这项工作得到了国家科学基金会的支持。CBET-1236351 和 GW 生物动力学和生物灵感工程中心 （COBRE）。

在这项工作中，壁挂式质极球体， 即 模型声乐折叠息肉，位于吸力型风洞的测试区间地板上，收缩比为5：1。通过油流可视化、墙压测量和粒子图像速度测量，对不稳定的三维流量分离及其对墙面压力加载的影响进行调查。不稳定的压力测量是使用带有压生应力传感器的十六个通道扫描压力传感器获得的。压力传感器的频率响应为 670 Hz。不锈钢管积形成的静态压力水龙头位于模型声折叠息肉的上下游，便于表面压力测量，并缩短扫描压力装置的使用时间。油流可视化和表面压力测量不能同时获得，因为油会流入压力水龙头，导致污染。
下一节提供了在安装在壁上层的质黄层半球体周围设置和获取油膜可视化和表面压力测量的协议。虽然正在获取相平均和时间解决的粒子图像速度测量，但 PIV 采集不包括在此协议中。作者建议拉菲尔 等人引用这些建议。36 和阿德里安和韦斯特维尔39 深入了解 PIV 实验设置、数据采集和数据处理。
1. 生成突起（即型号聚合）
<ol><li>构建具有所需几何形状的三维计算机辅助设计 （CAD） 模型。生成模型声乐折叠息肉作为一种质子半球体，长5.08厘米，宽2.54厘米，高1.27厘米。安装一个2.54厘米的方形底座，是0.64厘米厚的模型声乐折叠息肉的底部。此基础将用于将模型锚定到测试部分楼层。</li>
	<li>导出 3D CAD 模型作为立体图 （STL） 文件。STL 文件格式将模型表面生成为一系列三角形。选择适当的分辨率，以确保模型息肉表面光滑。建议分辨率至少为 600 点/in。</li>
	<li>将 STL 文件上传到适当的软件中，使用高分辨率三维打印机或构建层分辨率至少为 20μm 的快速原型打印 STL 文件。</li>
	<li>风洞测试部分约为30.48厘米×30.48厘米x121.92厘米，底部有可拆卸的板， 如图1所示。将一个2.54厘米见方的孔磨成约0.85厘米深的风洞测试区地板可拆卸板，安装模型声乐折叠息肉进行测试。孔应位于测试区宽的中心，并位于所需的下游位置进行测试。</li>
</ol>2. 油流可视化准备
<ol><li>为了准备测试部分，用白色胶纸覆盖风洞内的测试区面。小心放置并平滑胶粘纸，确保测试部分地板不会因气泡或粘合纸上的折痕而出现凸起。在测试区地板方孔上方的胶纸上切一个孔，以便模型聚锚连接到测试区壁上。</li>
	<li>将突起（模型声乐折叠息肉）插入锚位置，为测试做准备。见 图1。</li>
	<li>在风洞测试区上方安装高分辨率摄像头。对焦摄像机以查看所选视场，包括模型息肉和周围的测试区。设置用于测试的相机采集参数。视频设置应用于捕获油流可视化的瞬时部分，或者如果不稳定或脉动流感兴趣。</li>
	<li>通过将婴儿油、复制碳粉和煤油按体积 7：1：2 的比例组合，准备流式可视化油混合物。例如：将 35 毫升婴儿油、5 毫升复制碳粉和 10 毫升煤油混合在一起。将婴儿油和碳粉混合在容器中，搅拌至碳粉完全溶解。然后加入煤油，混合好。</li>
	<li>将混合物转移到喷雾瓶中，以便于应用到测试区表面。</li>
</ol>3. 油流可视化测量
<ol><li>每次涂油混合物之前，清洁和干燥测试区表面。</li>
	<li>使用装满油混合物的喷雾瓶在感兴趣的部分喷洒薄薄的，甚至一层液体。薄薄的油混合物层对于生成适当的油膜可视化图像非常重要。</li>
	<li>启动相机上的图像或视频采集。在风洞通电之前开始相机采集，以便捕捉初始瞬态油混合物运动。</li>
	<li>将吸风洞设置为所需的速度。油混合物将开始沿测试区表面流动。</li>
	<li>一旦油混合物停止流动并达到稳定状态（即 模式是静止的），或当所需的时间已经过去时，停止摄像机记录并关闭风洞供电。 注意： 视频 1 显示油混合物流动，直到达到稳定状态，皮肤摩擦模式变得静止。在视频中，流从左向右移动。</li>
</ol>4. 表面压力测量准备
<ol><li>通过钻孔将不锈钢管（0.16 厘米外径和 2.54 厘米长）安装到测试区板中，准备测试区板地面（可拆卸板），以构建静态压力水龙头。从质黄层半球的锚位置中线开始，在跨度方向跨越 8.89 厘米的网格上钻孔，在下游 22.86 厘米处钻孔，带 1.27 厘米跨度网格间距和 2.54 厘米下游网格间距（见 图 1）。不锈钢管一端有凸起，用于连接柔性管子，另一端直立安装。 注意：静态压力水龙头可以更紧密地定位，以获得更精细的压力采集位置网格。</li>
	<li>将围绕墙锚位置的凸起安装在测试区地板上所需的配置中，以备测试之需。管状应与测试区地板齐平。</li>
	<li>将短柔性管件（6.35 厘米长、0.159 厘米内径、0.475 厘米外径透明聚氯乙烯管）从安装的不锈钢管连接到扫描压力传感器测量端口。扫描压力传感器有 16 个压力端口。</li>
</ol>5. 表面压力测量采集
<ol><li>将扫描压力传感器连接到计算机，并使用扫描压力传感器软件配置采集参数。将采集软件设置为以 500 Hz 获取数据，以在所需的数据采集持续时间内获取数据。 注：由于低振荡频率的压力变化很小，以扫描压力传感器（500 Hz）的最大采样速率获取数据。</li>
	<li>将吸风洞设置为所需的速度。</li>
	<li>开始压力测量采集。压力测量可以与任何所需的流量诊断技术（如 PIV、激光多普勒气压计、热线测定 法等）同时获得。</li>
</ol>

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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coherent+structures+of+the+near+field+flow+in+a+self-oscillating+physical+model+of+the+vocal+folds.">Coherent structures of the near field flow in a self-oscillating physical model of the vocal folds.</a> J. Acoustic. Soc. Am. 121 (2), 1102-1118 (2007).</li><li>Krebs, F., Silva, F., Sciamarella, D., Artana, 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+three-dimensional+study+of+the+glottal+jet.">A three-dimensional study of the glottal jet.</a> Exp. Fluids. 52 (5), 1133-1147 (2011).</li><li>Adrian, R. J., Westerweel, 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> Particle image velocimetry. 30, (2010).</li><li>Tobak, M., Peake, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Topology+of+three-dimensional+separated+flows.">Topology of three-dimensional separated flows.</a> Ann. Rev. Fluid Mech. 14, 61-85 (1982).</li><li>Zhang, Y., Jiang, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Asymmetric+Spatiotemporal+Chaos+Induced+by+a+Polypoid+Mass+in+the+Excised+Canine+Larynx.">Asymmetric Spatiotemporal Chaos Induced by a Polypoid Mass in the Excised Canine Larynx.</a> Chaos. 18, 43102 (2008).</li><li>D&#233;lery, J. M., Jean, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Delery+Toward+the+elucidation+of+three-dimensional+separation.">Delery Toward the elucidation of three-dimensional separation.</a> Ann. Rev. Fluid Mech. 33, 129-154 (2001).</li></ol>

作者没有什么可透露的。

了解几何突起中涡流结构的形成和传播及其随后对驱动声乐折叠动力学的空气动力学负荷的影响，对于提供洞察力和模型以推进声折叠息肉和结核的处理是必要的。在这个实验中，由模型息肉引起的空气动力学负荷的变化预计将有助于在息肉13，41患者中观察到的不规则声折叠动力学。未来的工作包括利用粒子图像速度研究不稳定流量条件下的三维流量分离，并将结果与表面流可视化和表?...

声乐折叠是横跨声乐气道的两个组织带。当达到关键的肺压时，会产生语音，通过被导引的声乐折叠迫使空气。声乐折叠由许多层组织组成，通常由简化的双层身体覆盖系统1表示。细胞外基质，占覆盖层的大部分，由胶原蛋白和弹性蛋白纤维组成，提供非线性应力应变特性，这对声乐褶皱1，2的正确运动很重要。空气动力将能量传授给声折叠的组织，激发自我维持的振荡3。当声乐折叠振荡时，它们之间的开口，称为glottis，形成一个时空变化的孔，从收敛物过渡到制服，然后过渡到发散通道，然后关闭并重复周期4，6。正常语音的振动频率通常分别跨越男性和女性的100-220赫兹，形成一个脉冲流场，通过glottis7。对正常语音的流体结构能量交换过程进行了广泛的研究。然而，对于某些病理学来说，这一过程的中断并不十分清楚。声乐折叠的病理条件可能导致其动态发生巨大变化，并影响产生语音的能力。
息肉和结核是声乐褶皱的中间表面形成的几何异常。这些异常会影响患者的沟通能力。然而，直到最近，由于几何突起（如息肉）而中断了流场。研究表明，语音的"正常"流体结构能量交换过程发生了巨大变化，流场的改变是息肉和结核患者声质严重下降的最可能原因。尚未对脉动流中的息肉的三维流分离产生的流动结构进行全面了解。息肉的涡流结构的生成和繁殖，以及它们随后对驱动声波折叠动力学的空气动力学负荷的影响，是推进患者息肉手术修复的必要关键组成部分。
虽然在15-23日对稳定流动中安装的半球体的流量分离进行了调查，但令人惊讶的是，在受脉动或不稳定流动条件影响的墙壁上的半球体中，几乎没有关于不稳定的三维流分离的信息。Acarlar 和 Smith15 的开创性作品分析了层压边界层内安装的半球体的墙壁上稳定流动产生的三维连贯结构。阿卡拉和史密斯确定了两种类型的漩涡结构。一个站立的马蹄涡形成于半球状突起的上游，并延伸到两侧的突起下游。此外，发夹涡流定期从墙上安装的半球体脱落到唤醒。对发夹涡流的复杂运动和进展进行了详细的调查和描述。
以前曾研究过在湍流剪切流中凹凸的上和下游获得表面静态压力测量和表面油可视化的流经。油膜技术可可视化皮肤摩擦线、高速和低速区域以及表面流中的分离和连接点，并有助于研究壁挂物体的唤醒。对于此技术，感兴趣的表面涂有油底和细粉色素（即 灯黑、石墨粉或二氧化钛）混合物的薄膜。在所需的流动条件下，摩擦力使油沿着表面移动，导致颜料粉末沉积成条纹。临界点或奇点，剪切应力为零或平均速度的两个或两个以上成分为零的位置，可从由此产生的皮肤摩擦线图案中归类为鞍点或节点24-26。
对于山丘几何形状，在上游没有发现分离引起的奇点：这归因于颠簸的平稳上升轮廓，这并没有产生与半球突起发生的逆压梯度。因此，发现流加速，直到颠簸的顶峰之后，不稳定的鞍焦点分离点发展后不久的颠簸中心线，从发夹漩涡27，28的形成预期。在一项使用不同壁挂几何形状的类似实验技术的研究中，Martinuzzi 和 Tropea29 在表面安装的立方体周围稳定流动的油膜可视化显示物体上游的两条清晰的皮肤摩擦线。第一条皮肤摩擦线对应于由逆压梯度引起的主分离线，第二条皮肤摩擦线标记了马蹄涡的时间平均位置。在物体上游进行的表面压力测量显示，马蹄涡线沿线为局部最低值，主要分离线和马蹄涡线之间的局部压力最大值为局部压力。类似的上游分离线与其他表面安装的几何形状，包括圆形圆柱体，金字塔和锥形29-31形成。壁挂式物体下游的表面可视化通常显示由物体30后面的再循环区域引起的两个foci。两个涡流产生于卵泡位置，对应于壁挂式半球体32后看到的"拱形"或发夹涡流。
粒子图像速度 （PIV） 以前用于研究合成声乐折叠模型33-35的下游流量。PIV 是一种非侵入性可视化技术，它可在平面内拍摄跟踪器粒子运动，以捕捉时态流体动力学36。Neubauer等人研究了在振荡声折叠下游形成的三维连贯结构。37：观察到涡流生成、对流和喷射拍打。最近，克雷布斯等人38使用立体 PIV 研究了光子喷射的三维性，结果演示了光子喷射轴开关。Erath 和 Plesniak14调查了模型声乐折叠息肉在 7.5 倍放大动态驱动声乐折叠模型的中间表面上的影响。聚合物下游形成了一个再循环区，喷射动力学在整个语音周期中受到影响。先前的研究，除了由Erath和Plesniak14驱动的声乐折叠息肉研究，没有探索由中位声乐折叠息肉或结核引起的流体动力学。
在包括声折叠移动壁、诱导压力梯度、密闭几何体积和其他复杂情况之前，了解模型息肉在稳定且脉动流场中的流体动态效应非常重要。当前的工作重点是在稳定和不稳定的流量条件下，下游墙体上的流量结构的特征。从突出和下游壁脱落的涡流结构之间的相互作用对声折叠息肉和其他生物因素的调查非常感兴趣，因为这些相互作用会引起生物反应。

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		<tr height="126">
			<td height="126" style="height:126px;width:216px;">Rapid Prototyper</td>
			<td style="width:139px;">Objet</td>
			<td style="width:119px;">Objet24</td>
			<td style="width:227px;">Tray Size (X&#215;Y&#215;Z): 240 &#215; 200 &#215; 150 mm 
			Build layer thickness =&#160; 28 &#181;m&#160; 
			Accuracy = 0.1 mm 
			Build Resolution: X-axis: 600 dpi, Y-axis: 600 dpi, Z-axis: 900 dpi</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Rapid Prototyper Model Material</td>
			<td style="width:139px;">Objet</td>
			<td style="width:119px;">VeroWhite Plus Fullcure 835</td>
			<td style="width:227px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Rapid Prototyper Support Material</td>
			<td style="width:139px;">Objet</td>
			<td style="width:119px;">FullCure 705 Support</td>
			<td style="width:227px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Copy Toner</td>
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			<td style="width:227px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Kerosene</td>
			<td style="width:139px;">Sunnyside</td>
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			<td height="21" style="height:21px;width:216px;">Baby Oil</td>
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			<td style="width:227px;"></td>
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			<td height="21" style="height:21px;width:216px;">Adhesive Paper</td>
			<td style="width:139px;">Con-Tact Brand</td>
			<td style="width:119px;"></td>
			<td style="width:227px;">White adhesive covering</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Tygon Tubing</td>
			<td style="width:139px;">Tygon</td>
			<td style="width:119px;">PVC Tubing</td>
			<td style="width:227px;">1/16&#34; ID, 3/16&#34;OD</td>
		</tr>
		<tr height="151">
			<td height="151" style="height:151px;width:216px;">Pressure Scanner (16 channel)</td>
			<td style="width:139px;">Scanivalve</td>
			<td style="width:119px;">DSA3217</td>
			<td style="width:227px;">Used for gas pressure measurements 
			Pressure range = +/- 5&#34; H2O 
			Full scale accuracy = +/-0.3% full scale accuracy.&#160; 
			Maximum scan rate = 500 Hz/channel</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Stainless Steel Tubulations</td>
			<td style="width:139px;">Scanivalve</td>
			<td style="width:119px;">TUBN-063-1.0</td>
			<td style="width:227px;">0.063&#34; Diameter and 1&#34; Length</td>
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</table>

investigating the three-dimensional flow separation induced by a model vocal fold polyp

对正常语音的流体结构能量交换过程进行了广泛的研究，但对病理条件却知之不周。息肉和结节是声乐褶皱中间表面形成的几何异常，它们会破坏声波折叠动力学，从而对患者的沟通能力产生毁灭性影响。我们的实验室报告了粒子图像速度 （PIV） 测量，对位于 体外 驱动声折叠模型中间表面的模型息肉进行了调查，结果表明，这种几何异常会大大破坏光子喷射行为。这种流场调整是息肉患者声乐质量严重下降的一个可能原因。更全面地了解几何突起（如声折叠息肉）对涡流结构的形成和传播，以及由此对驱动声乐折叠动力学的空气动力学负荷的影响，对于推进这种病理条件的治疗是必要的。目前的调查涉及壁挂式石板半球体引起的三维流分离，其横流的纵横比为2：1， 即 使用油膜可视化技术的模型声乐折叠息肉。使用皮肤摩擦线可视化和墙压测量检查不稳定、三维流量分离及其对墙压加载的影响。

先前使用 7.5 倍放大动态驱动声乐折叠模型的工作表明，几何突起、模型声乐折叠息肉的存在，在整个声循环中会破坏光子喷射的正常动态。先前驱动声乐折叠模型研究的代表性结果显示在 图 2 和 视频 2 中。该视频演示了驱动声乐折叠从收敛到发散几何形状的运动。声乐折叠模型动态驱动在1.67赫兹与雷诺兹号码995和斯特鲁哈尔号码1.9 x10-2。数据是在息肉下游7.5?...

Watch this Scientific Journal Video about Investigating the Three-dimensional Flow Separation Induced by a Model Vocal Fold Polyp at JoVE.com

Investigating the Three-dimensional Flow Separation Induced by a Model Vocal Fold Polyp

声乐折叠息肉会破坏声波折叠动力学，从而对患者的沟通能力产生毁灭性的影响。使用颗粒图像速度、皮肤摩擦线可视化和墙压测量来检查壁挂模型息肉引起的三维流量分离及其对墙压加载的影响。

研究模型声乐折叠聚合物引起的三维流量分离

The fluid-structure energy exchange process for normal speech has been studied extensively, but it is not well understood for pathological conditions. ...

investigating-three-dimensional-flow-separation-induced-model-vocal

Research

JoVE Journal

Bioengineering

8.4K 次观看.  The George Washington University. 声乐折叠息肉会破坏声波折叠动力学，从而对患者的沟通能力产生毁灭性的影响。使用颗粒图像速度、皮肤摩擦线可视化和墙压测量来检查壁挂模型息肉引起的三维流量分离及其对墙压加载的影响。

视频: Investigating the Three-dimensional Flow Separation Induced by a Model Vocal Fold Polyp

The Three-Dimensional Human Skin Reconstruct Model: a Tool to Study Normal  Skin and Melanoma Progression

Most in vitro studies in experimental skin biology have been done in 2-dimensional (2D) monocultures, while accumulating evidence suggests that cells behave differently when they are grown within a 3D extra-cellular matrix and also interact with other cells (1-5). Mouse models have been broadly utilized to study tissue morphogenesis in vivo. However mouse and human skin have significant differences in cellular architecture and physiology, which makes it difficult to extrapolate mouse studies to humans. Since melanocytes in mouse skin are mostly localized in hair follicles, they have distinct biological properties from those of humans, which locate primarily at the basal layer of the epidermis. The recent development of 3D human skin reconstruct models has enabled the field to investigate cell-matrix and cell-cell interactions between different cell types. The reconstructs consist of a "dermis" with fibroblasts embedded in a collagen I matrix, an "epidermis", which is comprised of stratified, differentiated keratinocytes and a functional basement membrane, which separates epidermis from dermis. Collagen provides scaffolding, nutrient delivery, and potential for cell-to-cell interaction. The 3D skin models incorporating melanocytic cells recapitulate natural features of melanocyte homeostasis and melanoma progression in human skin. As in vivo, melanocytes in reconstructed skin are localized at the basement membrane interspersed with basal layer keratinocytes. Melanoma cells exhibit the same characteristics reflecting the original tumor stage (RGP, VGP and metastatic melanoma cells) in vivo. Recently, dermal stem cells have been identified in the human dermis (6). These multi-potent stem cells can migrate to the epidermis and differentiate to melanocytes.

In this report, we describe the three-dimensional skin reconstruct model which mimics human skin in architecture and composition. Melanocyte physiology, melanoma progression and the fate of dermal stem cells have been investigated using the skin reconstruct model. The model is also useful as a preclinical tool for drug assessment.

三维人体皮肤重建模型：一种工具来研究正常皮肤恶性黑色素瘤进展

Most in vitro studies in experimental skin biology have been done in 2-dimensional (2D) monocultures, while accumulating evidence suggests that cells ...

科研

生物工程

Planar and Three-Dimensional Printing of Conductive Inks

Printed electronics rely on low-cost, large-area fabrication routes to create flexible or multidimensional electronic, optoelectronic, and biomedical devices1-3. In this paper, we focus on one- (1D), two- (2D), and three-dimensional (3D) printing of conductive metallic inks in the form of flexible, stretchable, and spanning microelectrodes.
Direct-write assembly4,5 is a 1-to-3D printing technique that enables the fabrication of features ranging from simple lines to complex structures by the deposition of concentrated inks through fine nozzles (~0.1 - 250 &mu;m). This printing method consists of a computer-controlled 3-axis translation stage, an ink reservoir and nozzle, and 10x telescopic lens for visualization. Unlike inkjet printing, a droplet-based process, direct-write assembly involves the extrusion of ink filaments either in- or out-of-plane. The printed filaments typically conform to the nozzle size. Hence, microscale features (&lt; 1 &mu;m) can be patterned and assembled into larger arrays and multidimensional architectures.
In this paper, we first synthesize a highly concentrated silver nanoparticle ink for planar and 3D printing via direct-write assembly. Next, a standard protocol for printing microelectrodes in multidimensional motifs is demonstrated. Finally, applications of printed microelectrodes for electrically small antennas, solar cells, and light-emitting diodes are highlighted.

Planar and three-dimensional printing of conductive metallic inks is described. Our approach provides new avenues for fabricating printed electronic, optoelectronic, and biomedical devices in unusual layouts at the microscale.

平面和立体印刷的导电油墨

Printed electronics rely on low-cost, large-area fabrication routes to create flexible or multidimensional electronic, optoelectronic, and biomedical ...

Synthetic, Multi-Layer, Self-Oscillating Vocal Fold Model Fabrication

Sound for the human voice is produced via flow-induced vocal fold vibration. The vocal folds consist of several layers of tissue, each with differing material properties 1. Normal voice production relies on healthy tissue and vocal folds, and occurs as a result of complex coupling between aerodynamic, structural dynamic, and acoustic physical phenomena. Voice disorders affect up to 7.5 million annually in the United States alone 2 and often result in significant financial, social, and other quality-of-life difficulties. Understanding the physics of voice production has the potential to significantly benefit voice care, including clinical prevention, diagnosis, and treatment of voice disorders.
Existing methods for studying voice production include in vivo experimentation using human and animal subjects, in vitro experimentation using excised larynges and synthetic models, and computational modeling. Owing to hazardous and difficult instrument access, in vivo experiments are severely limited in scope. Excised larynx experiments have the benefit of anatomical and some physiological realism, but parametric studies involving geometric and material property variables are limited. Further, they are typically only able to be vibrated for relatively short periods of time (typically on the order of minutes).
Overcoming some of the limitations of excised larynx experiments, synthetic vocal fold models are emerging as a complementary tool for studying voice production. Synthetic models can be fabricated with systematic changes to geometry and material properties, allowing for the study of healthy and unhealthy human phonatory aerodynamics, structural dynamics, and acoustics. For example, they have been used to study left-right vocal fold asymmetry 3,4, clinical instrument development 5, laryngeal aerodynamics 6-9, vocal fold contact pressure 10, and subglottal acoustics 11 (a more comprehensive list can be found in Kniesburges et al. 12)
Existing synthetic vocal fold models, however, have either been homogenous (one-layer models) or have been fabricated using two materials of differing stiffness (two-layer models). This approach does not allow for representation of the actual multi-layer structure of the human vocal folds 1 that plays a central role in governing vocal fold flow-induced vibratory response. Consequently, one- and two-layer synthetic vocal fold models have exhibited disadvantages 3,6,8 such as higher onset pressures than what are typical for human phonation (onset pressure is the minimum lung pressure required to initiate vibration), unnaturally large inferior-superior motion, and lack of a "mucosal wave" (a vertically-traveling wave that is characteristic of healthy human vocal fold vibration).
In this paper, fabrication of a model with multiple layers of differing material properties is described. The model layers simulate the multi-layer structure of the human vocal folds, including epithelium, superficial lamina propria (SLP), intermediate and deep lamina propria (i.e., ligament; a fiber is included for anterior-posterior stiffness), and muscle (i.e., body) layers 1. Results are included that show that the model exhibits improved vibratory characteristics over prior one- and two-layer synthetic models, including onset pressure closer to human onset pressure, reduced inferior-superior motion, and evidence of a mucosal wave.

The methodology for fabricating synthetic vocal fold models is described. The models are life-sized and mimic the multi-layer structure of the human vocal folds. Results show the models to self-oscillate at pressures comparable to lung pressure and demonstrate flow-induced vibratory responses that are similar to those of human vocal folds.

合成，多层，自激振荡的声带模型制作

Sound for the human voice is produced via flow-induced vocal fold vibration. The vocal folds consist of several layers of tissue, each with differing ...

Three-dimensional Cell Culture Model for Measuring the Effects of Interstitial Fluid Flow on Tumor Cell Invasion

The growth and progression of most solid tumors depend on the initial transformation of the cancer cells and their response to stroma-associated signaling in the tumor microenvironment 1. Previously, research on the tumor microenvironment has focused primarily on tumor-stromal interactions 1-2. However, the tumor microenvironment also includes a variety of biophysical forces, whose effects remain poorly understood. These forces are biomechanical consequences of tumor growth that lead to changes in gene expression, cell division, differentiation and invasion3. Matrix density 4, stiffness 5-6, and structure 6-7, interstitial fluid pressure 8, and interstitial fluid flow 8 are all altered during cancer progression.
Interstitial fluid flow in particular is higher in tumors compared to normal tissues 8-10. The estimated interstitial fluid flow velocities were measured and found to be in the range of 0.1-3 &mu;m s-1, depending on tumor size and differentiation 9, 11. This is due to elevated interstitial fluid pressure caused by tumor-induced angiogenesis and increased vascular permeability 12. Interstitial fluid flow has been shown to increase invasion of cancer cells 13-14, vascular fibroblasts and smooth muscle cells 15. This invasion may be due to autologous chemotactic gradients created around cells in 3-D 16 or increased matrix metalloproteinase (MMP) expression 15, chemokine secretion and cell adhesion molecule expression 17. However, the mechanism by which cells sense fluid flow is not well understood. In addition to altering tumor cell behavior, interstitial fluid flow modulates the activity of other cells in the tumor microenvironment. It is associated with (a) driving differentiation of fibroblasts into tumor-promoting myofibroblasts 18, (b) transporting of antigens and other soluble factors to lymph nodes 19, and (c) modulating lymphatic endothelial cell morphogenesis 20.
The technique presented here imposes interstitial fluid flow on cells in vitro and quantifies its effects on invasion (Figure 1). This method has been published in multiple studies to measure the effects of fluid flow on stromal and cancer cell invasion 13-15, 17. By changing the matrix composition, cell type, and cell concentration, this method can be applied to other diseases and physiological systems to study the effects of interstitial flow on cellular processes such as invasion, differentiation, proliferation, and gene expression.

Interstitial fluid flow is elevated in solid tumors and can modulate tumor cell invasion. Here we describe a technique to apply interstitial fluid flow to cells embedded in a matrix and then measure its effects on cell invasion. This technique can be easily adapted to study other systems.

三维细胞培养模式的测量肿瘤细胞浸润间质流体流动的影响

The growth and progression of most solid tumors depend on the initial transformation of the cancer cells and their response to stroma-associated signaling ...

A Novel Three-dimensional Flow Chamber Device to Study Chemokine-directed Extravasation of Cells Circulating under Physiological Flow Conditions

Extravasation of circulating cells from the bloodstream plays a central role in many physiological and pathophysiological processes, including stem cell homing and tumor metastasis. The three-dimensional flow chamber device (hereafter the 3D device) is a novel in vitro technology that recreates physiological shear stress and allows each step of the cell extravasation cascade to be quantified. The 3D device consists of an upper compartment in which the cells of interest circulate under shear stress, and a lower compartment of static wells that contain the chemoattractants of interest. The two compartments are separated by porous inserts coated with a monolayer of endothelial cells (EC). An optional second insert with microenvironmental cells of interest can be placed immediately beneath the EC layer. A gas exchange unit allows the optimal CO2 tension to be maintained and provides an access point to add or withdraw cells or compounds during the experiment. The test cells circulate in the upper compartment at the desired shear stress (flow rate) controlled by a peristaltic pump. At the end of the experiment, the circulating and migrated cells are collected for further analyses. The 3D device can be used to examine cell rolling on and adhesion to EC under shear stress, transmigration in response to chemokine gradients, resistance to shear stress, cluster formation, and cell survival. In addition, the optional second insert allows the effects of crosstalk between EC and microenvironmental cells to be examined. The translational applications of the 3D device include testing of drug candidates that target cell migration and predicting the in vivo behavior of cells after intravenous injection. Thus, the novel 3D device is a versatile and inexpensive tool to study the molecular mechanisms that mediate cellular extravasation.

The three-dimensional flow chamber device is a novel in vitro technology for the quantitative and step-wise evaluation of the extravasation cascade of cells circulating under conditions of physiological shear stress. The device therefore fills a critical need for basic, preclinical, and clinical studies of cell migration.

一种新型三维流室装置研究生理流量条件下的趋化因子的细胞循环外渗

Extravasation of circulating cells from the bloodstream plays a central role in many physiological and pathophysiological processes, including stem cell ...

Human Cartilage Tissue Fabrication Using Three-dimensional Inkjet Printing Technology

Bioprinting, which is based on thermal inkjet printing, is one of the most attractive enabling technologies in the field of tissue engineering and regenerative medicine. With digital control&#160;cells, scaffolds, and growth factors can be precisely deposited to the desired two-dimensional (2D) and three-dimensional (3D) locations rapidly. Therefore, this technology is an ideal approach to fabricate tissues mimicking their native anatomic structures. In order to engineer cartilage with native zonal organization, extracellular matrix composition (ECM), and mechanical properties, we developed a bioprinting platform using a commercial inkjet printer with simultaneous photopolymerization capable for 3D cartilage tissue engineering. Human chondrocytes suspended in poly(ethylene glycol) diacrylate (PEGDA) were printed for 3D neocartilage construction via layer-by-layer assembly. The printed cells were fixed at their original deposited positions, supported by the surrounding scaffold in simultaneous photopolymerization. The mechanical properties of the printed tissue were similar to the native cartilage. Compared to conventional tissue fabrication, which requires longer UV exposure, the viability of the printed cells with simultaneous photopolymerization was significantly higher. Printed neocartilage demonstrated excellent glycosaminoglycan (GAG) and collagen type II production, which was consistent with gene expression. Therefore, this platform is ideal for accurate cell distribution and arrangement for anatomic tissue engineering.

The methods described in this paper show how to convert a commercial inkjet printer into a bioprinter with simultaneous UV polymerization. The printer is capable of constructing 3D tissue structure with cells and biomaterials. The study demonstrated here constructed a 3D neocartilage.

人体软骨组织制作采用三维喷墨打印技术

Bioprinting, which is based on thermal inkjet printing, is one of the most attractive enabling technologies in the field of tissue engineering and ...

Construction and Characterization of a Novel Vocal Fold Bioreactor

In vitro engineering of mechanically active tissues requires the presentation of physiologically relevant mechanical conditions to cultured cells. To emulate the dynamic environment of vocal folds, a novel vocal fold bioreactor capable of producing vibratory stimulations at fundamental phonation frequencies is constructed and characterized. The device is composed of a function generator, a power amplifier, a speaker selector and parallel vibration chambers. Individual vibration chambers are created by sandwiching a custom-made silicone membrane between a pair of acrylic blocks. The silicone membrane not only serves as the bottom of the chamber but also provides a mechanism for securing the cell-laden scaffold. Vibration signals, generated by a speaker mounted underneath the bottom acrylic block, are transmitted to the membrane aerodynamically by the oscillating air. Eight identical vibration modules, fixed on two stationary metal bars, are housed in an anti-humidity chamber for long-term operation in a cell culture incubator. The vibration characteristics of the vocal fold bioreactor are analyzed non-destructively using a Laser Doppler Vibrometer (LDV). The utility of the dynamic culture device is demonstrated by culturing cellular constructs in the presence of 200-Hz sinusoidal vibrations with a mid-membrane displacement of 40 &#181;m. Mesenchymal stem cells cultured in the bioreactor respond to the vibratory signals by altering the synthesis and degradation of vocal fold-relevant, extracellular matrix components. The novel bioreactor system presented herein offers an excellent in vitro platform for studying vibration-induced mechanotransduction and for the engineering of functional vocal fold tissues.

A novel vocal fold bioreactor capable of delivering physiologically relevant, vibratory stimulation to cultured cells is constructed and characterized. This dynamic culture device, when combined with a fibrous poly(&#949;-caprolactone) scaffold, creates a vocal fold-mimetic environment that modulates the behaviors of mesenchymal stem cells.

一种新型声带生物反应器的构建与鉴定

In vitro engineering of mechanically active tissues requires the presentation of physiologically relevant mechanical conditions to cultured cells. To ...

Analysis of Cell Migration within a Three-dimensional Collagen Matrix

The ability to migrate is a hallmark of various cell types and plays a crucial role in several physiological processes, including&#160;embryonic development, wound healing, and immune responses. However, cell migration is also a key mechanism in cancer enabling these cancer cells to detach from the primary tumor to start metastatic spreading. Within the past years various cell migration assays have been developed to analyze the migratory behavior of different cell types. Because the locomotory behavior of cells markedly differs between a two-dimensional (2D) and three-dimensional (3D) environment it can be assumed that the analysis of the migration of cells that are embedded within a 3D environment would yield in more significant cell migration data. The advantage of the described 3D collagen matrix migration assay is that cells are embedded within a physiological 3D network of collagen fibers representing the major component of the extracellular matrix. Due to time-lapse video microscopy real cell migration is measured allowing the determination of several migration parameters as well as their alterations in response to pro-migratory factors or inhibitors. Various cell types could be analyzed using this technique, including lymphocytes/leukocytes, stem cells, and tumor cells. Likewise, also cell clusters or spheroids could be embedded within the collagen matrix concomitant with analysis of the emigration of single cells from the cell cluster/ spheroid into the collagen lattice. We conclude that the 3D collagen matrix migration assay is a versatile method to analyze the migration of cells within a physiological-like 3D environment.

Cell migration is a biological phenomenon that is involved in a plethora of physiological, such as wound healing and immune responses, and pathophysiological processes, like cancer. The 3D-collagen matrix migration assay is a versatile tool to analyze the migratory properties of different cell types within in a 3D physiological-like environment.

在一个三维胶原蛋白矩阵分析细胞迁移

The ability to migrate is a hallmark of various cell types and plays a crucial role in several physiological processes, including&#160;embryonic ...

Generation of a Three-dimensional Full Thickness Skin Equivalent and Automated Wounding

In vitro models are a cost effective and ethical alternative to study cutaneous wound healing processes. Moreover, by using human cells, these models reflect the human wound situation better than animal models. Although two-dimensional models are widely used to investigate processes such as cellular migration and proliferation, models that are more complex are required to gain a deeper knowledge about wound healing. Besides a suitable model system, the generation of precise and reproducible wounds is crucial to ensure comparable results between different test runs. In this study, the generation of a three-dimensional full thickness skin equivalent to study wound healing is shown. The dermal part of the models is comprised of human dermal fibroblast embedded in a rat-tail collagen type I hydrogel. Following the inoculation with human epidermal keratinocytes and consequent culture at the air-liquid interface, a multilayered epidermis is formed on top of the models. To study the wound healing process, we additionally developed an automated wounding device, which generates standardized wounds in a sterile atmosphere.

The goal of this protocol is to build up a three-dimensional full thickness skin equivalent, which resembles natural skin. With a specifically constructed automated wounding device, precise and reproducible wounds can be generated under maintenance of sterility.

三维全层皮肤的生成等效和自动伤人

In vitro models are a cost effective and ethical alternative to study cutaneous wound healing processes. Moreover, by using human cells, these models ...

Studying Protein Function and the Role of Altered Protein Expression by Antibody Interference and Three-dimensional Reconstructions

A strict management of protein expression is not only essential to every organism alive, but also an important strategy to investigate protein functions in cellular models. Therefore, recent research invented different tools to target protein expression in mammalian cell lines or even animal models, including RNA and antibody interference. While the first strategy has gathered much attention during the past two decades, peptides &#160;mediating a translocation of antibody cargos across cellular membranes and into cells, obtained much less interest. In this publication, we provide a detailed protocol how to utilize a peptide carrier named Chariot in human embryonic kidney cells as well as in primary hippocampal neurons to perform antibody interference experiments and further illustrate the application of three-dimensional reconstructions in analyzing protein function. Our findings suggest that Chariot is, probably due to its nuclear localization signal, particularly well-suited to target proteins residing in the soma and the nucleus. Remarkably, when applying Chariot to primary hippocampal cultures, the reagent turned out to be surprisingly well accepted by dissociated neurons.

Controlling protein expression is not only essential to every organism alive, but also an important strategy to investigate protein functions in cellular models. The protocol presented shows the application of antibody interference in mammalian cells including primary hippocampal neurons and demonstrates the use of three-dimensional reconstructions in studying protein function.

研究蛋白质功能和改变的蛋白的表达由源抗体干扰和三维重建中的作用

A strict management of protein expression is not only essential to every organism alive, but also an important strategy to investigate protein functions ...