Ultrananocrystalline Diamond Microarray Biosensor for Neurochemical Detection

描述(申请人提供)：迫切需要开发一种新型的微阵列生物传感器，这种传感器具有足够的通用性、选择性、灵敏度和可靠性，可以研究大脑多个区域注射乙醇的随时间变化的神经化学事件。目前，在活体内实时监测神经递质的首选方法是快速扫描循环伏安法(FSCV)，首选微电极材料是碳纤维。我们建议开发下一代电极材料--掺硼超非晶金刚石(BD-UNCD)，与碳纤维相比，BD-UNCD具有更高的灵敏度和特异度、快速的响应时间、低的本底电流、长期的稳定性和抗污性。其目标是开发可长期植入的UNCD微阵列电极，用于长期(即数月至数年)记录多种神经化学物质，特别是在人类兼容的情况下。该项目的具体目标是：(I)利用循环伏安法和多巴胺(研究最广泛的神经递质)开发可靠、可扩展和可批量生产的UNCD微阵列，其具有微纳电极的电化学行为(即更高的信噪比)；(Ii)在修饰的UNCD微电极上显示谷氨酸检测；以及(Iii)通过多路复用检测两种神经化学物质(流动注射分析和麻醉大鼠脑中的多巴胺和谷氨酸)，展示UNCD微阵列的独特优势，这是迈向单一地点多神经化学检测的重要一步。作为概念验证，电极将用于测量这两种神经化学物质的生理浓度。所提出的微阵列化学/生物传感器有可能用于同时测量多个脑区的多巴胺、谷氨酸和许多其他重要的神经递质。如果该项目成功，它将实现NIH的主要任务目标，特别是：1)UNCD的生物惰性、低伪电容量和高选择性，由于其表面化学将大大增强“在体伏安法”；2)UNCD/对苯钝化是新颖的，并且对于慢性神经化学传感是完全“生物相容”的；3)UCND和纳米厚绝缘体的应用将极大地推进制造用于“纳米技术”的探针的方法；以及4)UNCD可以通过光化学或电化学手段很容易地用酶、抗体和寡核苷酸探针进行修饰，用于“生物传感器”。最近的一份传感器市场报告显示，医疗传感市场将在2012年达到109亿美元。根据一家领先的神经生理学微电极和仪器公司的支持信，FHC Inc.预计该产品的年销售额将“至少为1000-1500万美元”，并有望超过这个数字，是更广泛的神经科学市场的许多倍。此外，更好地了解该项目对神经递质的实时传感将使该技术的替代应用成为可能，包括：用于毒素、代谢物和疾病生物标记物的低成本、可使用的便携式传感器。 与公共健康相关：该项目将开发一种使用超纳米晶体钻石电极的微阵列生物传感器技术，以进一步推动神经科学领域(大脑功能和乙醇注射的影响)。它的多功能性、灵敏度和可靠性非常适合多种神经化学物质的实时、慢性测量和脑活动图谱。

DESCRIPTION (provided by applicant): There is an acute need for the development of a new class of microarray biosensors that are sufficiently versatile, selective, sensitive and reliable to allow investigation of the time-dependent neurochemical events of ethanol administration in multiple regions of the brain. Currently, the preferred method for monitoring neurotransmitters in vivo real time is fast-scan cyclic voltammetry (FSCV) and the preferred microelectrode material is carbon fiber. We propose development of the next generation electrode material, boron-doped ultrananocrystalline diamond (BD-UNCD) that offers superior sensitivity and specificity, fast response time, low background currents, long-term stability and resistance to fouling as compared to carbon fibers. The goal is to develop chronically implantable UNCD microarray electrodes for long-term (i.e., months to years) recording of multiple neurochemicals, especially if human compatible. The specific aims of this project are to: (i) develop a reliable, scalable and mass-producible UNCD microarray that exhibits micro or nano electrode electrochemical behavior (i.e. higher signal-to-noise ratio) using cyclic voltammetry and dopamine (the most widely studied neurotransmitter), (ii) demonstrate glutamate detection on a modified UNCD microelectrode and (iii) demonstrate the unique advantages of UNCD microarrays by measuring two neurochemicals (dopamine and glutamate with flow injection analysis and in an anesthetized rat brain) i.e. multiplexing, which is an important step towards multiple neurochemical detection at a single site. As a proof-of-concept, the electrodes will be used to measure the two neurochemicals down to physiological concentrations. The proposed microarray chemical/biosensor could potentially be used for simultaneous measurement of dopamine, glutamate and many other important neurotransmitters in multiple brain regions. If this project is successful, it will accomplish key NIH mission goals, specifically: 1) UNCD's bioinertness, low pseudo capacitance and high selectively due to its surface chemistry will greatly enhance "in vivo voltammetry"; 2) UNCD/parylene passivation is novel and completely "biocompatible" for chronic neurochemical sensing; 3) application of UCND and nanometer thick insulators will greatly advance the way in which probes are fabricated for "nanotechnologies' in general; and 4) UNCD can be easily modified with enzymes, antibodies and oligonucleotide probes through photochemical or electrochemical means for "biosensors". A recent sensor market report suggests that the medical sensing market will reach $10.9 billion in 2012. Based on a letter of support from a leading neurophysiological microelectrodes and instrumentation company, the expected annual sales for this product at FHC Inc., would be "at least $10-15 million" and would be expected to exceed this number many-fold over the broader neuroscience market. Also, a greater understanding of real-time sensing of neurotransmitters from this project would enable alternative applications for the technology, including: low-cost, point-of-use, portable sensors for toxins, metabolites and disease biomarkers. PUBLIC HEALTH RELEVANCE: This project will develop a microarray biosensor technology using ultrananocrystalline diamond electrodes to further advance the neuroscience field (brain function and the effects of ethanol administration). Its versatility, sensitivity and reliability are ideally suited for real-time, chronic measurement of multiple neurochemicals and brain activity mapping.