本文报告了由丹麦创新基金资助的 "植入式医疗设备先进表面处理" 项目所开展的工作。撰文人感谢欧洲创新培训网 MICROMAN "零缺陷网络形状 MICROMANufacturing 过程指纹" 的支持, 由2020欧洲研究和创新框架方案资助联盟。

1. 通过添加剂制造 (AM) 进行插入加工
<ol><li>通过计算机辅助设计软件设计所需的孔洞 (请参阅本工作中使用的文件的补充材料)。 注: 在不支持的情况下, 直接在建筑台上制造刀片, 避免在固化过程中翘曲刀片。公差为0.05 毫米。</li>
	<li>选择一个树脂为照片聚合, 特别是一个可以承受压力和热在注塑成型。 注: 我们选择的树脂 (见材料表) 的抗拉强度为56兆帕, 断裂伸长率为 3.5%, 弯曲强度为115兆帕, 弯曲模量为3350兆帕, 热偏转温度为140摄氏度18。</li>
	<li>混合光敏混合 (专有甲基丙烯酸甲酯和丙烯酰胺混合, 与2基的照片启动器) 彻底至少30分钟, 通过运行的材料罐在湿实验室瓶辊, 烧瓶振动筛或类似的混合装置。</li>
	<li>准备照片聚合机 (体素大小为16µm):<ol>
<li>对于自下而上的 AM 机器, 检查增值税涂层是否未损坏并彻底清洗。</li>
		<li>对于自上而下的机器, 检查擦拭系统是否有任何缺陷。</li>
		<li>检查生成阶段, 并使用100µm 规格箔调整生成板, 以正确地将生成板偏移到增值税。</li>
		<li>如果可能的话, 预先点燃机床的光源, 以达到稳态温度, 然后再进行。这温度应该是65°c 在轻的引擎和30°c 在增值税之内。</li>
	</ol>
</li>
	<li>将几何图形导入作业准备软件。遵循从机器制造商19的指导方针。<ol>
<li>分配适当的机器参数以匹配所选的光敏 (使用的机器的光强度和层厚度)。</li>
		<li>以最高的垂直机器分辨率 (本研究中的25µm) 运行生成。</li>
	</ol>
</li>
	<li>清洗打印的插入件。<ol>
<li>将其冲洗在异丙醇暴露于超声波浴中3分钟, 彻底冲洗三次, 并确保打印的刀片表面不留光敏残留物。</li>
		<li>允许溶剂在室温下完全蒸发, 并将干燥中的插入物放在室温下过夜。</li>
	</ol>
</li>
	<li>后处理的干燥插入使用 UV 光闪烁两次, 每次2000年闪烁每秒10闪烁频率 (见材料表)。</li>
</ol>2. 注塑成型 (IM)
<ol><li>在常规注塑机上安装微注塑模块 (见材料表)。 注: 在我们的情况下, 注射模块有一个螺钉安装在45°的角度, 螺钉直径为8毫米, 夹紧力为 100 kN。</li>
	<li>将刀片装入模具板上。</li>
</ol><img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57335/57335fig1.jpg"> 图 1: 注塑机与模具.(a) 注射方与板材装配。插入由红色圆圈突出显示。(b) 可移动侧与带有弹射销的板材装配。插入由红色圆圈突出显示。<a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/57335/57335fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<ol start="3"><li>为了适应打印过程中的变化, 手动对所需的插入件进行任何细微的修改以适合模具。</li>
	<li>拧紧机器上的模具板。</li>
	<li>将 PE 颗粒装入料斗。</li>
	<li>将机床参数 T 模设置为摄氏60摄氏度, t桶为175摄氏度, V型注塑为65毫米/秒. 允许部件的冷却时间足够 demolded。</li>
	<li>加热螺丝在31°c, 155 °c, 165 °c, 170 °c, 和175°c 从第一到第五届会议。当熔体温度为175摄氏度时, 开始精确的注塑成型。一旦腔被填满, 保持300巴的包装压力5秒, 以弥补 PE 收缩。</li>
	<li>打开模具并允许弹射销将 PE 部件从插入件的可移动侧推出。如果 PE 部件夹在插入件上, 请手动取出零件。</li>
	<li>在100次注塑过程中停止机器 (循环是从模具关闭直到部件被弹出时定义的)。</li>
</ol>3. 质量评估
<ol><li>用激光扫描数字显微镜20测量注塑成型前孔的直径和深度。两个刀片的测量;在每个插入, 测量四孔在两个区域以不同的距离对门 "在门附近" 和 "远离门"。</li>
</ol><img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57335/57335fig2.jpg"> 图 2: 在插入件的 CAD 图像上突出显示的测量区域.(a) 可移动侧插入对应于复制副本的屁股;(b) 注入端对应于复制副本的顶端。注射门位于中心。在研究中比较了两个区域, 分别与门的距离、"远离门" 和 "靠近门"。(这个数字已经从张等201722) 修改过了。<a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/57335/57335fig2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<ol start="2"><li>测量直径和柱子的高度从注射成型获得的履带尖尖。 注: 将所获得的 PE 零件分组成批次10件;即1-10 是第一批, 11-20 是第二批;直到最后一块。在每个批次中使用一个随机样本, 并在顶部和后侧进行测量;在两边, 测量四根柱子在两个区域以不同的距离对门 ("在门附近" 和 "远离门")。</li>
	<li>通过图像处理软件21的辅助分析数据, 以获得尺寸。</li>
</ol>

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作者没有什么可透露的。

该方法适用于复杂形状高分子零件的插入件的制作。它用一组由聚合物制成的软刀片代替注塑机中的刀具钢模腔。与传统的金属加工相比, 缩短了加工时间和成本;因此, 生产周期缩短。该工艺链适用于中等规模的产品 (从 1000年-1万周期注塑或类似) 生产, 但在设计上的变化很大。此外, 对于3D 印刷刀片, 不需要特殊的模具板。标准的商用注塑板被购买和加工, 以适应插入。
在当前的技术状态下, 软模具由不同的机制17失败。该失效机理已被确定为连接软模具插入件的热偏转温度, 而分解则被确定为由于出气。因此, 最关键的一步是选择合适的树脂为插入物生产的添加剂制造。热力学性能决定了插入件的寿命,即在注塑过程中能承受多少循环。它还决定了模塑聚合物的范围;模塑聚合物的模具温度不应高于插入材料的挠度温度。
协议中的第二个关键步骤是插入的设计。应遵循模具设计的一般规则, 在3D 印制聚合物插入件时应避免机械薄弱部件;否则, 刀具寿命会因裂纹等故障而受到影响。
所获得的注塑件表面质量受外加添加剂制造工艺的限制。后处理, 如化学蚀刻是一个可能的解决方案, 以提高表面质量。表面特性的精度是由于添加剂制造过程而引起的另一个问题。
该方法在满足工业需求的新生产平台上创造了在真实自由曲面上创建微特征的可能性。因此, 这种方法有可能被应用和研究的应用与下一代医疗设备, 需要微功能的复杂形状, 例如与医疗器械或植入设备14.该方法通过大幅度降低中小批量生产系列产品的成本来促进价值创造, 并对 1-10 个单独设备与实际批量生产之间的差距产生积极影响。它将开辟新的高附加值产品和设计方案。

本发明的目的是通过软加工工艺制造具有微特征的复杂表面,即利用高分子添加剂制造生产聚合物注塑成型的刀片。换言之, 具有功能表面的聚合物部件是由聚合物插入模塑而成。
表面功能可通过微特征实现;例如, 杜安等。1和 Luchetta等。2展示细胞生物学领域的功能表面, 以及胡等。3显示了一个光学元件的例子,等等.一种表面特征, 微柱, 已被深入研究, 以促进细胞增殖。如果微柱以一定的方式4,5, 它们能够增强增生组织与表面的结合。
对微特征的聚合物复制进行了深入研究, 并通过6多个工艺实现了精密成型。例如, Metwally等人报告了模塑零件和模具之间的高保真度, 以复制微和亚微特征在平坦表面7。
有许多制造微柱或特征的协议;然而, 它们大多只能应用在平坦的表面或具有恒定曲率的曲面上。例如, 年等。8表明, 在曲面上的热压花可以实现微特征。这些协议不适用于具有三维曲面的复杂形状, 这是大多数实际设备所必需的。显然, 表面具有微特征的三维腔的制造挑战了当前的协议;同时, 如果在复杂表面上的高纵横比柱子不垂直于脱模方向, 则部件的弹射可能会失败。Bissacco等。9 ) 采用3D 模刀片, 通过注塑成型获得亚微米特征;在研究中, 采用铝阳极氧化工艺, 在复杂组分上成功地复制了具有低长宽比的特异性亚微米特征。
研究人员试图在聚合物复制的过程链中加入添加剂制造, 以达到设计的表面纹理。Lantada等人描述了从 AM 原型开始的工艺链, 然后采用涂装技术获取注塑成型10的金属模刀片。由 AM 生产的高分子零件已被证明是直接适用于模具插入11,12, 这是软模具过程中提出的协议。
在我们以前的工作中, 我们证明了Ø4µm PEEK 柱 (2 µm 高) 成功 demolded 在垂直墙上注塑成型13。在本协议中, 所研究的产品是一个四尖的环, 每一个都有一个角度的一角。本产品已由张等研究。14、采用预制备的镍板进行微特征提取, 在齿尖上采用硅橡胶注射成型法, 得到了µm 的微柱 (Ø4), 其长宽比为0.5。
在所提出的方法中, 可以在软模具加工链所创建的复杂曲面上获得微特征。钢模腔被一组由还原光聚合为基础的镶件所取代。与金属相比, 基于光敏的 am 技术能够达到更高的精度15。而且, 与传统的数控加工工艺相比, 加工时间和成本大大降低。根据最近的案例研究16, 通过使用软模具进行热成型, 成本降低了 91%, 而消耗的时间减少了93%。该协议适用于要求高设计灵活性和中间生产量的产品。经证明, 碳纤维增强 photopolymers 制造的刀片在明显的模具变质17前可承受2500的聚乙烯注塑周期。注射成型材料的选择受所选光敏的热性能的限制。高熔融温度的聚合物在光敏腔中可能不适用。本研究选用聚乙烯 (PE) 进行注射成型试验。

<table><tbody><tr><td>Photopolymer resin</td><td>EnvisionTec</td><td>HTM140 V2</td><td></td></tr><tr><td>Resin mixing device</td><td>IKA</td><td>Vortex Genius 3</td><td></td></tr><tr><td>3d printer</td><td>Envisiontec</td><td>Perfactory 3&amp;nbsp;</td><td></td></tr><tr><td>UV light flash unit</td><td>EnvisionTec</td><td>Otoflash unit</td><td></td></tr><tr><td>Polyethylene</td><td>lyondellbasell</td><td>PE Purell 1840</td><td></td></tr><tr><td>Injection moulding machine</td><td>Arburg</td><td>Allrounder 370A&amp;nbsp;</td><td></td></tr><tr><td>Image processing</td><td>SPIP</td><td>6.2.8</td><td></td></tr></tbody></table>

a soft tooling process chain for injection molding of a 3d component with micro pillars

本文的目的是介绍一种采用添加剂制造 (AM) 的软模具工艺链制造具有微表面特征的注塑刀片的方法。软工具插入是由数字光处理 (vat 照片聚合) 制造的, 使用的光敏可以承受相对较高的 temperaturea。这里制造的部件有四尖角的角度。微柱 (Ø200µm, 长宽比 1) 由两排排列在表面上。聚乙烯 (PE) 注塑与软模具插入是用来制造最后的零件。该方法表明, 采用外加剂制造的刀片, 在复杂几何上获得具有显微结构的注塑件是可行的。与基于计算机数控 (CNC) 加工的传统模具相比, 加工时间和成本显著降低。微特征的尺寸受外加添加剂制造过程的影响。插入的寿命决定了此过程更适合于先导生产。刀片生产的精度也受到添加剂制造过程的限制。

图 3显示了由 AM 和注塑成型的 PE 零件制造的插入件。两行圆孔垂直于尖尖上的曲面 (图 3 (b))。插入孔的公称尺寸为Ø200µm, 深度为200µm, 中心到中心距离为400µm。由于 AM 过程的层结构清晰可见。在左下线有一个可看见的折叠的标记, 在准备期间无意中发生在 SEM。
脱模过程如图 4所示。柱子不平行于脱模方向。在所有研究样品中没有发现柱断裂 (图 5)。从这个意义上说, 脱模是成功的。由于压力下降, 远距门位置的柱子明显低于顶部, 这一点已经可见。关于直径, 区别从位置不一样突出象为高度。
图 6和图 7说明了复制在注塑成型的100个周期中的传播方式。复制的程度由柱子的尺寸和插入物的尺寸之间的比值来定义。沿100循环, 在每个位置上实现了垂直和横向复制的稳定过程。在注塑成型后, 插入孔的尺寸不变, 证实了这一结论。离闸门很远的柱子的高度低于浇口的位置, 因为聚合物流动增加了其粘度。
注射成型参数在材料数据表允许的范围内变化。在 "探索的过程" 窗口中, 大多数运行都达到了80个以上的周期, 确认在探索的过程窗口中, AM 插入的刀具寿命不受影响。但是, 在注射压力较高时, 在某些试验中, 注塑侧的插入件发生开裂。这是由于插入的中心部分更薄。
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57335/57335fig3.jpg"> 图 3: 插入和复制副本.(a) 由模具腔体组成的添加剂制造工艺制成的刀片;展示了一种由注塑成型的聚乙烯 (PE) 复制品。参考标尺上的标记为毫米;数字标记厘米。(b) 扫描电子显微镜 (SEM) 图像显示插入的表面;(c) SEM 图像显示注塑成型 PE 零件的表面。((a) 及 (b) 已由张等人修改 201722)<a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/57335/57335fig3large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57335/57335fig4.jpg"> 图 4: 成功的脱模.尽管柱子与脱模方向不平行, 脱模还是成功的。(a) 模具关闭和 (b) 模具开放脱模。(这个数字已经从张等201722) 修改过了。<a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/57335/57335fig4large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/57335/57335fig5.jpg"> 图 5: 一个随机齿尖侧面的 SEM 图像.所调查的四个位置被标记在图像上。(这个数字已经从张等201722) 修改过了。<a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/57335/57335fig5large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/57335/57335fig6.jpg"> 图 6: 柱高复制度.柱高度的复制程度是由孔的柱/深的高度来定义的。每批中显示四个位置的复制程度的平均值。每个批次中都测量了一个随机选取的样本。四位置是 "后远" 的位置远离门在后面, "后面的位置靠近门的后面," 顶部 "的位置远离大门在上面, 和" 顶部附近 "的位置附近的大门在顶部。(这个数字已经从张等2017 22) 修改过了。<a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/57335/57335fig6large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/57335/57335fig7.jpg"> 图 7: 柱径复制度.柱直径的复制程度由孔的柱直径或直径确定。每批中显示四个位置的复制程度的平均值。每个批次中都测量了一个随机选取的样本。四位置是 "后远" 的位置远离门在后面, "后近" 的位置附近的大门在后面, "顶部" 的位置远离大门在上面, 和 "顶部附近" 的位置附近的大门在顶端一侧。(这个数字已从张等2017 22) 修改。<a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/57335/57335fig7large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>

Watch this Scientific Journal Video about A Soft Tooling Process Chain for Injection Molding of a 3D Component with Micro Pillars at JoVE.com

A Soft Tooling Process Chain for Injection Molding of a 3D Component with Micro Pillars

微柱3D 构件注塑成型的软加工工艺链

提出了一种采用添加剂制造 (AM) 的表面具有微特征的复杂几何形状的注塑件的制作方案。

The purpose of this paper is to present the method of a soft tooling process chain employing Additive Manufacturing (AM) for fabrication of injection ...

a-soft-tooling-process-chain-for-injection-molding-3d-component-with

Nanyang Technological University

Research

JoVE Journal

Engineering

12.5K 次观看.  Technical University of Denmark. 提出了一种采用添加剂制造 (AM) 的表面具有微特征的复杂几何形状的注塑件的制作方案。

视频: A Soft Tooling Process Chain for Injection Molding of a 3D Component with Micro Pillars

Micropunching Lithography for Generating Micro- and Submicron-patterns on Polymer Substrates

Conducting polymers have attracted great attention since the discovery of high conductivity in doped polyacetylene in 19771. They offer the advantages of low weight, easy tailoring of properties and a wide spectrum of applications2,3. Due to sensitivity of conducting polymers to environmental conditions (e.g., air, oxygen, moisture, high temperature and chemical solutions), lithographic techniques present significant technical challenges when working with these materials4. For example, current photolithographic methods, such as ultra-violet (UV), are unsuitable for patterning the conducting polymers due to the involvement of wet and/or dry etching processes in these methods. In addition, current micro/nanosystems mainly have a planar form5,6. One layer of structures is built on the top surfaces of another layer of fabricated features. Multiple layers of these structures are stacked together to form numerous devices on a common substrate. The sidewall surfaces of the microstructures have not been used in constructing devices. On the other hand, sidewall patterns could be used, for example, to build 3-D circuits, modify fluidic channels and direct horizontal growth of nanowires and nanotubes.
A macropunching method has been applied in the manufacturing industry to create macropatterns in a sheet metal for over a hundred years. Motivated by this approach, we have developed a micropunching lithography method (MPL) to overcome the obstacles of patterning conducting polymers and generating sidewall patterns. Like the macropunching method, the MPL also includes two operations (Fig. 1): (i) cutting; and (ii) drawing. The "cutting" operation was applied to pattern three conducting polymers4, polypyrrole (PPy), Poly(3,4-ethylenedioxythiophen)-poly(4-styrenesulphonate) (PEDOT) and polyaniline (PANI). It was also employed to create Al microstructures7. The fabricated microstructures of conducting polymers have been used as humidity8, chemical8, and glucose sensors9. Combined microstructures of Al and conducting polymers have been employed to fabricate capacitors and various heterojunctions9,10,11. The "cutting" operation was also applied to generate submicron-patterns, such as 100- and 500-nm-wide PPy lines as well as 100-nm-wide Au wires. The "drawing" operation was employed for two applications: (i) produce Au sidewall patterns on high density polyethylene (HDPE) channels which could be used for building 3D microsystems12,13,14, and (ii) fabricate polydimethylsiloxane (PDMS) micropillars on HDPE substrates to increase the contact angle of the channel15.

A micropunching lithography approach is developed to generate micro- and submicron-patterns on top, sidewall and bottom surfaces of polymer substrates. It overcomes the obstacles of patterning conducting polymers and generating sidewall patterns. This method allows rapid fabrication of multiple features and is free of aggressive chemistry.

Micropunching为微型和亚微米模式聚合物基板上生成的光刻

Conducting polymers have attracted great attention since the discovery of high conductivity in doped polyacetylene in 19771. They offer the advantages of ...

科研

工程学

Process of Making Three-dimensional Microstructures using Vaporization of a Sacrificial Component

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material fabrication techniques are able to mimic the complexity of these structures while maintaining scalability. The Vaporization of a Sacrificial Component (VaSC) process is able to do so. This process uses sacrificial fibers as a template to form hollow, cylindrical microchannels embedded within a matrix. Tin (II) oxalate (SnOx) is embedded within poly(lactic) acid (PLA) fibers which facilitates the use of this process. The SnOx catalyzes the depolymerization of the PLA fibers at lower temperatures. The lactic acid monomers are gaseous at these temperatures and can be removed from the embedded matrix at temperatures that do not damage the matrix. Here we show a method for aligning these fibers using micromachined plates and a tensioning device to create complex patterns of three-dimensionally arrayed microchannels. The process allows the exploration of virtually any arrangement of fiber topologies and structures.

The Vaporization of a Sacrificial Component (VaSC) process is used to fabricate microvascular structures. This procedure uses sacrificial poly(lactic) acid fibers to form hollow microchannels with precise 3D geometric positioning provided by laser micromachined guide plates.

制作三维微结构，用牺牲部分汽化过程

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material ...

Manufacturing of Three-dimensionally Microstructured Nanocomposites through Microfluidic Infiltration

Microstructured composite beams reinforced with complex three-dimensionally (3D) patterned nanocomposite microfilaments are fabricated via nanocomposite in&#64257;ltration of 3D interconnected microfluidic networks. The manufacturing of the reinforced beams begins with the fabrication of microfluidic networks, which involves layer-by-layer deposition of fugitive ink filaments using a dispensing robot, filling the empty space between filaments using a low viscosity resin, curing the resin and finally removing the ink.&#160;Self-supported 3D structures with other geometries and many layers (e.g.&#160;a few hundreds layers) could be built using this method. The resulting tubular micro&#64258;uidic networks are then infiltrated with thermosetting nanocomposite suspensions containing nanofillers (e.g.&#160;single-walled carbon nanotubes), and subsequently cured. The infiltration is done by applying a pressure gradient between two ends of the empty network (either by applying a vacuum or vacuum-assisted microinjection). Prior to the infiltration, the nanocomposite suspensions are prepared by dispersing nanofillers into polymer matrices using ultrasonication and three-roll mixing methods. The nanocomposites (i.e.&#160;materials infiltrated) are then solidified under UV exposure/heat cure, resulting in a 3D-reinforced composite structure. The technique presented here enables the design of functional nanocomposite macroscopic products for microengineering applications such as actuators and sensors.

Three-dimensional (3D) microstructured composite beams are fabricated through the directed and localized infiltration of nanocomposites into 3D porous microfluidic networks. The flexibility of this manufacturing method enables the utilization of different thermosetting materials and nanofillers in order to achieve a variety of functional 3D reinforced nanocomposite macroscopic products.

通过微流体渗透制备三维微结构纳米复合材料的制造

Microstructured composite beams reinforced with complex three-dimensionally (3D) patterned nanocomposite microfilaments are fabricated via nanocomposite ...

化学

Micro-masonry for 3D Additive Micromanufacturing

Transfer printing is a method to transfer solid micro/nanoscale materials (herein called &#8216;inks&#8217;) from a substrate where they are generated to a different substrate by utilizing elastomeric stamps. Transfer printing enables the integration of heterogeneous materials to fabricate unexampled structures or functional systems that are found in recent advanced devices such as flexible and stretchable solar cells and LED arrays. While transfer printing exhibits unique features in material assembly capability, the use of adhesive layers or the surface modification such as deposition of self-assembled monolayer (SAM) on substrates for enhancing printing processes hinders its wide adaptation in microassembly of microelectromechanical system (MEMS) structures and devices. To overcome this shortcoming, we developed an advanced mode of transfer printing which deterministically assembles individual microscale objects solely through controlling surface contact area without any surface alteration. The absence of an adhesive layer or other modification and the subsequent material bonding processes ensure not only mechanical bonding, but also thermal and electrical connection between assembled materials, which further opens various applications in adaptation in building unusual MEMS devices.

This paper introduces a 3D additive micromanufacturing strategy (termed &#8216;micro-masonry&#8217;) for the flexible fabrication of microelectromechanical system (MEMS) structures and devices. This approach involves transfer printing-based assembly of micro/nanoscale materials in conjunction with rapid thermal annealing-enabled material bonding techniques.

微砌筑的3D添加剂Micromanufacturing

Transfer printing is a method to transfer solid micro/nanoscale materials (herein called &#8216;inks&#8217;) from a substrate where they are generated to ...

Microfabrication of Chip-sized Scaffolds for Three-dimensional Cell cultivation

Using microfabrication technologies is a prerequisite to create scaffolds of reproducible geometry and constant quality for three-dimensional cell cultivation. These technologies offer a wide spectrum of advantages not only for manufacturing but also for different applications. The size and shape of formed cell clusters can be influenced by the exact and reproducible architecture of the microfabricated scaffold and, therefore, the diffusion path length of nutrients and gases can be controlled.1 This is unquestionably a useful tool to prevent apoptosis and necrosis of cells due to an insufficient nutrient and gas supply or removal of cellular metabolites.
Our polymer chip, called CellChip, has the outer dimensions of 2 x 2 cm with a central microstructured area. This area is subdivided into an array of up to 1156 microcontainers with a typical dimension of 300 m edge length for the cubic design (cp- or cf-chip) or of 300 m diameter and depth for the round design (r-chip).2
So far, hot embossing or micro injection moulding (in combination with subsequent laborious machining of the parts) was used for the fabrication of the microstructured chips. Basically, micro injection moulding is one of the only polymer based replication techniques that, up to now, is capable for mass production of polymer microstructures.3 However, both techniques have certain unwanted limitations due to the processing of a viscous polymer melt with the generation of very thin walls or integrated through holes. In case of the CellChip, thin bottom layers are necessary to perforate the polymer and provide small pores of defined size to supply cells with culture medium e.g. by microfluidic perfusion of the containers.
In order to overcome these limitations and to reduce the manufacturing costs we have developed a new microtechnical approach on the basis of a down-scaled thermoforming process. For the manufacturing of highly porous and thin walled polymer chips, we use a combination of heavy ion irradiation, microthermoforming and track etching. In this so called "SMART" process (Substrate Modification And Replication by Thermoforming) thin polymer films are irradiated with energetic heavy projectiles of several hundred MeV introducing so-called "latent tracks" Subsequently, the film in a rubber elastic state is formed into three dimensional parts without modifying or annealing the tracks. After the forming process, selective chemical etching finally converts the tracks into cylindrical pores of adjustable diameter.

We present two processes for the microfabrication of porous polymer chips for three-dimensional cell cultivation. The first one is hot embossing combined with a solvent vapour welding process. The second one uses a recently developed microthermoforming process combined with ion track technology leading to a significant simplification of manufacture.

芯片尺寸支架的三维细胞培养的微细

Using microfabrication technologies is a prerequisite to create scaffolds of reproducible geometry and constant quality for three-dimensional cell ...

生物学

Rapid and Low-cost Prototyping of Medical Devices Using 3D Printed Molds for Liquid Injection Molding

Biologically inert elastomers such as silicone are favorable materials for medical device fabrication, but forming and curing these elastomers using traditional liquid injection molding processes can be an expensive process due to tooling and equipment costs. As a result, it has traditionally been impractical to use liquid injection molding for low-cost, rapid prototyping applications. We have devised a method for rapid and low-cost production of liquid elastomer injection molded devices that utilizes fused deposition modeling 3D printers for mold design and a modified desiccator as an injection system. Low costs and rapid turnaround time in this technique lower the barrier to iteratively designing and prototyping complex elastomer devices. Furthermore, CAD models developed in this process can be later adapted for metal mold tooling design, enabling an easy transition to a traditional injection molding process. We have used this technique to manufacture intravaginal probes involving complex geometries, as well as overmolding over metal parts, using tools commonly available within an academic research laboratory. However, this technique can be easily adapted to create liquid injection molded devices for many other applications.

We have devised a method for low-cost and rapid prototyping of liquid elastomer rubber injection molded devices by using fused deposition modeling 3D printers for mold design and a modified desiccator as a liquid injection system.

医疗器械的使用3D印刷模具的液体注射成型快速，低成本原型

Biologically inert elastomers such as silicone are favorable materials for medical device fabrication, but forming and curing these elastomers using ...

生物工程

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, ...

Assembly and Characterization of an External Driver for the Generation of Sub-Kilohertz Oscillatory Flow in Microchannels

Microfluidic technology has become a standard tool in chemical and biological laboratories for both analysis and synthesis. The injection of liquid samples, such as chemical reagents and cell cultures, is predominantly accomplished through steady flows that are typically driven by syringe pumps, gravity, or capillary forces. The use of complementary oscillatory flows is seldom considered in applications despite its numerous advantages as recently demonstrated in the literature. The significant technical barrier to the implementation of oscillatory flows in microchannels is likely responsible for the lack of its widespread adoption. Advanced commercial syringe pumps that can produce oscillatory flow, are often more expensive and only work for frequencies less than 1 Hz. Here, the assembly and operation of a low-cost, plug-and-play type speaker-based apparatus that generates oscillatory flow in microchannels is demonstrated. High-fidelity harmonic oscillatory flows with frequencies ranging from 10-1000 Hz can be achieved along with independent amplitude control. Amplitudes ranging from 10-600 &#181;m can be achieved throughout the entire range of operation, including amplitudes &#62; 1 mm at the resonant frequency, in a typical microchannel. Although the oscillation frequency is determined by the speaker, we illustrate that the oscillation amplitude is sensitive to fluid properties and channel geometry. Specifically, the oscillation amplitude decreases with increasing channel circuit length and liquid viscosity, and in contrast, the amplitude increases with increasing speaker tube thickness and length. Additionally, the apparatus requires no prior features to be designed on the microchannel and is easily detachable. It can be used simultaneously with a steady flow created by a syringe pump to generate pulsatile flows.

The protocol demonstrates a convenient method to produce harmonic oscillatory flow from 10-1000 Hz in microchannels. This is performed by interfacing a computer-controlled speaker diaphragm to the microchannel in a modular manner.

用于在微通道中产生亚千赫兹振荡流的外部驱动器的组装和表征

Microfluidic technology has become a standard tool in chemical and biological laboratories for both analysis and synthesis. The injection of liquid ...

Three-dimensional Printing of Thermoplastic Materials to Create Automated Syringe Pumps with Feedback Control for Microfluidic Applications

Microfluidics has become a critical tool in research across the biological, chemical, and physical sciences. One important component of microfluidic experimentation is a stable fluid handling system capable of accurately providing an inlet flow rate or inlet pressure. Here, we have developed a syringe pump system capable of controlling and regulating the inlet fluid pressure delivered to a microfluidic device. This system was designed using low-cost materials and additive manufacturing principles, leveraging three-dimensional (3D) printing of thermoplastic materials and off-the-shelf components whenever possible. This system is composed of three main components: a syringe pump, a pressure transducer, and a programmable microcontroller. Within this paper, we detail a set of protocols for fabricating, assembling, and programming this syringe pump system. Furthermore, we have included representative results that demonstrate high-fidelity, feedback control of inlet pressure using this system. We expect this protocol will allow researchers to fabricate low-cost syringe pump systems, lowering the entry barrier for the use of microfluidics in biomedical, chemical, and materials research.

Here we present a protocol to construct a pressure-controlled syringe pump to be used in microfluidic applications. This syringe pump is made from an&#160;additively manufactured body, off-the-shelf hardware, and open-source electronics. The resulting system is low-cost, straightforward to build, and delivers well-regulated fluid flow to enable rapid microfluidic research.

三维热塑性材料的印刷, 以创建自动注射器泵的反馈控制微流控应用

Microfluidics has become a critical tool in research across the biological, chemical, and physical sciences. One important component of microfluidic ...

Interlinked Macroporous 3D Scaffolds from Microgel Rods

A two-component system of functionalized microgels from microfluidics allows for fast interlinking into 3D macroporous constructs in aqueous solutions without further additives. Continuous photoinitiated on-chip gelation enables variation of the microgel aspect ratio, which determines the building block properties for the obtained constructs. Glycidyl methacrylate (GMA) or 2-aminoethyl methacrylate (AMA) monomers are copolymerized into the microgel network based on polyethylene glycol (PEG) star-polymers to achieve either epoxy or amine functionality. A focusing oil flow is introduced into the microfluidic outlet structure to ensure continuous collection of the functionalized microgel rods. Based on a recent publication, microgel rod-based constructs result in larger pores of several hundred micrometers and, at the same time, lead to overall higher scaffold stability in comparison to a spherical-based model. In this way, it is possible to produce higher-volume constructs with more free volume while reducing the amount of material required. The interlinked macroporous scaffolds can be picked up and transported without damage or disintegration. Amine and epoxy groups not involved in interlinking remain active and can be used independently for post-modification. This protocol describes an optimized method for the fabrication of microgel rods to form macroporous interlinked scaffolds that can be utilized for subsequent cell experiments.

Microgel rods with complementary reactive groups are produced via microfluidics with the ability to interlink in aqueous solution. The anisometric microgels jam and interlink into stable constructs with larger pores compared to spherical-based systems. Microgels modified with GRGDS-PC form macroporous 3D constructs that can be used for cell culture.

来自微凝胶棒的互连大孔3D支架

A two-component system of functionalized microgels from microfluidics allows for fast interlinking into 3D macroporous constructs in aqueous solutions ...