Name: using adhesive patterning to construct 3d paper microfluidic devices
Uploaded: 2016-04-01T14:00:00.000+00:00
Duration: 7 min 53 s
Description: Watch this Scientific Journal Video about Using Adhesive Patterning to Construct 3D Paper Microfluidic Devices at JoVE.com

这项工作是由加州大学河滨分校的工程学院商Bourns的基金支持。 BK从龙文仔纪念奖在机械设计获得了奖学金。

1.平面4层设备（堆积层）建筑<ol><li>该装置9的每一层上使用固体墨打印机每片滤纸的打印阵列11,12放置在170℃的加热板上对每次2分钟滤纸。这将熔化蜡类墨水，并允许它充分渗入纸张的厚度，从而形成疏水性的障碍。 注:使用的具体设计，可作为补充文件。 </li><li>从热板移除滤纸并让其冷却至室温。 </li><li>存4微升5毫染料（红色:诱惑红;黄色:柠檬黄;蓝色:罂红钠盐;绿色:10:1混合柠檬黄的:罂红钠盐）层3的每个分支（每个分支一种颜色）（第三使用微量从已完成的器件的顶部层）。 </li><li>与最底层开始。夹紧模具和僵硬的后盾，如一块玻璃板之间的过滤纸，使用的粘合剂夹S，或其他类似的临时方法。确保模板是针对纸张平整。这将最大限度地减少模板投射到任何纸喷阴影。 </li><li>用大约1.33秒（在180 BPM四计数）约24厘米喷雾应用粘合剂（见材料和设备列表）。9,10-在此期间，以中等速度移动越过模板粘合剂的罐。太慢越过模板行进会导致粘合剂积聚在模版本身，堵塞了。过快的旅行将无法在纸张上存入足够的粘性。在此期间，四道次（上下-上下）在防止喷雾阴影足够。 </li><li>除去模板和该装置的下一层放置（编号的层可作为补充文件）刚喷涂层之上，对准纸张的边缘。用力按下两层一起。 </li><li>替换模版并重复喷涂工艺的装置的每个层。取下站设备和地点横跨底层的打包带的CK。这是为了防止在设备的任何流体泄漏。使用从薄片上切割单个设备剪刀，继印刷区域的边缘。 </li></ol> 2.平面4层设备（折纸折层）建筑<ol><li>使用固体墨打印机包含设备的所有层在滤纸上打印纸。放置滤纸上，在170℃的热板2分钟。从热板移除滤纸并让其冷却至室温。 注:使用的具体设计，可作为补充文件。 </li><li>存4微升5毫染料（红色:诱惑红;黄色:柠檬黄;蓝色:罂红钠盐;绿色:10:1混合柠檬黄的:罂红钠盐）层3的每个分支（每个分支一种颜色）（第三从通过微量完成的器件的顶部）层。 </li><li>夹住模板和硬后盾，设备之间的板如一块平板玻璃使用binderclips，或其他类似的临时方法。确保模板是针对纸张平整。 </li><li>用约1.33秒（180 BPM四计数）约24厘米喷涂应用胶粘剂（见的材料和设备清单）。在此期间，四道次（上下-上下）在防止喷雾阴影足够。 </li><li>删除模板和转板过来。更换模板和喷雾后面的纸边。除去装置的片材，并开始以手风琴褶折叠，如在图1中描绘。用剪刀从片剪下每个设备时，下面的印刷区的边缘。将在底部层包装带。 </li></ol> 3.非平面（折纸）设备施工<ol><li>使用固体墨打印机，并放置在滤纸上的热板上在170℃下进行2分钟的打印设备（ 图2A）在滤纸上。从烤盘删除设备，并允许其冷却至室温。 注意:所用的确切设计可作为补充文件。 </li><li>打印折痕图案（ 图2C）上使用固体墨打印机打印纸并切成滤纸的尺寸。放置在170℃下进行2分钟的加热板折痕图案，以熔化蜡，导致图案是从纸张的两侧可见。从热板移除折痕图案并让其冷却至室温。 </li><li>对准折痕图案到包含信道模式的纸张的边缘的边缘，并使用粘合剂的剪辑，或其他类似的临时方法附上的两张纸。 </li><li>用钝手写笔跟踪的折痕模式，运用足够的力量将标记出现在设备表上，但不能太硬，折缝花纹纸撕裂。如果发生这种情况，该设备有可能被损坏。 Precreasing使纸更容易地折叠，并允许在折叠更大的准确性和精确度。 </li><li>首先山区河谷折叠装置根据折痕图案折叠。一旦粘合剂已经应用，整个装置必须装配非常快，所以折叠装置尽可能之前粘合剂的应用是非常有益的。 </li><li>一旦装置被折叠，展开设备以暴露需要粘合剂的设备的部分。用以限制对设备粘合剂切出口罩（ 图2D）可以应用，用剃刀刀片。 </li><li>夹紧模具和面具和一个僵硬的后盾，之间的设备，如一块玻璃板。确保模板是对设备持平。用约1.33秒（180 BPM四计数）约24厘米喷涂应用胶粘剂（见名单的材料和设备）。在此期间，四道次（上下-上下）在防止喷雾阴影足够。删除模板和转板过来。更换模板和面具和喷雾后面的纸边。 </li><li>立即从模板上去除装置，并开始折叠设备。一旦装置被完全折叠时，将压力施加到收容部直到粘合剂已经干燥的粘合剂。 注:粘合剂的干燥时间是至环境湿度很敏感，因此在低湿度的地方，在湿度受控室折叠允许更多的时间来在设备折叠。 </li></ol> 4.排汗试验4层设备<ol><li>随机选取20个设备，以前按上述协议组装。在一个位置放置的设备从任何风或微风屏蔽，以减少水分蒸发。存40微升水在每个装置的入口。记录它需要对每个设备都有其所有网点完全充满染料的时间。 </li></ol> 5.折纸排汗比较<ol><li>根据上述协议（第3节），以及其他没有粘合剂应用期间使用的模板之一 - 构造两个折纸孔雀。 </li><li>将小P的一端预习铅（大约5毫米×5厘米长的宽）到每一个孔雀的身体。 </li><li>放置两个孔雀在保持在高的相对湿度（&gt; 90％），以使蒸发最小化的腔室。将每个孔雀每条腿和铅放入盛有5毫米染料（红:诱惑红，黄:柠檬黄，蓝:罂红二钠盐）的容器。记录芯吸过程用数码相机。 </li></ol>

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作者什么都没有透露。

上述协议使用穿孔金属板作为模板申请气溶胶粘合剂构建平面和非平面的3D纸微流体装置。在平面器件，这具有使粘合剂不破坏设备已经干燥后的设备是完全展开的优点。在其它基于粘合剂的建筑技术，这几乎是不可能的，尽管某些设计允许部分破坏性拆卸通过unpeeling与可移除的粘合剂保持在一起成两半。14无胶结构确实允许使用之后被展开设备，但需要定制夹具或外壳每个设备8 在与主要横向吸收设备，胶粘剂显著慢排汗。通过图案化粘合剂，施加到芯吸区域粘合剂的量可以显著降低，限制了任何潜在的芯吸的干扰。主要具有垂直芯设备也显示出所造成的粘合剂同样缓慢排汗，尽管在较小的程度。模版能完全阻挡了所有的芯吸区域，限制粘合剂应用到疏水区只，可以消除任何潜在的芯吸的干扰，而且还可能增加相当对准时间到施工过程的设计。 在非平面器件，图案化的粘合剂显着地简化了折叠，作为被施加到纸粘合剂的量减少，使得折叠比具有均匀地涂敷粘接剂层显著容易。纸胶粘剂完全覆盖困难得多折当纸张的不同区域之间的偶然接触会导致粘附性，从而在继续之前必须撤销。 对于有大量相对疏水区域排汗面积平面三维多层器件，折纸有气溶胶粘合配对很可能不是最优的施工技术NIQUE由于粘合剂的无法保持润湿的纸层一起同时克服折痕的倾向展开。与设计，包括足够的疏水性边界设备会增加折纸折叠设备的成功率。使用更强的结合强度粘着也可能有助于解决此问题，防止水削弱纸张粘合。 层叠层设备整体表现较好，因为它们缺乏折痕，这往往展开设备。另外，在粘合剂应用中使用模版的降低粘合剂的施加，大大减少用于流体层之间的芯吸所需的时间总量。 在设计非平面的3D纸微流体装置，还有一些问题需要考虑。它到折叠装置的折痕图案比较的信道的布局，与将信道沿着折痕将迫使折痕在水imbibi打开是重要化，由于肿胀纤维素纤维。取决于具体的装置中，虽然，这可能或可能不期望的行为的设计。在环境条件下的设备的存储是不利于设备的可行性，10从而在干燥空气长期贮存，建议以防止减弱各层之间的粘结。 如先前由路易斯指出。等，9利用气溶胶粘合剂提供一种有效的手段来迅速产生大量三维纸微流体装置。通过构图这种粘合剂，新设备可以被更快速地开发出了利用能够在使用后要展开的优势。 此外，图形化使非平面的3D纸微流体装置的建设和发展。这样的装置，预计能够提供以前未在平面纸微流体，如集成的致动和感测发现功能。例如，致动可以是通过创建从水反应性聚合物膜15和图案化纸基材的双层来实现。在从这样的双层构造的装置中，致动会产生沿装置的通道时水灯芯和与薄膜相互作用。一旦膜干燥时，该设备将返回到其初始配置，离开它准备再次使用。

近年来，造纸微流体已经获得了相当的知名度了它的潜力，提供护理低成本点（POC）诊断设备1-3 POC设备提供类似的格式允许的结果是那些基于实验室的测试功能获得比较快。从纸做POC设备成本低，重量轻，易于使用的替代昂贵的微流控芯片和微型实验室，使它们非常适合在资源有限的环境中使用。最常见的纸微流体装置是一维的横向流动装置，但平面的三维（3D）纸微流体装置保持承诺提供占用一个小得多的足迹比通过二维装置5需要复用诊断装置4和相应地使用较小的样品体积。 最初，平面三维纸微流体装置被单独装配，层 - 层的Wi个图案化的纸层用激光切割双面胶带交替。切带层在仔细对准孔被填充有纤维素粉末，以确保层间的流体输送。4许多替代方法随后开发的，设备的6-9每改善不同方面。特别是，通过避开粘合剂，设备可以经由与通过外部夹具保持在一起的层折纸技术折叠。8这消除在诊断试验任何潜在的粘合剂干扰和允许装置被展开后期使用，可能允许更小的样品通过内部显示结果卷。可替代地，通过使用每个纸层之间施加的气溶胶粘合剂，装置的片材可以同时装配，不需费时构图和磁带的对准。9 然而，通过模版施加气溶胶粘合剂，有可能获得的好处这两种技术。通过模版喷洒粘合剂，只有粘合剂的一小部分被施加到装置中，最小化与层间流体传送的任何潜在干扰。此外，仔细模版选择，粘合剂的图案可以应用的结果在半永久粘接，允许设备使用之后被展开，同时仍然提供足够的层间接触，以允许流体层之间毛细作用。 最后，通过模版施加气溶胶粘合剂简化非平面三维纸微流体装置的结构，通过减少施加到，可能需要频繁的折叠和施工期间展开相邻面的粘合剂的量。10此外，使用图案化的粘接剂的使设备成为使用更方便储存后展开。预期非平面三维纸微流体装置被用于任务，否则将在平面三维德维克是不可能即， 图1描述了用于构建平面和非平面三维器件的一般处理流程。

<table><tbody><tr><td>Camera</td><td>Nikon</td><td>D5100</td><td></td></tr><tr><td>Solid-ink printer</td><td>Xerox</td><td>ColorQube 8880</td><td></td></tr><tr><td>Hotplate</td><td>Torrey Pines</td><td>HS60</td><td></td></tr><tr><td>Humidity chamber</td><td>Electro-Tech Systems</td><td>5503-E</td><td></td></tr><tr><td>Spray adhesive</td><td>3M</td><td>62497749309</td><td>Super 77 (16.75 oz can)</td></tr><tr><td>Filter paper</td><td>Whatman</td><td>Grade 4</td><td></td></tr><tr><td>Perforated steel sheet</td><td>MetalsDepot</td><td>PS16116</td><td></td></tr><tr><td>Tartrazine</td><td>Sigma-Aldritch</td><td>T0388</td><td></td></tr><tr><td>Allura Red</td><td>Sigma-Aldritch</td><td>458848</td><td></td></tr><tr><td>Erioglaucine disodium salt</td><td>Sigma-Aldritch</td><td>861146</td><td></td></tr></tbody></table>

using adhesive patterning to construct 3d paper microfluidic devices

We demonstrate the use of patterned aerosol adhesives to construct both planar and nonplanar 3D paper microfluidic devices. By spraying an aerosol adhesive through a metal stencil, the overall amount of adhesive used in assembling paper microfluidic devices can be significantly reduced. We show on a simple 4-layer planar paper microfluidic device that the optimal adhesive application technique and device construction style depends heavily on desired performance characteristics. By moderately increasing the overall area of a device, it is possible to dramatically decrease the wicking time and increase device success rates while also reducing the amount of adhesive required to keep the device together. Such adhesive application also causes the adhesive to form semi-permanent bonds instead of permanent bonds between paper layers, enabling single-use devices to be non-destructively disassembled after use. Nonplanar 3D origami devices also benefit from the semi-permanent bonds during folding, as it reduces the likelihood that unrelated faces may accidently stick together. Like planar devices, nonplanar structures see reduced wicking times with patterned adhesive application vs uniformly applied adhesive.

4层设备测试是在一个密封室中进行，不受任何风或微风，可能导致有限的沉积液量的过度蒸发屏蔽他们。多数在4层器件的芯吸的是在该装置的中间层，因此，在芯吸由于蒸发速度差异预计为最小。此外，还有最小的横向芯吸，与入口和任何个别出口之间只有13毫米，这表明在芯吸时间的变化可能是由于垂直，中间层的流体传输。平均芯吸时间和成功率与不同量的施加的粘合剂构成的4层器件示于表1。 在堆叠的器件，均匀的粘接剂覆盖导致相对较高的成功率是降低，因为我们增加粘合剂的量。图形粘合剂covera戈导致非常低的成功率时粘合剂仅施加到一个侧面，但有更高的成功率和更快的芯吸时间，当图案化粘合剂施加到两侧。典型的成功在图3A描绘。这有观察行为几个可能的解释，其中的任何组合可以适用。所施加的粘合剂可以是在物理阻断，部分或完全中，孔在纸张的表面上，从而导致纸层之间​​的更小的有效接触面积。另外，粘合剂本身可以充当另一多孔基材，粘合剂结果，所以较重的涂层在一个较厚的粘合剂层，其流体必须芯吸通过，从而导致更长的芯吸时间。图案化粘合剂，另一方面，产生粘合剂"点"，只有部分闭塞的接触区域，允许更多的流体从纸层灯芯直接纸层，这降低了芯吸次。然而，这种非常红眼化在粘合剂覆盖率也降低纸层之间的粘结强度，导致降低的成功率溶胀纤维和展开折痕引起层以足够的，它们是在接触不再分开时。通过围绕渠道边框的规模扩大一倍（增加由〜30％的整体设备区），为单，双双面胶应用的成功率提高。两个尺寸之间的比较示于图4，典型的堆叠式装置故障是其特征在于未能与染料完全填满，或需要较长的时间超过5分钟，以填补网点。这在图3B中所描绘。 在折纸折叠装置，均匀粘合剂覆盖导致与施加粘合剂的存在于叠层，均匀，单面粘合设备的当量时得到的完全失败低的成功率。图形粘合剂盖年龄导致了低得多的成功率;然而，这种减少是通过使用具有3毫米边界稍大设备偏移。典型的折纸设备故障的特点是未能填补与染料的任何数量的网点。这些网点均只位于沿包含的折痕设备的两侧。这在图3C中描绘。 根据不同喷涂方法施加粘合剂的质量示于表2中 。1.33秒的上述喷雾的持续时间（四计数在180 BPM）粘合剂的沉积物0.26毫克/厘米2（干重）横跨片均匀地喷洒时设备，而只能通过一个模板，这是23％的开放时喷沉积0.02毫克/厘米2（干重）。 在非平面的三维结构，胶粘剂均匀覆盖导致更加困难的折叠，为相邻面<html>过早地粘在一起。一旦该粘合剂干燥结构内的层不能展开，并尝试在碎纸这样做的结果。图形粘合剂覆盖国产折叠容易得多，因为任何意外的附着力很容易被撤消。一旦该粘合剂干燥，所述层可以分开，而不在纸张的任何撕开或撕裂拉动。胶粘剂的应用这两种方法导致的设备，成功地传送液体的通道，没有混合长度;然而，与均匀地施加粘合剂的设备是明显变慢。这种芯吸的时间推移示于图5。芯吸在湿度受控室中进行保持在&gt; 90％的相对湿度，以减少蒸发，与降低相对湿度蒸发增加。由于存在于该设计的长通道，最多到165毫米长，蒸发可显著增加芯吸时间，甚至具有无限流体贮存器。 内容"FO:保together.within页="1"&gt; <img alt="图1" src="/files/ftp_upload/53805/53805fig1.jpg" /> 图1.器件制造流程。（A）堆叠式装置制造。 （B）折纸器件制造。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53805/53805fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/53805/53805fig2.jpg" /> 图2:孔雀图案。（A）渠道模式，其中黑色表示疏水区域。 （B）的箭头指示由每个染料所采取的路径。圆圈表示层和虚线之间的接触点指示的垂直芯吸路径。从其相应入口到尾部边缘每个通道的长度以毫米表示。信道宽度2之间，平均为3毫米的尾部区域。 （C）折痕图案（从13修改）。红色线对应于在最终的结构山褶皱;黑线对应于谷部;蓝线对应于未在最终结构折叠折痕，但在初步折叠步骤帮助。 （D）放置在折纸装置和胶粘剂应用，其中白色部分被除去在金属模具之间的面具。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53805/53805fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图3" src="/files/ftp_upload/53805/53805fig3.jpg" /> 图3. 典型 的 成功和失败的 （A）典型的成功-所有网点完全充满染料。 （ 二 ）典型堆积失败-网点失败无明显PATTERN在它们的分布。 （C）典型折纸失败-失败填补分别位于沿最左边的或最右边的列中，最接近皱折的所有出口。所有比例尺为5毫米。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53805/53805fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图4" src="/files/ftp_upload/53805/53805fig4.jpg" /> 图4.设备 大小的比较。（A）较小的器件（1.6毫米边框）。 （B）放大装置（3毫米边框）。所有比例尺为5毫米。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53805/53805fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图5" src="/files/ftp_upload/53805/53805fig5.jpg" /> 图5。 。折纸孔雀左时间的推移:胶粘剂均匀覆盖。右:图形粘合剂报道<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53805/53805fig5large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <table fo:keep-together.within-page="1"><tbody><tr><td> 设备样式 </td><td> 粘合剂类型（时间/边框/侧） </td><td> 平均±SD（秒） </td><td> 成功率 </td></tr><tr><td>折纸</td><td>统一（1.33秒/ 1.6毫米/双人间） </td><td> 44±14 </td><td> 45％ </td></tr><tr><td></td><td>统一（0.67秒/ 1.6毫米/双人间） </td><td> 0±0 </td><td> 0％ </td></tr><tr><td></td><td>图案（1.33秒/ 1.6毫米/双人间） </td><td> 41±13 </td><td> 15％ </td></tr><tr><td></td><td>图案（1.33秒/ 3毫米/双人间） </td><td> 64±50 </td><td> 40％</td></tr><tr><td>叠放</td><td>统一（1.33秒/ 1.6毫米/单） </td><td> 152±66 </td><td> 80％ </td></tr><tr><td></td><td>统一（1.33秒/ 1.6毫米/双人间） </td><td> 119±68 </td><td> 60％ </td></tr><tr><td></td><td>图案（1.33秒/ 1.6毫米/单） </td><td> 164±75 </td><td> 25％ </td></tr><tr><td></td><td>图案（1.33秒/ 1.6毫米/双人间） </td><td> 81±25 </td><td> 80％ </td></tr><tr><td></td><td>图案（1.33秒/ 3毫米/单） </td><td> 116±63 </td><td> 85％ </td></tr><tr><td></td><td>图案（1.33秒/ 3毫米/双人间） </td><td> 80±55 </td><td> 100％ </td></tr></tbody></table> 表1. 四层器件的性能。平均排汗不同的胶粘剂应用条件的时间和成功率。 N = 20。 <table fo:keep-together.within页="1"&gt; <tbody><tr><td> 胶覆盖 </td><td> 喷雾持续时间（秒） </td><td> 平均质谱±SD（毫克/平方厘米） </td></tr><tr><td>制服</td><td> 1.33 </td><td> 0.26±0.05 </td></tr><tr><td>制服</td><td> 0.67 </td><td> 0.14±0.03 </td></tr><tr><td>图案</td><td> 1.33 </td><td> 0.02±0.01 </td></tr><tr><td>没有</td><td> 0 </td><td> -0.01±0 </td></tr></tbody></table> 表2.应用胶粘剂金额。平均胶厚（干重）涂在9x9的厘米见方的不同喷雾条件下。 N = 10。

Watch this Scientific Journal Video about Using Adhesive Patterning to Construct 3D Paper Microfluidic Devices at JoVE.com

Using Adhesive Patterning to Construct 3D Paper Microfluidic Devices

我们演示了如何使用图形化的气溶胶粘合剂来构建三维纸微流体装置。的粘合剂的申请表格该方法的层间半永久债券，使单次使用的装置是非破坏性地拆卸使用后，缓解折叠复杂的非平面结构。

使用粘性图案构建3D纸微流体装置

We demonstrate the use of patterned aerosol adhesives to construct both planar and nonplanar 3D paper microfluidic devices. By spraying an aerosol ...

using-adhesive-patterning-to-construct-3d-paper-microfluidic-devices

Nanyang Technological University

Research

JoVE Journal

Bioengineering

7.5K 次观看.  University of California, Riverside. 我们演示了如何使用图形化的气溶胶粘合剂来构建三维纸微流体装置。的粘合剂的申请表格该方法的层间半永久债券，使单次使用的装置是非破坏性地拆卸使用后，缓解折叠复杂的非平面结构。 

视频: Using Adhesive Patterning to Construct 3D Paper Microfluidic Devices

Origami Inspired Self-assembly of Patterned and Reconfigurable Particles

There are numerous techniques such as photolithography, electron-beam lithography and soft-lithography that can be used to precisely pattern two dimensional (2D) structures. These technologies are mature, offer high precision and many of them can be implemented in a high-throughput manner. We leverage the advantages of planar lithography and combine them with self-folding methods1-20 wherein physical forces derived from surface tension or residual stress, are used to curve or fold planar structures into three dimensional (3D) structures. In doing so, we make it possible to mass produce precisely patterned static and reconfigurable particles that are challenging to synthesize.
In this paper, we detail visualized experimental protocols to create patterned particles, notably, (a) permanently bonded, hollow, polyhedra that self-assemble and self-seal due to the minimization of surface energy of liquefied hinges21-23 and (b) grippers that self-fold due to residual stress powered hinges24,25. The specific protocol described can be used to create particles with overall sizes ranging from the micrometer to the centimeter length scales. Further, arbitrary patterns can be defined on the surfaces of the particles of importance in colloidal science, electronics, optics and medicine. More generally, the concept of self-assembling mechanically rigid particles with self-sealing hinges is applicable, with some process modifications, to the creation of particles at even smaller, 100 nm length scales22, 26 and with a range of materials including metals21, semiconductors9 and polymers27. With respect to residual stress powered actuation of reconfigurable grasping devices, our specific protocol utilizes chromium hinges of relevance to devices with sizes ranging from 100 &mu;m to 2.5 mm. However, more generally, the concept of such tether-free residual stress powered actuation can be used with alternate high-stress materials such as heteroepitaxially deposited semiconductor films5,7 to possibly create even smaller nanoscale grasping devices.

We describe experimental details of the synthesis of patterned and reconfigurable particles from two dimensional (2D) precursors. This methodology can be used to create particles in a variety of shapes including polyhedra and grasping devices at length scales ranging from the micro to centimeter scale.

折纸灵感的图案和可重构颗粒自组装

There are numerous techniques such as photolithography, electron-beam lithography and soft-lithography that can be used to precisely pattern two ...

科研

化学

Creating Adhesive and Soluble Gradients for Imaging Cell Migration with Fluorescence Microscopy

Cells can sense and migrate towards higher concentrations of adhesive cues such as the glycoproteins of the extracellular matrix and soluble cues such as growth factors. Here, we outline a method to create opposing gradients of adhesive and soluble cues in a microfluidic chamber, which is compatible with live cell imaging. A copolymer of poly-L-lysine and polyethylene glycol (PLL-PEG) is employed to passivate glass coverslips and prevent non-specific adsorption of biomolecules and cells. Next, microcontact printing or dip pen lithography are used to create tracks of streptavidin on the passivated surfaces to serve as anchoring points for the biotinylated peptide arginine-glycine-aspartic acid (RGD) as the adhesive cue. A microfluidic device is placed onto the modified surface and used to create the gradient of adhesive cues (100% RGD to 0% RGD) on the streptavidin tracks. Finally, the same microfluidic device is used to create a gradient of a chemoattractant such as fetal bovine serum (FBS), as the soluble cue in the opposite direction of the gradient of adhesive cues.

A method for the assembly of adhesive and soluble gradients in a microscopy chamber for live cell migration studies is described. The engineered environment combines antifouling surfaces and adhesive tracks with solution gradients and therefore allows one to determine the relative importance of guidance cues.

创建的胶粘剂和可溶性梯度荧光显微镜成像细胞迁移

Cells can sense and migrate towards higher concentrations of adhesive cues such as the glycoproteins of the extracellular matrix and soluble cues such as ...

生物工程

Cell Patterning on Photolithographically Defined 
Parylene-C: SiO2 Substrates

Cell patterning platforms support broad research goals, such as construction of predefined in vitro neuronal networks and the exploration of certain central aspects of cellular physiology. To easily combine cell patterning with Multi-Electrode Arrays (MEAs) and silicon-based &#8216;lab on a chip&#8217; technologies, a microfabrication-compatible protocol is required. We describe a method that utilizes deposition of the polymer parylene-C on SiO2&#160;wafers. Photolithography enables accurate and reliable patterning of parylene-C at micron-level resolution. Subsequent activation by immersion in fetal bovine serum (or another specific activation solution) results in a substrate in which cultured cells adhere to, or are repulsed by, parylene or SiO2 regions respectively. This technique has allowed patterning of a broad range of cell types (including primary murine hippocampal cells, HEK 293 cell line, human neuron-like teratocarcinoma cell line, primary murine cerebellar granule cells, and primary human glioma-derived stem-like cells). Interestingly, however, the platform is not universal; reflecting the importance of cell-specific adhesion molecules. This cell patterning process is cost effective, reliable, and importantly can be incorporated into standard microfabrication (chip manufacturing) protocols, paving the way for integration of microelectronic technology.

Cell Patterning on Photolithographically Defined 
Parylene-C: SiO2 Substrates

This protocol describes a microfabrication-compatible method for cell patterning on SiO2. A predefined parylene-C design is photolithographically printed on SiO2 wafers. Following incubation with serum (or other activation solution) cells adhere specifically to (and grow according to the conformity of) underlying parylene-C, whilst being repulsed by SiO2 regions.

在光刻技术定义的聚对二甲苯-C细胞图案：二氧化硅<sub&gt; 2</sub&gt;基板

Cell patterning platforms support broad research goals, such as construction of predefined in vitro neuronal networks and the exploration of certain ...

Microfluidic Genipin Deposition Technique for Extended Culture of Micropatterned Vascular Muscular Thin Films

The chronic nature of vascular disease progression requires the development of experimental techniques that simulate physiologic and pathologic vascular behaviors on disease-relevant time scales. Previously, microcontact printing has been used to fabricate two-dimensional functional arterial mimics through patterning of extracellular matrix protein as guidance cues for tissue organization. Vascular muscular thin films utilized these mimics to assess functional contractility. However, the microcontact printing fabrication technique used typically incorporates hydrophobic PDMS substrates. As the tissue turns over the underlying extracellular matrix, new proteins must undergo a conformational change or denaturing in order to expose hydrophobic amino acid residues to the hydrophobic PDMS surfaces for attachment, resulting in altered matrix protein bioactivity, delamination, and death of the tissues.
Here, we present a microfluidic deposition technique for patterning of the crosslinker compound genipin. Genipin serves as an intermediary between patterned tissues and PDMS substrates, allowing cells to deposit newly-synthesized extracellular matrix protein onto a more hydrophilic surface and remain attached to the PDMS substrates. We also show that extracellular matrix proteins can be patterned directly onto deposited genipin, allowing dictation of engineered tissue structure. Tissues fabricated with this technique show high fidelity in both structural alignment and contractile function of vascular smooth muscle tissue in a vascular muscular thin film model. This technique can be extended using other cell types and provides the framework for future study of chronic tissue- and organ-level functionality.

We present a method for microfluidic deposition of patterned genipin and fibronectin on PDMS substrates, allowing extended viability of vascular smooth muscle cell-dense tissues. This tissue fabrication method is combined with previous vascular muscular thin film technology to measure vascular contractility over disease-relevant time courses.

微京尼平沉积技术的微模式化血管肌肉薄膜的扩展文化

The chronic nature of vascular disease progression requires the development of experimental techniques that simulate physiologic and pathologic vascular ...

Construction of Modular Hydrogel Sheets for Micropatterned Macro-scaled 3D Cellular Architecture

Hydrogels can be patterned at the micro-scale using microfluidic or micropatterning technologies to provide an in vivo-like three-dimensional (3D) tissue geometry. The resulting 3D hydrogel-based cellular constructs have been introduced as an alternative to animal experiments for advanced biological studies, pharmacological assays and organ transplant applications. Although hydrogel-based particles and fibers can be easily fabricated, it is difficult to manipulate them for tissue reconstruction. In this video, we describe a fabrication method for micropatterned alginate hydrogel sheets, together with their assembly to form a macro-scale 3D cell culture system with a controlled cellular microenvironment. Using a mist form of the calcium gelling agent, thin hydrogel sheets are easily generated with a thickness in the range of 100 - 200 &#181;m, and with precise micropatterns. Cells can then be cultured with the geometric guidance of the hydrogel sheets in freestanding conditions. Furthermore, the hydrogel sheets can be readily manipulated using a micropipette with an end-cut tip, and can be assembled into multi-layered structures by stacking them using a patterned polydimethylsiloxane (PDMS) frame. These modular hydrogel sheets, which can be fabricated using a facile process, have potential applications of in vitro drug assays and biological studies, including functional studies of micro- and macrostructure and tissue reconstruction.

We describe the fabrication of micropatterned hydrogel sheets using a simple process, which can be assembled and manipulated in a freestanding form. Using these modular hydrogel sheets, a simple macro-scaled 3D cell culture system can be generated with a controlled cellular microenvironment.

构建模块化水凝胶片的微模式化宏观缩放3D细胞结构

Hydrogels can be patterned at the micro-scale using microfluidic or micropatterning technologies to provide an in vivo-like three-dimensional (3D) tissue ...

Micropatterning and Assembly of 3D Microvessels

In vitro platforms to study endothelial cells and vascular biology are largely limited to 2D endothelial cell culture, flow chambers with polymer or glass based substrates, and hydrogel-based tube formation assays. These assays, while informative, do not recapitulate lumen geometry, proper extracellular matrix, and multi-cellular proximity, which play key roles in modulating vascular function. This manuscript describes an injection molding method to generate engineered vessels with diameters on the order of 100 &#181;m. Microvessels are fabricated by seeding endothelial cells in a microfluidic channel embedded within a native type I collagen hydrogel. By incorporating parenchymal cells within the collagen matrix prior to channel formation, specific tissue microenvironments can be modeled and studied. Additional modulations of hydrodynamic properties and media composition allow for control of complex vascular function within the desired microenvironment. This platform allows for the study of perivascular cell recruitment, blood-endothelium interactions, flow response, and tissue-microvascular interactions. Engineered microvessels offer the ability to isolate the influence from individual components of a vascular niche and precisely control its chemical, mechanical, and biological properties to study vascular biology in both health and disease.

This manuscript presents an injection molding method to engineer microvessels that recapitulate physiological properties of endothelium. The microfluidic-based process creates patent 3D vascular networks with tailorable conditions, such as flow, cellular composition, geometry, and biochemical gradients. The fabrication process and examples of potential applications are described.

缩微和3D微血管大会

In vitro platforms to study endothelial cells and vascular biology are largely limited to 2D endothelial cell culture, flow chambers with polymer or glass ...

Patterning of Microorganisms and Microparticles through Sequential Capillarity-assisted Assembly

Controlled patterning of microorganisms into defined spatial arrangements offers unique possibilities for a broad range of biological applications, including studies of microbial physiology and interactions. At the simplest level, accurate spatial patterning of microorganisms would enable reliable, long-term imaging of large numbers of individual cells and transform the ability to quantitatively study distance-dependent microbe-microbe interactions. More uniquely, coupling accurate spatial patterning and full control over environmental conditions, as offered by microfluidic technology, would provide a powerful and versatile platform for single-cell studies in microbial ecology. 
This paper presents a microfluidic platform to produce versatile and user-defined patterns of microorganisms within a microfluidic channel, allowing complete optical access for long-term, high-throughput monitoring. This new microfluidic technology is based on capillarity-assisted particle assembly and exploits the capillary forces arising from the controlled motion of an evaporating suspension inside a microfluidic channel to deposit individual microsized objects in an array of traps microfabricated onto a polydimethylsiloxane (PDMS) substrate. Sequential depositions generate the desired spatial layout of single or multiple types of micro-sized objects, dictated solely by the geometry of the traps and the filling sequence. 
The platform has been calibrated using colloidal particles of different dimensions and materials: it has proven to be a powerful tool to generate diverse colloidal patterns and perform surface functionalization of trapped particles. Furthermore, the platform was tested on microbial cells, using Escherichia coli cells as a model bacterium. Thousands of individual cells were patterned on the surface, and their growth was monitored over time. In this platform, the coupling of single-cell deposition and microfluidic technology allows both geometric patterning of microorganisms and precise control of environmental conditions. It thus opens a window into the physiology of single microbes and the ecology of microbe-microbe interactions, as shown by preliminary experiments.

We present a technology that uses capillarity-assisted assembly in a microfluidic platform to pattern micro-sized objects suspended in a liquid, such as bacteria and colloids, into prescribed arrays on a polydimethylsiloxane substrate.

通过顺序毛细管辅助组装对微生物和微粒进行图案化

Controlled patterning of microorganisms into defined spatial arrangements offers unique possibilities for a broad range of biological applications, ...

工程学

Fabrication of Three-dimensional Paper-based Microfluidic Devices for Immunoassays

Paper wicks fluids autonomously due to capillary action. By patterning paper with hydrophobic barriers, the transport of fluids can be controlled and directed within a layer of paper. Moreover, stacking multiple layers of patterned paper creates sophisticated three-dimensional microfluidic networks that can support the development of analytical and bioanalytical assays. Paper-based microfluidic devices are inexpensive, portable, easy to use, and require no external equipment to operate. As a result, they hold great promise as a platform for point-of-care diagnostics. In order to properly evaluate the utility and analytical performance of paper-based devices, suitable methods must be developed to ensure their manufacture is reproducible and at a scale that is appropriate for laboratory settings. In this manuscript, a method to fabricate a general device architecture that can be used for paper-based immunoassays is described. We use a form of additive manufacturing (multi-layer lamination) to prepare devices that comprise multiple layers of patterned paper and patterned adhesive. In addition to demonstrating the proper use of these three-dimensional paper-based microfluidic devices with an immunoassay for human chorionic gonadotropin (hCG), errors in the manufacturing process that may result in device failures are discussed. We expect this approach to manufacturing paper-based devices will find broad utility in the development of analytical applications designed specifically for limited-resource settings.

We detail a method to fabricate three-dimensional paper-based microfluidic devices for use in the development of immunoassays. Our approach to device assembly is a type of multilayer, additive manufacturing. We demonstrate a sandwich immunoassay to provide representative results for these types of paper-based devices.

三维纸基微流体装置的制造用于免疫分析

Paper wicks fluids autonomously due to capillary action. By patterning paper with hydrophobic barriers, the transport of fluids can be controlled and ...

A Versatile Method of Patterning Proteins and Cells

Substrate and cell patterning techniques are widely used in cell biology to study cell-to-cell and cell-to-substrate interactions. Conventional patterning techniques work well only with simple shapes, small areas and selected bio-materials. This article describes a method to distribute cell suspensions as well as substrate solutions into complex, long, closed (dead-end) polydimethylsiloxane (PDMS) microchannels using negative pressure. This method enables researchers to pattern multiple substrates including fibronectin, collagen, antibodies (Sal-1), poly-D-lysine (PDL), and laminin. Patterning of substrates allows one to indirectly pattern a variety of cells. We have tested C2C12 myoblasts, the PC12 neuronal cell line, embryonic rat cortical neurons, and amphibian retinal neurons. In addition, we demonstrate that this technique can directly pattern fibroblasts in microfluidic channels via brief application of a low vacuum on cell suspensions. The low vacuum does not significantly decrease cell viability as shown by cell viability assays. Modifications are discussed for application of the method to different cell and substrate types. This technique allows researchers to pattern cells and proteins in specific patterns without the need for exotic materials or equipment and can be done in any laboratory with a vacuum.

This report describes a simple, easy to perform technique, using low pressure vacuum, to fill microfluidic channels with cells and substrates for biological research.

图案蛋白质和细胞的通用的方法

Substrate and cell patterning techniques are widely used in cell biology to study cell-to-cell and cell-to-substrate interactions. Conventional patterning ...

纳米纤维素纸基分析装置的微压花制备  

Microembossing: A Convenient Process for Fabricating Microchannels on Nanocellulose Paper-Based Microfluidics

Nanopaper, derived from nanofibrillated cellulose, has generated considerable interest as a promising material for microfluidic applications. Its appeal lies in a range of excellent&#160;qualities, including an exceptionally smooth surface, outstanding optical transparency, a uniform nanofiber matrix with nanoscale porosity, and customizable chemical properties. Despite the rapid growth of nanopaper-based microfluidics, the current techniques used to create microchannels on nanopaper, such as 3D printing, spray coating, or manual cutting and assembly, which are crucial for practical applications, still possess certain limitations, notably susceptibility to contamination. Furthermore, these methods are restricted to the production of millimeter-sized channels. This study introduces a straightforward process that utilizes convenient plastic micro-molds for simple microembossing operations to fabricate microchannels on nanopaper, achieving a minimum width of 200 &#181;m. The developed microchannel outperforms existing approaches, achieving a fourfold improvement, and can be fabricated within 45 min. Furthermore, fabrication parameters have been optimized, and a convenient quick-reference table is provided for application developers. The proof-of-concept for a laminar mixer, droplet generator, and functional nanopaper-based analytical devices (NanoPADs) designed for Rhodamine B sensing using surface-enhanced Raman spectroscopy was demonstrated. Notably, the NanoPADs exhibited exceptional performance with improved limits of detection. These outstanding results can be attributed to the superior optical properties of nanopaper and the recently developed accurate microembossing method, enabling the integration and fine-tuning of the NanoPADs.

作者聚焦：通过纳米纸上的微通道制造彻底改变微流体 

This protocol describes a straightforward process that utilizes convenient plastic micro-molds for simple microembossing operations to fabricate microchannels on nanofibrillated cellulose paper, achieving a minimum width of 200 &#181;m.

微压花：在纳米纤维素纸基微流控上制造微通道的便捷工艺

Nanopaper, derived from nanofibrillated cellulose, has generated considerable interest as a promising material for microfluidic applications. Its appeal ...

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