Name: a performance-testing platform for a conduction micropump with an fr-4 copper-clad electrode plate
Uploaded: 2017-10-09T13:00:00.000+00:00
Duration: 6 min 46 s
Description: Watch this Scientific Journal Video about A Performance-testing Platform for a Conduction Micropump with an FR-4 Copper-clad Electrode Plate at JoVE.com

这项工作是由中国国家自然科学基金 (51375176) 主办的;中国广东省自然科学基金 (2014A030313264);和中国广东省科技规划项目 (2014B010126003)。

警告: 请在使用前查阅所有相关的材料安全数据表 (MSDS)。丙酮是高度易燃的, 可以引起眼睛和呼吸道发炎。所涉及的电压高达几千伏;因此, 在进行实验时, 电火花是预期的。在一个通风良好的房间里进行实验, 以避免爆炸和火花引发的火灾. 
 1. 板和支架的制作 注意: 在这项工作中, 电极板和支架是由工厂的生产线制造的。由于复杂的工艺过程, 本文将只介绍材料和各部分的参数. 
<ol> <li> 电极板的材料和尺寸 <ol> <li> 使用1.4 毫米 FR-4 覆铜板制作电极板, 其厚度为35和 #181; m。有关电极板的详细参数, 请参见 图 1 . </li>
	电极的 </ol> </li> <li> 参数 <ol> <li> 从工厂订购电极板。有关详细信息, 请参见 图 2 . </li>
	</ol> </li> <li> 在电极板的制备后检查电极板 <ol>, 在100X 和300X 放大倍数下, 使用电子显微镜检查电极是否有明显的缺陷。请注意, 电极表面的任何微小缺陷都可能导致短路, 如 图 3 所示. </li>
		<li> 检查和测量电极的宽度和间距, 以确定尺寸精度是否满足要求. </li>
		<li> 用电流表测试板以查看是否发生了电短路. </li>
	</ol> </li> <li> 准备的腔板 <ol> <li> 将一些硅膜切割成与电极板相同的尺寸, 如 图 4 所示。选择不同厚度的硅膜, 使不同高度的腔板. </li>
		<li> 使用特殊的冲孔工具来穿孔腔室孔, 如图5所示 . </li>
	持有者 <ol> <li> 的 </ol> </li> <li> 处理命令从工厂订购持有人。详细参数如 图 6 所示. </li>
	</ol> </li> <li> 制作盖板 <ol> <li> 在盖板顶部钻两个孔, 使用钻孔机安装进气管和出水管。有关它们的位置和大小, 请参见 图 7 . </li>
	</ol> </li> </ol> 2。微泵的组件 <ol> <li> 使用丙酮清洗所有的板、支架、入口和出口管, 以及在实验中使用的其他工具。把这些工具和盘子放在烧杯里, 然后倒入足够的99.5% 丙酮浸泡。把烧杯放进超声波清洗机里打开超声波清洗机, 将定时器设置为5分钟. </li>
	<li> 将进口和出口不锈钢管插入盖板上的两个孔中. </li>
	<li> 将硅膜制成的腔板放在电极板上, 然后用盖板盖住. </li>
	<li> 堆叠并将盖板、腔板和电极板从上到下对齐, 并将对齐的板插入刀柄. 
	<ol> <li> 使用 M5 螺栓固定托架内的板。如 图 8 和 图 9 所示, 分别查看装配式微泵的爆炸视图和普通视图. </li>
		<li> 通过拧紧螺栓将板按在一起. 
		注: 腔板上的管和腔将形成工作液的通道。该弹性室板还可以密封板之间的间隙, 以防止液体流出。分别查看 图 8 和 图 9 中所装配的微泵的分解视图和普通视图. </li>
	</ol> </li> <li> 使用两个外部直径为 4 mm 和内径为 2 mm 的聚氨酯软管, 以连接入口和出口不锈钢管. </li>
	<li> 连接电流表、500 V DC 电源和串联微泵。在电流表和电源之间插入1毫安保险丝以保护电流表, 以防微泵短路. </li>
	<li> 将进口软管插入50毫升的烧杯中, 内有20-30 毫升丙酮. 
	注意: 图 10 显示了已完成的平台. </li>
</ol> 3。实验过程 <ol> <li> 在实验前准备工作 <ol> 使用一个圆柱来注入丙酮来填满微泵。液位达到出口软管后, 继续注入10毫升的丙酮, 直到所有气泡被推离会议厅. 
		注: 不可能看到是否有气泡留在会议厅内, 因为盖板和电极板是不透明的。连续注射丙酮有助于消除气泡, 但不能保证在微泵内没有气泡。气泡可能堵塞液体的通道, 或者它们可能短路, 导致微泵内部的微小爆炸, 这将烧毁电极。气泡对水泵运行的影响还不完全清楚, 但它们造成的故障已经被多次观察到. </li>
		<li> 将20-30 毫升丙酮倒入烧杯中, 并将入口软管放入烧杯中。确保液位至少比进气道高出5毫米, 这样丙酮就能流入泵内, 没有空气可以吸入微泵腔. </li>
	</ol> </li> <li> 静态压力测试 <ol> <li> 将出口软管连接到一个小的框架, 以便软管可以保持直和垂直。把尺子放在出水管旁边, 以测量液位. </li>
		<li> 将微泵连接到电源. </li>
		<li> 通过按下开关开始测试, 然后标记初始液位. </li>
		<li> 液位变稳定后, 记录时间、最终液位和电流. </li>
		<li> 继续记录液位和电流每年十年代直到微泵崩溃. </li>
	</ol> </li> <li> 流量测试 <ol> <li> 使用大型测量气缸来收集出水软管流出的液体。一定要修复出口软管, 使其末端保持在与烧杯中液位相同的高度. </li>
		<li> 将微泵连接到电源. </li>
		<li> 通过按下开关开始测试, 然后标记初始液位. </li>
		<li> 当液体开始从出口软管流出时, 每年十年代记录测量气缸内的丙酮量。随着实验的进行, 在烧杯中加入丙酮以保持液位. </li>
	</ol> </li> <li> 可靠性测试 <ol> <li> 使用平均工作时间来评估泵的可靠性。在流量试验和静压试验中, 在泵坏前记录操作时间。在实验过程中记录每个击穿的详细现象, 并在事后对电极板表面进行检查, 进一步分析. </li>
	</ol>
	</li>
</ol>

<ol>
	<li>Kazemi, P. Z., Selvaganapathy, P. R., Ching, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+micropillar+electrode+spacing+on+the+performance+of+electrohydrodynamic+micropumps.">Effect of micropillar electrode spacing on the performance of electrohydrodynamic micropumps.</a> J Electrostat. 68 (4), 376-383 (2010).</li><li>Kano, I., Nishina, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+electrode+arrangements+on+EHD+conduction+pumping.">Effect of electrode arrangements on EHD conduction pumping.</a> IEEE Trans Ind Appl. 49 (2), 679-684 (2013).</li><li>Laser, D. J., Santiago, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+micropumps.">A review of micropumps.</a> J Micromech Microeng. 14 (6), R35 (2004).</li><li>Fylladitakis, E. D., Theodoridis, M. P., Moronis, A. X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+on+the+history,+research,+and+applications+of+electrohydrodynamics.">Review on the history, research, and applications of electrohydrodynamics.</a> IEEE Trans Plasma Sci. 42 (2), 358-375 (2014).</li><li>Yazdani, M., Seyed-Yagoobi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Electrostatics Joint Conf. , (2009).</li><li>Gharraei, R., Esmaeilzadeh, E., Hemayatkhah, M., Danaeefar, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+investigation+of+electrohydrodynamic+conduction+pumping+of+various+liquids+film+using+flush+electrodes.">Experimental investigation of electrohydrodynamic conduction pumping of various liquids film using flush electrodes.</a> J Electrostat. 69 (1), 43-53 (2011).</li><li>Gharraei, R., Esmaeilzadeh, E., Nobari, M. R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Numerical+investigation+of+conduction+pumping+of+dielectric+liquid+film+using+flush-mounted+electrodes.">Numerical investigation of conduction pumping of dielectric liquid film using flush-mounted electrodes.</a> Theor Comp Fluid Dyn. 28 (1), 89 (2014).</li><li>Jeong, S. -. I., Seyed-Yagoobi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+study+of+electrohydrodynamic+pumping+through+conduction+phenomenon.">Experimental study of electrohydrodynamic pumping through conduction phenomenon.</a> J Electrostat. 56 (2), 123-133 (2002).</li><li>Seyed-Yagoobi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrohydrodynamic+pumping+of+dielectric+liquids.">Electrohydrodynamic pumping of dielectric liquids.</a> J Electrostat. 63 (6), 861-869 (2005).</li><li>Hojjati, M., Esmaeilzadeh, E., Sadri, B., Gharraei, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrohydrodynamic+conduction+pumps+with+cylindrical+electrodes+for+pumping+of+dielectric+liquid+film+in+an+open+channel.">Electrohydrodynamic conduction pumps with cylindrical electrodes for pumping of dielectric liquid film in an open channel.</a> Colloid Surface A. 392 (1), 294-299 (2011).</li><li>Yazdani, M., Seyed-Yagoobi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Numerical+investigation+of+electrohydrodynamic-conduction+pumping+of+liquid+film+in+the+presence+of+evaporation.">Numerical investigation of electrohydrodynamic-conduction pumping of liquid film in the presence of evaporation.</a> J Heat Trans-T ASME. 131 (1), 011602 (2009).</li><li>Vafaie, R. H., Ghavifekr, H. B., Lintel, H., Brugger, J., Renaud, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bi-directional+AC+electrothermal+micropump+for+on-chip+biological+applications.">Bi-directional AC electrothermal micropump for on-chip biological applications.</a> Electrophoresis. 37 (5-6), 719-726 (2016).</li><li>Pearson, M. R., Seyed-Yagoobi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+Study+of+Linear+and+Radial+Two-Phase+Heat+Transport+Devices+Driven+by+Electrohydrodynamic+Conduction+Pumping.">Experimental Study of Linear and Radial Two-Phase Heat Transport Devices Driven by Electrohydrodynamic Conduction Pumping.</a> J Heat Trans-T ASME. 137 (2), 022901 (2015).</li></ol>

作者没有什么可透露的。

该协议中的关键步骤之一是仔细检查电极板。电极边缘的小毛刺会导致短路, 而表面的完整性会大大影响泵的性能。电极板和支架的清洗也是非常重要的。电极室高度小于1毫米, 所以细小的尘埃颗粒会堵塞工作液流, 造成短路。在试验前, 将丙酮注入腔室可以除去腔室外的气泡。
微泵的性能会受到腔室高度的严重影响。为了消除这种影响, 弹性腔板可以用较硬的材料代替。
<...

泵可以在比大多数水泵更小的范围内驱动液体流动。近年来, 各种驱动方案已成功应用于微流控系统1,2,3,4,5。体 (EHD) 泵可以直接施加在液体上的力, 没有任何运动部件, 这使得制造6变得更加简单和容易。根据充电类型, EHD 泵可分为喷射泵、感应泵或导电泵。感应泵不工作的等温液体, 而喷射泵改变液体电导率。由于缺乏这样的问题, 传导泵更稳定, 并有更广泛的应用。
传导泵是基于液体分子的离解和复合速率的不匹配。通常, 离解和重组过程可以表示如下7,8: 
<img alt="Equation" src="/files/ftp_upload/55867/55867eq1.jpg"> 如果重组速率为kr为常量, 而离解率kd是电场强度的函数。当电场强度达到一定值时, 离解率将超过重组速率。然后, 越来越多的免费的电荷旅行到两个相反极性的电极, 和 heterocharge 层形式。这些 heterocharge 层是泵的关键, 因为电荷的运动推动了液体分子的前进。因此, 净体力可以产生于腔内的液体中使用不对称电极或正负离子的流动性不匹配9,10,11,12.
介绍了一种用于导电泵的对称平面电极板的制作方法。在 FR-4 覆铜板上制备了电极板, 通过微细加工制备了泵腔。制造过程比其他生产方法, 例如纳米, 相对地简单和更加方便。建立了测试平台, 研究了不同条件下导电微泵的性能。此外, 还研究了在不同情况下导电微泵的可靠性。

<table><tbody><tr><td>Amperemeter</td><td>-</td><td>85C1-MA</td><td></td></tr><tr><td>DC high voltage power supply</td><td>NanTong Jianuo electric device company</td><td>GY-WY500-1</td><td></td></tr><tr><td>Fuse</td><td>-</td><td>-</td><td></td></tr><tr><td>Ultrasonic cleaner</td><td>Derui ultrasonic device company</td><td>-</td><td></td></tr><tr><td>Soldering iron</td><td>-</td><td>-</td><td></td></tr></tbody></table>

a performance-testing platform for a conduction micropump with an fr-4 copper-clad electrode plate

在 flame-retardant 玻璃增强环氧树脂 (FR-4) 覆铜板 (CCL) 上制备了对称平面电极对的导电微泵。研究了在使用丙酮作工作液时, 燃烧室尺寸对导电微泵性能的影响, 并确定了导电泵的可靠性。建立了测试平台, 对不同条件下的导电微泵性能进行了评价。当燃烧室高度为0.2 毫米时, 泵压达到峰值。

如图 11所示, 当电压增加时, 泵的压力和增加的速率会上升。当电压达到500伏时, 泵压力达到 1100 Pa。
当燃烧室高度低于0.2 毫米时, 泵的静压随泵腔高度的增大而升高。当燃烧室高度为0.2 毫米时, 泵的性能达到最高点。然后, 静压下降时, 室的高度继续增加。它被相信0.2 毫米是最佳的价值为房间高度。结果?...

Watch this Scientific Journal Video about A Performance-testing Platform for a Conduction Micropump with an FR-4 Copper-clad Electrode Plate at JoVE.com

A Performance-testing Platform for a Conduction Micropump with an FR-4 Copper-clad Electrode Plate

本文提出了用对称平面电极在 flame-retardant 玻璃增强环氧树脂 (FR-4) 覆铜板 (CCL) 上制备导电微泵的协议, 以测试燃烧室尺寸对其性能的影响。导电微泵。

FR-4 铜包电极板导电微泵性能测试平台

Here, a conduction micropump with symmetric planar electrode pairs prepared on flame-retardant glass-reinforced epoxy (FR-4) copper-clad laminate (CCL) is ...

a-performance-testing-platform-for-conduction-micropump-with-an-fr-4

Research

JoVE Journal

Bioengineering

5.9K 次观看.  South China University of Technology. 本文提出了用对称平面电极在 flame-retardant 玻璃增强环氧树脂 (FR-4) 覆铜板 (CCL) 上制备导电微泵的协议, 以测试燃烧室尺寸对其性能的影响。导电微泵。

视频: A Performance-testing Platform for a Conduction Micropump with an FR-4 Copper-clad Electrode Plate

Real-Time DC-dynamic Biasing Method for Switching Time Improvement in Severely Underdamped Fringing-field Electrostatic MEMS Actuators

Mechanically underdamped electrostatic fringing-field MEMS actuators are well known for their fast switching operation in response to a unit step input bias voltage. However, the tradeoff for the improved switching performance is a relatively long settling time to reach each gap height in response to various applied voltages. Transient applied bias waveforms are employed to facilitate reduced switching times for electrostatic fringing-field MEMS actuators with high mechanical quality factors. Removing the underlying substrate of the fringing-field actuator creates the low mechanical damping environment necessary to effectively test the concept. The removal of the underlying substrate also a has substantial improvement on the reliability performance of the device in regards to failure due to stiction. Although DC-dynamic biasing is useful in improving settling time, the required slew rates for typical MEMS devices may place aggressive requirements on the charge pumps for fully-integrated on-chip designs. Additionally, there may be challenges integrating the substrate removal step into the back-end-of-line commercial CMOS processing steps. Experimental validation of fabricated actuators demonstrates an improvement of 50x in switching time when compared to conventional step biasing results. Compared to theoretical calculations, the experimental results are in good agreement.

The robust device design of fringing-field electrostatic MEMS actuators results in inherently low squeeze-film damping conditions and long settling times when performing switching operations using conventional step biasing. Real-time switching time improvement with DC-dynamic waveforms reduces the settling time of fringing-field MEMS actuators when transitioning between up-to-down and down-to-up states.

实时直流偏置的动态法切换时间改善严重欠阻尼边缘化场静电MEMS致动器

Mechanically underdamped electrostatic fringing-field MEMS actuators are well known for their fast switching operation in response to a unit step input ...

科研

工程学

Hollow Microneedle-based Sensor for Multiplexed Transdermal Electrochemical Sensing

The development of a minimally invasive multiplexed monitoring system for rapid analysis of biologically-relevant molecules could offer individuals suffering from chronic medical conditions facile assessment of their immediate physiological state. Furthermore, it could serve as a research tool for analysis of complex, multifactorial medical conditions. In order for such a multianalyte sensor to be realized, it must be minimally invasive, sampling of interstitial fluid must occur without pain or harm to the user, and analysis must be rapid as well as selective.
Initially developed for pain-free drug delivery, microneedles have been used to deliver vaccines and pharmacologic agents (e.g., insulin) through the skin.1-2 Since these devices access the interstitial space, microneedles that are integrated with microelectrodes can be used as transdermal electrochemical sensors. Selective detection of glucose, glutamate, lactate, hydrogen peroxide, and ascorbic acid has been demonstrated using integrated microneedle-electrode devices with carbon fibers, modified carbon pastes, and platinum-coated polymer microneedles serving as transducing elements.3-7,8
This microneedle sensor technology has enabled a novel and sophisticated analytical approach for in situ and simultaneous detection of multiple analytes. Multiplexing offers the possibility of monitoring complex microenvironments, which are otherwise difficult to characterize in a rapid and minimally invasive manner. For example, this technology could be utilized for simultaneous monitoring of extracellular levels of, glucose, lactate and pH,9 which are important metabolic indicators of disease states7,10-14 (e.g., cancer proliferation) and exercise-induced acidosis.15

This article details the construction of a multiplexed microneedle-based sensor. The device is being developed for in situ sampling and electrochemical analysis of multiple analytes in a rapid and selective manner. We envision clinical medicine and biomedical research uses for these microneedle-based sensors.

复透皮电化学传感的空心微针为基础的传感器

The development of a minimally invasive multiplexed monitoring system for rapid analysis of biologically-relevant molecules could offer individuals ...

生物工程

High Throughput Microfluidic Rapid and Low Cost Prototyping Packaging Methods

In this work, 3 different packaging and assembly techniques are presented. They can be classified into two categories: one-time use and reusable packaging techniques.
The one-time use packaging technique employs UV-based and temperature curing epoxies to connect microtubes to access holes, wire-bonding for integrated circuit connections, and silver epoxy for electrical connections. This method is based on a robust assembly technique that can support relatively high pressure close to 1 psi and does not need any support to strengthen the microfluidic architecture.
Reusable packaging techniques consist of PDMS-based microtube interconnectors and anisotropic adhesive films for electrical connections. These devices are more sensitive and fragile. Consequently, Plexiglas support is added to the microfluidic structure to improve the electrical contact when anisotropic adhesive films are used, and also to strengthen the microfluidic architecture. In addition, a micromanipulator is needed to maintain tubes while using a thin PDMS layer to connect them to the access holes. Different PDMS layer thicknesses, ranging from 0.45-3 mm, are tested to compare the best adherence versus injection rates. Applied injection rates are varied from 50-300 &#956;l/hr for 0.45-3 mm PDMS layers, respectively. These techniques are mainly applicable for low-pressure applications. However, they can be extended for high-pressure ones through plasma-oxygen process to permanently seal the PDMS to glass substrates. The main advantage of this technique, besides the fact that it is reusable, consists of keeping the device observable when the microchannel length is very short (in the range of 3 mm or lower).

In this article we describe different techniques for microfluidic rapid prototyping platforms. The proposed techniques are based on ultraviolet (UV) sensitive and temperature curing epoxies, polydimethylsiloxane (PDMS) based tubing, wire-bonding, and anisotropic adhesive films. The assembling procedures presented are developed for both one-time use devices as well as reusable microfluidic systems.

In this work, 3 different packaging and assembly techniques are presented. They can be classified into two categories: one-time use and reusable packaging ...

A Microfluidic Platform for Precision Small-volume Sample Processing and Its Use to Size Separate Biological Particles with an Acoustic Microdevice

A major advantage of microfluidic devices is the ability to manipulate small sample volumes, thus reducing reagent waste and preserving precious sample. However, to achieve robust sample manipulation it is necessary to address device integration with the macroscale environment. To realize repeatable, sensitive particle separation with microfluidic devices, this protocol presents a complete automated and integrated microfluidic platform that enables precise processing of 0.15&#8211;1.5 ml samples using microfluidic devices. Important aspects of this system include modular device layout and robust fixtures resulting in reliable and flexible world to chip connections, and fully-automated fluid handling which accomplishes closed-loop sample collection, system cleaning and priming steps to ensure repeatable operation. Different microfluidic devices can be used interchangeably with this architecture. Here we incorporate an acoustofluidic device, detail its characterization, performance optimization, and demonstrate its use for size-separation of biological samples. By using real-time feedback during separation experiments, sample collection is optimized to conserve and concentrate sample. Although requiring the integration of multiple pieces of equipment, advantages of this architecture include the ability to process unknown samples with no additional system optimization, ease of device replacement, and precise, robust sample processing.

This protocol describes a system architecture for performing automated small volume (0.15&#8211;1.5 ml) particle separations using a microfluidic device, and discusses methods to optimize acoustofluidic device performance and operation.

微流体平台精密小批量来样加工及它的使用尺寸分离生物颗粒的声微型

A major advantage of microfluidic devices is the ability to manipulate small sample volumes, thus reducing reagent waste and preserving precious sample. ...

Fabrication and Characterization of Thickness Mode Piezoelectric Devices for Atomization and Acoustofluidics

We present a technique to fabricate simple thickness mode piezoelectric devices using lithium niobate (LN). Such devices have been shown to atomize liquid more efficiently, in terms of &#64258;ow rate per power input, than those that rely on Rayleigh waves and other modes of vibration in LN or lead zirconate titanate (PZT). The complete device is composed of a transducer, a transducer holder, and a &#64258;uid supply system. The fundamentals of acoustic liquid atomization are not well known, so techniques to characterize the devices and to study the phenomena are also described. Laser Doppler vibrometry (LDV) provides vibration information essential in comparing acoustic transducers and, in this case, indicates whether a device will perform well in thickness vibration. It can also be used to &#64257;nd the resonance frequency of the device, though this information is obtained more quickly via impedance analysis. Continuous &#64258;uid atomization, as an example application, requires careful &#64258;uid flow control, and we present such a method with high-speed imaging and droplet size distribution measurements via laser scattering.

Fabrication of piezoelectric thickness mode transducers via direct current sputtering of plate electrodes on lithium niobate is described. Additionally, reliable operation is achieved with a transducer holder and &#64258;uid supply system and characterization is demonstrated via impedance analysis, laser doppler vibrometry, high-speed imaging, and droplet size distribution using laser scattering.

用于原子化和抗波流体的厚度模式压电器件的制造和特性

We present a technique to fabricate simple thickness mode piezoelectric devices using lithium niobate (LN). Such devices have been shown to atomize liquid ...

Dry Film Photoresist-based Electrochemical Microfluidic Biosensor Platform: Device Fabrication, On-chip Assay Preparation, and System Operation

In recent years, biomarker diagnostics became an indispensable tool for the diagnosis of human disease, especially for the point-of-care diagnostics. An easy-to-use and low-cost sensor platform is highly desired to measure various types of analytes (e.g., biomarkers, hormones, and drugs) quantitatively and specifically. For this reason, dry film photoresist technology - enabling cheap, facile, and high-throughput fabrication - was used to manufacture the microfluidic biosensor presented here. Depending on the bioassay used afterwards, the versatile platform is capable of detecting various types of biomolecules. For the fabrication of the device, platinum electrodes are structured on a flexible polyimide (PI) foil in the only clean-room process step. The PI foil serves as a substrate for the electrodes, which are insulated with an epoxy-based photoresist. The microfluidic channel is subsequently generated by the development and lamination of dry film photoresist (DFR) foils onto the PI wafer. By using a hydrophobic stopping barrier in the channel, the channel is separated into two specific areas: an immobilization section for the enzyme-linked assay and an electrochemical measurement cell for the amperometric signal readout.
The on-chip bioassay immobilization is performed by the adsorption of the biomolecules to the channel surface. The glucose oxidase enzyme is used as a transducer for electrochemical signal generation. In the presence of the substrate, glucose, hydrogen peroxide is produced, which is detected at the platinum working electrode. The stop-flow technique is applied to obtain signal amplification along with rapid detection. Different biomolecules can quantitatively be measured by means of the introduced microfluidic system, giving an indication of different types of diseases, or, in regard to therapeutic drug monitoring, facilitating a personalized therapy.

A microfluidic biosensor platform was designed and fabricated using low-cost dry film photoresist technology for the rapid and sensitive quantification of various analytes. This single-use system allows for the electrochemical readout of on-chip-immobilized enzyme-linked assays by means of the stop-flow technique.

干膜 Photoresist-based 电化学微流控生物传感器平台: 器件制备、片上检测制备及系统运行

In recent years, biomarker diagnostics became an indispensable tool for the diagnosis of human disease, especially for the point-of-care diagnostics. An ...

Fabrication and Validation of an Organ-on-chip System with Integrated Electrodes to Directly Quantify Transendothelial Electrical Resistance

Organs-on-chips, in vitro models involving the culture of (human) tissues inside microfluidic devices, are rapidly emerging and promise to provide useful research tools for studying human health and disease. To characterize the barrier function of cell layers cultured inside organ-on-chip devices, often transendothelial or transepithelial electrical resistance (TEER) is measured. To this end, electrodes are usually integrated into the chip by micromachining methods to provide more stable measurements than is achieved with manual insertion of electrodes into the inlets of the chip. However, these electrodes frequently hamper visual inspection of the studied cell layer or require expensive cleanroom processes for fabrication. To overcome these limitations, the device described here contains four easily integrated electrodes that are placed and fixed outside of the culture area, making visual inspection possible. Using these four electrodes the resistance of six measurement paths can be quantified, from which the TEER can be directly isolated, independent of the resistance of culture medium-filled microchannels. The blood-brain barrier was replicated in this device and its TEER was monitored to show the device applicability. This chip, the integrated electrodes and the TEER determination method are generally applicable in organs-on-chips, both to mimic other organs or to be incorporated into existing organ-on-chip systems.

This publication describes the fabrication of an organ-on-chip device with integrated electrodes for direct quantification of transendothelial electrical resistance (TEER). For validation, the blood-brain barrier was mimicked inside this microfluidic device and its barrier function was monitored. The presented methods for electrode integration and direct TEER quantification are generally applicable.

用集成电极直接量化 Transendothelial 电阻的 Organ-on-chip 系统的制作与验证

Organs-on-chips, in vitro models involving the culture of (human) tissues inside microfluidic devices, are rapidly emerging and promise to provide useful ...

Mechano-Node-Pore Sensing: A Rapid, Label-Free Platform for Multi-Parameter Single-Cell Viscoelastic Measurements

Cellular mechanical properties are involved in a wide variety of biological processes and diseases, ranging from stem cell differentiation to cancer metastasis. Conventional methods for measuring these properties, such as atomic force microscopy (AFM) and micropipette aspiration (MA), capture rich information, reflecting a cell's full viscoelastic response; however, these methods are limited by very low throughput. High-throughput approaches, such as real-time deformability cytometry (RT-DC), can only measure limited mechanical information, as they are often restricted to single-parameter readouts that only reflect a cell's elastic properties. In contrast to these methods, mechano-node-pore sensing (mechano-NPS) is a flexible, label-free microfluidic platform that bridges the gap in achieving multi-parameter viscoelastic measurements of a cell with moderate throughput. A direct current (DC) measurement is used to monitor cells as they transit a microfluidic channel, tracking their size and velocity before, during, and after they are forced through a narrow constriction. This information (i.e., size and velocity) is used to quantify each cell's transverse deformation, resistance to deformation, and recovery from deformation. In general, this electronics-based microfluidic platform provides multiple viscoelastic cell properties, and thus a more complete picture of a cell's mechanical state. Because it requires minimal sample preparation, utilizes a straightforward electronic measurement (in contrast to a high-speed camera), and takes advantage of standard soft lithography fabrication, the implementation of this platform is simple, accessible, and adaptable to downstream analysis. This platform's flexibility, utility, and sensitivity have provided unique mechanical information on a diverse range of cells, with the potential for many more applications in basic science and clinical diagnostics.

Presented here is a method to mechanically phenotype single cells using an electronics-based microfluidic platform called mechano-node-pore sensing (mechano-NPS). This platform maintains moderate throughput of 1-10 cells/s while measuring both the elastic and viscous biophysical properties of cells.

机械节点孔传感:用于多参数单细胞粘弹性测量的快速、无标记平台

Cellular mechanical properties are involved in a wide variety of biological processes and diseases, ranging from stem cell differentiation to cancer ...

通过调幅电变形对 RBC 进行机械疲劳测试

Amplitude-Modulated Electrodeformation to Evaluate Mechanical Fatigue of Biological Cells

Red blood cells (RBCs) are known for their remarkable deformability. They repeatedly undergo considerable deformation when passing through the microcirculation. Reduced deformability is seen in physiologically aged RBCs. Existing techniques to measure cell deformability cannot easily be used for measuring fatigue, the gradual degradation in cell membranes caused by cyclic loads. We present a protocol to evaluate mechanical degradation in RBCs from cyclic shear stresses using amplitude shift keying (ASK) modulation-based electrodeformation in a microfluidic channel. Briefly, the interdigitated electrodes in the microfluidic channel are excited with a low voltage alternating current at radio frequencies using a signal generator. RBCs in suspension respond to the electric field and exhibit positive dielectrophoresis (DEP), which moves cells to the electrode edges. Cells are then stretched due to the electrical forces exerted on the two cell halves, resulting in uniaxial stretching, known as electrodeformation. The level of shear stress and the resultant deformation can be easily adjusted by changing the amplitude of the excitation wave. This enables quantifications of nonlinear deformability of RBCs in response to small and large deformations at high throughput. Modifying the excitation wave with the ASK strategy induces cyclic electrodeformation with programmable loading rates and frequencies. This provides a convenient way for the characterization of RBC fatigue. Our ASK-modulated electrodeformation approach enables, for the first time, a direct measurement of RBC fatigue from cyclic loads. It can be used as a tool for general biomechanical testing, for analyses of cell deformability and fatigue in other cell types and diseased conditions, and can also be combined with strategies to control the microenvironment of cells, such as oxygen tension and biological and chemical cues.

作者聚焦:通过调节循环细胞的电变形行为来研究循环细胞的生物力学 

Presented here is a protocol for mechanical fatigue testing in the case of human red blood cells using an amplitude-modulated electrodeformation approach. This general approach can be used to measure the systematic changes in morphological and biomechanical characteristics of biological cells in a suspension from cyclic deformation.