微纳电极阵列检测丘脑底核电刺激引起的纹状体神经元活动变化

丘脑底核(STN)深部脑刺激(DBS)已成为帕金森病的重要外科治疗手段,然而其确切的作用机理尚不明确.本研究采用微机电系统(MEMS)技术制备了一种16通道植入式微电极阵列(MEA),在MEA表面修饰了铂黑-还原氧化石墨烯-Nafion膜(Pt/RGO/Nafion)纳米材料,用于同步检测麻醉大鼠脑内纹状体神经元在STN电刺激前后多巴胺(DA)含量和动作电位(Spike)发放变化.STN-DBS结果表明,电刺激20 s后,DA含量开始升高,最高达1.72 μmol/L,较高浓度状态保持约50 s后回落至正常水平.与此同时, 检测到在DA上升阶段中间神经元Spike发放活动增强,在保持高于DA正常浓度水平阶段,中等多棘神经元(MSNs)放电频率增加.本研究制备的微电极阵列传感器能够实现脑内多巴胺和电生理的原位实时检测,有望成为神经信息检测的有力工具.     

基于微电极阵列的睡眠剥夺大鼠海马区神经电活动检测

Sleep deprivation (SD) is the partial or complete loss of sleep and has long been used as a tool in sleep research to interfere with normal sleep cycles in rodents and humans. The progressively-accumulating sleep pressure induced by sleep deprivation can lead to a variety of physiological changes and even death. Compared to traditional detection methods, in vivo detection of neuronal activity using micro-electromechanical system (MEMS) technology following sleep deprivation can help fully elucidate the effects of sleep deprivation at the cellular level. Herein, a computer-controlled rotary roller was used to completely deprive rats of sleep for 14 days and 16-channel microelectrode arrays (MEAs) were fabricated and implanted into the rat hippocampus to measure neural spikes and local field potentials (LFPs) in real-time. The hippocampus is involved in learning and memory and has been the focus of intensive research aimed at understanding the function of sleep. This study was performed to measure the changes in neuronal activity in the rat hippocampus induced by sleep deprivation as well as their overall impact on the brain. After sleep deprivation, both the pyramidal- and inter-neurons showed a higher amplitude and more intense firing patterns. The fast-firing pattern of the neurons after sleep deprivation indicated elevated excitability in the prolonged awake state. In addition, the LFP of the sleep deprived rats fluctuated more frequently. The power of the LFPs in the low-frequency band (0–50 Hz) was calculated, showing increased power of the delta, theta, alpha, and beta bands after sleep deprivation, especially for the delta band (0.1–4 Hz). Generally, LFPs are generated by all types of neural activity in the neural circuit, and the changes in the low frequency band power suggested decreased arousal and increased sleep pressure induced by sleep deprivation, which could further impair brain function. This study was mainly aimed at measuring electrophysiological changes induced by sleep deprivation in the rat brain. Typically, neuronal activity changes were accompanied by the alternation of specific neurotransmitters in the brain. In the future, it will be essential to focus on measuring the concurrent change of electrophysiological and neurochemical signals to better examine the impact of sleep deprivation on brain function.     

基于微电极阵列的睡眠剥夺大鼠海马区神经电活动检测（英文）

睡眠剥夺是一种能够实现个体睡眠部分或完全丧失的技术手段,由睡眠干扰所引发的逐渐积累的睡眠压力能导致多种生理方面的变化,甚至是个体的死亡。在本次研究中,我们使用旋转滚动式睡眠剥夺仪对大鼠进行了长达14天的睡眠剥夺,同时我们制作了一种16通道的微电极阵列并将其植入到大鼠海马区进行实时电生理信号检测。结果显示睡眠剥夺之后,大鼠海马区内的椎体神经元和中间神经元动作电位幅值提升,两种神经元动作电位的发放频率也显著增大。同时,场电位的波动也更加剧烈。神经细胞在睡眠剥夺后的快速发放模式表明长期清醒状态下神经细胞兴奋性的提升。此外,场电位在0–50 Hz频段的平均功率计算结果显示,睡眠剥夺之后各个频段的功率均有所提升,且在δ频段的变化最为明显。场电位在低频段的功率改变表明了睡眠剥夺所致的睡眠压力增大,此改变还将会进一步损伤大脑的相关功能。     

微电极研究 ⅩⅤ.微带电极及阵列微带电极上的扩散

本文讨论了微带电极的计时电流、扩散层与时间的关系;研究了微带阵列电极的扩散层交叠情况及其对计时电流的影响;进而对微带阵列电极上电极间的屏蔽效应进行了研究,屏蔽效应与电解时间、电极间距离及电极宽度有关,用已有的实验结果验证了本文的理论分析.     

同时测定血清中4种电解质的流动注射微电极串联电化学自动分析系统

基于流动注射-微电极串联的动态电化学技术,建立了能快速、自动、同时测定血清中K(+),Na(+),Cl(-)和Ca(2+)的分析方法和系统,并成功用于血清样品的测定.为稳定4种电极的基线电位、加快电极响应速度,优化了载流的组分:23mmol/L Na2B4O7-H3BO3(pH 7.40),0.25mmol/L K(+...     

阵列微电极研究Nd~(3+)对金属铜在3.5% NaCl溶液中腐蚀电化学行为的影响

利用阵列微电极技术测量了金属铜的自腐蚀电位、阻抗及表面腐蚀产物膜层载流子密度,并结合扫描电子显微镜,研究了Nd3+对金属铜在3.5%(w)NaCl溶液中腐蚀电化学行为的影响.结果表明,加入Nd3+使得金属铜表面生成的腐蚀产物膜层的形貌及结构发生了变化,腐蚀产物膜层变薄,腐蚀产物由片状结构转变为粒状结构,颗粒均匀分散分布;Nd3+的存在使得金属铜表面各区域的电位方差由0.034下降为0.026,阻抗标准方差由32805下降为6940,电位及阻抗分布趋于均匀化,有利于抑制局部腐蚀的发生;并且加入Nd3+将造成金属铜表面绝大部分区域腐蚀产物膜层的半导体类型由n型转变为p型,表面腐蚀产物膜层载流子密度标准方差由1.89×1017上升为4.10×1017,载流子密度分布趋于不均匀.     

集成微流体驱动泵的微流控微珠阵列芯片用于基因突变检测的研究

建立了一种基于微泵集成微流控微珠阵列芯片及三磷酸腺苷双磷酸酶(Apyrase)介导的等位基因特异性延伸的基因突变检测方法。将微流控芯片、引物修饰微珠阵列及基于毛细和蒸发作用的微流体驱动泵集成构建检测芯片,待测目标序列流过装配的微球阵列并与微球表面延伸引物杂交,在Apyrase和去除外切酶活性的Klenow DNA聚合酶协同作用下,引物3’末端碱基与目标序列包含的基因突变检测位点匹配则能够发生延伸,并将生物素化的dCTP掺入到引物的延伸序列中并固定在微球表面,链霉亲和素修饰量子点能与微球表面引物延伸序列中的生物素结合并提供荧光信号,而引物3’末端与目标序列存在单碱基不匹配则不能发生延伸。结果表明:采用这种单碱基识别技术,微泵驱动的芯片内可以检测0.2 pmol/L目标序列(信背比>3),液压驱动的芯片内能识别0.5 pmol/L目标序列,而芯片外检测只能识别0.1 nmol/L目标序列,微泵集成芯片在检测基因突变时其灵敏度较芯片外基因突变分析提高了500倍,并在0.5～30 pmol/L目标序列浓度范围内待测序列浓度与检测信号呈良好的线性关系。测定了一个人基因组样本中多药耐药蛋白基因1(MDR1)的两个多态性位点C3435T及G2677T,结果显示该样本具有3435CT及2677TT的基因型组合,此结果与DNA测序结果一致。本方法用于基因突变分析,具有良好的特异性、灵敏性及稳定性。     

硫酸溶液中Pt电极表面过程的EQCM研究

应用电化学循环伏安和石英晶体微天平(EQCM)方法研究了0.1mol·L-1硫酸溶液中Pt电极表面的吸附和氧化过程.从电极表面质量变化的结果分析,可认为正向电位扫描时氢区表面质量的增加是由于水分子取代Had引起的,而双电层区的质量增加则是由于水的吸附模式逐渐由氢端吸附转向氧端吸附所致.根据频率变化和电量数据,进一步推算出水在双电层区是以低放电吸附形式出现的,1molPt原子和水分子只发生0.054mol的电荷转移.本文结果可为认识Pt电极表面过程提供定量的新数据.     

与生物医学植入器件中的神经电刺激过程相关的电化学研究(英文)

生物医学工程、微电子加工技术和神经科学的进展推动了用于神经电刺激的新型和先进的生物医学器件的问世,使各类患者的某些感官功能得以恢复,并改善了患者的生活质量.在这些生物医学器件中,人工耳蜗植入器件、人工视觉植入器件、深层脑部刺激器件和脊髓刺激器件都取得了很大进展.刺激电极是生物医学植入器件中的关键部件之一.当刺激电极与活体组织相接触时,形成了电子器件和生物体组织间的接触界面.本文首先以耳蜗植入器件和视觉植入器件为例,简要介绍了生物医学植入器件的工作原理和现状.在此基础上,着重对神经电刺激器件所涉及的电化学概念、测试方法及其进展进行了评述.介绍了电刺激和电极/活体组织界面上电荷注入的基本原理和机制.也对常用的电极材料和微电极加工技术进行了评介.讨论了植入式器件研发过程中所遇到的与电化学相关的挑战,诸如电极反应、电极阻抗、电荷注入容量、微电极阵列、电极腐蚀以及生物兼容性等.此外,也讨论了微型传感器和微型生物传感器在植入式器件中的应用前景.刺激电极长期处于活体组织内的苛刻条件下会渐渐失效,腐蚀、氧化和脱壳等情况的出现都会降低器件的使用寿命,甚至危及机体.本文也对此进行了讨论.对设计和加工所面临挑战的清醒认识促使包括电化学家在内的多学科专家和工程技术人员共同努力,以推进神经刺激生物医学植入器件的长足进展和实际应用,使感官功能失效的患者得以受惠.     

Use of a Carbon-ink Microelectrode Array for Signal Enhancement in Microchip Electrophoresis with Electrochemical Detection

In this communication, we demonstrate that a carbon ink microelectrode array, where the electrodes are held at the same potential, affords significant signal enhancement in microchip electrophoresis with amperometric detection. The ability to fabricate an array of carbon ink microelectrodes with a palladium decoupler was demonstrated and the resulting electrodes were integrated with a valving microchip design. The use of an 8 electrode array led to a significant improvement in the limits of detection at the expense of separation resolution due to the increased detection zone size. It is also shown that microdialysis sampling can be integrated with the microchip device and a multi-analyte separation achieved.     

An In Situ Copper Plated Boron‐Doped Diamond Microelectrode Array for the Sensitive Electrochemical Detection of Nitrate

The first example of using a copper microelectrode array for use in electroanalysis is explored and exemplified with the electroanalytical quantification of nitrate. The analytical approach is based upon the in situ deposition of copper at a boron‐doped diamond (BDD) microelectrode array. The immobilized copper layer is electrocatalytic for nitrate reduction and exhibits an analytically useful range from 1.2 to 124 μM with a marked selectivity for nitrate ion over nitrate, with a limit of detection of 0.76 μM. The analytical applicability was examined through standard addition determinations of nitrate in drinking and river water samples.