支持由NIH资助的HD052670。

1。与ECM蛋白涂层板<ol><li>在无菌条件下，混合冷无菌1X PBS每盘12毫升120微克的粘连。 </li><li>采取Bioflex未处理板，并添加到每口井的解决方案2毫升（粘连最后的浓度为2微克/厘米2）。另外，其他的ECM蛋白可以使用，如胶原-1 [10微克/厘米2]，纤维连接蛋白[5微克/厘米2]，玻[0.5微克/厘米2]或弹性[10微克/厘米2]。什么是粘连涂层的涂层技术是类似的。确保井完全覆盖解决方案。 </li><li>包装用塑料板，并在4°C过夜允许的粘连吸附井底部放在一个平面上。在这种情况下，板可以存储至少一个星期，同时仍然保持良好的ECM功能。 </li><li>第二天，在无菌条件下，用1X PBS洗井的3倍。 </li><l&gt;加入1％BSA的1×PBS 1ml到每口井，并于37°C 1H阻止膜的非特异性结合位点。 </li><li>冲洗板3次用1X PBS删除unadsorbed蛋白质。 </li><li>保持在37°Ç的DMEM板，直至细胞分离步骤2.14。 </li></ol> 2。胎鼠肺II型上皮细胞的分离隔离前一天有不同大小的尼龙网格蒸压和准备的屏幕杯。 <ol><li>定时怀孕小鼠/大鼠获得E17的19对妊娠胎儿肺部。转移到50毫升锥形管含有DMEM培养基的组织和它放置在冰上。 </li><li>在50毫升锥形管消化缓冲液：（10毫升）。此卷，来自约20个从小鼠/大鼠胎儿肺组织使用。 8.5毫升培养液 500mm的pH值0.5毫升7.4肝素钠 5毫克胶原酶1 5毫克胶原酶1A 1毫升鸡血清，热灭活</li><li>拌匀，直到所有的组件都溶解并通过0.2微米的无菌罩内的注射器过滤器的过滤器。将锥形管水浴中含有消化缓冲液在37°C。 </li><li>从步骤2.1锥形管的DMEM培养基和组织转移到无菌培养皿。 </li><li>剁碎，用无菌剪刀或刀片的肺组织块小于1毫米，并组织转移到锥形管预热的消化缓冲包含从步骤2.3。 </li><li>消化吸取了组织： 与10毫升吸管的100倍 用5毫升吸管的100倍 巴斯德吸管的100倍</li><li>在1300转离心5分钟，在室温下匀浆。 </li><li>小心取出吸上清，重新悬浮颗粒细胞中含有15毫升加20％胎牛血清的DMEM。 </li><li>取出屏幕杯与100 - 30 - 15微米尼龙网及地方日EM在无菌的150毫升烧杯。 </li><li>从步骤2.8中加入细胞匀浆和顺序筛选到100 - 30 - 15微米筛网杯。 </li><li>收集从30成群的非过滤的细胞 - 促进非上皮细胞过滤后用DMEM加10％胎牛血清的几个洗和15微米的网格。 </li><li>丢弃滤液，其中包含主要是成纤维细胞从15微米网。 </li><li>孵化75厘米2瓶30分钟（approximatelly10瓶悬浮细胞每毫升）从步骤2.11细胞，净化进一步II型细胞。 </li><li>收集上清1300转的离心机在室温下5分钟沉淀细胞。 </li><li>小心取出吸上清，重新悬浮颗粒含有细胞在无血清DMEM。悬浮量取决于组织的处理量。约，我们板相当于细胞获得在每口井（2毫升），以ACHI从一个胎儿前夕之间的60-70％汇合翌日。 </li><li>预涂板暂停Bioflex六孔板细胞与层粘连蛋白或纤维连接蛋白。 </li></ol> 3。胎鼠肺成纤维细胞的分离<ol><li>按照相同的步骤如上所述II型细胞的分离，至2.11。 </li><li>取滤液从15微米网（没有先前洗涤;近似体积为10-15毫升）和板在37°C为30-60分钟，使成纤维细胞坚持到75厘米2。 </li><li>吸的supernantant及更换无血清培养液孵育过夜。 </li><li>第二天，收获细胞，0.25％（重量/体积）胰蛋白酶在0.4毫米EDTA和他们Bioflex板与纤维连接蛋白预涂板。 </li></ol> 4。提供机械刺激肺细胞的实验系统<ol><li>种子细胞在无血清培养液（2毫升/孔），并让他们重视和SPRE的Bioflex文化板块（约50％汇合）广告之前至少6小时的实验。在我们的实验室一般维持约24小时前应用机械应变细胞培养。如果一个特定的细胞数量的实验需要，经隔离后，II型细胞保持在无血清培养液75厘米2瓶，第二天，细胞胰酶消化，计数，然后播种。 </li><li>第二天，媒体与新鲜无血清培养液（2毫升/）和bioflex的板取代安装在Flexcell FX-5000应变单位。单层应不大于80％汇合前开始实验。 </li><li> equibiaxial应变膜。应变方案，取决于模拟体内的机械力量（见讨论）。 </li><li>并行培养的非拉伸膜生长的细胞作为对照。 </li><li>在实验结束时，单层可以处理，分析基因表达的变化（如表面活性蛋白C）同时实时-PCR技术，蛋白印迹，等丰度，单层可固定的免疫细胞化学实验。这种技术，固定后，硅橡胶膜切出板和玻片上安装使用安装代理前通透性和抗体的潜伏期为10-20μL水。上清也可用于研究生长因子，细胞因子等的存在</li></ol> 5。代表结果 图1和图2显示了代表相衬照片E18胎鼠II型细胞的分离，使用在这个手稿中描述的技术。 图3表明，机械应变诱导胎儿型作为标记使用表面活性蛋白C型II上皮细胞的分化。 <img src="/files/ftp_upload/3543/3543fig1.jpg" /> 图1。声望余丹丹相衬拍照后显示胎儿II型细胞成群的外观隔离。 <img src="/files/ftp_upload/3543/3543fig2.jpg" /> 图2。E18胎儿II型上皮细胞分离这里粘连涂bioflex板和镀。这张照片是采取后翌日非拉伸细胞，多聚甲醛固定。细胞的纯度被确定为90±5％的上皮细胞形态和免疫组化SP-C的微观分析。 <img src="/files/ftp_upload/3543/3543fig3.jpg" /> 图3。胎儿II型上皮细胞暴露于循环应变5％，在40次/分钟为16H。）表面活性蛋白C（SP-C）的mRNA表达，应变诱导II型细胞分化，使用不同的ECM基板Northern杂交。 + / - 符号代表接触或训练，分别。数据作为意味着+ / -扫描电镜（SEM），N = 3; *，P &lt;0.05），荧光免疫细胞化学图像展示（绿色）SP-C蛋白水平在胎儿的II型细胞暴露或不能（控制）机械应变。 counterstained细胞核用DAPI（蓝色）。酒吧，10微米C）西部三个实验的印迹结果显示，机械牵张增加SP-C蛋白。 n = 3 * P &lt;0.05;

<ol>
	<li>Sanchez-Esteban, J., Tsai, S. W., Sang, J., Qin, J., Torday, J. S., Rubin, L. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+mechanical+forces+on+lung-specific+gene+expression.">Effects of mechanical forces on lung-specific gene expression.</a> Am. J. Med. Sci. 316, 200-204 (1998).</li><li>Sanchez-Esteban, J., Cicchiello, L. A., Wang, Y., Tsai, S. W., Williams, L. K., Torday, J. S., Rubin, L. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+stretch+promotes+alveolar+epithelial+type+II+cell+differentiation.">Mechanical stretch promotes alveolar epithelial type II cell differentiation.</a> J. Appl. Physiol. 91, 589-595 (2001).</li><li>Sanchez-Esteban, J., Wang, Y., Cicchiello, L. A., Rubin, L. 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Lung. Cell. Mol. Physiol. 291, L820-L827 (2006).</li><li>Sanchez-Esteban, J., Wang, Y., Filardo, E. J., Rubin, L. P., Ingber, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integrins+{beta}1,+{alpha}6,+and+{alpha}3+contribute+to+mechanical+strain-induced+differentiation+of+fetal+lung+type+II+epithelial+cells+via+distinct+mechanisms.">Integrins {beta}1, {alpha}6, and {alpha}3 contribute to mechanical strain-induced differentiation of fetal lung type II epithelial cells via distinct mechanisms.</a> Am. J. Physiol. Lung. Cell. Mol. Physiol. 290, L343-L350 (2006).</li><li>Wang, Y., Maciejewski, B. S., Soto-Reyes, D., Lee, H. S., Warburton, D., Sanchez-Esteban, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+stretch+promotes+fetal+type+II+epithelial+cell+differentiation+via+shedding+of+HB-EGF+and+TGF-alpha.">Mechanical stretch promotes fetal type II epithelial cell differentiation via shedding of HB-EGF and TGF-alpha.</a> J. Physiol. 587, 1739-1753 (2009).</li><li>Wang, Y., Maciejewski, B. S., Drouillard, D., Santos, M., Hokenson, M. A., Hawwa, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+role+for+caveolin-1+in+mechanotransduction+of+fetal+type+II+epithelial+cells.">A role for caveolin-1 in mechanotransduction of fetal type II epithelial cells.</a> Am. J. Physiol. Lung. Cell. Mol. Physiol. 298, L775-L783 (2010).</li><li>Lee, H. S., Wang, Y., Maciejewski, B. 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没有利益冲突的声明。

在这个手稿中，我们描述了一种方法来隔离胎儿II型上皮细胞和成纤维细胞和揭露他们使用的Flexcell应变仪的机械刺激。我们已经用这种技术来评估上皮细胞的分化1,2和研究舒展3-9激活的受体和信号通路的。此外，这种方法也可以用来研究由10,11机械损伤诱导细胞反应。胶原酶消化肺组织的程序是基于。它需要利用II型细胞的倾向消化后聚集在一起。在执行这一技术的重要?...

<table border="1">
	<tbody>
		<tr>
			<td>Name of the reagent</td>
			<td>Company</td>
			<td>Catalogue number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Sigma</td>
			<td>D5648</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Sigma</td>
			<td>H3375</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Collagenase 1</td>
			<td>Sigma</td>
			<td>C0130</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Collagenase 1A</td>
			<td>Sigma</td>
			<td>C9891</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Chicken serum</td>
			<td>Sigma</td>
			<td>C5405</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Screen cups</td>
			<td>Sigma</td>
			<td>CD1-1KT</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Syringe filters</td>
			<td>Fisher Scientific</td>
			<td>09-754-25</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>100 micron nylon mesh</td>
			<td>Small Parts, INC</td>
			<td>CMN-100-D</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>30 micron mesh</td>
			<td>Small Parts, INC</td>
			<td>CMN-30-D</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>15 micron mesh</td>
			<td>Dynamic Aqua-Supply Ltd.</td>
			<td>NTX15</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Laminin</td>
			<td>Sigma</td>
			<td>L2020</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Collagen-1</td>
			<td>Collagen Biomed</td>
			<td>PC0701</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Fibronectin</td>
			<td>Sigma</td>
			<td>F1141</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Vitronectin</td>
			<td>Sigma</td>
			<td>V-0132</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Elastin</td>
			<td>Sigma</td>
			<td>E-6402</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Bioflex plate</td>
			<td>Flexcell International</td>
			<td>BF-3001U</td>
			<td>Uncoated</td>
		</tr>
		<tr>
			<td>Flexcell Strain Unit</td>
			<td>Flexcell International</td>
			<td>FX-5000</td>
			<td>&nbsp;</td>
		</tr>
	</tbody>
</table>

an experimental system to study mechanotransduction in fetal lung cells

在子宫内产生的机械力通过重复呼吸运动和流体腹胀是正常的肺发育的关键。肺发育的一个关键组成部分是分化的肺泡Ⅱ型上皮细胞，肺表面活性物质的主要来源。这些细胞也参与流体的动态平衡，在肺泡腔，宿主防御，损伤修复。此外，远端肺组织细胞，可以直接暴露在机械通气，出生后夸张的拉伸。然而，其中肺细胞感应机械刺激影响肺癌的发展和促进肺损伤的确切的细胞和分子机制尚未完全了解。在这里，我们提供了一个简单的和高纯度的方法来隔离II型细胞和啮齿动物胎肺成纤维细胞。然后，我们描述了在体外系统，Flexcell的应变单位，提供机械刺激胎儿细胞，模拟机械力胎儿肺发育或肺损伤。该实验系统提供了一个极好的工具来暴露伸展胎儿肺细胞的细胞和分子机制研究。使用这种方法，我们的实验室已经确定了几个受体和信号转导蛋白在胎儿肺发育和肺损伤，机械传导参加。

Watch this Scientific Journal Video about An Experimental System to Study Mechanotransduction in Fetal Lung Cells at JoVE.com

An Experimental System to Study Mechanotransduction in Fetal Lung Cells

机械力发挥关键作用，在肺发育和肺损伤。在这里，我们描述了一个隔离啮齿动物胎儿肺Ⅱ型上皮细胞和成纤维细胞，并揭露他们使用的机械刺激的方法<em&gt;在体外</em&gt;系统。

在胎儿肺细胞的机械传导的实验系统研究

Mechanical forces generated in utero by repetitive breathing-like movements and by fluid distension are critical for normal lung development. A key ...

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Research

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Bioengineering

12.9K 次观看.  Alpert Medical School of Brown University. 机械力发挥关键作用，在肺发育和肺损伤。在这里，我们描述了一个隔离啮齿动物胎儿肺Ⅱ型上皮细胞和成纤维细胞，并揭露他们使用的机械刺激的方法在体外系统。

视频: An Experimental System to Study Mechanotransduction in Fetal Lung Cells

Axon Stretch Growth: The Mechanotransduction of Neuronal Growth

During pre-synaptic embryonic development, neuronal processes traverse short distances to reach their targets via growth cone. Over time, neuronal somata are separated from their axon terminals due to skeletal growth of the enlarging organism (Weiss 1941; Gray, Hukkanen et al. 1992). This mechanotransduction induces a secondary mode of neuronal growth capable of accommodating continual elongation of the axon (Bray 1984; Heidemann and Buxbaum 1994; Heidemann, Lamoureux et al. 1995; Pfister, Iwata et al. 2004).
Axon Stretch Growth (ASG) is conceivably a central factor in the maturation of short embryonic processes into the long nerves and white matter tracts characteristic of the adult nervous system. To study ASG in vitro, we engineered bioreactors to apply tension to the short axonal processes of neuronal cultures (Loverde, Ozoka et al. 2011). Here, we detail the methods we use to prepare bioreactors and conduct ASG. First, within each stretching lane of the bioreactor, neurons are plated upon a micro-manipulated towing substrate. Next, neurons regenerate their axonal processes, via growth cone extension, onto a stationary substrate. Finally, stretch growth is performed by towing the plated cell bodies away from the axon terminals adhered to the stationary substrate; recapitulating skeletal growth after growth cone extension.
Previous work has shown that ASG of embryonic rat dorsal root ganglia neurons are capable of unprecedented growth rates up to 10mm/day, reaching lengths of up to 10cm; while concurrently resulting in increased axonal diameters (Smith, Wolf et al. 2001; Pfister, Iwata et al. 2004; Pfister, Bonislawski et al. 2006; Pfister, Iwata et al. 2006; Smith 2009). This is in dramatic contrast to regenerative growth cone extension (in absence of mechanical stimuli) where growth rates average 1mm/day with successful regeneration limited to lengths of less than 3cm (Fu and Gordon 1997; Pfister, Gordon et al. 2011). Accordingly, further study of ASG may help to reveal dysregulated growth mechanisms that limit regeneration in the absence of mechanical stimuli.

A unique tissue engineering method was developed to elongate numerous nerve fibers in culture by recapitulating axon stretch growth; a form of nervous system growth whereby nerves elongate in conjunction with growth of the enlarging body.

轴突伸展生长：神经生长Mechanotransduction

During pre-synaptic embryonic development, neuronal processes traverse short distances to reach their targets via growth cone. Over time, neuronal somata ...

科研

生物工程

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

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic valve leaflets are composed of interstitial cells suspended within an extracellular matrix (ECM) and are lined with an endothelial cell monolayer. The valve withstands a harsh, dynamic environment and is constantly exposed to shear, flexion, tension, and compression. Research has shown calcific lesions in diseased valves occur in areas of high mechanical stress as a result of endothelial disruption or interstitial matrix damage1-3. Hence, it is not surprising that epidemiological studies have shown high blood pressure to be a leading risk factor in the onset of aortic valve disease4. 
The only treatment option currently available for valve disease is surgical replacement of the diseased valve with a bioprosthetic or mechanical valve5. Improved understanding of valve biology in response to physical stresses would help elucidate the mechanisms of valve pathogenesis. In turn, this could help in the development of non-invasive therapies such as pharmaceutical intervention or prevention. Several bioreactors have been previously developed to study the mechanobiology of native or engineered heart valves6-9. Pulsatile bioreactors have also been developed to study a range of tissues including cartilage10, bone11 and bladder12. The aim of this work was to develop a cyclic pressure system that could be used to elucidate the biological response of aortic valve leaflets to increased pressure loads. 
The system consisted of an acrylic chamber in which to place samples and produce cyclic pressure, viton diaphragm solenoid valves to control the timing of the pressure cycle, and a computer to control electrical devices. The pressure was monitored using a pressure transducer, and the signal was conditioned using a load cell conditioner. A LabVIEW program regulated the pressure using an analog device to pump compressed air into the system at the appropriate rate. The system mimicked the dynamic transvalvular pressure levels associated with the aortic valve; a saw tooth wave produced a gradual increase in pressure, typical of the transvalvular pressure gradient that is present across the valve during diastole, followed by a sharp pressure drop depicting valve opening in systole. The LabVIEW program allowed users to control the magnitude and frequency of cyclic pressure. The system was able to subject tissue samples to physiological and pathological pressure conditions. This device can be used to increase our understanding of how heart valves respond to changes in the local mechanical environment.

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

A cyclic pressure bioreactor capable of subjecting heart valve tissue to physiological and pathological pressure conditions has been designed. A LabVIEW program allows users to control pressure magnitude, amplitude and frequency. This device can be used to study the mechanobiology of heart valve tissue or isolated cells.

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 ...

Constructing a Low-budget Laser Axotomy System to Study Axon Regeneration in C. elegans

Laser axotomy followed by time-lapse microscopy is a sensitive assay for axon regeneration phenotypes in C. elegans1. The main difficulty of this assay is the perceived cost ($25-100K) and technical expertise required for implementing a laser ablation system2,3. However, solid-state pulse lasers of modest costs (&lt;$10K) can provide robust performance for laser ablation in transparent preparations where target axons are "close" to the tissue surface. Construction and alignment of a system can be accomplished in a day. The optical path provided by light from the focused condenser to the ablation laser provides a convenient alignment guide. An intermediate module with all optics removed can be dedicated to the ablation laser and assures that no optical elements need be moved during a laser ablation session. A dichroic in the intermediate module allows simultaneous imaging and laser ablation. Centering the laser beam to the outgoing beam from the focused microscope condenser lens guides the initial alignment of the system. A variety of lenses are used to condition and expand the laser beam to fill the back aperture of the chosen objective lens. Final alignment and testing is performed with a front surface mirrored glass slide target. Laser power is adjusted to give a minimum size ablation spot (&lt;1um). The ablation spot is centered with fine adjustments of the last kinematically mounted mirror to cross hairs fixed in the imaging window. Laser power for axotomy will be approximately 10X higher than needed for the minimum ablation spot on the target slide (this may vary with the target you use). Worms can be immobilized for laser axotomy and time-lapse imaging by mounting on agarose pads (or in microfluidic chambers4). Agarose pads are easily made with 10% agarose in balanced saline melted in a microwave. A drop of molten agarose is placed on a glass slide and flattened with another glass slide into a pad approximately 200 um thick (a single layer of time tape on adjacent slides is used as a spacer). A "Sharpie" cap is used to cut out a uniformed diameter circular pad of 13mm. Anesthetic (1ul Muscimol 20mM) and Microspheres (Chris Fang-Yen personal communication) (1ul 2.65% Polystyrene 0.1 um in water) are added to the center of the pad followed by 3-5 worms oriented so they are lying on their left sides. A glass coverslip is applied and then Vaseline is used to seal the coverslip and prevent evaporation of the sample.

Constructing a Low-budget Laser Axotomy System to Study Axon Regeneration in C. elegans

Laser axotomy followed by time-lapse imaging is a sensitive way to assay the effects of mutations in C. elegans on axon regeneration. A high quality, but inexpensive, laser ablation system can be easily added to most microscopes. Time lapse imaging over 15 hours requires careful immobilization of the worm.

构建一个低预算的激光干切断系统研究轴突再生 C。线虫</em

Laser axotomy followed by time-lapse microscopy is a sensitive assay for axon regeneration phenotypes in C. elegans1.  The main difficulty of this assay ...

Luminescence Resonance Energy Transfer to Study Conformational Changes in Membrane Proteins Expressed in Mammalian Cells

Luminescence Resonance Energy Transfer, or LRET, is a powerful technique used to measure distances between two sites in proteins within the distance range of 10-100 &#197;. By measuring the distances under various ligated conditions, conformational changes of the protein can be easily assessed. With LRET, a lanthanide, most often chelated terbium, is used as the donor fluorophore, affording advantages such as a longer donor-only emission lifetime, the flexibility to use multiple acceptor fluorophores, and the opportunity to detect sensitized acceptor emission as an easy way to measure energy transfer without the risk of also detecting donor-only signal. Here, we describe a method to use LRET on membrane proteins expressed and assayed on the surface of intact mammalian cells. We introduce a protease cleavage site between the LRET fluorophore pair. After obtaining the original LRET signal, cleavage at that site removes the specific LRET signal from the protein of interest allowing us to quantitatively subtract the background signal that remains after cleavage. This method allows for more physiologically relevant measurements to be made without the need for purification of protein.

We describe here an improved Luminescence Resonance Energy Transfer (LRET) method where we introduce a protease cleavage site between the donor and acceptor fluorophore sites. This modification allows us to obtain specific LRET signals arising from membrane proteins of interest, allowing for the study of membrane proteins without protein purification.

荧光共振能量转移研究构象变化的膜蛋白在哺乳动物细胞中表达

Luminescence Resonance Energy Transfer, or LRET, is a powerful technique used to measure distances between two sites in proteins within the distance range ...

Electrotaxis Studies of Lung Cancer Cells using a Multichannel Dual-electric-field Microfluidic Chip

The behavior of directional cell migration under a direct current electric-field (dcEF) is referred to as electrotaxis. The significant role of physiological dcEF in guiding cell movement during embryo development, cell differentiation, and wound healing has been demonstrated in many studies. By applying microfluidic chips to an electrotaxis assay, the investigation process is shortened and experimental errors are minimized. In recent years, microfluidic devices made of polymeric substances (e.g., polymethylmethacrylate, PMMA, or acrylic) or polydimethylsiloxane (PDMS) have been widely used in studying the responses of cells to electrical stimulation. However, unlike the numerous steps required to fabricate a PDMS device, the simple and rapid construction of the acrylic micro&#64258;uidic chip makes it suitable for both device prototyping and production. Yet none of the reported devices facilitate the efficient study of the simultaneous chemical and dcEF effects on cells. In this report, we describe our design and fabrication of an acrylic-based multichannel dual-electric-field (MDF) chip to investigate the concurrent effect of chemical and electrical stimulation on lung cancer cells. The MDF chip provides eight combinations of electrical/chemical stimulations in a single test. The chip not only greatly shortens the required experimental time but also increases accuracy in electrotaxis studies.

Many microfluidic devices have been developed for use in the study of electrotaxis. Yet, none of these chips allows the efficient study of the simultaneous chemical and electric-field (EF) effects on cells. We developed a polymethylmethacrylate-based device that offers better-controlled coexisting EF and chemical stimulation for use in electrotaxis research.

使用多通道双电场微流控芯片肺癌细胞Electrotaxis研究

The behavior of directional cell migration under a direct current electric-field (dcEF) is referred to as electrotaxis. The significant role of ...

Generation of ESC-derived Mouse Airway Epithelial Cells Using Decellularized Lung Scaffolds

Lung lineage differentiation requires integration of complex environmental cues that include growth factor signaling, cell-cell interactions and cell-matrix interactions. Due to this complexity, recapitulation of lung development in vitro to promote differentiation of stem cells to lung epithelial cells has been challenging. In this protocol, decellularized lung scaffolds are used to mimic the 3-dimensional environment of the lung and generate stem cell-derived airway epithelial cells. Mouse embryonic stem cell are first differentiated to the endoderm lineage using an embryoid body (EB) culture method with activin A. Endoderm cells are then seeded onto decellularized scaffolds and cultured at air-liquid interface for up to 21 days. This technique promotes differentiation of seeded cells to functional airway epithelial cells (ciliated cells, club cells, and basal cells) without additional growth factor supplementation. This culture setup is defined, serum-free, inexpensive, and reproducible. Although there is limited contamination from non-lung endoderm lineages in culture, this protocol only generates airway epithelial populations and does not give rise to alveolar epithelial cells. Airway epithelia generated with this protocol can be used to study cell-matrix interactions during lung organogenesis and for disease modeling or drug-discovery platforms of airway-related pathologies such as cystic fibrosis.

This protocol efficiently directs mouse embryonic stem cell-derived definitive endoderm to mature airway epithelial cells. This differentiation technique uses 3-dimensional decellularized lung scaffolds to direct lung lineage specification, in a defined, serum-free culture setting.

用脱细胞支架龙ESC衍生鼠气道上皮细胞的生成

Lung lineage differentiation requires integration of complex environmental cues that include growth factor signaling, cell-cell interactions and ...

An Experimental Protocol for Assessing the Performance of New Ultrasound Probes Based on CMUT Technology in Application to Brain Imaging

The possibility to perform an early and repeatable assessment of imaging performance is fundamental in the design and development process of new ultrasound (US) probes. Particularly, a more realistic analysis with application-specific imaging targets can be extremely valuable to assess the expected performance of US probes in their potential clinical field of application.
The experimental protocol presented in this work was purposely designed to provide an application-specific assessment procedure for newly-developed US probe prototypes based on Capacitive Micromachined Ultrasonic Transducer (CMUT) technology in relation to brain imaging.
The protocol combines the use of a bovine brain fixed in formalin as the imaging target, which ensures both realism and repeatability of the described procedures, and of neuronavigation techniques borrowed from neurosurgery. The US probe is in fact connected to a motion tracking system which acquires position data and enables the superposition of US images to reference Magnetic Resonance (MR) images of the brain. This provides a means for human experts to perform a visual qualitative assessment of the US probe imaging performance and to compare acquisitions made with different probes. Moreover, the protocol relies on the use of a complete and open research and development system for US image acquisition, i.e. the Ultrasound Advanced Open Platform (ULA-OP) scanner.
The manuscript describes in detail the instruments and procedures involved in the protocol, in particular for&#160;the calibration, image acquisition and registration of US and MR images. The obtained results prove the effectiveness of the overall protocol presented, which is entirely open (within the limits of the instrumentation involved), repeatable, and covers the entire set of acquisition and processing activities for US images.

The development of new ultrasound (US) probes based on Capacitive Micromachined Ultrasonic Transducer (CMUT) technology requires an early realistic assessment of imaging capabilities. We describe a repeatable experimental protocol for US image acquisition and comparison with magnetic resonance images, using an ex vivo bovine brain as an imaging target.

基于 CMUT 技术的新型超声探头在脑成像中的应用研究

The possibility to perform an early and repeatable assessment of imaging performance is fundamental in the design and development process of new ...

DNA Nanotubes as a Versatile Tool to Study Semiflexible Polymers

Mechanical properties of complex, polymer-based soft matter, such as cells or biopolymer networks, can be understood in neither the classical frame of flexible polymers nor of rigid rods. Underlying filaments remain outstretched due to their non-vanishing backbone stiffness, which is quantified via the persistence length (lp), but they are also subject to strong thermal fluctuations. Their finite bending stiffness leads to unique, non-trivial collective mechanics of bulk networks, enabling the formation of stable scaffolds at low volume fractions while providing large mesh sizes. This underlying principle is prevalent in nature (e.g., in cells or tissues), minimizing the high molecular content and thereby facilitating diffusive or active transport. Due to their biological implications and potential technological applications in biocompatible hydrogels, semiflexible polymers have been subject to considerable study. However, comprehensible investigations remained challenging since they relied on natural polymers, such as actin filaments, which are not freely tunable. Despite these limitations and due to the lack of synthetic, mechanically tunable, and semiflexible polymers, actin filaments were established as the common model system. A major limitation is that the central quantity lp cannot be freely tuned to study its impact on macroscopic bulk structures. This limitation was resolved by employing structurally programmable DNA nanotubes, enabling controlled alteration of the filament stiffness. They are formed through tile-based designs, where a discrete set of partially complementary strands hybridize in a ring structure with a discrete circumference. These rings feature sticky ends, enabling the effective polymerization into filaments several microns in length, and display similar polymerization kinetics as natural biopolymers. Due to their programmable mechanics, these tubes are versatile, novel tools to study the impact of lp on the single-molecule as well as the bulk scale. In contrast to actin filaments, they remain stable over weeks, without notable degeneration, and their handling is comparably straightforward.

Semiflexible polymers display unique mechanical properties that are extensively applied by living systems. However, systematic studies on biopolymers are limited since properties such as polymer rigidity are inaccessible. This manuscript describes how this limitation is circumvented by programmable DNA nanotubes, enabling experimental studies on the impact of filament rigidity.

DNA 纳米管作为研究半聚合物的万能工具

Mechanical properties of complex, polymer-based soft matter, such as cells or biopolymer networks, can be understood in neither the classical frame of ...

An Orbital Shaking Culture of Mammalian Cells in O-shaped Vessels to Produce Uniform Aggregates

Suspension cultures of mammalian cell aggregates are required for various applications in medical and biotechnological fields. The disposable bag-based method is one of the simplest techniques for the mass production of cellular aggregates, but it does not protect the cultures against over-aggregation, which occurs when they gather at the bottom center of the culture vessel. To solve this problem, we developed an O-shaped dish and an O-shaped bag, neither of which contains a central region. Aggregates grown in either O-shaped culture vessel were noticeably more uniform in size than aggregates grown in conventional vessels. Histological analyses showed that aggregates in conventional culture dishes contained necrotic cores most likely caused by a poor oxygen supply. In contrast, aggregates that were grown in the O-shaped bag, even those with similar diameters to aggregates in conventional culture dishes, did not show necrotic cores. These results suggest that the O-shaped bag provides sufficient oxygen to the aggregates due to the oxygen permeability of the bag material. We, therefore, propose that this novel gas-permeable O-shaped culture bag is suitable for the mass production of uniform aggregates that are necessary in various biotechnological fields.

Here we present a protocol for using O-shaped vessels, specialized for suspension cultures of cellular aggregates, with orbital shaking. The HEK293 cells grown in this bag form more homogeneous aggregates than those grown in conventional culture vessels.

o 型血管哺乳动物细胞产生均匀集料的轨道晃动培养

Suspension cultures of mammalian cell aggregates are required for various applications in medical and biotechnological fields. The disposable bag-based ...

A Novel Surgical Technique As a Foundation for In Vivo Partial Liver Engineering in Rat

Organ engineering is a novel strategy to generate liver organ substitutes that can potentially be used in transplantation. Recently, in vivo liver engineering, including in vivo organ decellularization followed by repopulation, has emerged as a promising approach over ex vivo liver engineering. However, postoperative survival was not achieved. The aim of this study is to develop a novel surgical technique of in vivo selective liver lobe perfusion in rats as a prerequisite for in vivo liver engineering. We generate a circuit bypass only through the left lateral lobe. Then, the left lateral lobe is perfused with heparinized saline. The experiment is performed with 4 groups (n = 3 rats per group) based on different perfusion times of 20 min, 2 h, 3 h, and 4 h. Survival, as well as the macroscopically visible change of color and the histologically determined absence of blood cells in the portal triad and the sinusoids, is taken as an indicator for a successful model establishment. After selective perfusion of the left lateral lobe, we observe that the left lateral lobe, indeed, turned from red to faint yellow. In a histological assessment, no blood cells are visible in the branch of the portal vein, the central vein, and the sinusoids. The left lateral lobe turns red after reopening the blocked vessels. 12/12 rats survived the procedure for more than one week. We are the first to report a surgical model for in vivo single liver lobe perfusion with a long survival period of more than one week. In contrast to the previously published report, the most important advantage of the technique presented here is that perfusion of 70% of the liver is maintained throughout the whole procedure. The establishment of this technique provides a foundation for in vivo partial liver engineering in rats, including decellularization and recellularization.

A Novel Surgical Technique As a Foundation for In Vivo Partial Liver Engineering in Rat

We establish a novel surgical technique for an in vivo single liver lobe perfusion model in rat as a prerequisite for further studying in vivo partial liver engineering in the future.