提交人承认来自海军研究奖 N00014-17-12306 和 N00014-15-1-2502 的支持, 以及来自空军科研奖 FA9550-13-1-0108 和国家科学基金会赠款1709238号的支助。

1. 注射器泵3级打印和组装
<ol><li>
准备和 3 d 打印注射器泵组件
	<ol>
<li>下载。STL 设计文件从本文的补充文件。 注: 有六。stl 文件, 标题为 "JoVE_Syringe_Clamp_10mL_Size"、"JoVE_Syringe_Platform"、"JoVE_Syringe_Plunger_Connectors"、"JoVE_Syringe_Pump_End_Stop. stl"、"JoVE_Syringe_Pump_Motor_Connector. stl" 和 "JoVE_Syringe_Pump_Traveler_"在补充文件中推. stl。这些文件对应于注射器泵的3维打印部件。</li>
		<li>通过在专用于转换的软件包中打开这些文件以进行打印。STL 模型文件到正在使用的 3 d 打印机的可执行指令集。确保使用适当的软件作为某些打印机需要专有软件, 而另一些则可以直接从。STL 文件。</li>
		<li>使用高品质的 3 d 打印机设置, 用丙烯腈丁二烯苯乙烯 (ABS) 打印塑料部件。如果使用其他常见的 3 d 印刷材料, 如聚乳酸 (PLA) 或其他热塑性弹性体, 确保所完成的机械性能 (如弹性、屈服强度) 与 ABS 相媲美。</li>
		<li>将打印部件从 3 d 打印机的打印平台中分离出来。从成品部件中取出打印的支撑结构。 注意: 支持结构是由用于转换的特定于打印机的软件设计的。STL 模型文件到 3 d 打印机的可执行指令集。支持材料的数量和结构可能因使用的软件而异。</li>
		<li>使用砂纸打磨任何粗糙的边缘, 平滑打印的组件。为达到最佳效果, 请使用砂粒大小约为220的砂纸。请确保所有组件在装配前都是平滑的。</li>
		<li>确保所有七个部件都已打印。 注: 这些部件已命名如下: (I) 马达连接器, (II) 旅行者推挤, (III) 末端中止, (IV) 注射器平台, (V) 注射器钳, (VI) 注射器柱塞男性连接器和 (七) 注射器柱塞女性连接器。图 2A中引用了每个组件的罗马数字。在材料表中找到了装配机械零件的详细清单。</li>
	</ol>
</li>
	<li>
组装注射器泵 (图 2)
	<ol>
<li>使用带有固定螺钉的马达轴 Z 轴柔性耦合器将步进电机固定在螺纹杆上。在继续之前, 请确保旋转步进电机轴驱动螺纹杆而不打滑。</li>
		<li>将注射器平台连接到马达连接器上, 将注射器平台的连接钉牢牢地按在马达连接器顶部的联接孔上。</li>
		<li>通过电机连接器将四 16 mm 螺钉固定在步进1.2.1 中, 将组装部件与步骤1.2.2 中的部件连接起来。</li>
		<li>将两个直线球轴承和一个0.8 毫米的六角螺母插入到位于旅行者推底的开口处。</li>
		<li>通过在旅行者推上的0.8 毫米六角螺母将马达接头上的螺纹杆对准。</li>
		<li>插入两个直线轴通过旅客推和电机连接器。</li>
		<li>将两个六角螺母放在电机连接件的六角空间中, 然后使用两个16毫米螺钉拧紧连接, 确保直线轴不动。</li>
		<li>将球轴承插入末端停止的中间开口。</li>
		<li>从步骤1.2.7 连接到已装配元件的端停止。</li>
		<li>将两个六角螺母放在末端停止片的六角空间中, 然后使用两个 16 mm 螺钉拧紧连接以将末端停止贴到组件上。</li>
		<li>使用两个钢锁螺母和两个 16 mm 螺钉将注射器柱塞女性连接件连接到旅行者推片上。</li>
		<li>将10毫升注射器放在泵的顶部。确保柱塞头与注射器柱塞女性连接件的缺口对齐, 注射器筒的顶部固定在电机接头的插槽中。</li>
		<li>插入注射器柱塞男性连接件进入注射器柱塞女性连接器。确保男性和女性部件之间有紧密的配合, 保证活塞到位。</li>
		<li>使用两个六角螺母和两个35毫米螺钉将注射器钳连接到注射器平台, 确保注射器筒固定在注射器钳的插槽中。</li>
	</ol>
</li>
</ol>2. 微流控装置的制备
<ol><li>
使用光刻法制造主模具 注: 在以前的文献12中可以找到详细介绍微流控器件制造主模的设计和制作过程。<ol>
<li>使用首选计算机辅助设计 (CAD) 软件, 为光掩模创建所需的绘图, 并将其打印到玻璃或石英板上。 注: 其他材料可根据所用掩模光刻的要求接受。这些光掩膜的打印通常由第三方供应商完成。</li>
		<li>使用光刻方法从光掩模创建主模具。在洁净室环境中执行此过程。</li>
		<li>将制造的主模暴露在真空干燥中的 fluorosilane 蒸气中。 注: 此过程便于在制造微流控器件时从主模中释放烷 ()。要处理主模具, 在烧杯中加入三滴 fluorosilane, 将烧杯放在真空室中。</li>
		<li>应用真空1分钟关闭真空室, 但保持主模具在会议厅内30分钟, 以允许沉积的 fluorosilane。作为安全预防措施, 在通风罩中执行此步骤, 以限制暴露于危险的 fluorosilane 蒸气。</li>
	</ol>
</li>
	<li>
制造聚甲基硅器件
	<ol>
<li>称重船中的聚合物预聚合体。尽管最终的所需厚度可能有所不同, 但30克的预聚合物工作良好的主模具直径为100毫米。</li>
		<li>测量和添加一个固化剂在1:10 的比例对预聚合物。对于直径为100毫米的主模具, 添加3克固化剂。</li>
		<li>使用一次性刮刀, 用手大力搅拌预聚合剂和固化剂。三十年代后, 检查溶液中是否有小的、定期分离的气泡, 表明预聚合剂和固化剂的混合良好。</li>
		<li>将主模具放在培养板上, 并小心地将其混合在主模具上。 注: 所需的聚硅烷设备的厚度可能因其应用而异。</li>
		<li>将混合物在真空干燥中加成1小时. 确保在混合物中没有可见气泡。如果存在气泡, 请快速释放真空压力, 然后重新应用真空。在这个过程之后, 允许混合物至少坐10分钟。</li>
		<li>将该混合料移动到90摄氏度的烤箱。允许混合物治疗30分钟。</li>
		<li>从主模具中取出。用剃刀刀片将其切成所需尺寸。戴上手套以限制其接触污染物。</li>
		<li>带23克配药针的入口和出口端口的冲孔孔。为方便这一过程, 用金属锉或砂纸将针头锉削, 以锐化钝端。确保每次穿刺后, 从针头中取出的内壁圆筒。 注: 不同尺寸的针头可用于冲孔。确保大小比本协议步骤3中使用的针头稍大。</li>
		<li>使用装有0.2 µm 过滤器的空气或氮气源, 用过滤过的去离子水和空气干燥的方法清洗该硅烷。 注: 确切的压力并不重要, 从建筑物中央系统得到的加压气体源对这一步骤很有效。</li>
		<li>用表面活性剂 (如粉状洗涤剂) 清洁1号硼硅酸盐盖玻璃基板, 并使用装有0.2 µm 过滤器的加压空气源将其风干。彻底清洁, 因为盖玻璃经常涂有疏水性润滑剂, 不能绑定到, 除非它是正确的清洁。</li>
		<li>使用压敏胶带, 轻轻触碰所用的硅烷, 除去残余灰尘。为确保模压功能不受损, 请勿按下磁带上的大量力。</li>
		<li>将该设备和清洁后的盖玻璃放入氧气等离子清洗器中1分钟. 确保从等离子清洗室的颜色是明亮的洋红在过程中。确保在等离子清洗器中, 该设备的模压特性暴露在表面, 正面朝上。</li>
		<li>从等离子清洗机中拿出该产品和盖玻璃, 然后将盖子玻璃, 面朝下, 放到该装置上。 注: 这将导致盖板玻璃和在几乎立即债券。如果绑定不可见, 请轻轻按下盖玻璃, 在一个没有模压功能的部分。这将导致在与玻璃之间的粘结发生。</li>
		<li>将该设备放入烤箱中90摄氏度, 至少12小时, 以确保其和盖玻璃的粘合良好。</li>
	</ol>
</li>
</ol>3. 反馈控制注射器泵系统总成
<ol><li>使用剃刀从压力传感器的电缆中取出适当量的电线绝缘长度和屏蔽。在切割时要保持柔和, 以确保导线不超过所需长度。一旦绝缘和屏蔽被删除, 连接到男性矩形连接线。</li>
	<li>使用类似的方法上一步, 删除 1-2 cm 的电线绝缘从步进电机的引线, 并连接到男性矩形连接线。</li>
	<li>将注射器贴到压力传感器的入口侧。将22克配药针连接到压力传感器的出口侧。</li>
	<li>将0.51 厘米直径油管的一端滑动到压力传感器所附的22克配药针上。</li>
	<li>将0.51 厘米直径油管的另一端滑动至22克, 可连接到微流控装置上。将针头连接到微流控装置的入口端。</li>
	<li>使用22克针和0.51 厘米直径油管将微流控装置的出口端口连接到废物处理水库, 类似于入口口的连接。</li>
	<li>根据图 3中的图, 在原型案板上装配电子电路。 注: 此案板用于条件由单片机监视压力传感器的信号。其他兼容的微控制器可用于监测压力传感器信号。</li>
	<li>将步进电机的导线与步进电机驱动程序连接起来。根据图 3中的示意图, 将压力传感器和步进电机驱动程序的导线与案板连接。压力传感器暴露的导线是彩色编码的, 应按如下方式连接: 红色应该连接到 v +, 黑色应该连接到 v-, 绿色应该连接到信号 +, 白色应该连接到信号-。</li>
	<li>将输出信号从案板连接到单片机上的模拟输入销。</li>
	<li>将步进电机驱动程序的逻辑输入针脚与单片机上的数字针脚连接起来。步进电机驱动器上的步长输入与单片机上的数字引脚脉宽调制 (PWM) 端口连接, 用 "~" 符号表示。</li>
	<li>根据图 3中的图, 将电源与案板连接。将电源设置为案板和步进电机驱动程序的 10 V。</li>
</ol>4. 压力传感器校准
注: 根据本文所选择的放大器, 计算增益的公式为 g = 5 + (200 k/Rg), Rg = R1 和 g = 放大器增益。放大器增益在这里大约是606。通过更改用于 R1 的电阻, 可以更改此值。此外, 由于单片机电路板的逻辑电平为 5 v, 仪器为 10 v, 一个简单的分压器电路, R2 和 R3, 用于保证输出信号不超过 5 v。
<ol><li>为微控制器下载并安装适当的集成开发环境 (IDE)。</li>
	<li>从补充文件下载标题为 "Pressure_Sensing" 的控制器代码。使用此代码是从双压力传感器获取压力信号。 注: 本文使用的单片机和控制器代码包括10位分辨率的模拟输入销, 它每200毫秒读取来自压力传感器的模拟信号, 以驱动步进电机。analogRead () 托架中的数字对应于图 3中压力传感器电路中的电压分频器电路上与输出信号相连的模拟输入销。延迟变量表示在 ms 中对信号进行重新评估的间隔和相应的输出。</li>
	<li>将已知压力应用于传感器的入口, 并测量输出信号。 注: 一种简单的校准压力传感器的方法是使用带有不同高度的水油藏。由此产生的引力压力将允许一个校准压力传感器。</li>
	<li>在 x 轴和 y 轴上的压力信号 (V) 上绘制带有校准压力 (Pa) 的图, 以获得 y 截距的数值。</li>
	<li>在控制器代码中应用此数值, 如 sensor1Offset 和 sensor2Offset 变量在 "Dual_Pump_PID_Control" 的补充文件代码中, 以校准反馈控制系统中的压力值。</li>
</ol>5. 从微流控装置捕获图像
<ol><li>通过串行接口将微控制器连接到开放源码的单板计算机上, 以便由微型计算机捕获的图像触发微控制器所采取的压力测量。</li>
	<li>将用于单板计算机的照相机模块连接到显微镜的一个眼件。在这里, 20X 放大器用于图像微流控设备。</li>
</ol>6. 控制注射器压力泵
<ol><li>打开 IDE 以打开源代码微控制器。下载计时器. h13和 AccelStepper14库到微控制器的 IDE 库目录。</li>
	<li>从补充文件下载标题为 "Dual_Pump_PID_Control" 的控制器代码。该编码用于控制带有两个泵的反馈控制的注射器泵系统。</li>
	<li>对控制器代码进行编程, 使其符合正在进行的实验。修改控制参数或定时参数, 以适应实验所需的响应和持续时间。在运行实验之前, 将代码编译并上载到微控制器。 注: 在控制器代码中, setPoint1/2 值用于改变压力电平, stepper1/2Out 值用于调整泵的速度。AccelStepper stepper1/2 列中的最后两个值对应于微控制器上的端口号。milliTiming 变量规定了从压力传感器读取模拟信号的频率, 而 printTiming 变量决定了输出速度和压力值到串行显示器进行检测的频率。所有单位都在 ms. maxError 变量是由单片机板的逻辑电平确定的。这里使用的值为 5, 因为该协议中的微控制器为 5 v。</li>
	<li>打开注射器泵系统的电源。将电压设置为 10 V, 以便步进电机供电。</li>
</ol>7. 调节 PID 控制器参数
注意: 理想的控制器参数值可能因应用程序和微流控设备几何图形而异。例如, 对于长期研究 (小时), 较低比例常数 (Kp) 可能更可取, 以减少超调, 以牺牲响应时间。这些权衡取决于实验条件和目标。
<ol><li>使用手动方法调整控制器, 首先调整比例常数 (Kp), 以提高步长函数的响应时间。 注意: 尽管可以使用算法方法, 但本文所示的微流控应用程序的手动调整工作。</li>
	<li>接下来, 改变积分 (基) 和微分 (Kd) 参数, 以最小化超调, 并确保设置点稳定性。</li>
	<li>在补充文件的控制器代码中设置 Kp、基和 Kd 变量的 PID 值。</li>
</ol>

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C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-cost+feedback-controlled+syringe+pressure+pumps+for+microfluidics+applications.">Low-cost feedback-controlled syringe pressure pumps for microfluidics applications.</a> PLoS One. 12 (4), (2017).</li><li>Kong, D. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Open-source,+community-driven+microfluidics+with+metafluidics.">Open-source, community-driven microfluidics with metafluidics.</a> Nature Biotechnology. 35 (6), 523-529 (2017).</li><li>Wijnen, B., Hunt, E. J., Anzalone, G. C., Pearce, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Open-source+syringe+pump+library.">Open-source syringe pump library.</a> PLoS One. 9 (9), e107216 (2014).</li><li>Ferry, M. S., Razinkov, I. A., Hasty, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidics+for+synthetic+biology:+from+design+to+execution.">Microfluidics for synthetic biology: from design to execution.</a> Methods in Enzymology. , 295-372 (2011).</li><li>. Arduino Libraries for Timer.h Available from: <a target="_blank" href="https://github.com/JChristensen/Timer">https://github.com/JChristensen/Timer</a> (2018)</li><li>. 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作者没有什么可透露的。

在这里, 我们提出了一个新的设计的注射器泵系统的闭环压力控制。这是通过集成一个 3 d-打印注射器泵与压阻式压力传感器和开放源码微控制器。通过采用 PID 控制器, 能够精确控制进气压力, 提供快速响应时间, 同时保持设定点的稳定性。
许多使用微流控器件的实验都需要精确的射流控制, 并能开发出具有良好特征的层流剖面。一个稳定的流量剖面很重要的例子包括探索时间和空间浓度梯度15的实验, 并产生精确的射流胶囊进一步分析16.通过使用 PID 控制器来保持高性能响应, 本协议中描述的系统产生了研究这种层流实验所需的流量调节和长期稳定性。
然而, 重要的是要认识到, 微流控装置和实验涉及他们有微妙的变化和差异。例如, 不同的微流控几何 (通道宽度和高度) 可能需要不同的流剖面。因此, 必须相应地调整 PID 控制器的参数。此外, 一些实验可能需要严格调节压力范围。在这些情况下, 压力超调可能是不能接受的。因此, 必须调整 PID 控制参数, 使超调降到最小, 通常是以牺牲响应时间为代价的。
由于这种注射器泵系统的低成本生产, 研究人员应该能够迅速发展微流控实验。3 d 打印的注射器泵、单片机和压力传感器电路的估计成本约为130美元。与商用的替代品, 如蠕动和回流泵相比, 这种注射器泵系统提供了一个灵活和直接的平台, 可适应各种实验室使用。虽然这里没有讨论, 但更简单的控制策略, 如砰砰的控制器, 可用于长期微流控研究。此外, 注射器泵系统可用于对控制容积施加真空压力。
这个注射器泵系统的一个潜在的限制使用 PID 控制器是依赖于恒定的电源。由于 PID 控制方法需要步进电机的恒通电, 因此有较大的功率要求。相比之下, 砰砰的控制器只在必要时给步进电机供电, 使用的功率大大降低。通过开发一种混合控制结构, 实现 PID 控制器初始达到设定点范围, 然后在给定的集点范围内对步进电机线圈进行能量消除, 从而可以减轻这种功耗要求。另外, 还可以使用一个简单的霹雳棒控制器。
此外, 这种注射器泵系统允许灵活的性能和控制, 改变的大小, 步进电机和注射器本身。在以前的实验中, 我们使用了1毫升、5毫升、10毫升和30毫升的注射器。当然, 每个注射器泵可能需要略有不同的 PID 控制器参数, 因此, 要求个性化参数调整。然而, 这种灵活性使得本协议中所描述的注射器泵系统可以在一系列应用中使用。
应该指出的是, microdevice 失败的一个共同领域是无法有效地将该硅烷与盖玻璃结合起来。对于微流控器件的制备, 如果结合效果不佳, 应优化等离子体清洗器的功率。此外, 任何润滑剂或杂质的封面玻璃 ' 的表面上应删除之前的粘合, 以确保与该板的强粘结。彻底清洗和清除来自该组件的任何灰尘, 将有助于确保在两个玻璃之间形成良好的密封。
本文介绍的低成本、反馈控制的注射器泵系统允许研究人员以灵活的方式操作具有高度稳定性的流体剖面。该系统通过将压力传感模块与简单的 PID 控制方法相结合, 能够提供高性能的压力驱动流量控制。此工具可以广泛应用于许多研究领域, 其中微流体工具正在使用中。

微流控工具已成为科学家在生物和化学研究的有用。由于体积利用率低, 快速测量能力和明确的流量剖面, 微流体在基因组和蛋白质研究、高通量筛选、医学诊断、纳米技术和单细胞分析1,2,3,4。此外, 微流控装置设计的灵活性容易使基础科学研究, 如调查细菌菌落的时空动态5。
许多类型的流体喷射系统已经开发, 以准确地提供流到微流控设备。这种喷射系统的例子包括蠕动和循环泵6、压力控制器系统7和注射器泵8。这些注射系统, 包括注射器泵, 通常由昂贵的精密工程部件组成。通过闭环反馈控制输出流中的压力, 增加这些系统的成本。作为回应, 我们以前开发了一个健壮的, 低成本的注射器泵系统, 使用闭环反馈控制, 以调节输出流量压力。采用闭环压力控制, 对昂贵的精密工程部件的需求被废止9。
可负担得起的 3 d 打印硬件和相关开源软件的显著增长组合使得微流控设备的设计和制造越来越多地从各种学科10的研究人员那里获得。然而, 用于通过这些设备驱动流体的系统仍然很昂贵。为了满足对低成本流体控制系统的需求, 我们开发了一个可以由实验室的研究人员制作的设计, 只需要少量的装配步骤。尽管它的成本低且简单, 但该系统可以提供精确的流量控制, 并提供了一种替代商用, 闭环注射器泵系统, 这可能是令人望而却步的昂贵。
在这里, 我们为我们开发的闭环控制注射器泵系统的建造和使用提供了协议 (图 1)。流体处理系统由以前的研究11、单片机和压阻式压力传感器所启发的物理注射器泵组成。当用比例积分-导数 (PID) 控制器组装和编程时, 系统能够向微流控装置提供良好的受控压力驱动流。这为高成本商业产品提供了低成本和灵活的替代方案, 使更广泛的研究人员能够在工作中使用微流体。

<table border="0" cellpadding="0" cellspacing="0" width="1268">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:289px;">Arduino IDE</td>
			<td style="width:245px;">Arduino.org</td>
			<td style="width:169px;"></td>
			<td style="width:565px;">Arduino Uno R3 control software</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Header Connector, 2 Positions</td>
			<td>Digi-Key</td>
			<td>WM4000-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Header Connector, 3 Positions</td>
			<td>Digi-Key</td>
			<td>WM4001-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Header Connector, 4 Positions</td>
			<td>Digi-Key</td>
			<td>WM4002-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hook-up Wire, 22 Gauge, Black</td>
			<td>Digi-Key</td>
			<td>1528-1752-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hook-up Wire, 22 Gauge, Blue</td>
			<td>Digi-Key</td>
			<td>1528-1757-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hook-up Wire, 22 Gauge, Red</td>
			<td>Digi-Key</td>
			<td>1528-1750-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hook-up Wire, 22 Gauge, White</td>
			<td>Digi-Key</td>
			<td>1528-1768-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hook-up Wire, 22 Gauge, Yellow</td>
			<td>Digi-Key</td>
			<td>1528-1751-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Instrumentation Amplifier</td>
			<td>Texas Instruments</td>
			<td>INA122P</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Microcontroller, Arduino Uno R3</td>
			<td>Arduino.org</td>
			<td>A000066</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mini Breadboard</td>
			<td>Amazon</td>
			<td>B01IMS0II0</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Power Supply</td>
			<td>BK Precision</td>
			<td>1550</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Pressure Sensor</td>
			<td>PendoTech</td>
			<td>PRESS-S-000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Rectangular Connectors, Housings</td>
			<td>Digi-Key</td>
			<td>WM2802-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Rectangular Connectors, Male</td>
			<td>Digi-Key</td>
			<td>WM2565CT-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Resistors, 10k Ohm&#160;</td>
			<td>Digi-Key</td>
			<td>1135-1174-1-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Resistors, 330 Ohm&#160;</td>
			<td>Digi-Key</td>
			<td>330ADCT-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Stepper Motor Driver, EasyDriver</td>
			<td>Digi-Key</td>
			<td>1568-1108-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">USB 2.0 Cable, A-Male to B-Male</td>
			<td>Amazon</td>
			<td>PC045</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">3D Printed Material, Z-ABS&#160;</td>
			<td>Zortrax</td>
			<td></td>
			<td>A variety of colors are available</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">3D Printer</td>
			<td>Zortrax</td>
			<td>M200</td>
			<td>Printing out the syringe pump components</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ball Bearing, 17x6x6mm</td>
			<td>Amazon</td>
			<td>B008X18NWK</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hex Machine Screws, M3x16mm&#160;</td>
			<td>Amazon</td>
			<td>B00W97MTII</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hex Machine Screws, M3x35mm&#160;</td>
			<td>Amazon</td>
			<td>B00W97N2UW</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hex Nut, M3 0.5&#160;</td>
			<td>Amazon</td>
			<td>B012U6PKMO</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hex Nut, M5&#160;</td>
			<td>Amazon</td>
			<td>B012T3C8YQ</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Lathe Round Rod</td>
			<td>Amazon</td>
			<td>B00AUB73HW</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Linear Ball Bearing</td>
			<td>Amazon</td>
			<td>B01IDKG1WO</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Linear Flexible Coupler</td>
			<td>Amazon</td>
			<td>B010MZ8SQU</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Steel Lock Nut, M3 0.5</td>
			<td>Amazon</td>
			<td>B000NBKLOQ</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Stepper Motor, NEMA-17, 1.8o/step</td>
			<td>Digi-Key</td>
			<td>1568-1105-ND</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Syringe, 10mL, Luer-Lok Tip</td>
			<td>BD</td>
			<td>309604</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Threaded Rod</td>
			<td>Amazon</td>
			<td>B01MA5XREY</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">1H,1H,2H,2H-Perfluorooctyltrichlorosilane</td>
			<td>FisherScientific</td>
			<td>AAL1660609</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Camera Module</td>
			<td>Raspberry Pi Foundation</td>
			<td>V2</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Compact Oven</td>
			<td>FisherScientific</td>
			<td>PR305220G</td>
			<td>Baking PDMS pre-polymer mixture and the device</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dispensing Needle, 22 Gauge</td>
			<td>McMaster-Carr</td>
			<td>75165A682</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dispensing Needle, 23 Gauge</td>
			<td>McMaster-Carr</td>
			<td>75165A684</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fisherbrand Premium Cover Glasses</td>
			<td>FisherScientific</td>
			<td>12-548-5C</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Glass Culture Petri Dish, 130x25mm</td>
			<td>American Educational Products</td>
			<td>7-1500-5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Plasma Cleaner</td>
			<td>Harrick Plasma</td>
			<td>PDC-32G</td>
			<td>Binding the cover glass with the PDMS device</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Razor Blades</td>
			<td>FisherScientific</td>
			<td>7071A141&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Scotch Magic Tape</td>
			<td>Amazon</td>
			<td>B00RB1YAL6</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Single-board Computer</td>
			<td>Raspberry Pi Foundation</td>
			<td>Raspberry Pi 2 model B</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Smart Spatula</td>
			<td>FisherScientific</td>
			<td>EW-06265-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sylgard 184 Silicone Elastomer Kit</td>
			<td>FisherScientific</td>
			<td>NC9644388</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Syringe Filters</td>
			<td>Thermo Scientific</td>
			<td>7252520</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Tygon Tubing</td>
			<td>ColeParmer&#160;</td>
			<td>EW-06419-01</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Vacuum Desiccator</td>
			<td>FisherScientific</td>
			<td>08-594-15C</td>
			<td>Degasing PDMS pre-polymer mixture and coating fluorosilane on the master mold</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Weighing Dishes</td>
			<td>FisherScientific</td>
			<td>S67090A</td>
			<td></td>
		</tr>
	</tbody>
</table>

three-dimensional printing of thermoplastic materials to create automated syringe pumps with feedback control for microfluidic applications

微流体已成为研究跨生物、化学和物理科学的重要工具。微流控实验的一个重要组成部分是稳定的流体处理系统, 能够准确地提供进水流速率或进气压力。在这里, 我们开发了一种注射器泵系统, 能够控制和调节输送到微流控装置的入口流体压力。该系统的设计采用低成本材料和添加剂制造原则, 利用三维 (3D) 印刷热塑性材料和现成的组件, 只要可能的话。该系统由三主要部件组成: 注射器泵、压力传感器和可编程微控制器。在本文中, 我们详细介绍了一组用于制造、装配和编程这个注射器泵系统的协议。此外, 我们还包括了具有代表性的结果, 证明了高保真度, 反馈控制的入口压力使用这个系统。我们预计这项协议将允许研究人员制造低成本的注射器泵系统, 降低在生物医学、化学和材料研究中使用微流体的进入屏障。

在这里, 我们提出了一个建立一个反馈控制的注射器泵系统的协议, 并展示了它的潜在用途的微流控应用。图 1显示了注射器泵、压力传感器、微流控装置、单片机、压力传感器电路和步进电机驱动程序的连接系统。注射器泵总成的详细标注见图 2 , 压力传感电子电路示意图载于图 3。调整控制参数的过程如图 4所示。最后, 在两进制 Y 形微流控装置中控制进气压力的一个典型结果如图 5所示。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57532/57532fig1.jpg"> 图 1: 设置反馈控制的注射器泵系统.该图像显示了注射器泵系统的设置。注射器含有注射液, 由 3 d-打印的注射器泵驱动。作为.压阻式压力传感器与B 连接.注射器泵和C.微流控装置, 检测到设备的压力, 并将其转换成电信号到D.压力传感器电路与仪表放大器一旦液体通过油管交付。来自压力传感器的信号由E 读取.开源微控制器板, 然后将所需信号传送到F.步进电机驱动控制注射器泵的驱动。G.电源和H.需要一台笔记本电脑来操作和编程系统。<a href="/files/ftp_upload/57532/57532fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57532/57532fig2.jpg"> 图 2: 3 d-打印注射器泵的装配照片.此图显示了 3 d 打印的注射器泵组件的分步说明, 其中的照片与该协议步骤1.2 中的步骤相对应。这个图像显示了注射器泵总成的材料。这张图片显示了步进电机是如何连接到螺纹杆 (步骤 1.2.1)。C.此图像显示了协议的步骤1.2.1 中的部件是如何从协议的步骤 1.2.2 (步骤 1.2.3) 连接到部件的。这个图像显示了旅行者推片的装配 (步骤 1.2.5)。E.此图像显示停止连接的方式 (步骤 1.2.10)。F.此图像显示了注射器柱塞女性连接件如何连接到组装部件 (步骤 1.2.11)。这个图像显示了注射器柱塞男性连接件 (步骤 1.2.13) 的装配。H.此图像显示了如何连接注射器钳 (步骤 1.2.14)。<a href="/files/ftp_upload/57532/57532fig2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57532/57532fig3.jpg"> 图 3: 单片机和压力传感器电路的插图.该电路允许单片机板测量压力传感器的放大压力信号。这是电路的装配图。这个数字显示电路板的布局。压力传感器暴露的导线是彩色编码的, 应按如下方式连接: 红色应该连接到 v +, 黑色应该连接到 v-, 绿色应该连接到信号 +, 白色应该连接到信号-。<a href="/files/ftp_upload/57532/57532fig3large.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/57532/57532fig4.jpg"> 图 4: 控制参数的调整.用于调节注射器泵流体压力的 PID 控制器可以通过修改比例 (Kp)、积分 (基) 和微分 (Kd) 参数来调整。在这里, 我们演示如何调整 (使用 Kp) 将有助于减少响应时间。进一步调谐 (使用基和 Kd) 可以帮助确保设定的稳定性和减少超调。在本协议中, 控制器主要使用手动的试错方法进行调整。<a href="/files/ftp_upload/57532/57532fig4large.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/57532/57532fig5.jpg"> 图 5: 层流流体微流控装置进气压力的控制.Y 形微流控装置是根据本协议步骤2中详细说明的步骤制作的。该设备具有两个入口端口和一个出口端口。两个注射器泵系统组装, 以控制进口压力。其中一个注射器装有蓝色染料, 另一只装有水。这两种泵所提供的相同压力所产生的流体流动的图像是使用本议定书步骤6中详细说明的方法捕获的.这个数字显示了如何使用图 4中调谐的 PID 控制器监控和控制进气压力。可以观察到设定点的紧密附着。较短的和更长的 (h) 实验表明了类似的结果。<a href="/files/ftp_upload/57532/57532fig5large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>

Watch this Scientific Journal Video about Three-dimensional Printing of Thermoplastic Materials to Create Automated Syringe Pumps with Feedback Control for Microfluidic Applications at JoVE.com

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

在这里, 我们提出了一个协议, 建立一个压力控制注射器泵用于微流控应用。这种注射器泵是由一个加法制造的身体, 现成的硬件, 和开源电子。由此产生的系统成本低廉, 容易建立, 并提供良好的调节流体流动, 使快速微流控研究。

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 ...

three-dimensional-printing-thermoplastic-materials-to-create

Nanyang Technological University

Research

JoVE Journal

Bioengineering

12.3K 次观看.  University of Pittsburgh. 在这里, 我们提出了一个协议, 建立一个压力控制注射器泵用于微流控应用。这种注射器泵是由一个加法制造的身体, 现成的硬件, 和开源电子。由此产生的系统成本低廉, 容易建立, 并提供良好的调节流体流动, 使快速微流控研究。

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

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 ...

科研

生物工程

Designing Silk-silk Protein Alloy Materials for Biomedical Applications

Fibrous proteins display different sequences and structures that have been used for various applications in biomedical fields such as biosensors, nanomedicine, tissue regeneration, and drug delivery. Designing materials based on the molecular-scale interactions between these proteins will help generate new multifunctional protein alloy biomaterials with tunable properties. Such alloy material systems also provide advantages in comparison to traditional synthetic polymers due to the materials biodegradability, biocompatibility, and tenability in the body. This article used the protein blends of wild tussah silk (Antheraea pernyi) and domestic mulberry silk (Bombyx mori) as an example to provide useful protocols regarding these topics, including how to predict protein-protein interactions by computational methods, how to produce protein alloy solutions, how to verify alloy systems by thermal analysis, and how to fabricate variable alloy materials including optical materials with diffraction gratings, electric materials with circuits coatings, and pharmaceutical materials for drug release and delivery. These methods can provide important information for designing the next generation multifunctional biomaterials based on different protein alloys.

Blending is an efficient approach to generate biomaterials with a broad range of properties and combined features. By predicting the molecular interactions between different natural silk proteins, new silk-silk protein alloy platforms with tunable mechanical resiliency, electrical response, optical transparency, chemical processability, biodegradability, or thermal stability can be designed.

设计丝绸蚕丝蛋白合金生物医用材料

Fibrous proteins display different sequences and structures that have been used for various applications in biomedical fields such as biosensors, ...

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 ...

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 ...

Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications

Superhydrophobic materials, with surfaces possessing permanent or metastable non-wetted states, are of interest for a number of biomedical and industrial applications. Here we describe how electrospinning or electrospraying a polymer mixture containing a biodegradable, biocompatible aliphatic polyester (e.g., polycaprolactone and poly(lactide-co-glycolide)), as the major component, doped with a hydrophobic copolymer composed of the polyester and a stearate-modified poly(glycerol carbonate) affords a superhydrophobic biomaterial. The fabrication techniques of electrospinning or electrospraying provide the enhanced surface roughness and porosity on and within the fibers or the particles, respectively. The use of a low surface energy copolymer dopant that blends with the polyester and can be stably electrospun or electrosprayed affords these superhydrophobic materials. Important parameters such as fiber size, copolymer dopant composition and/or concentration, and their effects on wettability are discussed. This combination of polymer chemistry and process engineering affords a versatile approach to develop application-specific materials using scalable techniques, which are likely generalizable to a wider class of polymers for a variety of applications.

Two- and three-dimensional superhydrophobic polymeric materials are prepared by electrospinning or electrospraying biodegradable polymers blended with a lower surface energy polymer of similar composition.

制造超疏水高分子材料生物医学应用

Superhydrophobic materials, with surfaces possessing permanent or metastable non-wetted states, are of interest for a number of biomedical and industrial ...

Fabrication of Inverted Colloidal Crystal Poly(ethylene glycol) Scaffold: A Three-dimensional Cell Culture Platform for Liver Tissue Engineering

The ability to maintain hepatocyte function in vitro, for the purpose of testing xenobiotics&#39; cytotoxicity, studying virus infection and developing drugs targeted at the liver, requires a platform in which cells receive proper biochemical and mechanical cues. Recent liver tissue engineering systems have employed three-dimensional (3D) scaffolds composed of synthetic or natural hydrogels, given their high water retention and their ability to provide the mechanical stimuli needed by the cells. There has been growing interest in the inverted colloidal crystal (ICC) scaffold, a recent development, which allows high spatial organization, homotypic and heterotypic cell interaction, as well as cell-extracellular matrix (ECM) interaction. Herein, we describe a protocol to fabricate the ICC scaffold using poly (ethylene glycol) diacrylate (PEGDA) and the particle leaching method. Briefly, a lattice is made from microsphere particles, after which a pre-polymer solution is added, properly polymerized, and the particles are then removed, or leached, using an organic solvent (e.g., tetrahydrofuran). The dissolution of the lattice results in a highly porous scaffold with controlled pore sizes and interconnectivities that allow media to reach cells more easily. This unique structure allows high surface area for the cells to adhere to as well as easy communication between pores, and the ability to coat the PEGDA ICC scaffold with proteins also shows a marked effect on cell performance. We analyze the morphology of the scaffold as well as the hepatocarcinoma cell (Huh-7.5) behavior in terms of viability and function to explore the effect of ICC structure and ECM coatings. Overall, this paper provides a detailed protocol of an emerging scaffold that has wide applications in tissue engineering, especially liver tissue engineering.

Fabrication of Inverted Colloidal Crystal Polyethylene glycol Scaffold: A Three-dimensional Cell Culture Platform for Liver Tissue Engineering

This manuscript presents a detailed protocol for the fabrication of an emerging three-dimensional hepatocyte culture platform, the inverted colloidal crystal scaffold, and the concomitant techniques to assess hepatocyte behavior. The size-controllable pores, interconnectivity and ability to conjugate extracellular matrix proteins to the poly(ethylene glycol) (PEG) scaffold enhance Huh-7.5 cell performance.

倒胶体晶体聚（乙二醇）脚手架制作:肝脏组织工程三维细胞培养平台

The ability to maintain hepatocyte function in vitro, for the purpose of testing xenobiotics&#39; cytotoxicity, studying virus infection and developing ...

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 ...

Melt Electrospinning Writing of Three-dimensional Poly(&#949;-caprolactone) Scaffolds with Controllable Morphologies for Tissue Engineering Applications

This tutorial reflects on the fundamental principles and guidelines for electrospinning writing with polymer melts, an additive manufacturing technology with great potential for biomedical applications. The technique facilitates the direct deposition of biocompatible polymer fibers to fabricate well-ordered scaffolds in the sub-micron to micro scale range. The establishment of a stable, viscoelastic, polymer jet between a spinneret and a collector is achieved using an applied voltage and can be direct-written. A significant benefit of a typical porous scaffold is a high surface-to-volume ratio which provides increased effective adhesion sites for cell attachment and growth. Controlling the printing process by fine-tuning the system parameters enables high reproducibility in the quality of the printed scaffolds. It also provides a flexible manufacturing platform for users to tailor the morphological structures of the scaffolds to their specific requirements. For this purpose, we present a protocol to obtain different fiber diameters using melt electrospinning writing (MEW) with a guided amendment of the parameters, including flow rate, voltage and collection speed. Furthermore, we demonstrate how to optimize the jet, discuss often experienced technical challenges, explain troubleshooting techniques and showcase a wide range of printable scaffold architectures.

This protocol serves as a comprehensive guideline to fabricate scaffolds via electrospinning with polymer melts in a direct writing mode. We systematically outline the process and define the appropriate parameter settings for achieving targeted scaffold architectures.

用于组织工程应用的三维聚 (ε-内) 支架的熔体静电纺丝

This tutorial reflects on the fundamental principles and guidelines for electrospinning writing with polymer melts, an additive manufacturing technology ...

Antimicrobial Characterization of Advanced Materials for Bioengineering Applications

The development of new advanced materials with enhanced properties is becoming more and more important in a wide range of bioengineering applications. Thus, many novel biomaterials are being designed to mimic specific environments required for biomedical applications such as tissue engineering and controlled drug delivery. The development of materials with improved properties for the immobilization of cells or enzymes is also a current research topic in bioprocess engineering. However, one of the most desirable properties of a material in these applications is the antimicrobial capacity to avoid any undesirable infections. For this, we present easy-to-follow protocols for the antimicrobial characterization of materials based on (i) the agar disk diffusion test (diffusion method) and (ii) the ISO 22196:2007 norm to measure the antimicrobial activity on material surfaces (contact method). This protocol must be performed using Gram-positive and Gram-negative bacteria and yeast to cover a broad range of microorganisms. As an example, 4 materials with different chemical natures are tested following this protocol against Staphylococcus aureus, Escherichia coli, and Candida albicans.The results of these tests exhibit non-antimicrobial activity for the first material and increasing antibacterial activity against Gram-positive and Gram-negative bacteria for the other 3 materials. However, none of the 4 materials are able to inhibit the growth of Candida albicans.

We present a protocol for the antimicrobial characterization of advanced materials. Here, the antimicrobial activity on material surfaces is measured by two methods that complement each other: one is based on the agar disk diffusion test, and the other is a standard procedure based on the ISO 22196:2007 norm.

生物工程应用先进材料的抗菌性能研究

The development of new advanced materials with enhanced properties is becoming more and more important in a wide range of bioengineering applications. ...

Three-dimensional Patterning of Engineered Biofilms with a Do-it-yourself Bioprinter

Biofilms are aggregates of bacteria embedded in a self-produced spatially-patterned extracellular matrix. Bacteria within a biofilm develop enhanced antibiotic resistance, which poses potential health dangers, but can also be beneficial for environmental applications such as purification of drinking water. The further development of anti-bacterial therapeutics and biofilm-inspired applications will require the development of reproducible, engineerable methods for biofilm creation. Recently, a novel method of biofilm preparation using a modified three-dimensional (3D) printer with a bacterial ink has been developed. This article describes the steps necessary to build this efficient, low-cost 3D bioprinter that offers multiple applications in bacterially-induced materials processing. The protocol begins with an adapted commercial 3D printer in which the extruder has been replaced with a bio-ink dispenser connected to a syringe pump system enabling a controllable, continuous flow of bio-ink. To develop a bio-ink suitable for biofilm printing, engineered Escherichia coli bacteria were suspended in a solution of alginate, so that they solidify in contact with a surface containing calcium. The inclusion of an inducer chemical within the printing substrate drives expression of biofilm proteins within the printed bio-ink. This method enables 3D printing of various spatial patterns composed of discrete layers of printed biofilms. Such spatially-controlled biofilms can serve as model systems and can find applications in multiple fields that have a wide-ranging impact on society, including antibiotic resistance prevention or drinking water purification, among others.

This article describes a method of transforming a low-cost commercial 3D printer into a bacterial 3D printer that can facilitate printing of patterned biofilms. All necessary aspects of preparing the bioprinter and bio-ink are described, as well as verification methods to assess the formation of biofilms.

工程生物膜的三维造型

Biofilms are aggregates of bacteria embedded in a self-produced spatially-patterned extracellular matrix. Bacteria within a biofilm develop enhanced ...