2）提供稳定的神经元界面，以通过有效的谷氨酸氧化物固定化来改变体内谷氨酸浓度。使用针对实现此目标的独特材料设置的微加工过程来实现这一目标。将实施一种新型的刺激响应性聚合物纳米复合材料，聚（乙酸乙烯酯）（PVAC-NC），以最大程度地减少对植入物的炎症反应，从而最大程度地提高生物/非生物界面的稳定性。 PVAC-NC具有高弹性 模量（Edry〜4 GPA）处于干燥状态，可以将针状插入脑组织中，但在遭受物理液体痛苦后，弹性模量（EWET〜12 MPA）的三个刻度顺序降低，与皮质组织的机械不匹配很大（Ecortex〜10 kpa）。高谷氨酸敏感性和选择性将通过将金电极位点与纳米结构的导电聚合物纳米线层（例如多吡咯）涂覆，该酶将有助于固定谷氨酸氧化物，谷氨酸氧化物是一种选择性地与谷氨酸反应的酶，以形成多种产物，包括多种氢氧化物。然后，过氧化氢将通过通过外部电子施加到电气的电势氧化，并测量氧化电流。该电流的大小与电极附近的谷氨酸浓度线性相关。第二个目的是扩大谷氨酸传感器的动态线性范围，以确保在正常和受伤的大脑中预期的整个范围内保持测得的电流和实际谷氨酸浓度之间的线性性。为此，薄膜金电极将被碳基石墨烯电极位点代替。将石墨烯集成到PVAC-NC上需要一个传输过程，因为PVAC-NC与石墨烯的生长温度不相容。然后，这些电极将使用与针对第一个目标开发的方法相当，但适用于基于石墨烯的电极的方法，将这些电极与氧化谷氨酸官能化。两种类型的电化学传感器将在体外进行表征和校准，然后在TBI的啮齿动物模型中在体内进行测试，以评估电极稳定性和与确定的体外校准参数的体内行为的对应关系。 公共卫生相关性： 关于退伍军人的健康，脑外伤（TBI）和其他神经系统疾病是重要的关注点，尤其是对于那些涉及最近战斗行动的退伍军人而言。在最初受伤之外，严重的神经瘤的许多症状和影响持续多年，导致永久性严重残疾。这些后遗症与神经化学调节的改变有关，但由于缺乏可用于监测神经化学水平的工具不断在医院的重症监护室范围外连续监测神经化学水平。拟议的生物传感器将在正常活动期间继续监测神经化学水平，并以非常高的空间和临时分辨率进行监测。通过增强建立良好的传感器检测和解释电信神经信号的功能，我们将对神经瘤的长期影响，行为与神经化学之间的关系有了新的了解，并开发了治疗神经特征和调节神经化学的新方法。