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 width="683">
	<tbody>
		<tr height="21">
			<td height="21" style="width:207px;height:21px;">Amperemeter</td>
			<td style="width:311px;">-</td>
			<td style="width:101px;">85C1-MA</td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:207px;height:21px;">DC high voltage power supply</td>
			<td style="width:311px;">NanTong Jianuo electric device company</td>
			<td style="width:101px;">GY-WY500-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:207px;height:21px;">Fuse</td>
			<td style="width:311px;">-</td>
			<td style="width:101px;">-</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:207px;height:21px;">Ultrasonic cleaner</td>
			<td style="width:311px;">Derui ultrasonic device company</td>
			<td style="width:101px;">-</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:207px;height:21px;">Soldering iron</td>
			<td style="width:311px;">-</td>
			<td style="width:101px;">-</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

Universidad de Cartagena UDEC

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

Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization

Implantable microdevices are gaining significant attention for several biomedical applications1-4. Such devices have been made from a range of materials, each offering its own advantages and shortcomings5,6. Most prominently, due to the microscale device dimensions, a high modulus is required to facilitate implantation into living tissue. Conversely, the stiffness of the device should match the surrounding tissue to minimize induced local strain7-9. Therefore, we recently developed a new class of bio-inspired materials to meet these requirements by responding to environmental stimuli with a change in mechanical properties10-14. Specifically, our poly(vinyl acetate)-based nanocomposite (PVAc-NC) displays a reduction in stiffness when exposed to water and elevated temperatures (e.g. body temperature). Unfortunately, few methods exist to quantify the stiffness of materials in vivo15, and mechanical testing outside of the physiological environment often requires large samples inappropriate for implantation. Further, stimuli-responsive materials may quickly recover their initial stiffness after explantation. Therefore, we have developed a method by which the mechanical properties of implanted microsamples can be measured ex vivo, with simulated physiological conditions maintained using moisture and temperature control13,16,17. 
To this end, a custom microtensile tester was designed to accommodate microscale samples13,17 with widely-varying Young's moduli (range of 10 MPa to 5 GPa). As our interests are in the application of PVAc-NC as a biologically-adaptable neural probe substrate, a tool capable of mechanical characterization of samples at the microscale was necessary. This tool was adapted to provide humidity and temperature control, which minimized sample drying and cooling17. As a result, the mechanical characteristics of the explanted sample closely reflect those of the sample just prior to explantation.
The overall goal of this method is to quantitatively assess the in vivo mechanical properties, specifically the Young's modulus, of stimuli-responsive, mechanically-adaptive polymer-based materials. This is accomplished by first establishing the environmental conditions that will minimize a change in sample mechanical properties after explantation without contributing to a reduction in stiffness independent of that resulting from implantation. Samples are then prepared for implantation, handling, and testing (Figure 1A). Each sample is implanted into the cerebral cortex of rats, which is represented here as an explanted rat brain, for a specified duration (Figure 1B). At this point, the sample is explanted and immediately loaded into the microtensile tester, and then subjected to tensile testing (Figure 1C). Subsequent data analysis provides insight into the mechanical behavior of these innovative materials in the environment of the cerebral cortex.

Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization

A method is discussed by which the in vivo mechanical behavior of stimuli-responsive materials is monitored as a function of time. Samples are tested ex vivo using a microtensile tester with environmental controls to simulate the physiological environment. This work further promotes understanding the in vivo behavior of our material.

环境控制机械自适应聚合物纳米复合材料的微拉伸测试<em&gt;体外</em&gt;表征

Implantable microdevices are gaining significant attention for several biomedical applications1-4. Such devices have been made from a range of materials, ...

科研

生物工程

A Versatile Automated Platform for Micro-scale Cell Stimulation Experiments

Study of cells in culture (in vitro analysis) has provided important insight into complex biological systems. Conventional methods and equipment for in vitro analysis are well suited to study of large numbers of cells (&ge;105) in milliliter-scale volumes (&ge;0.1 ml). However, there are many instances in which it is necessary or desirable to scale down culture size to reduce consumption of the cells of interest and/or reagents required for their culture, stimulation, or processing. Unfortunately, conventional approaches do not support precise and reproducible manipulation of micro-scale cultures, and the microfluidics-based automated systems currently available are too complex and specialized for routine use by most laboratories. To address this problem, we have developed a simple and versatile technology platform for automated culture, stimulation, and recovery of small populations of cells (100 - 2,000 cells) in micro-scale volumes (1 - 20 &mu;l). The platform consists of a set of fibronectin-coated microcapillaries ("cell perfusion chambers"), within which micro-scale cultures are established, maintained, and stimulated; a digital microfluidics (DMF) device outfitted with "transfer" microcapillaries ("central hub"), which routes cells and reagents to and from the perfusion chambers; a high-precision syringe pump, which powers transport of materials between the perfusion chambers and the central hub; and an electronic interface that provides control over transport of materials, which is coordinated and automated via pre-determined scripts. As an example, we used the platform to facilitate study of transcriptional responses elicited in immune cells upon challenge with bacteria. Use of the platform enabled us to reduce consumption of cells and reagents, minimize experiment-to-experiment variability, and re-direct hands-on labor. Given the advantages that it confers, as well as its accessibility and versatility, our platform should find use in a wide variety of laboratories and applications, and prove especially useful in facilitating analysis of cells and stimuli that are available in only limited quantities.

We have developed an automated cell culture and interrogation platform for micro-scale cell stimulation experiments. The platform offers simple, versatile, and precise control in cultivating and stimulating small populations of cells, and recovering lysates for molecular analyses. The platform is well suited to studies that use precious cells and/or reagents.

一种多功能自动化平台微尺度细胞刺激实验

Study of cells in culture (in vitro analysis) has provided important insight into complex biological systems. Conventional methods and equipment for in ...

Investigating Receptor-ligand Systems of the Cellulosome with AFM-based Single-molecule Force Spectroscopy

Cellulosomes are discrete multienzyme complexes used by a subset of anaerobic bacteria and fungi to digest lignocellulosic substrates. Assembly of the enzymes onto the noncatalytic scaffold protein is directed by interactions among a family of related receptor-ligand pairs comprising interacting cohesin and dockerin modules. The extremely strong binding between cohesin and dockerin modules results in dissociation constants in the low picomolar to nanomolar range, which may hamper accurate off-rate measurements with conventional bulk methods. Single-molecule force spectroscopy (SMFS) with the atomic force microscope measures the response of individual biomolecules to force, and in contrast to other single-molecule manipulation methods (i.e.&#160;optical tweezers), is optimal for studying high-affinity receptor-ligand interactions because of its ability to probe the high-force regime (&#62;120 pN). Here we present our complete protocol for studying cellulosomal protein assemblies at the single-molecule level. Using a protein topology derived from the native cellulosome, we worked with enzyme-dockerin and carbohydrate binding module-cohesin (CBM-cohesin) fusion proteins, each with an accessible free thiol group at an engineered cysteine residue. We present our site-specific surface immobilization protocol, along with our measurement and data analysis procedure for obtaining detailed binding parameters for the high-affinity complex. We demonstrate how to quantify single subdomain unfolding forces, complex rupture forces, kinetic off-rates, and potential widths of the binding well. The successful application of these methods in characterizing the cohesin-dockerin interaction responsible for assembly of multidomain cellulolytic complexes is further described.

Cellulosomes are multienzyme complexes designed for digesting cellulose. AFM-based SMFS was used to study the mechanical properties and folding configuration of cellulosome-associated protein assemblies. We present a complete workflow for protein immobilization, data acquisition, and data analysis to study the interactions of individual receptor-ligand complexes involved in cellulosome assembly.

调查纤维素酶与基于AFM的单分子力谱受体 - 配体系统

Cellulosomes are discrete multienzyme complexes used by a subset of anaerobic bacteria and fungi to digest lignocellulosic substrates. Assembly of the ...

Cell Squeezing as a Robust, Microfluidic Intracellular Delivery Platform

Rapid mechanical deformation of cells has emerged as a promising, vector-free method for intracellular delivery of macromolecules and nanomaterials. This technology has shown potential in addressing previously challenging applications; including, delivery to primary immune cells, cell reprogramming, carbon nanotube, and quantum dot delivery. This vector-free microfluidic platform relies on mechanical disruption of the cell membrane to facilitate cytosolic delivery of the target material. Herein, we describe the detailed method of use for these microfluidic devices including, device assembly, cell preparation, and system operation. This delivery approach requires a brief optimization of device type and operating conditions for previously unreported applications. The provided instructions are generalizable to most cell types and delivery materials as this system does not require specialized buffers or chemical modification/conjugation steps. This work also provides recommendations on how to improve device performance and trouble-shoot potential issues related to clogging, low delivery efficiencies, and cell viability.

Rapid mechanical deformation of cells has emerged as a promising, vector-free method for intracellular delivery of macromolecules and nanomaterials. This protocol provides detailed steps on how to use the system for a broad range of applications.

电池挤压作为一种强大的，微流控细胞内传送平台

Rapid mechanical deformation of cells has emerged as a promising, vector-free method for intracellular delivery of macromolecules and nanomaterials. This ...

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. ...

Three-Dimensionally Printed Microfluidic Cross-flow System for Ultrafiltration/Nanofiltration Membrane Performance Testing

Minimization and management of membrane fouling is a formidable challenge in diverse industrial processes and other practices that utilize membrane technology. Understanding the fouling process could lead to optimization and higher efficiency of membrane based filtration. Here we show the design and fabrication of an automated three-dimensionally (3-D) printed microfluidic cross-flow filtration system that can test up to 4 membranes in parallel. The microfluidic cells were printed using multi-material photopolymer 3-D printing technology, which used a transparent hard polymer for the microfluidic cell body and incorporated a thin rubber-like polymer layer, which prevents leakages during operation. The performance of ultrafiltration (UF), and nanofiltration (NF) membranes were tested and membrane fouling could be observed with a model foulant bovine serum albumin (BSA). Feed solutions containing BSA showed flux decline of the membrane. This protocol may be extended to measure fouling or biofouling with many other organic, inorganic or microbial containing solutions. The microfluidic design is especially advantageous for testing materials that are costly or only available in small quantities, for example polysaccharides, proteins, or lipids due to the small surface area of the membrane being tested. This modular system may also be easily expanded for high throughput testing of membranes.&#160;

Design and fabrication of a three-dimensionally (3-D) printed microfluidic cross-flow filtration system is demonstrated. The system is used to test performance and observe fouling of ultrafiltration and nanofiltration (thin film composite) membranes.

超滤/纳滤膜性能测试三维印刷微流控横流系统

Minimization and management of membrane fouling is a formidable challenge in diverse industrial processes and other practices that utilize membrane ...

Microfluidic Platform with Multiplexed Electronic Detection for Spatial Tracking of Particles

Microfluidic processing of biological samples typically involves differential manipulations of suspended particles under various force fields in order to spatially fractionate the sample based on a biological property of interest. For the resultant spatial distribution to be used as the assay readout, microfluidic devices are often subjected to microscopic analysis requiring complex instrumentation with higher cost and reduced portability. To address this limitation, we have developed an integrated electronic sensing technology for multiplexed detection of particles at different locations on a microfluidic chip. Our technology, called Microfluidic CODES, combines Resistive Pulse Sensing with Code Division Multiple Access to compress 2D spatial information into a 1D electrical signal. In this paper, we present a practical demonstration of the Microfluidic CODES technology to detect and size cultured cancer cells distributed over multiple microfluidic channels. As validated by the high-speed microscopy, our technology can accurately analyze dense cell populations all electronically without the need for an external instrument. As such, the Microfluidic CODES can potentially enable low-cost integrated lab-on-a-chip devices that are well suited for the point-of-care testing of biological samples.

We demonstrate a microfluidic platform with an integrated surface electrode network that combines resistive pulse sensing (RPS) with code division multiple access (CDMA), to multiplex detection and sizing of particles in multiple microfluidic channels.

与复用电子检测的粒子的空间跟踪微流体平台

Microfluidic processing of biological samples typically involves differential manipulations of suspended particles under various force fields in order to ...

An Ultrasonic Tool for Nerve Conduction Block in Diabetic Rat Models

Nerve conduction block with a high intensity-focused ultrasound (HIFU) transducer has been performed in normal and diabetic animal models recently. HIFU can reversibly block the conduction of peripheral nerves without damaging the nerves while using an appropriate ultrasonic parameter. Temporary and partial block of the action potentials of nerves shows that HIFU has the potential to be a useful clinical treatment for pain relief. This work demonstrates the procedures for suppressing the action potentials of neuropathic nerves in diabetic rats in vivo using an HIFU transducer. The first step is to generate adult male diabetic neuropathic rats by streptozotocin (STZ) injection. The second step is to evaluate the peripheral diabetic neuropathy in STZ-induced diabetic rats by an electronic von Frey probe and a hot plate. The final step is to record in vivo extracellular action potentials of the nerve exposed to HIFU sonication. The method showed here may benefit the study of ultrasound analgesic applications.

This work presents the methodology of applying high intensity-focused ultrasound to block the action potentials of diabetic neuropathic nerves.

糖尿病大鼠模型神经传导阻滞的超声工具

Nerve conduction block with a high intensity-focused ultrasound (HIFU) transducer has been performed in normal and diabetic animal models recently. HIFU ...

A Microfluidic Platform for Longitudinal Imaging in Caenorhabditis elegans

In the last decade, microfluidic techniques have been applied to study small animals, including the nematode Caenorhabditis elegans, and have proved useful as a convenient live imaging platform providing capabilities for precise control of experimental conditions in real time. In this article, we demonstrate live imaging of individual worms employing WormSpa, a previously-published custom microfluidic device. In the device, multiple worms are individually confined to separate chambers, allowing multiplexed longitudinal surveillance of various biological processes. To illustrate the capability, we performed proof-of-principle experiments in which worms were infected in the device with pathogenic bacteria, and the dynamics of expression of immune response genes and egg laying were monitored continuously in individual animals. The simple design and operation of this device make it suitable for users with no previous experience with microfluidic-based experiments. We propose that this approach will be useful for many researchers interested in longitudinal observations of biological processes under well-defined conditions.

A Microfluidic Platform for Longitudinal Imaging in Caenorhabditis elegans

In this article, we demonstrate live imaging of individual worms employing a custom microfluidic device. In the device, multiple worms are individually confined to separate chambers, allowing multiplexed longitudinal surveillance of various biological processes.

秀丽线虫纵向成像的微流控平台

In the last decade, microfluidic techniques have been applied to study small animals, including the nematode Caenorhabditis elegans, and have proved ...

An Ultrahigh-throughput Microfluidic Platform for Single-cell Genome Sequencing

Sequencing technologies have undergone a paradigm shift from bulk to single-cell resolution in response to an evolving understanding of the role of cellular heterogeneity in biological systems. However, single-cell sequencing of large populations has been hampered by limitations in processing genomes for sequencing. In this paper, we describe a method for single-cell genome sequencing (SiC-seq) which uses droplet microfluidics to isolate, amplify, and barcode the genomes of single cells. Cell encapsulation in microgels allows the compartmentalized purification and tagmentation of DNA, while a microfluidic merger efficiently pairs each genome with a unique single-cell oligonucleotide barcode, allowing &gt;50,000 single cells to be sequenced per run. The sequencing data is demultiplexed by barcode, generating groups of reads originating from single cells. As a high-throughput and low-bias method of single-cell sequencing, SiC-seq will enable a broader range of genomic studies targeted at diverse cell populations.

Single-cell sequencing reveals genotypic heterogeneity in biological systems, but current technologies lack the throughput necessary for the deep profiling of community composition and function. Here, we describe a microfluidic workflow for sequencing &gt;50,000 single-cell genomes from diverse cell populations.

单细胞基因组测序的超高通量微流控平台

Sequencing technologies have undergone a paradigm shift from bulk to single-cell resolution in response to an evolving understanding of the role of ...