16通道神经信息双模检测分析仪的研制与应用

研制了一种可检测分析神经电生理信号和递质化学信号的16通道双模检测分析仪.仪器山硬件和软件系统组成,其电流和电压分辨率分别为10 pA和0.6 μV,具备实时峰电位分离,数字IIR滤波,计时电流法,循环伏安法等常用电生理和电化学检测分析方法.为验证仪器的性能分别进行了电生理信号和电化学信号的检测实验.在SD大鼠脑部电生...     

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。     

纳米TiN修饰平面微电极阵列在神经信息双模检测中的应用

采用氮化钛(TiN)修饰平面微电极阵列(pMEA),对其性能进行改进,开展了离体神经电生理和神经递质电化学的检测研究。采用磁控溅射法在实验室自制微电极阵列上修饰具有纳米结构的TiN材料,修饰后的微电极阻抗降低近一个数量级,背景噪声基线降至±6μV,信噪比是修饰前的1.7倍。在SD大鼠离体脑片神经电生理信号检测中,信噪比可达10∶1,能分离提取±12μV的微弱信号。神经递质多巴胺电化学信号检测下限达50 nmol/L(信噪比2∶1),浓度在0.05~100μmol/L内与电流响应的线性相关系数为0.998。实验结果表明,在微电极表面修饰纳米TiN,降低了微电极阻抗,提高了信噪比,实现了对神经信息微弱信号的检测。     

铝对多巴胺和左旋多巴氧化的化学催化作用的电化学和光谱学研究

用电化学、紫外-可见光谱和^13C-核磁共振谱研究了铝(Ⅲ)对多巴胺和左旋多巴氧化的化学催化作用。结果表明,在中性和碱性条件下铝(Ⅲ)均能促进多巴胺和左旋多巴的氧化,这一促进作用提高了用多巴胺和左旋多巴作电活性配体示差脉冲伏安法间接测铝的灵敏度。但是抗坏血酸有抑制铝(Ⅲ)的催化效应的作用。     

基于碳纳米材料的神经电极技术

As a powerful tool for monitoring and modulating neural activities, implantable neural electrodes constitute the basis for a wide range of applications, including fundamental studies of brain circuits and functions, treatment of various neurological diseases, and realization of brain-machine interfaces. However, conventional neural electrodes have the issue of mechanical mismatch with soft neural tissues, which can result in tissue inflammation and gliosis, thus causing degradation of function over chronic implantation. Furthermore, implantable neural electrodes, especially depth electrodes, can only carry out limited data sampling within predefined anatomical regions, making it challenging to perform large-area brain mapping. With excellent electrical, mechanical, and chemical properties, carbon-based nanomaterials, including graphene and carbon nanotubes (CNTs), have been used as materials of implantable neural electrodes in recent years. Electrodes made from graphene and CNT fibers exhibit low electrochemical impedance, benefiting from the porous microstructure of the fibers. This enables a much smaller size of neural electrode. Together with the low Young's modulus of the fibers, this small size results in very soft electrodes. Soft neural electrodes made from graphene and CNT fibers show a much-reduced inflammatory response and enable stable chronic in vivo action potential recording for 4-5 months. Combining different modalities of neural interfacing, including electrophysiological measurement, optical imaging/stimulation, and magnetic resonance imaging (MRI), could leverage the spatial and temporal resolution advantages of different techniques, thus providing new insights into how neural circuits process information. Transparent neural electrode arrays made from graphene or CNTs enable simultaneous calcium imaging through the transparent electrodes, from which concurrent electrical recording is taken, thus providing complementary cellular information in addition to high-temporal-resolution electrical recording. Transparent neural electrodes from carbon-based nanomaterials can record well-defined neuronal response signals with negligible light-induced artifacts from cortical surfaces under optogenetic stimulation. Graphene and CNT-based materials were used to fabricate MRI-compatible neural electrodes with negligible artifacts under high field MRI. Simultaneous deep brain stimulation (DBS) and functional magnetic resonance imaging (fMRI) with graphene fiber electrodes in the subthalamic nucleus (STN) in Parkinsonian rats revealed robust blood oxygenation level dependent responses along the basal ganglia-thalamocortical network in a frequency-dependent manner, with responses from some regions not previously detectable. This review introduces the recent development and application of neural electrode technologies based on graphene and CNTs. We also discuss biological safety issues and challenges faced by neural electrodes made from carbon nanomaterials. The use of carbon-based nanomaterials for the fabrication of various soft and multi-modality compatible neural electrodes will provide a powerful platform for both fundamental and translational neuroscience research.     

基于网络的化学中心实验室仪器管理初探

介绍网络环境下化学中心实验室仪器综合管理系统的设计与实现,按照国家化学基础课实验教学示范中心建设标准,对网络平台下实验室仪器管理的过程进行了初步探讨。     

电化学法检测水果中抗坏血酸含量的本科生综合化学实验

将电化学检测方法引入到本科教学实验中,设计了利用循环伏安法检测水果中抗坏血酸含量的综合探究性实验。采用多壁碳纳米管为活性物质,通过红外光谱表征材料化学组成,通过透射电子显微镜表征材料形貌特征,利用抗坏血酸在电极表面的氧化反应,通过反应电流曲线定量测定水果中抗坏血酸的含量。该实验原料贴近生活,能够提高学生参与积极性,所涵盖电化学理论较系统,有助于学生灵活掌握课本上的电化学知识,涉及了部分科研类大型仪器设备,帮助学生学习和了解仪器使用方法及工作机理,提高学生钻研热情。该实验可作为化学化工类本科生专业综合性实验开设。     

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.     

Dual-mode Detection of Dopamine Based on Enhanced Fluorescent and Colorimetric Signals of Fe3+-H2O2-o-Phenylenediamine System

A fluorescent and colorimetric dual-mode “light-on” assay for the detection of dopamine (DA) was developed based on Fe³⁺-H₂O₂-OPD system. In general, Fe³⁺ could catalyze the H₂O₂-mediated oxidation of colorless and nonfluorescent o-phenylenediamine (OPD), and the resultant 2,3-diaminophenazine (DAP) exhibits a visible yellow color and yellow fluorescence. However, the reaction rate is extremely slow. By comparison, the introduction of DA can trigger a typical Fenton reaction that generates hydroxyl radical (?OH) continuously, thus increasing the conversion rate of OPD to DAP. Correspondingly, both color and fluorescence of the sensing system are enhanced obviously. On the basis of this fact, a sensor with dual readout for the detection of DA was established via measuring the fluorescent and colorimetric signals of the Fe³⁺-H₂O₂-OPD system. The linear ranges were 0.05–20 mM and 0.10–18 mM, and the detection limits were calculated to be 15 and 65 nM (S/N = 3) for fluorescent and colorimetric detection, respectively. The proposed dual-readout method features with simplicity, high sensitivity, visualization and good accuracy. Moreover, the method has been successfully applied to the detection of DA in human urine with satisfactory results.     

银纳米粒子探针等离子共振散射光谱法测定抗坏血酸

利用抗坏血酸(VC)还原银氨溶液生成具有强烈等离子体共振散射特性的银纳米粒子,导致体系共振光散射信号的增强,散射最大峰位于544 nm。 在最佳条件下,体系的共振散射强度与抗坏血酸浓度在0.2~7.0 μmol/L范围内呈线性关系,相关系数为0.9988,检出限为8.1 nmol/L。 抗坏血酸的氧化产物能与银纳米粒子相互作用使之分散均匀且保持稳定,因此该体系不需要添加稳定剂或分散剂。 以此建立了用银纳米粒子为探针的测定抗坏血酸的高灵敏、简捷的共振散射新方法。 同时讨论了最佳反应条件和其它影响因素。 该方法用于ＶＣ片及饮料中抗坏血酸的测定,加标回收率在94.5%~97.0%之间。 结果表明,方法具有操作简单,灵敏度高和回收率较好等优点。     

双柱碳纤维微电极的研究及其在测定多巴胺中的应用

报道了双柱微电极的制作方法,提出了用双柱碳纤维微电极在抗坏血酸存在下选择性地测定多巴胺.探讨了电极反应机理.多巴胺的浓度在5.0×10^-4～5.0×10^-6mol/L范围内与收集电流成正比.抗坏血酸浓度<5.0×10^-4mol/L时对测定结果无影响.     

基于钴离子介导信号转换的抗坏血酸比色分析

抗坏血酸是许多生化过程所必需的一种生物小分子。借助于羟基氧化钴纳米片的氧化性和钴离子与硫氰酸根离子之间强的螯合作用,本文报道了一种基于钴离子介导信号转换的新方法用于抗坏血酸的比色分析。在抗坏血酸存在时,羟基氧化钴纳米片被还原降解产生二价钴离子,钴离子与硫氰酸根离子之间通过螯合作用生成蓝色的阴离子络合物[Co(NCS)₄]^2-,在625nm处产生可见吸收信号。在优化条件下,体系625nm处的吸收值与抗坏血酸浓度在0.03～0.45 mmol/L范围内呈良好的线性关系,线性方程为A₆₂₅=0.638c(mmol/L)+0.042,相关系数R=0.993,检测限(3S/N)为1.5μmol/L。     

聚乙烯亚胺功能化石墨烯修饰电极同时测定抗坏血酸、 多巴胺、尿酸和色氨酸

制备了聚乙烯亚胺(PEI)功能化的石墨烯(G)修饰电极以实现抗坏血酸(AA)、 多巴胺(DA)、 尿酸(UA)和色氨酸(Trp)的分离及同时测定. 采用红外光谱(FTIR)、 紫外-可见吸收光谱(UV-Vis)、 X射线粉末衍射仪(XRD)和透射电子显微镜(TEM)对电极修饰材料进行了表征, 并优化了该修饰电极同时测定AA, DA, UA和Trp的实验条件. 在聚乙烯亚胺功能化石墨烯修饰的玻碳电极(PEI-G/GCE)上实现了AA, DA, UA 和Trp氧化峰的分离, AA-DA, DA-UA和UA-Trp的氧化峰电位差分别为298, 130和350 mV. 该修饰电极对AA, DA, UA和Trp的检测线性范围分别为50~5800, 30~2570, 0.05~400和6~1000 μmol/L; 检出限分别为16.67, 10, 0.017和2 μmol/L.     

电流型电化学遥测系统的研制与应用

研制了一种微型嵌入式遥测系统,并利用此系统实现了电化学传感检测。遥测系统的输出电压范围为-0.5~0.5 V,分辨率<1 mV;电流检测范围为-1~1μA,最小分辨率为0.2 nA。此遥测系统是基于ADuCM360微处理器设计的,包括恒电位仪、电流检测模块和无线模块,尺寸大小为24 mm ×13 mm ×11 mm。利用LabVIEW开发上位机软件,用于数据存储和实时显示。为了验证该系统的精度和可靠性,对系统进行了电学性能测试。应用遥测系统检测不同浓度抗坏血酸溶液的电流响应,电极施加的工作电位为30 mV,在浓度范围50~300μmol/L 内,抗坏血酸电极的电流响应与其浓度呈现良好的线性关系,线性方程为I(nA)=2.98CAA(μmol/L)-137.39,线性相关系数R2=0.984。并以脑缺血模型为例,探索了仪器在活体动物研究中的适用性。结果表明,该系统可用于相关动物模型的研究。     

Imidazolium Based Surface Active Ionic Liquids as Novel Micellar Media for Simultaneous and Sensitive Electrochemical Detection of Dopamine and Ascorbic Acid

Surface active ionic liquid (SAIL) micelle assisted, simultaneous and highly sensitive electrochemical sensing of dopamine (DA) and ascorbic acid (AA) is presented. Results presented herein establish that SAILs viz.1‐dodecyl‐3‐methyl imidazolium chloride ([DDMIM][Cl]), 1‐octyl‐3‐methyl imidazolium chloride ([OMIM][Cl]) and 1‐butyl‐3‐methyl imidazolium chloride ([BMIM][Cl]) exhibit a probe and SAIL nature/concentration specific impact on the redox behaviour of hydroquinone (H₂Q), dopamine (DA) and ascorbic acid (AA). To our observations, the electrochemical behaviour of DA and AA is affected oppositely by SAILs with the apparent effects being more appreciable in presence of [DDMIM][Cl]. In the presence of [DDMIM][Cl] micelles, the electro‐oxidation of AA was observed to occur at potentials about 350 mV less positive than required for electrooxidation of DA, an important advantage that minimises the interference of former in sensing of the later. The peak to peak potential separation of 350 mV observed in presence of [DDMIM][Cl] micelles is the largest to be reported so far. The DPV signal for DA and AA displayed a linear response in the concentration range of 6.6 to 99.9 μM and 6.6 to 131.5 μM respectively. Very low detection limits of 0.0161 μM for DA in presence of 39.8 μM AA and 0.0227 μM for AA in presence of 39.8 μM DA were estimated in micellar phase of [DDMIM][Cl].     

Analytical Application of Pyramidal,Rodlike, and Spherical Gold Nanostructures: Simultaneous Detection of Ascorbic Acid and Uric Acid

Simultaneous detection of ascorbic (AA) and uric acid (UA) is developed at pyramidal (NP), rodlike (NR), and spherical (NS) gold nanostructures, due to their high electrocatalytic activities toward the oxidation of AA and UA. Unlike at bare gold electrode, the fouling resulted from the oxidized product of AA is eliminated at the nanostructured gold electrode. The voltammetric signals of AA and UA are completely separated with a potential difference of 216 mV, 158 mV and 195 mV, respectively, at the pyramidal, rodlike, and spherical gold surfaces. The experimental results reveal that solution pH effects the peak separation of AA and UA, acidic solution is more favorable for the simultaneous determination of AA and UA than neutral one, than alkaline one. The coexistence of a large excess of AA does not interfere with the voltammetric sensing of UA, vice versa. All the three kinds of nanostructured gold electrodes show excellent sensitivity, stability, selectivity, low detection limit, quick response and wide linear range in the repeated detection of AA and UA. The practical utility of the present nanostructured gold electrodes is demonstrating by determining the concentration of AA in fruit juice and UA in urine sample.