用于增强神经化学检测的金纳米粒子改性碳纤维微电极
Summary
在这项研究中,我们用金纳米粒子修改碳纤维微电极,以提高神经递质检测的灵敏度。
Abstract
30多年来,碳纤维微电极(CFMEs)一直是神经递质检测的标准。通常,碳纤维被吸进玻璃毛细血管,拉到细锥体,然后用环氧树脂密封,以创建用于快速扫描循环伏特测量测试的电极材料。不过,使用裸粮和公司有几个限制。首先,碳纤维主要含有基平面碳,其表面积相对较低,灵敏度低于其他纳米材料。此外,石墨碳受其时间分辨率和相对较低的导电性的限制。最后,已知神经化学和大分子在碳电极表面结垢,形成非导电聚合物,阻止进一步的神经递质吸附。在这项研究中,我们用金纳米粒子修改CFME,通过快速扫描循环伏特测量来增强神经化学测试。Au3+是从胶体溶液电镀或浸渍到CFM表面的。由于黄金是一种稳定且相对惰性的金属,是神经化学分析测量的理想电极材料。金纳米粒子改性(AuNP-CFMEs)对多巴胺反应的稳定性超过4小时。此外,AuNP-CFME 表现出比未改性 CFM 更高的灵敏度(循环伏象图的峰值氧化电流)和更快的电子转移动力学(较低 +EP或峰值分离)。AuNP-CFMEs 的发展为在检测的较低限度下检测多巴胺浓度和其他神经化学品的快速变化提供了新型电化学传感器的创建。这项工作在增强神经化学测量方面有着巨大的应用。金纳米粒子改性CFM的产生对于开发新型电极传感器以检测啮齿动物体内的神经递质至关重要,研究药物滥用、抑郁、中风、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺血、缺和其他行为和疾病状态。
Introduction
碳纤维微电极(CFMEs)1最好用作生物传感器,用于检测几个关键神经递质2的氧化,包括多巴胺3、去甲肾上腺素4、血清素5、腺苷6、组胺7,和其他人8。碳纤维的生物相容性和尺寸使它们最适合植入,因为与较大的标准电极相比,可减轻组织损伤。9 CME 已知具有有用的电化学特性,并且能够快速测量时使用快速电化学技术,最常见的快速扫描循环伏特测量 (FSCV)10,11。FSCV是一种技术,扫描应用电位快速,并提供特定的循环伏象图的特定分析物12,13。快速扫描产生的大充电电流在碳纤维上稳定,可以背景减去以产生特定的环伏图。
由于其最优的电化学和神经生物学的重要性,多巴胺得到了广泛的研究。儿茶酚胺多巴胺是一种重要的化学信使,在神经系统内的运动、记忆、认知和情绪控制中起着关键作用。多巴胺的过剩或缺乏会导致许多神经和心理干扰;其中包括帕金森病、精神分裂症和成瘾行为。今天,帕金森病仍然是一种普遍的疾病,由于参与多巴胺合成的中脑神经元的退化14。帕金森病的症状包括震颤、运动缓慢、僵硬和保持平衡的问题。另一方面,可卡因15和安非他明16、17等兴奋剂促进了多巴胺的溢出。药物滥用最终取代多巴胺的常规流动,使大脑需要多巴胺过剩,最终导致成瘾行为。
近年来,在神经递质检测18中,一直强调提高电极功能。提高电极灵敏度的最广泛方法是涂覆纤维表面。令人惊讶的是,对金属纳米粒子电极位置对碳纤维的研究有限。黄金等金属纳米粒子,可与其他功能材料一起电沉积在纤维表面20。例如,增加神经递质吸附的电活性表面积。电沉积金属纳米颗粒形成迅速,可纯化,并附着在碳纤维上。电化学对于贵金属纳米粒子的沉积和碳纤维的表面增强仍然具有重要意义,因为它能够控制这些纳米粒子的成核和生长。最后,增加的催化和导电特性,以及改进的大众运输是利用金属纳米粒子进行电分析的其他优势。
美国大学高级实验室序列课程(实验生物化学I和II CHEM 471/671-472/672)是分析、物理和生物化学实验室的组合。第一学期是实验室技术概述。第二学期是一个学生驱动和主导的研究项目21。对于这些项目,学生以前曾研究过生物分子、蛋白质、肽和氨基酸促进合成金纳米粒子22、23的机制。最近的工作侧重于在电极表面上形成金纳米粒子(AuNP)生产,以及评估AuNPs对CFM检测神经递质的能力的影响。在目前的工作中,实验室应用了该技术来证明CFM在检测多巴胺氧化方面的灵敏度是通过AuNP在纤维表面的电镀来增强的。每个裸CFME的特点是在检测多巴胺氧化电流以测量CFME表面多巴胺氧化时,扫描速率、稳定性和多巴胺浓度各不相同。然后,Au3+被电化为 Au 0,同时电沉积到光纤表面作为纳米粒子,然后进行一系列表征实验。经过直接比较,发现AuNP-CFM具有较高的多巴胺检测灵敏度。AuNP通过电极定位均匀涂覆到纤维表面,使电活性表面积更高;从而增加多巴胺在改性电极表面的吸附。这导致更高的多巴胺氧化电流。AuNP-CFME多巴胺氧化和还原峰(+Ep)的潜在分离也较小,表明电子转移动力学更快。这项研究的未来工作包括对裸和AuNP-CFME进行体内测试,以检测多巴胺。
Protocol
Representative Results
Discussion
在这项研究中,我们演示了一种利用快速扫描循环伏位测量来检测神经递质(如多巴胺)的金纳米粒子改性碳纤维微电极的新方法。该方法是提高生物分子检测灵敏度的一种高效、绿色、相对廉价的方法。沉积在碳纤维表面的金的厚度可以通过电镀时间和电极液中黄金的浓度加以控制。除更快的电子转移动力学外,金改用碳纤维微电极的电活性表面积明显高于裸电极。与裸露的未改性电极材料相比,它?…
Divulgations
The authors have nothing to disclose.
Acknowledgements
我们要感谢美国大学、学院研究支持赠款、美国宇航局DC太空赠款和NSF-MRI+1625977。
Materials
| Dopamine hydrochloride | Sigma Aldrich | H8502-5G | |
| Phosphate Buffered Saline | Sigma Aldrich | P5493-1L | |
| Pine WaveNeuro Potentiostat | Pine Instruments | NEC-WN-BASIC | This orders comes in bulk with all other accessories such as headstages, adapters, cords, and other electronics |
| Pine Flow Cell and Micromanipulator | Pine Instruments | NEC-FLOW-1 | This is also another bulk order including the micromanipulator, flow cell, knobs, tubing, connectors, etc. |
| Glass-Capillary | A-M Systems | 602500 | |
| T-650 Carbon Fiber | Goodfellow | C 005711 | |
| Epon 828 Epoxy | Miller-Stephenson | EPON 828 TDS | |
| Diethelynetriamine | Sigma Aldrich | D93856-5ML | |
| Gold (III) chloride | Sigma Aldrich | 254169 | Comes as either HAuCl4 or AuCl3 |
| pH meter | Fisher | S90528 | |
| Farraday Cage | AMETEK TMC | 81-334-03 | |
| Syringe Pump | NEW ERA PUMP | NE-1000 | |
| Eppendorf Pipettes and Tips | Eppendorf | 2231000222 | This is also a bulk order containing multiple pipettes and tips |
| 10 -1,000 mL beakers | VWR | 10536-390 | |
| Carbon fiber | Goodfellow | C 005711 | |
| SEM | JEOL | JSM-IT100 |
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