我们非常感谢，组装振动探测系统的帮助下，普渡大学，瘫痪研究中心教授理查德Borgens。这项研究是由内授予美国国立卫生研究院1R01EY019101支持MZ和BR，和部分的加州再生医学RB1 - 01417研究所，美国国家科学基金会MCB - 0951199，赠款和不受限制从研究津贴，防止盲目性，加州大学戴维斯分校的眼科。

1。探头制造空白探头均购自世界精密仪器（elgiloy /不锈钢聚对二甲苯涂层的微电极）（见下文"特定的试剂和仪器表"）。探头切背后的提示25-30毫米，二甲苯绝缘约5毫米刮切端用手术刀（＃11刀片），以确保良好的连接。探头安装在一个黄金R30的连接器使用载银导电环氧树脂（如祭乐SL65）[*见下文注]。探头是在室温下储存在一夜之间让环氧树脂硬化。接下来，探头尖端镀有黄金和铂金，使用纳安的电源。探头尖端在丙酮冲洗，并连接到一个纳安电源负输出。探头尖端被认为在解剖显微镜下（X40），镀金溶液（钾dicyanoaurate（W / V蒸馏水九（CN）2（DH 2 O）的0.2％）。一个参考线连接到正摆在首位输出和在溶液中完成的电路。电流5娜是5分钟，然后上升到20 nA的，直到提示是大约一半所需的最终大小（约10-15微米）应用。卫生署冲洗探头尖端2，然后platinizing解决方案（氯铂酸水合物; 1％W / V H2PtCl6 * 6H 2 O）加铅（II）醋酸（0.1％W / V PB（CH3CO 2）2 * 3H 2 O在卫生署2 O），适用于电流250 nA的是5分钟，然后直到提示是理想的最终大小约80％提高到500 nA的电流增加至1μA和应用阵阵，直到最后的尖端直径在1秒（约30-35微米），最后提示是在卫生署2 O探针冲洗，可以在室温下保存下去。如果探头损坏，黄金R30的连接器可重新使用。 [*注:一些探测系统的探头安装直接连接到放大器进行信号。其他系统有一个单独的安装点和信号连接器。在后一种情况下，短期（2-3厘米）与R30的一端连接器的导线焊接到第一R30的连接器前安装探头（见图2A）。] 2。探针系统探头连接到一个压电式电动弯管机安装在一个3维微定位器（图1）。探头振动控制，振动探头电源，这也使得振动幅度和频率调整。探头电源发送一个参考信号锁定放大器，这也显示了振动频率和相位角。连接示波器，以便有一个快速视觉参考探头振动，它也是有用的。从探头的信号锁定放大器。要测量探针和样品可以被看作在解剖显微镜（放大倍数5233至X40）光纤照明。在校准和样品测量，参考和地面（接地线），必须在解决方案（见图2b）。放大器是通过模拟 - 数字（I / O）接口连接到电脑上。数据记录使用斯特拉斯克莱德电软件的全细胞程序（WinWCP）。 锁定放大器设置:灵敏度200μV]，动态分辨率[正常]，[]的偏移，展开[X1]，时间常数:前[10秒]，后[0.1秒]。如果需要更快的反应是，预时间常数可以减少到3秒偏移量的控制是用来将探头跟踪，靠近屏幕中心的。如果大的反应，预计，跟踪可移动或向下。 WCP的软件设置:记录时间[204.8小号]，每个声道的样本[1024]，采样间隔[0.2秒]，电压范围+ / - 0.2 V]。如果预计大电流，电压范围可提高到1 V或5 V。 3。探头设置新探针进行测试，并确定其独特的频率和相位角。是摆在新的探头校准室含生理盐水（图2B）。电源开启时，出现的频率，直到最大的震动是观察。这是探头的谐振频率。使用在这个频率的探头，可以导致不稳定和在录音产生的噪声，使探头是"调整"减去10 Hz到探头的工作频率（一般为150-200赫兹）。振幅调整，使探针振动的距离是尖端直径相同，从而使振动探头时探头尖端的"双重形象"是看到（见图2b）。要确定的相位角，探头放在生理盐水中，在校准室和电流1.5μA/ 厘米 2反复应用。相位角放大器锁进行调整，直到没有任何反应。加上或减去90 °角度给出了最大的反应，这个角度是探头的工作相角。每个探头的频率和相位角指出以供将来使用。在一项实验中，重要的是，这些设置不会改变频率，振幅和相位角，因为这将改变探头的响应。为方便起见，当电流流经南到北"，这应该产生在录音跟踪向上偏转（这里被称为"峰"），电流流过"北 - 南"应该表现出向下偏转（参见图3A）。如果这是走错了路，再加入180 °相位角将修复翻转反应一轮。探测函数背后的理论，校准等详细信息， 请参见雷德等。 校准:一个"标准化"目前正是1.5μA/厘米2，适用于在校准室的探头，探头的响应是用于计算样品中的电流（见图2B，3A） 。样品测​​量之前，将探头校准在适当的解决方案，如BSS +人工泪液对角膜解决方案。当前应用:南北和南北两个方向产生一个向上和向下偏转，分别相当于外向和内向电流，根据样品的方向。探头跟踪应该有一个稳定的基线，噪音低（比较图3A和3B）。在实验中使用的解决方案，以补偿由于蒸发的渗透压改变的探头校准。在分析数据时，从上半年的实验测量，计算结束校准下半年开始校准值，测量，可以计算出。 样品测​​定:分庭可以进行设计，以保持和固定样本。例如，图3C显示培养皿用钢丝环举行的眼睛角膜测量。含生理盐水的培养皿置于显微镜下解剖和重点放在视野样本的兴趣领域。探针，然后放置在溶液中和导向平行样品的表面和重点也的，所以要测量的样品点同一水平上。探头移动方便（例如1-2厘米）远离样品，振动开启（和记录的计算机软件），以建立一个稳定的（水平）基线（见图4A）。然后探头移动到测量位置，从表面约50微米。当新的（"峰"）的价值是稳定的，探头是搬回参考位置和跟踪返回到基线。这可以在固定的时间点重复生产timelapse数据，或样品移动/旋转略有反复在不同的位置，产生空间的当前映射数据（见图4B，5B）。 数据分析:数据分析使用WinWCP（见图5a）。水平的红色"零"线是向上或向下移动，所以它是平行跟踪基线测量峰值前。垂直绿化测量线北移，以跟踪基准。输出绿色阅读在绿线的底部应接近零（如0.00012）。这个数字显示的红色和绿色线的交叉点，的，和蓝线之间的differnce。红线，然后向上移动，直到它与高峰的顶端平行。绿色输出读数mV峰的大小。的数据，所有测量的山峰，和校准数据放入一个Microsoft Excel电子表格模板（见表1）。如日期，探头的数量，电压范围（VR），解决方案中使用，测量位置，时间点等相关信息，也可以在电子表格中。电流的方向（或样品的那样:"I / O"）指出，和内向电流也给予了在"高峰期"一栏中负值。在右栏的电流计算公式:电流=峰*（1.5/calibration）1.5μA/ 厘米 2应用目前在校准。因此:"unw1&#39;= 12.45 *（1.5/56.12）= 0.33276907μA/厘米2。 4。成功的秘诀在所有的电，重要设备的接地（接地），有助于消除噪音。因此，至少微定位器和显微镜的机箱应接地，也许还有光源（见图1）。用户也可以将静电的来源，因此，通过手腕带接地可以防止在某些情况下，探针不稳定，但并不总是必要的。一个法拉第笼是没有必要的，在锁定了所有的频率（如60Hz的电网），除了频率放大器，过滤器的探头振动。一个振动隔离表是有用的，但不是必需的。坚实，稳定的工作台或桌子作品一样好。除了基本的在Excel试算表的信息（见上文），它是有用的记录在自己的实验室书额外的有用信息，如温度的变化，药物补充，等，如果照片是显微镜，注意放大倍率。如果相关，它也是有用的绘制草图显示位置和/或探针测量的方向（见图6）（S）的样品。 挑战性的步骤<ol class="lalpha"><li>使探头:探头和R30的连接器之间必须有一个良好的电气连接。如果没有在电镀阶段的情况，那么这可能是原因。 </li><li>校准:使用适当生理盐水或培养基中，你将测量样品。不要过高或过低，填补校准室，因为这可以改变的响应。液体的表面应平整，跨室顶部。 </li><li>样品测​​量:提前计划，如你需要作出特别室举行/装入样品（见图3C）的吗？从样品测量时，探头应为导向的长期轴平行样品表面，使探头的振动方向（并因此目前正在测量方向）是垂直的样品表面（例如（图4B） ）。样本可移动和/或在不同的位置测量旋转。重要的是保持一致的探针和样品表面之间的距离，测量时。测量电流是从样品表面的距离成正比;探头移动距离样品表面，由平方反比定律的电流下降。也就是说，当测量样品表面产生了电流，电流检测是从表面的距离的平方成反比。目镜刻度可以用来判断探针和样品表面之间的距离。 </li></ol>故障排除<ul><li>问题:没有回应，在校准。解决方案:检查生理盐水接触电极。在恒定电流校准器，检查电池。 </li><li>问题:小的反响。解决方案:在DH 2 O和/或丙酮的清洁探头。检查相位角。 </li><li>问题:噪音或不稳定的基准（参见图3B）。解决方案:检查接地线。 </li><li>问题:关闭屏幕跟踪跳跃。解决方案:不要让探头尖端触摸样品。 </li></ul> 5。代表性的成果图3a显示校准跟踪的一个很好的例子。注意稳定（水平）基准，低噪声和大的反响。作为比较，图3b显示嘈杂的跟踪与不稳定的基线。在小鼠角膜伤口的不同位置的电流测量，如图4B所示。顶部面板显示探头的位置，中间的面板显示的探头在电脑上记录的痕迹，下部面板是在不同位置的电流的的图形，呈现出伤口目前的个人资料。图5b给出了在小鼠的皮肤伤口，在固定的时间间隔生产在伤口上的当前时间，当然的数据的测量。 <img src="/files/ftp_upload/2358/2358fig1.jpg" alt="图1" /> 图1。振动探测系统。见详细的说明文字。蓝色文字描述的连接线的功能。绿色符号显示接地点。 <img src="/files/ftp_upload/2358/2358fig2.jpg" alt="图2" /> 图2:A。探头安装。探头粘成黄金R30的载银环氧树脂，以电穿孔前连接器。在某些系统中，第二个连接器进行信号的短丝焊接。比例尺3毫米。白金球是不是规模。 B.探头校准。恒定电流校准器（左）适用于目前的1.5μA/厘米2的探头校准室（右）。左下:近距离的探测。当探头（右下），振捣振幅调整，所以被认为是一个尖端的双图像。比例尺100微米。 <img src="/files/ftp_upload/2358/2358fig3.jpg" alt="图3" /> 图3。A。探头校准跟踪。一个良好的探头校准跟踪，基线平稳，低噪声和大的反响，示例。电流南到北给出了一个向上的偏转，北到南的电流产生一个向下偏转。 B.一个不稳定的，嘈杂的探测跟踪。 C.钱伯斯提出安装鼠标（左）或鼠（右）眼睛角膜测量。比例尺5毫米。 <img src="/files/ftp_upload/2358/2358fig4.jpg" alt="图4" /> 图4证明测量的例子。答:建立一个稳定的基线是1-2从样品中的参考位置的探头。当探头移动到附近的样品的测量位置，它检测到一个当前和跟踪偏转向上（向外目前）。 B.在整个鼠标角膜的不同位置测量。探头导向平行于表面，使振动方向垂直。向上峰显示外向电流。最大电流在伤口边缘（职位B＆F）。探头的原理是测量位置F（右伤口边缘）所示。比例尺300微米。 <img src="/files/ftp_upload/2358/2358fig5.jpg" alt="图5" /> 图5。A。分析探头的痕迹。上游面板:红色零线是向上或向下移动，因此它是平行与跟踪基准，那么绿色的测线跨越基线移动，因此，在绿色的输出读数接近零（0.00012）。下半部分:红线是当时的感动，了，直到它与跟踪峰顶部平行，输出读数显示mV峰值（12.45）的大小。电流计算使用校正数据（见表1）。 B.老鼠的皮肤伤口timelapse数据。前伤人的电流在零时刻（红色符号）。测量是在相同的位置在伤人后定期的时间点的小鼠皮肤伤口。经过初步的瞬态内向电流（低于零），目前扭转和外向电流（正）缓慢上升，并趋于稳定。 <img src="/files/ftp_upload/2358/2358fig6.jpg" alt="图6" /> 图6显示探针测量位置的实验室书草图。 A.大鼠脑红点显示，测量位置和探头符号显示探头的方向。 B.大鼠角膜伤口;红点显示测量位置和箭头显示当前测量的方向。 <img src="/files/ftp_upload/2358/2358tab1.jpg" alt="表1" /> 表1。Excel中用于存储和量化探针数据的电子表格的例子。 pN2_cal1 =开始校准; CAL +和CAL - = mV校准值; VR =电压范围，峰值在MV =样品测量，I / O =电流（或样品）。

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我们描述了一种成本低，基本的，但高度敏感的振动探头在各种生物系统的非侵入性电流测量系统。 可能的修改<ol><li>如果铂/铱电极（世界精密仪器;猫＃PTM23B20）是用于代替不锈钢，镀金阶段被淘汰。 </li></ol>应用我们用振动探头测量电流:大鼠角膜2;大鼠晶状体3,4;小鼠皮肤5; 6 爪蟾蝌蚪;人体皮肤的7...

<table><tbody><tr><td>Eligoy-Stainless Electrode</td><td>World Precision Instruments, Inc.</td><td>SSM33A70</td><td>76 mm, 7 M&amp;#937;, 1-2&amp;#x03BC;m tip</td></tr><tr><td>Gold R30 connector</td><td>www.vectorelect.com</td><td>R30</td><td>Re-usable</td></tr><tr><td>Silver-loaded epoxy</td><td>3M</td><td>SL65</td><td>Mix 1-part Resin with 1-part Hardener</td></tr><tr><td>Dissecting microscope</td><td>Olympus Corporation</td><td>SZ40</td><td>Magnification x6 to x40</td></tr><tr><td>Potassium dicyanoaurate (KAu(CN)&lt;sub&gt;2&lt;/sub&gt;)</td><td>Sigma-Aldrich</td><td>379867</td><td>CAUTION: Toxic</td></tr><tr><td>Chloroplatinic acid hydrate (H&lt;sub&gt;2&lt;/sub&gt;PtCl&lt;sub&gt;6&lt;/sub&gt; x 6H&lt;sub&gt;2&lt;/sub&gt;O)</td><td>Sigma-Aldrich</td><td>520896</td><td>CAUTION: Toxic</td></tr><tr><td>Lead(II) acetate trihydrate (Pb(CH&lt;sub&gt;3&lt;/sub&gt;CO&lt;sub&gt;2&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt; x 3H&lt;sub&gt;2&lt;/sub&gt;O)</td><td>Sigma-Aldrich</td><td>185191</td><td>CAUTION: Toxic</td></tr><tr><td>Nano-Amp power source</td><td>Home made</td><td>-</td><td>Powered by six 1.5 V (AAA) batteries</td></tr><tr><td>3-dimensional micro-positioner</td><td>Line Tool Co.</td><td>Model H</td><td></td></tr><tr><td>Lock-in amplifier</td><td>Stanford Research Systems</td><td>SR530</td><td></td></tr><tr><td>Digital I/O interface</td><td>National Instruments</td><td>PCI-6220</td><td></td></tr><tr><td>Shielded Connector Block with BNC connections</td><td>National Instruments</td><td>BNC-2110</td><td></td></tr><tr><td>Strathclyde Electrophysiology Software</td><td>University of Strathclyde Institute of Pharmacy and Biomedical Sciences, UK</td><td>WinWCP V4.1.5</td><td>Free download from: &lt;a href=&quot;http://spider.science.strath.ac.uk/sipbs/software_ses.htm&quot;&gt;http://spider.science.strath.ac.uk/sipbs/software_ses.htm&lt;/a&gt;</td></tr><tr><td>Calibration Chamber</td><td>Home made</td><td></td><td></td></tr><tr><td>Constant Current Calibrator</td><td>Vibrating Probe Company</td><td></td><td>Powered by one 9 V (PP3) battery</td></tr></tbody></table>

measurement of bioelectric current with a vibrating probe

离子的主动运输所产生的电场，在许多生物系统中，往往成为重要的组织和器官的功能。例如，他们发挥了重要作用，直接在伤口愈合细胞迁移。在这里，我们描述了超灵敏的振动测量细胞外的电流探头的制造和使用。该探测器是一个绝缘的，削尖的一个小的铂黑尖（30-35微米），它可以检测在μA/厘米2的范围在生理盐水中的离子电流的金属丝。该探测器是由压电德尔振捣在200赫兹左右。离子电流的存在，探测器检测到其运动的极端之间的电压差。一个锁在了外来噪声放大器，过滤器，锁定探头的振动频率。数据记录到计算机中。探头校准的开始和结束在适当的盐水实验，用一腔适用于电流完全相同1.5μA/厘米2。我们描述了如何使探针，将系统设置为和校准。我们也证明了角膜测量技术，并表现出一些有代表性的成果从不同标本（角膜，皮肤，脑）。

Watch this Scientific Journal Video about Measurement of Bioelectric Current with a Vibrating Probe at JoVE.com

Measurement of Bioelectric Current with a Vibrating Probe

制造，校准和使用非侵入性的振动探头来测量各种生物系统中的生物电的电流的描述。

生物电电流测量振动探头

Electric fields, generated by active transport of ions, are present in many biological systems and often serve important functions in tissues and organs. ...

measurement-of-bioelectric-current-with-a-vibrating-probe

Universidad de Cartagena UDEC

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JoVE Core

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Physics

Bioengineering

Unit 1

Current and Resistance

SCIENTISTS IN ACTION

14.1K 次观看.  University of California, Davis. 制造，校准和使用非侵入性的振动探头来测量各种生物系统中的生物电的电流的描述。

视频: Measurement of Bioelectric Current with a Vibrating Probe

Characterizing Electron Transport through Living Biofilms

Here we demonstrate the method of electrochemical gating used to characterize electrical conductivity of electrode-grown microbial biofilms under physiologically relevant conditions.1 These measurements are performed on living biofilms in aqueous medium using source and drain electrodes patterned on a glass surface in a specialized configuration referred to as an interdigitated electrode (IDA) array. A biofilm is grown that extends across the gap connecting the source and drain. Potentials are applied to the electrodes (ES and ED) generating a source-drain current (ISD) through the biofilm between the electrodes. The dependency of electrical conductivity on gate potential (the average of the source and drain potentials, EG = [ED + ES]/2) is determined by systematically changing the gate potential and measuring the resulting source-drain current. The dependency of conductivity on gate potential provides mechanistic information about the extracellular electron transport process underlying the electrical conductivity of the specific biofilm under investigation. The electrochemical gating measurement method described here is based directly on that used by M. S. Wrighton2,3 and colleagues and R. W. Murray4,5,6 and colleagues in the 1980&#39;s to investigate thin film conductive polymers.

A protocol for measuring electrical conductivity of living microbial biofilms under physiologically relevant conditions is presented.

通过活生物膜表征电子传输

Here we demonstrate the method of electrochemical gating used to characterize electrical conductivity of electrode-grown microbial biofilms under ...

科研

化学

Voltage Biasing, Cyclic Voltammetry, &amp; Electrical Impedance Spectroscopy for Neural Interfaces

Electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measure properties of the electrode-tissue interface without additional invasive procedures, and can be used to monitor electrode performance over the long term. EIS measures electrical impedance at multiple frequencies, and increases in impedance indicate increased glial scar formation around the device, while cyclic voltammetry measures the charge carrying capacity of the electrode, and indicates how charge is transferred at different voltage levels. As implanted electrodes age, EIS and CV data change, and electrode sites that previously recorded spiking neurons often exhibit significantly lower efficacy for neural recording. The application of a brief voltage pulse to implanted electrode arrays, known as rejuvenation, can bring back spiking activity on otherwise silent electrode sites for a period of time. Rejuvenation alters EIS and CV, and can be monitored by these complementary methods. Typically, EIS is measured daily as an indication of the tissue response at the electrode site. If spikes are absent in a channel that previously had spikes, then CV is used to determine the charge carrying capacity of the electrode site, and rejuvenation can be applied to improve the interface efficacy. CV and EIS are then repeated to check the changes at the electrode-tissue interface, and neural recordings are collected. The overall goal of rejuvenation is to extend the functional lifetime of implanted arrays.

Voltage Biasing, Cyclic Voltammetry, & Electrical Impedance Spectroscopy for Neural Interfaces

The electrode-tissue interface of neural recording electrodes can be characterized with electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Application of voltage biasing changes the electrochemical properties of the electrode-tissue interface and can improve recording capability. Voltage biasing, EIS, CV, and neural recordings are complementary.

偏置电压，循环伏安，神经接口电阻抗光谱

Electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measure properties of the electrode-tissue interface without additional invasive ...

神经科学

Electric Cell-substrate Impedance Sensing for the Quantification of Endothelial Proliferation, Barrier Function, and Motility

Electric Cell-substrate Impedance Sensing (ECIS) is an in vitro impedance measuring system to quantify the behavior of cells within adherent cell layers. To this end, cells are grown in special culture chambers on top of opposing, circular gold electrodes. A constant small alternating current is applied between the electrodes and the potential across is measured. The insulating properties of the cell membrane create a resistance towards the electrical current flow resulting in an increased electrical potential between the electrodes. Measuring cellular impedance in this manner allows the automated study of cell attachment, growth, morphology, function, and motility. Although the ECIS measurement itself is straightforward and easy to learn, the underlying theory is complex and selection of the right settings and correct analysis and interpretation of the data is not self-evident. Yet, a clear protocol describing the individual steps from the experimental design to preparation, realization, and analysis of the experiment is not available. In this article the basic measurement principle as well as possible applications, experimental considerations, advantages and limitations of the ECIS system are discussed. A guide is provided for the study of cell attachment, spreading and proliferation; quantification of cell behavior in a confluent layer, with regard to barrier function, cell motility, quality of cell-cell and cell-substrate adhesions; and quantification of wound healing and cellular responses to vasoactive stimuli. Representative results are discussed based on human microvascular (MVEC) and human umbilical vein endothelial cells (HUVEC), but are applicable to all adherent growing cells.

This protocol reviews Electric Cell-substrate Impedance Sensing, a method to record and analyze the impedance spectrum of adherent cells for the quantification of cell attachment, proliferation, motility, and cellular responses to pharmacological and toxic stimuli. Detection of endothelial permeability and assessment of cell-cell and cell-substrate contacts are emphasized.

电动细胞基质阻抗传感的内皮细胞增殖，屏障功能的定量和能动性

Electric Cell-substrate Impedance Sensing (ECIS) is an in vitro impedance measuring system to quantify the behavior of cells within adherent cell layers. ...

生物工程

Measuring the Induced Membrane Voltage with Di-8-ANEPPS

Placement of a cell into an external electric field causes a local charge redistribution inside and outside of the cell in the vicinity of the cell membrane, resulting in a voltage across the membrane. This voltage, termed the induced membrane voltage (also induced transmembrane voltage, or induced transmembrane potential difference) and denoted by &Delta;&Phi;, exists only as long as the external field is present. If the resting voltage is present on the membrane, the induced voltage superimposes (adds) onto it. By using one of the potentiometric fluorescent dyes, such as di-8-ANEPPS, it is possible to observe the variations of &Delta;&Phi; on the cell membrane and to measure its value noninvasively. di-8-ANEPPS becomes strongly fluorescent when bound to the lipid bilayer of the cell membrane, with the change of the fluorescence intensity proportional to the change of &Delta;&Phi;. This video shows the protocol for measuring &Delta;&Phi; using di-8-ANEPPS and also demonstrates the influence of cell shape on the amplitude and spatial distribution of &Delta;&Phi;.

External electric field induces a voltage on the membrane of a cell, termed the induced membrane voltage (&Delta;&Phi;). By using the potentiometric dye di-8-ANEPPS, it is possible to measure the &Delta;&Phi; noninvasively. This video shows the protocol for measuring &Delta;&Phi; using di-8-ANEPPS.

诱导膜电压测量与DI - 8 - ANEPPS

Placement of a cell into an external electric field causes a local charge redistribution inside and outside of the cell in the vicinity of the cell ...

生物学

External Excitation of Neurons Using Electric and Magnetic Fields in One- and Two-dimensional Cultures

A neuron will fire an action potential when its membrane potential exceeds a certain threshold. In typical activity of the brain, this occurs as a result of chemical inputs to its synapses. However, neurons can also be excited by an imposed electric field. In particular, recent clinical applications activate neurons by creating an electric field externally. It is therefore of interest to investigate how the neuron responds to the external field and what causes the action potential. Fortunately, precise and controlled application of an external electric field is possible for embryonic neuronal cells that are excised, dissociated and grown in cultures. This allows the investigation of these questions in a highly reproducible system.
In this paper some of the techniques used for controlled application of external electric field on neuronal cultures are reviewed. The networks can be either one dimensional, i.e. patterned in linear forms or allowed to grow on the whole plane of the substrate, and thus two dimensional. Furthermore, the excitation can be created by the direct application of electric field via electrodes immersed in the fluid (bath electrodes) or by inducing the electric field using the remote creation of magnetic pulses.

Neuronal cultures are a good model for studying emerging brain stimulation techniques via their effect on single neurons or a population of neurons. Presented here are different methods for stimulation of patterned neuronal cultures by an electric field produced directly by bath electrodes or induced by a time-varying magnetic field.

使用电动和一维和二维文化磁场神经元的外部激励

A neuron will fire an action potential when its membrane potential exceeds a certain threshold. In typical activity of the brain, this occurs as a result ...

Measurement of Extracellular Ion Fluxes Using the Ion-selective Self-referencing Microelectrode Technique

Cells from animals, plants and single cells are enclosed by a barrier called the cell membrane that separates the cytoplasm from the outside. Cell layers such as epithelia also form a barrier that separates the inside from the outside or different compartments of multicellular organisms. A key feature of these barriers is the differential distribution of ions across cell membranes or cell layers. Two properties allow this distribution: 1) membranes and epithelia display selective permeability to specific ions; 2) ions are transported through pumps across cell membranes and cell layers. These properties play crucial roles in maintaining tissue physiology and act as signaling cues after damage, during repair, or under pathological condition. The ion-selective self-referencing microelectrode allows measurements of specific fluxes of ions such as calcium, potassium or sodium at single cell and tissue levels. The microelectrode contains an ionophore cocktail which is selectively permeable to a specific ion. The internal filling solution contains a set concentration of the ion of interest. The electric potential of the microelectrode is determined by the outside concentration of the ion. As the ion concentration varies, the potential of the microelectrode changes as a function of the log of the ion activity. When moved back and forth near a source or sink of the ion (i.e. in a concentration gradient due to ion flux) the microelectrode potential fluctuates at an amplitude proportional to the ion flux/gradient. The amplifier amplifies the microelectrode signal and the output is recorded on computer. The ion flux can then be calculated by Fick&#8217;s law of diffusion using the electrode potential fluctuation, the excursion of microelectrode, and other parameters such as the specific ion mobility. In this paper, we describe in detail the methodology to measure extracellular ion fluxes using the ion-selective self-referencing microelectrode and present some representative results.

Transporters in cell membranes allow differential segregation of ions across cell membranes or cell layers and play crucial roles during tissue physiology, repair and pathology. We describe the ion-selective self-referencing microelectrode that allows the measurement of specific ion fluxes at single cells and tissues in vivo.

细胞外离子流的使用离子选择性自引用的微电极技术测量

Cells from animals, plants and single cells are enclosed by a barrier called the cell membrane that separates the cytoplasm from the outside. Cell layers ...

Evaluation of Fluid Overload by Bioelectrical Impedance Vectorial Analysis

Early detection and management of fluid overload are critically important in acute illness, as the impact of therapeutic intervention can result in decreased or increased mortality rates. Accurate fluid status assessment entails appropriate therapy. Unfortunately, as the gold standard method of radioisotopic fluid measurement is costly, time-consuming, and lacks sensitivity in the acute care clinical setting, other less-accurate methods are typically used, such as clinical examination or 24 h output. Bioelectrical impedance vectorial analysis (BIVA) is an alternative impedance-based approach, where the raw parameter resistance and reactance of a subject are plotted to produce a vector, the position of which can be evaluated relative to tolerance intervals in an R-Xc graph. The fluid status is then interpreted as normal or abnormal, based on the distance from the mean vector derived from a healthy reference population. The objective of the present study is to demonstrate how to evaluate the presence of fluid overload through bioelectrical impedance vectorial analysis and the impedance ratio measured with tetrapolar multi-frequency equipment in patients admitted to the emergency department.

In this study, we demonstrate how to evaluate the presence of fluid overload through bioelectrical impedance vectorial analysis (BIVA) and the impedance ratio measured using tetrapolar multi-frequency equipment in patients admitted to the emergency department. BIVA and impedance ratio are reliable and useful tools to predict poor outcomes.

通过生物电阻抗矢量分析评估流体过载

Early detection and management of fluid overload are critically important in acute illness, as the impact of therapeutic intervention can result in ...

医学

<meta charset="utf8"></head><body> 为临床前啮齿动物模型制造肌外肌电图电极

Development of a Low-cost Epimysial Electromyography Electrode: A Simplified Workflow for Fabrication and Testing

Electromyography (EMG) is a valuable diagnostic tool for detecting neuromuscular abnormalities. Implantable epimysial electrodes are commonly used to measure EMG signals in preclinical models. Although classical resources exist describing the principles of epimysial electrode fabrication, there is a sparsity of illustrative information translating electrode theory to practice. To remedy this, we provide an updated, easy-to-follow guide on fabricating and testing a low-cost epimysial electrode. 
Electrodes were made by folding and inserting two platinum-iridium foils into a precut silicone base to form the contact surfaces. Next, coated stainless steel wires were welded to each contact surface to form the electrode leads. Lastly, a silicone mixture was used to seal the electrode. Ex vivo testing was conducted to compare our custom-fabricated electrode to an industry standard electrode in a saline bath, where high levels of signal agreement (sine [intraclass correlation - ICC= 0.993], square [ICC = 0.995], triangle [ICC = 0.958]), and temporal-synchrony (sine [r = 0.987], square [r = 0.990], triangle [r= 0.931]) were found across all waveforms. Low levels of electrode impedance were also quantified via electrochemical impedance spectroscopy. 
An in vivo performance assessment was also conducted where the vastus lateralis muscle of a rat was surgically instrumented with the custom-fabricated electrode and signaling was acquired during uphill and downhill walking. As expected, peak EMG activity was significantly lower during downhill walking (0.008 &plusmn; 0.005 mV) than uphill (0.031 &plusmn; 0.180 mV, p = 0.005), supporting the validity of the device. The reliability and biocompatibility of the device were also supported by consistent signaling during level walking at 14 days and 56 days post implantation (0.01 &plusmn; 0.007 mV, 0.012 &plusmn; 0.007 mV respectively; p &gt; 0.05) and the absence of histological inflammation. Collectively, we provide an updated workflow for the fabrication and testing of low-cost epimysial electrodes.

<meta charset="utf8"></head><body>作者聚焦:ACL 损伤研究中的肌外膜电极制造和测试

Our purpose was to provide an updated, easy-to-follow guide on the fabrication and testing of epimysial electromyography electrodes. To that end, we provide instructions for material sourcing and a detailed walkthrough of the fabrication and testing process.

低成本肌外肌电图电极的开发:简化的制造和测试工作流程

Electromyography (EMG) is a valuable diagnostic tool for detecting neuromuscular abnormalities. Implantable epimysial electrodes are commonly used to ...

生物电电流测量振动探头

摘要

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此视频中的章节

通过活生物膜表征电子传输

偏置电压，循环伏安，神经接口电阻抗光谱

电动细胞基质阻抗传感的内皮细胞增殖，屏障功能的定量和能动性

诱导膜电压测量与DI - 8 - ANEPPS

使用电动和一维和二维文化磁场神经元的外部激励

细胞外离子流的使用离子选择性自引用的微电极技术测量

通过生物电阻抗矢量分析评估流体过载

低成本肌外肌电图电极的开发:简化的制造和测试工作流程

低成本肌外肌电图电极的开发:简化的制造和测试工作流程

低成本肌外肌电图电极的开发:简化的制造和测试工作流程