Name: generating controlled, dynamic chemical landscapes to study microbial behavior
Uploaded: 2020-01-31T14:30:00
Description: Watch this Scientific Journal Video about Generating Controlled, Dynamic Chemical Landscapes to Study Microbial Behavior at JoVE.com

作者感谢苏黎世ETH的FIRST微制造设施。这项工作得到了澳大利亚研究理事会发现早期职业研究员奖DE180100911（D.R.B.），戈登和贝蒂摩尔海洋微生物倡议调查员奖GBMF3783（R.S.）和瑞士国家科学基金会赠款的支持。1-002745-000（至 R.S.）。

1. 单化学脉冲实验微流体装置的制造
<ol><li>使用计算机辅助设计 （CAD） 软件设计通道并将其打印到透明胶片上以创建照片蒙版（图 1A）。</li>
	<li>通过软光刻（在洁净室条件下）制作主人。<ol>
<li>用丙酮、甲醇和异丙醇快速连续清洁硅片（4英寸），然后用氮气干燥。在 130°C 的烤箱中烘烤晶圆 5 分钟。</li>
		<li>将晶圆放在纺布机的中心，并将 SU-8 光刻胶倒在?...

<ol>
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R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemotactic+signal+integration+in+bacteria.">Chemotactic signal integration in bacteria.</a> Proceedings of the National Academy of Sciences of the United States of America. 92 (21), 9757-9761 (1995).</li><li>Sagawa, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-Cell+E.+coli+Response+to+an+Instantaneously+Applied+Chemotactic+Signal.">Single-Cell E. coli Response to an Instantaneously Applied Chemotactic Signal.</a> Biophysical Journal. 107 (3), 730-739 (2014).</li><li>Xie, L., Lu, C., Wu, X. 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R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacteria+push+the+limits+of+chemotactic+precision+to+navigate+dynamic+chemical+gradients.">Bacteria push the limits of chemotactic precision to navigate dynamic chemical gradients.</a> Proceedings of the National Academy of Sciences of the United States of America. 116 (22), 10792-10797 (2019).</li><li>Aran, K., Sasso, L. A., Kamdar, N., Zahn, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Irreversible,+direct+bonding+of+nanoporous+polymer+membranes+to+PDMS+or+glass+microdevices.">Irreversible, direct bonding of nanoporous polymer membranes to PDMS or glass microdevices.</a> Lab on a Chip. 10 (5), 548 (2010).</li><li>ZoBell, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+cultural+requirements+of+heterotrophic+aerobes.">The cultural requirements of heterotrophic aerobes.</a> Journal of Marine Research. 4, 42-75 (1941).</li><li>Canepari, M., Nelson, L., Papageorgiou, G., Corrie, J. E. T., Ogden, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photochemical+and+pharmacological+evaluation+of+7-nitroindolinyl-and+4-methoxy-7-nitroindolinyl-amino+acids+as+novel,+fast+caged+neurotransmitters.">Photochemical and pharmacological evaluation of 7-nitroindolinyl-and 4-methoxy-7-nitroindolinyl-amino acids as novel, fast caged neurotransmitters.</a> Journal of Neuroscience Methods. 112 (1), 29-42 (2001).</li><li>Trigo, F. F., Corrie, J. E. T., Ogden, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laser+photolysis+of+caged+compounds+at+405nm:+Photochemical+advantages,+localisation,+phototoxicity+and+methods+for+calibration.">Laser photolysis of caged compounds at 405nm: Photochemical advantages, localisation, phototoxicity and methods for calibration.</a> Journal of Neuroscience Methods. 180 (1), 9-21 (2009).</li><li>Ribeiro, A. C. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutual+diffusion+coefficients+of+L-glutamic+acid+and+monosodium+L-glutamate+in+aqueous+solutions+at+T=298.15K.">Mutual diffusion coefficients of L-glutamic acid and monosodium L-glutamate in aqueous solutions at T=298.15K.</a> The Journal of Chemical Thermodynamics. 74, 133-137 (2014).</li><li>Sharqawy, M. H., Lienhard, J. H., Zubair, S. 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Implications for remote detection by colonizing zooplankters.</a> Marine Ecology Progress Series. 211, 15-25 (2001).</li><li>Blackburn, N., Fenchel, T., Mitchell, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microscale+nutrient+patches+in+planktonic+habitats+shown+by+chemotactic+bacteria.">Microscale nutrient patches in planktonic habitats shown by chemotactic bacteria.</a> Science. 282 (5397), 2254-2256 (1998).</li><li>Stocker, R., Seymour, J. R., Samadani, A., Hunt, D. E., Polz, M. 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该方法使研究人员能够在微流体和微流体器件的受控动态梯度下研究细菌化学，从而实现可重现的数据采集。光溶在微尺度上几乎瞬间产生化学脉冲，目的是从各种来源再现细菌在野外遇到的营养脉冲类型，例如，下沉的海洋颗粒25背后的羽状物扩散，或从溶化浮游植物细胞26中传播的营养。
我们提出了这种方法的两个应用：1） 释放单个?...

微生物依靠化学，检测化学梯度和改变运动的过程，以响应1，导航化学景观，接近营养源和宿主，并逃脱有毒物质。这些微尺度过程决定了微生物与其环境相互作用的宏观动力学2，3。微流体和微加工技术（包括软光刻4）的最新进展彻底改变了我们创造受控微环境的能力，从而研究微生物的相互作用。例如，过去的实验通过产生高可控、稳定的中间至高营养浓度梯度5、6来研究细菌化学。然而，在自然环境中，微尺度化学梯度可能寿命短，通过分子扩散消散，背景条件通常高度稀薄7。为了直接测量首次暴露于不稳定化学环境中的微生物种群的化学反应，我们设计并介绍了将微流体技术与光解相结合的方法，从而模拟野生细菌在自然界中遇到的梯度。
解封技术采用光敏探头，以功能方式将生物分子封装为非活性形式。辐照释放笼状分子，允许生物过程的靶向扰动8。由于细胞化学的快速和精确控制，解开提供9，光解笼化合物传统上使用生物学家，生理学家和神经科学家研究基因10，电通道11和神经元12的激活。最近，科学家利用光分析的显著优势，研究了化学13，确定了暴露于步进化学刺激14、15的单个细菌细胞的旗杆切换动力学，并研究了单精子细胞在三维（3D）梯度16中的运动模式。
在我们的方法中，我们在微流体装置中实现笼体氨基酸的光解，以研究细菌群体对受控化学脉冲的行为反应，这些脉冲通过光释放几乎瞬间可用。使用低放大率（4x）物（NA = 0.13，聚焦深度约40μm）既可观察大视场（3.2 mm x 3.2 mm）上数千种细菌的种群级聚合反应，也可用于单细胞水平的运动测量。我们提出了这种方法的两个应用：1） 释放单个化学脉冲以研究从均匀条件开始的细菌积累 -耗散动力学;2i） 释放多个脉冲来描述在时变、空间异质化学吸引条件下的细菌积累动力学。该方法已在海洋细菌Vibrio ordalii上对氨基酸谷氨酸17进行化学试验，但该方法广泛适用于不同物种和化学吸引剂的组合，以及化学酶以外的生物过程（例如，营养摄入、抗生素暴露、仲裁检测）。这种方法有望帮助阐明真实环境中微生物的生态和行为，并揭示单个细菌在导航瞬时动态梯度时所面临的隐藏权衡。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>(3-Aminopropyl) triethoxysilane (APTES)</td>
			<td>Sigma-Aldrich</td>
			<td>A3648</td>
			<td>&#62;98% purity, highly toxic</td>
		</tr>
		<tr>
			<td>CELLSTAR tube</td>
			<td>Greiner Bio-One</td>
			<td>210261</td>
			<td>50 ml</td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Eppendorf</td>
			<td>5424R</td>
			<td>to eliminate spent media from the bacterial culture</td>
		</tr>
		<tr>
			<td>Digital Incubators Incu-Line</td>
			<td>VWR-CH</td>
			<td>390-0384</td>
			<td>to bake 3D master</td>
		</tr>
		<tr>
			<td>Duster</td>
			<td>VWR-CH</td>
			<td>16650-22</td>
			<td>to clean the wafer and microchannels</td>
		</tr>
		<tr>
			<td>Hot plate</td>
			<td>VWR-CH</td>
			<td>444-0601</td>
			<td>to bond the microchannels</td>
		</tr>
		<tr>
			<td>Isopropanol</td>
			<td>Sigma-Aldrich</td>
			<td>W292907</td>
			<td></td>
		</tr>
		<tr>
			<td>LightSafe micro centrifuge tubes</td>
			<td>Sigma-Aldrich</td>
			<td>Z688312</td>
			<td>1.5 ml</td>
		</tr>
		<tr>
			<td>MATLAB</td>
			<td>Mathworks</td>
			<td></td>
			<td>for image analysis and bacterial tracking</td>
		</tr>
		<tr>
			<td>Microcentrifuge tube</td>
			<td>Eppendorf</td>
			<td>30120086</td>
			<td>1.5 ml</td>
		</tr>
		<tr>
			<td>Microscope glass slide</td>
			<td>VWR-CH</td>
			<td>631-1552</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope Nikon Eclipse TiE</td>
			<td>Nikon Instruments</td>
			<td>MEA53100</td>
			<td>with motorized stage</td>
		</tr>
		<tr>
			<td>MNI-Glutamate</td>
			<td>Tocris Bioscience</td>
			<td>1490</td>
			<td>&#62;98 % purity, photosensitive</td>
		</tr>
		<tr>
			<td>Mold printing equipment</td>
			<td>Stratasys</td>
			<td></td>
			<td>Objet30 3D printer</td>
		</tr>
		<tr>
			<td>Mold printing service</td>
			<td>3D Printing Studios</td>
			<td>Custom</td>
			<td><a href="https://www.3dprintingstudios.com/" target="_blank">https://www.3dprintingstudios.com/</a></td>
		</tr>
		<tr>
			<td>Nanodrop One UV-Vis Spectrophotometer</td>
			<td>Thermo Fisher Scientific</td>
			<td>ND-ONE-W</td>
			<td>to calibrate the uncaging</td>
		</tr>
		<tr>
			<td>NIS Elements</td>
			<td>Nikon Instruments</td>
			<td></td>
			<td>Microscope Imaging Software</td>
		</tr>
		<tr>
			<td>Oven Venti-Line</td>
			<td>VWR-CH</td>
			<td>466-3516</td>
			<td>to bake PDMS (with forced convection)</td>
		</tr>
		<tr>
			<td>Photoresist SU-8-3050</td>
			<td>MicroChem Corp.</td>
			<td>SU8-3050</td>
			<td></td>
		</tr>
		<tr>
			<td>Plasma chamber Zepto</td>
			<td>Diener Electronic</td>
			<td>ZEPTO-1</td>
			<td>to functionalize the surfaces before bonding</td>
		</tr>
		<tr>
			<td>Polycarbonate membrane</td>
			<td>Sterlitech</td>
			<td>PCT0447100</td>
			<td>0.4 &#181;m pore size, 19 % open area, 24 &#181;m thickness</td>
		</tr>
		<tr>
			<td>Polyethylene microtubing</td>
			<td>Scientific Commodities</td>
			<td>BB31695-PE/2</td>
			<td>I.D. x O.D.: 0.015&#34; x 0.043&#34; / 0.38mm x 1.09mm</td>
		</tr>
		<tr>
			<td>Polystyrene Petri dish</td>
			<td>VWR-CH</td>
			<td>25373-100</td>
			<td>bottom surface (90 mm x 15 mm) to bond the millifluidic device</td>
		</tr>
		<tr>
			<td>Scale</td>
			<td>VWR-CH</td>
			<td>611-2605</td>
			<td>to weight PDMS mixture</td>
		</tr>
		<tr>
			<td>sCMOS camera Andor Zyla</td>
			<td>Oxford Instruments</td>
			<td></td>
			<td>for phase contrast and fluorescence microscopy (max 100 fps)</td>
		</tr>
		<tr>
			<td>Sea salt</td>
			<td>Instant Ocean</td>
			<td>Product No. SS1-160p</td>
			<td></td>
		</tr>
		<tr>
			<td>SolidWorks 2015</td>
			<td>Dassault Systemes SolidWorks</td>
			<td></td>
			<td>Used to design the mold</td>
		</tr>
		<tr>
			<td>Spectra X light engine</td>
			<td>Lumencolor</td>
			<td></td>
			<td>for LED 395 nm</td>
		</tr>
		<tr>
			<td>Sylgard 184</td>
			<td>Dow Corning</td>
			<td>110-41-155</td>
			<td>PDMS Si Elastomer Kit; curing agent</td>
		</tr>
		<tr>
			<td>Syringe (Luer-Lok)</td>
			<td>B Braun Omnifix</td>
			<td>4616308F</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe Needle</td>
			<td>Agani</td>
			<td>A228</td>
			<td>from 10 to 30 ml</td>
		</tr>
		<tr>
			<td>Syringe Pump 11 Pico Plus Elite</td>
			<td>Harvard Apparatus</td>
			<td>70-4506</td>
			<td>Terumo Agani 23 gauge 5/8 inch (16mm)</td>
		</tr>
		<tr>
			<td>VeroGrey</td>
			<td>Stratasys</td>
			<td></td>
			<td>Dual Syringe Pump</td>
		</tr>
		<tr>
			<td>Vortex-Genie</td>
			<td>Scientific Industries</td>
			<td>SI-0236</td>
			<td>Mold Material</td>
		</tr>
	</tbody>
</table>

generating controlled, dynamic chemical landscapes to study microbial behavior

我们演示了一种生成受控动态化学脉冲的方法，即局部化学吸引剂在微观尺度上突然出现，为微生物化学实验创造微环境。为了产生化学脉冲，我们开发了一个系统，通过在含有细菌悬浮液的聚二甲基硅氧烷（PDMS）微流体室中对笼体氨基酸进行光解，在近乎瞬间引入氨基酸源。我们应用了这种方法的化学细菌，Vibrio ordalii，它可以积极爬上这些动态化学梯度，同时通过视频显微镜跟踪。氨基酸，通过化学改性与可拆卸保护组进行化学修饰，在悬浮液中均匀存在，但在它们突然释放之前不能食用，这种释放通过近UV-A聚焦LED光束在用户定义的时间和空间点发生。脉冲中释放的分子数量可以通过暴露时间和未处理分数之间的校准关系来确定，其中光解后的吸收光谱使用 UV-Vis 光谱进行特征。纳米多孔聚碳酸酯 （PCTE） 膜可集成到微流体装置中，以便通过流动连续去除未结折合的化合物和废介质。PCTE膜与PDMS微流体结构之间的强、不可逆的粘结，是通过用3-氨基丙烯氧硅烷（APTES）溶液涂覆膜，然后对要粘结的表面进行等离子体活化来实现的。计算机控制的系统可以在不同位置和不同强度下生成用户定义的脉冲序列，从而创造具有规定的空间和时间可变性的资源景观。在每个化学环境中，可以获得单个尺度的细菌运动动态及其在种群层面的积累，从而能够量化化学战术性能及其对生态相关环境中细菌聚集的影响。

我们使用微流体和微流体装置（图1）来研究动态营养条件下的细菌积累谱。细菌轨迹是从通过相对比显微镜获得的细菌群体在光解释放的化学脉冲后积累-消散动力学的录影视频中提取的（图2和图3）。通过平均数百万条轨迹，得到了径向漂移速度和细菌浓度的时空动力学。在没有化学梯度的情况下进行游泳的统计数据是在空间和...

Watch this Scientific Journal Video about Generating Controlled, Dynamic Chemical Landscapes to Study Microbial Behavior at JoVE.com

Generating Controlled, Dynamic Chemical Landscapes to Study Microbial Behavior

提出了在微流体和微流体设置中通过光液生成动态化学景观的协议。该方法适用于研究不同的生物过程，包括单细胞和种群层面的移动行为、营养摄入或对微生物化学物质的适应。

生成受控动态化学景观，研究微生物行为

We demonstrate a method for the generation of controlled, dynamic chemical pulses&#8213;where localized chemoattractant becomes suddenly available at the ...

该方法可以阐明微尺度生态学和微生物在动态化学梯度中的行为，并揭示其在生态相关微环境中的隐性权衡、营养动力学和种群动态。通过将微流体技术与光解相结合，我们生成受控化学脉冲，其中局部化学反应物在微尺度上突然可用，以测量微生物群首先暴露在不稳定的化学梯度下的化学反应。使用 CAD 软件设计通道，并打印到透明胶片上以创建照片蒙版。根据手稿，在洁净的房间里用软光刻制作主人。在 40 毫升烧杯中，以 10 比 1 的比例将弹性体与固化剂结合，准备 PDMS 混合物。用塑料刀，大力混合，直到液体是均匀的。立即在真空室中脱气 PDMS 混合物，在室温下 45 分钟。为了加快过程，定期释放真空，以打破接口上形成气泡。使用加压清洁剂清除主机表面的灰尘。然后将脱气的PDMS混合物倒入主炉上，在80摄氏度的烤箱中烘烤两小时。在大约 5 毫米的距离内，用刀片切割 PDMS，然后小心地从主结构上剥下 PDMS。打孔作为微通道的入口和出口。用胶带密封微通道，防止灰尘积聚。使用 3D 设计软件设计 3D 形状，并使用高分辨率 3D 打印机打印 PDMS 模具的主形状。在准备和脱气 PDMS 混合物之前一样，通过用胶带涂抹清洁母体表面。将母版放在刻度上。然后，在避开主的中央区域的同时，倒入 23.4 克未处理的 PDMS 混合物，以便通过将主主的高度与 0.5 毫米的高度相匹配，获得所需的 PDMS 高度。借助压缩空气清除任何剩余的气泡。将 PDMS 在 45 摄氏度的烤箱中放入主机上，烘烤至少 12 小时。然后，轻轻剥离硬化的PDMS层，并打孔入口和出口孔，用于注射细菌悬浮液。使用氧气等离子体激活培养皿表面和 PDMS 模具两分钟。将 PDMS 模具粘合在培养皿上，轻轻将模具压在培养皿上。避免按要素的位置。将培养皿粘合到 PDMS 3D 模具中，在 45 摄氏度的烤箱中至少 12 小时，以加强化学粘结。接下来，在室温下在氧离子室中激活纳米聚碳酸酯膜一分钟。在化学罩下，使用聚丙烯管将三氨基丙基三氧硅烷在去维化水中的商用溶液按体积稀释至1%。将稀释的3氨基丙基三氧硅烷溶液转移到培养皿中，将活性膜浸入3-氨基丙基三氧硅烷溶液中20分钟。然后，用钳子从3氨基丙基三氧硅烷溶液中去除膜，放在洁净室擦拭干燥。对于位于膜上的PDMS微流体通道的制造，允许清洗细菌竞技场，重复制造微流体装置进行单化学脉冲实验，如以前一样。要将 PDMS 洗涤通道与功能化膜粘合，请首先使用氧等离子室激活 PDMS 洗涤通道和聚碳酸酯膜两分钟。血浆处理后，通过轻轻将 PDMS 洗涤通道轻轻压到膜上，将功能化膜和 PDMS 洗涤通道接触。轻轻压在一起 PDMS 和膜非常重要，否则膜可能会不可逆转地粘合到 200 微米高度 PDMS 微通道的天花板上。然后，激活粘合层压 PDMS 洗涤通道聚碳酸酯膜和以前粘合到 Petri 盘的 3D PDMS 模具，将其放入氧气等离子室两分钟。将膜夹在两个 PDMS 层之间，然后一起按压。将培养皿粘合到烤箱中的三明治结构中，在 45 摄氏度下至少 12 小时，以加强化学粘结。首先，在真空下保持毫流体室20分钟。然后，将含有毫流体室的培养皿放在显微镜舞台上。使用移液器，在人工海水中用一毫摩尔4-甲氧-7-硝基丁醇-笼-L-谷氨酸溶液中GP-荧光Vibrio ordalii的稀释细菌悬浮液填充膜下方的腔室。用细菌悬浮液填充通道后，用纸巾多吸溶液，用 PDMS 插头密封进气口和插座，轻轻将其压入孔中。将注射器填充为一毫摩尔4-甲氧-7-硝基丁醇-笼-L-谷氨酸的人工海水溶液，并附在膜上方洗涤通道的入口和出口上。将油管连接到废物储液罐，并确保油管完全浸入液体废物储液罐中，以避免压力振荡。将注射器泵上的流量设置为每分钟 50 微升。启动注射器泵，以建立膜上方洗涤通道中的流量。启动控制 LED 光束和显微镜阶段的软件，并在不同位置和强度生成用户定义的脉冲序列。在数小时和多个连续位置使用 4 倍目标以覆盖大型表面的常规时间间隔录制视频。在这项研究中，微流体和毫流体装置用于研究动态营养条件下的细菌化疗反应和积累特征。最大强度预测显示细菌位置，由白色痕迹指示，在脉冲释放后 0.5 秒的间隔内和脉冲释放后 40 秒。在脉冲释放后60秒，细菌轨迹也以黑色显示。阴影区域表示光解在视场中间时间零秒释放的化学脉冲，随后扩散。此处显示了细菌浓度，以及视场中心脉冲释放后径向漂移速度的时间动力学。漂移速度的负值对应于向脉冲中心定向的化学运动。在没有化学梯度的情况下，这里提供了细菌种群的游泳统计数据。轨迹表示微通道中三维细菌运动的二维投影。测量的细菌游速的概率分布由伽马分布拟合。从细菌轨迹中，提取了连续方向之间时间的概率分布。利用调整方向模式、游泳速度分布和生物体的重新定向统计为个体模型提供信息。这种方法已经测试在海洋细菌Vibrio ordalii对氨基酸谷氨酸进行化疗，但建议的方法广泛适用于不同的物种和化学跟踪物组合，以及化学外的生物过程，如空间异构和动态条件下的人口和社区动力学。微生物生态学和微生物学的经典技术，如批量培养或化疗的生长，在很大程度上忽视了微生物生境的时空特征。通过光解在微尺度上近乎瞬时地产生化学脉冲，旨在从各种来源再现海洋细菌在野外遇到的营养脉冲类型，例如，在下沉的有机颗粒背后的羽状物扩散，或从开水浮游植物细胞传播的养分。氨基硅烷溶液毒性极重，应格外小心处理。我们仅在烟罩下工作，并佩戴防护设备，如实验室外套、安全护目镜和手套。我们还负责处理产生的废物。

Research

JoVE Journal

Bioengineering

Micropatterned Surfaces to Study Hyaluronic Acid Interactions with Cancer Cells

Micropatterned表面透明质酸与肿瘤细胞相互作用的研究

Cancer invasion and progression involves a motile cell phenotype, which is under complex regulation by growth factors/cytokines and extracellular matrix ...

科研

生物工程

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

循环压力为生物反应器的设计体外主动脉心脏瓣膜的研究

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic ...

Synthesis of an Intein-mediated Artificial Protein Hydrogel

内含肽介导的人工蛋白水凝胶的合成

We present the synthesis of a highly stable protein hydrogel mediated by a split-intein-catalyzed protein trans-splicing reaction. The building blocks of ...

Controlled Microfluidic Environment for Dynamic Investigation of Red Blood Cell Aggregation

微流控控制环境的红细胞聚集动态调查

Blood, as a non-Newtonian biofluid, represents the focus of numerous studies in the hemorheology field. Blood constituents include red blood cells, white ...

A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities

一种新型生物反应器为不同的微生物群落的高密度栽培

A novel reactor design, coined a high density bioreactor (HDBR), is presented for the cultivation and study of high density microbial communities. Past ...

Alternating Magnetic Field-Responsive Hybrid Gelatin Microgels for Controlled Drug Release

交变磁场敏感的混合明胶微凝胶药物控释

Magnetically-responsive nano/micro-engineered biomaterials that enable a tightly controlled, on-demand drug delivery have been developed as new types of ...

Expanding Nanopatterned Substrates Using Stitch Technique for Nanotopographical Modulation of Cell Behavior

扩大奈米基材使用缝合技术的细胞行为Nanotopographical调制

Substrate nanotopography has been shown to be a potent modulator of cell phenotype and function. To dissect nanotopography modulation of cell behavior, a ...

Modeling Ovarian Cancer Multicellular Spheroid Behavior in a Dynamic 3D Peritoneal Microdevice

模拟卵巢癌多细胞球体行为动态三维微型腹膜

Ovarian cancer is characterized by extensive peritoneal metastasis, with tumor spheres commonly found in the malignant ascites. This is associated with ...

Environmental Dynamic Mechanical Analysis to Predict the Softening Behavior of Neural Implants

预测神经植入物软化行为的环境动力力学分析

When using dynamically softening substrates for neural implants, it is important to have a reliable in vitro method to characterize the softening behavior ...

Stepwise Cell Seeding on Tessellated Scaffolds to Study Sprouting Blood Vessels

逐步在泰瑟尔脚手架上播种，研究发芽血管

The cardiovascular system is a key player in human physiology, providing nourishment to most tissues in the body; vessels are present in different sizes, ...