这项工作得到了中国国家自然科学基金 (51420105006 和51322501号) 的支持。我们感谢丹尼尔对高粘度思想的有益讨论。

1. 生产一种相反转的共流毛细管装置, 用于观察含直径为500微米的高粘度水滴的生成过程。
注: 此处使用的方形外管用于拍摄高粘度水滴的生成过程的图像。如果不需要拍摄图像, 则可以根据协议步骤2对设备进行简化版本。
<ol><li>
为毛细管装置的组装准备三个不同尺寸的玻璃管。
	<ol>
<li>取一个方形的玻璃管, 内部尺寸为1.05 毫米, 并切割一条管子的长度为4厘米。这将是设备的外管。</li>
		<li>取一圆玻璃管, 内径为580微米, 外径 (外径) 为1毫米, 并切割一条管子的长度为3厘米。这将是设备的中间管。</li>
		<li>取一圆玻璃管与身份证 = 200 微米和外径 = 330 微米, 并且切开管子的片断 ~ 2 cm 长度。这将是设备的内管。</li>
	</ol>
</li>
	<li>
修改中间管一端的表面润湿性为疏水性。
	<ol>
<li>取一个1毫升的玻璃瓶, 并添加0.3 毫升的氯 () 硅烷 (升) 到玻璃瓶。</li>
		<li>把中间管与身份证 = 580 微米准备在协议步骤 1.1.2, 并把它的一端浸入玻璃瓶中的十年代。</li>
		<li>取出中间管, 用氮气从未处理的末端冲洗管子。</li>
	</ol>
</li>
	<li>
为毛细管装置的入口准备针头。
	<ol>
<li>采取一个20G 钝尖配药针, 并削减一个插槽与0.5 毫米 x 0.5 毫米的边缘, 塑料鲁尔轮毂与刀片。 注: 此针可作为低粘度油相的入口。</li>
		<li>再拿一个20G 钝尖配药针, 在塑料鲁尔中心的边缘切两个插槽。将两个插槽与通过鲁尔集线器直径的直线对齐。 注: 一个插槽的尺寸为0.5 毫米 x 0.5 毫米, 而另一个插槽的尺寸为1.0 毫米 x 1.0 毫米。该针可作为高粘度水相的入口。</li>
		<li>再拿一个20G 钝尖配药针, 在塑料鲁尔中心的边缘切两个插槽。将两个插槽与通过鲁尔集线器直径的直线对齐。 注: 一个插槽的尺寸为1.5 毫米 x 1.5 毫米;而另一个插槽的尺寸为1.0 毫米 x 1.0 毫米。此针可作为清洗用的入口。</li>
	</ol>
</li>
	<li>
按下装配玻璃管图 1A。<ol>
<li>以常规的7.62 厘米 x 2.54 厘米的玻璃幻灯片作为毛细管装置的基板。</li>
		<li>把外管与 id = 1.05 毫米, 准备在协议步骤 1.1.1, 在玻璃幻灯片与〜1厘米挤出玻璃滑动的短边缘。</li>
		<li>带 id 为580微米的中间管, 在协议步骤1.2 中制备, 并将中间管的疏水端插入玻璃滑动端的外管, 并将中间管的1厘米保持在外管外。</li>
		<li>取内径为200微米的内管, 在协议步骤1.1.3 中制备, 并将内管一端插入中间管, 并将内管的1厘米保持在中间管外。</li>
		<li>使用环氧树脂胶固定在玻璃滑块中心位置的三管。然后等待 ~ 5 分钟或更长的胶水完全凝固。</li>
	</ol>
</li>
	<li>
在毛细管装置上装配入口。
	<ol>
<li>采取在协议步骤1.3.1 中制备的低粘度油相的入口针, 并让鲁尔集线器覆盖基体上的内管末端, 然后使用环氧树脂胶固定基板上的鲁尔轮毂。</li>
		<li>采用进口针为高粘度水相, 在协议步骤1.3.2 中制备, 并让鲁尔集线器覆盖内管和中间管之间的连接, 然后用环氧树脂胶将鲁尔轮毂固定到基体上。</li>
		<li>取入口针, 准备在协议步骤 1.3.3, 并为清洗, 让鲁尔枢纽覆盖中间管和外管之间的连接, 然后使用环氧树脂胶固定在基板上的鲁尔集线器。</li>
		<li>等待 ~ 5 分钟或更长的胶水完全凝固。</li>
		<li>使用环氧树脂胶封在基板上的针鲁尔集线器。</li>
	</ol>
</li>
	<li>等待 ~ 30 分钟或更长的胶水完全凝固, 然后设备准备使用。</li>
</ol>2. 制作一种相反转、共流毛细管装置, 用于制造直径为500微米的水性高粘度水滴。
注意: 此处所做的设备是协议步骤1中设备的简化版本。
<ol><li>
为毛细管装置的组装准备两个不同尺寸的玻璃管。
	<ol>
<li>取一圆玻璃管与身份证 = 580 微米和外径 = 1 毫米, 并且切开一条管子与 3 cm 长度。这将是设备的中间管。</li>
		<li>取一圆玻璃管与身份证 = 200 微米和外径 = 330 微米, 并且切开一条管子与 2 cm 长度。这将是设备的内管。</li>
	</ol>
</li>
	<li>
修改中间管一端的表面润湿性为疏水性。
	<ol>
<li>在1毫升的玻璃瓶中加入0.3 毫升的培养基。</li>
		<li>用 id 为580微米的中间管, 在协议步骤2.1.1 中准备, 并将它的一端浸入玻璃瓶中的 "十年代"。</li>
		<li>取出中间管, 然后用氮气从未处理的末端冲洗管子。</li>
	</ol>
</li>
	<li>
为毛细管装置的入口准备针头。
	<ol>
<li>准备一个20G 钝尖配药针, 这将成为低粘油阶段的入口。然后, 用刀片在塑料鲁尔集线器的边缘切割一个0.5 毫米 x 0.5 毫米的插槽。</li>
		<li>再拿一个20G 钝尖配药针, 在塑料鲁尔中心的边缘切两个插槽。将两个插槽与通过鲁尔集线器直径的直线对齐。 注: 一个插槽的尺寸为0.5 毫米 x 0.5 毫米, 而另一个插槽的尺寸为1.0 毫米 x 1.0 毫米。第二针将作为高粘度水相的入口。</li>
	</ol>
</li>
	<li>
按下装配玻璃管图 1A.
	<ol>
<li>以常规的7.62 厘米 x 2.54 厘米的玻璃幻灯片作为毛细管装置的基板。</li>
		<li>将中间管与 id = 580 微米, 准备在协议步骤 2.2, 在玻璃滑动与疏水性端挤出 ~ 1 厘米在玻璃滑梯的短边缘。</li>
		<li>取内径为200微米的内管, 在协议步骤2.1.2 中进行制备, 并将内管的一端插入到中间管中, 从玻璃滑块上未处理的端部, 并在中间管外保持1厘米的内管。</li>
		<li>使用环氧树脂胶固定在玻璃滑块中心位置的两个管。</li>
		<li>等待5分钟或更长的胶水完全凝固。</li>
	</ol>
</li>
	<li>
在毛细管装置上装配入口。
	<ol>
<li>采取在协议步骤2.3.1 中制备的低粘度油相的入口针, 并让鲁尔集线器覆盖基体上的内管末端, 然后使用环氧树脂胶固定基板上的鲁尔轮毂。</li>
		<li>采用进口针为高粘度水相, 在协议步骤2.3.2 中制备, 并让鲁尔轮毂覆盖内管和中间管之间的连接, 然后使用环氧树脂胶固定在基板上的鲁尔轮毂。 注: 中间管的另一端是装置的出口。</li>
		<li>等待 ~ 5 分钟或更长的胶水完全凝固。</li>
		<li>使用环氧树脂胶封在基板上的针鲁尔集线器。</li>
	</ol>
</li>
	<li>等待 ~ 30 分钟或更长的胶水完全凝固。</li>
	<li>将中间管的自由端与出口油管连接, i. e., 带 id 的聚乙烯油管长度为0.86 毫米和 ~ 20 毫米。 注意: 外部油管的轻微变形将确保连接的密封, 因此这里不需要胶水。出口油管作为一个更广泛的外管的相反转。此时, 设备可以使用。</li>
</ol>3. 制作相逆共流毛细管装置, 观察直径为200微米的高粘度水滴的生成过程。
注意: 此处所做的设备是协议步骤1的设备的较小版本, 可以制作更小的水滴。
<ol><li>
为毛细管装置的组装准备三个不同尺寸的玻璃管。
	<ol>
<li>取一个方形的玻璃管与身份证 = 400 微米, 并且切开管子的片断〜 4 cm 长度, 将是设备的外在管子。</li>
		<li>取一圆玻璃管与身份证 = 200 微米和外径 = 330 微米, 并且切开管子的片断 ~ 3 cm 长度, 将是设备的中间管子。</li>
		<li>取一圆玻璃管与身份证 = 100 微米和外径 = 170 微米, 并且切开管子的片断 ~ 2 cm 长度, 将是设备的内管。</li>
	</ol>
</li>
	<li>
修改中间管一端的表面润湿性为疏水性。
	<ol>
<li>拿一个1毫升的玻璃瓶, 并添加0.3 毫升的增加到玻璃瓶。</li>
		<li>用 id 为200微米的中间管, 在协议步骤3.1.2 中准备, 并将它的一端浸入玻璃瓶中的 "十年代"。</li>
		<li>取出中间管, 然后用氮气从未处理的末端冲洗管子。</li>
	</ol>
</li>
	<li>
为毛细管装置的入口准备针头。
	<ol>
<li>准备一个20G 钝尖配药针, 这将成为低粘油阶段的入口。然后, 用刀片, 切一个插槽〜0.2 毫米 x 0.2 毫米的边缘的塑料鲁尔枢纽。</li>
		<li>准备另一20G 钝尖配药针, 并削减两个插槽的边缘塑料鲁尔枢纽。将两个插槽与通过鲁尔集线器直径的直线对齐。 注: 一个插槽的尺寸为0.2 毫米 x 0.2 毫米, 而另一个插槽的尺寸为0.4 毫米 x 0.4 毫米。第二针将作为高粘度水相的入口。</li>
		<li>再拿一个20G 钝尖配药针, 在塑料鲁尔中心的边缘切两个插槽。两个插槽在通过鲁尔中心直径的线对齐。 注: 一个插槽的尺寸为0.8 毫米 x 0.8 毫米, 而另一个插槽的尺寸为0.4 毫米 x 0.4 毫米。这第三针将作为一个入口为清洁目的。</li>
	</ol>
</li>
	<li>按照协议步骤 1.4-1.6 完成该设备, 使用在协议步骤3.1 中编写的玻璃管, 而不是在协议步骤1.1 中编写的, 使用在协议步骤3.3 中编写的针, 而不是在协议步骤1.3 中编写的。</li>
</ol>4. 观察液体石蜡中甘油滴的产生
注: 为拍摄图1B 中显示的图像, 请使用在协议步骤1中编写的设备;要拍摄图 3中显示的图像, 请使用在协议步骤3中准备的设备。
<ol><li>
准备在实验中使用的解决方案。
	<ol>
<li>以甘油为高粘度水相, 并加0.5 的甲苯胺蓝 O 染成蓝色。</li>
		<li>采用液体石蜡作为低粘度油相, 并在其上加入1% 的 80, 作为表面活性剂。</li>
	</ol>
</li>
	<li>
准备三1毫升注射器和三注射器泵。 注: 三在议定书步骤4.1 中制备的液体用注射器: 一种用于注射在协议步骤4.1.1 中制备的高粘度甘油, 另两种用于注射低黏度液体石蜡, 分别在协议步骤4.1.2 中制备。<ol>
<li>将含有甘油的注射器连接到中间管。</li>
		<li>将含有液体石蜡的注射器连接到内胎的入口, 同时将其连接到入口以进行清洗。</li>
	</ol>
</li>
	<li>将在1号协议步骤中准备的设备放置在倒置显微镜下, 并将一块 Kimwipe 置于外管的出口处, 以吸收泄漏的液体。 注意: 不要让流体在 Kimwipe 区域外泄漏。</li>
	<li>
设置注射器泵的流速。 注: 当中间管出口周围有陷泡或水滴时, 使用与外管连接的注射器泵进行清洗。否则, 就把水泵停了。<ol>
<li>将甘油的流速设置为Qw = 10 ul/分钟的中间管。</li>
		<li>设置向Qo = 30 ul/分钟内管注入液体石蜡的流速。</li>
		<li>运行两个泵产生甘油滴。</li>
	</ol>
</li>
	<li>等待0.5 分钟, 直到流量稳定, 甘油滴在中间管出口均匀生成。然后, 拍下水滴生成过程的视频或图像。 注意: 图1B 中的图像可以使用在协议步骤1中编写的设备, 而图 3A中的图像可以使用在协议步骤3中编写的设备进行。一旦拍摄完视频或图像, 立即停止所有的水泵, 立即将设备从显微镜上取出。</li>
	<li>
准备收集高粘度的水滴。
	<ol>
<li>将设备放在垂直平面上, 并将插座指向下方, 并将培养皿放在插座下。使用胶带修复设备与出口〜2毫米以上的培养皿底部。</li>
		<li>将在协议步骤4.1.2 中制备的液体石蜡倒入培养皿中, 然后浸入装置的出口。</li>
	</ol>
</li>
	<li>再次运行两个注射器泵在Qw = 10 ul/分钟和Qo = 30 ul/分钟, 并收集在培养皿中的甘油滴。 注: 等待 ~ 1 分钟, 直到流量稳定, 甘油滴在外管出口均匀生成, 可以采取培养皿中的水滴的图像, 如图 1D中所示的协议1中编写的设备, 或者是在协议步骤3中准备的设备的图 3B 。</li>
</ol>5. 用步骤2中制备的简化装置在液体石蜡中生成和收集甘油滴。
注: 这是为了拍摄在不同流速比的Qo/Qw生成的甘油水滴的图像, 并测量图 2中数据点的相应大小变化。
<ol><li>按照协议步骤 4.1, 准备在实验中使用的解决方案。</li>
	<li>
准备两个1毫升注射器和两个注射器泵。 注: 在协议步骤4.1 中制备的液体用两个注射器: 一种注射高粘度甘油, 在协议步骤4.1.1 中制备, 另一种用于注射低黏度液体石蜡, 分别在协议步骤4.1.2 中制备。<ol>
<li>将含有0.8 毫升甘油的注射器连接到中间管的入口。</li>
		<li>将含有0.8 毫升液体石蜡的注射器连接到内胎的入口。</li>
	</ol>
</li>
	<li>
准备收集高粘度的水滴。
	<ol>
<li>将设备放在垂直平面上, 并将插座指向下方, 并将35毫米的培养皿放在插座下。使用胶带修复设备与出口〜2毫米以上的培养皿底部。</li>
		<li>将在协议步骤4.1.2 中制备的液体石蜡倒入培养皿中, 然后浸入装置的出口。</li>
	</ol>
</li>
	<li>
设置注射器泵的流速。 注: 对于图 2中的每个流量比率, 请固定甘油qw = 2 ul/分钟的流量, 同时根据所需的 q 的流速比率增加液体石蜡Qo到不同值的流量. o/Qw。对于每个流速比, 等待 ~ 1 分钟, 直到流稳定和均匀甘油滴在培养皿中收集, 然后采取水滴的图像。<ol>
<li>设置在Qw = 2 ul/分钟的中间管中注入的甘油的流速。</li>
		<li>设置在Qo = 6 ul/分钟内管中注入的液体石蜡的流速。</li>
		<li>运行两个泵产生甘油滴。 注: 水滴的产生过程可以用手机相机直接观察到, 或者是安装在三脚架上的数码相机。</li>
	</ol>
</li>
	<li>等待 ~ 1 分钟, 直到流量稳定, 并改变一个新的培养皿收集均匀甘油滴。</li>
</ol>6. 采用相倒置共流装置, 在液体石蜡中产生其它高粘度滴。
注意: 这是为图 4中的图像提供的。实验中使用的低粘度油相与协议步骤4.1.2 中所用的方法相同。
<ol><li>使用纯蜂蜜作为图 4A的高粘度水相。</li>
	<li>为图 4B准备 6% 的淀粉溶液。 注意: 使用适当的高温玻璃介质瓶和高温帽。佩戴耐热手套。<ol>
<li>在100毫升的玻璃介质瓶中添加47克水, 并在瓶子里放一个搅拌棒。</li>
		<li>把瓶子放在水浴中, 把温度设置为100摄氏度。</li>
		<li>水浴达到100摄氏度后, 将3克淀粉粉加入热水中。</li>
		<li>盖子的瓶盖, 并保持搅拌4小时, 直到解决方案是明确的。</li>
		<li>等到溶液冷却到室温, 然后再使用。</li>
	</ol>
</li>
	<li>为图 4C准备 10 PVA-124% 的解决方案。 注意: 使用适当的高温玻璃介质瓶和高温帽。佩戴耐热手套。<ol>
<li>在100毫升的玻璃介质瓶中添加45克水, 并在瓶子里放一个搅拌棒。</li>
		<li>把瓶子放在水浴中, 把温度设置为70摄氏度。</li>
		<li>在水浴达到70摄氏度后, 在瓶子中加入5克 PVA-124 粉。</li>
		<li>盖子的瓶盖, 并保持搅拌1小时, 直到解决方案是明确的。</li>
		<li>等到溶液冷却到室温, 然后再使用。</li>
	</ol>
</li>
	<li>
在液体石蜡中产生高粘度滴。
	<ol>
<li>使用步骤 6.1-6.3 中准备的高粘度流体, 而不是在协议步骤5中的甘油, 遵循协议步骤5。</li>
		<li>使用Qw = 1 ul/分钟的流速设置, Qo = 5 ul/分钟图 4。</li>
	</ol>
</li>
</ol>

<ol>
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Soc. 100, 41-48 (2017).</li><li>Chen, H., Man, J., Li, Z., Li, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+generation+of+high-viscosity+droplets+by+surface-controlled+breakup+of+segment+flow.">Microfluidic generation of high-viscosity droplets by surface-controlled breakup of segment flow.</a> ACS Appl. Mater. Interfaces. 9, 21059-21064 (2017).</li><li>Man, J., Li, Z., Li, J., Chen, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phase+inversion+of+slug+flow+on+step+surface+to+form+high+viscosity+droplets+in+microchannel.">Phase inversion of slug flow on step surface to form high viscosity droplets in microchannel.</a> Appl. Phys. Lett. 110, 181601 (2017).</li></ol>

作者没有什么可透露的。

反相共流装置提供了一种简单、直接的方法, 能产生单分散高粘度水滴。该装置与普通共流装置具有相似的结构, 因为基本的共流结构由插入在中间管中的内管组成, 其出口与出口油管相连。然而, 相逆共流装置与普通共流装置之间存在两个主要区别, 即产生粘度为η > 1 Pa·s 的高粘度水滴。
首先, 在常用的共流装置中, 采用锥形尖端的内管, 而直内管可用于相倒置的共流装...

水滴的产生正在成为各种应用的关键技术, 如药物输送, 材料合成, 3D 生物打印, 细胞化验, 食品工程 1, 2, 3, 4,5,6. 带 T 形连接7、8、co 流1、9或流聚焦10、11结构的微流控设备广泛用于生成单分散单乳液滴。选择一个更粘性的连续相将有助于形成水滴12, 并且连续和分散的流体的粘度通常低于 0.1 Pas 在液滴微流体 13.然而, 在许多应用中, 分散相的粘度可能比水高几倍, 例如甘油14、含有纳米粒子15、蛋白质16或聚合物17的溶液。,18,19, 而在微流控设备中, 很难直接从稳定的滴水状态11中的高粘度流体中实现单分散液滴, 特别是对于具有η > 1 Pa·s14的粘度的流体.,17,18,19。此外, 还报告了13、18 , 认为液滴形成的典型微流控方法要求流体具有相对较低的粘度和适度的界面张力, 形成稳定滴水中的均匀水滴。政权。
对于具有稍大于 0.1 Pas 的粘度的分散相位, 有几种可能的方法可以通过典型的 T 连接、共流或流聚焦微流控装置来促进液滴的形成: (1) 降低分散的粘度在挥发性溶剂11,20中稀释它的相位;(2) 通过增加连续相位1,11的粘度, 减少分散到连续的粘度比;(3) 将分散相的流速降低到极低的值, 同时保持高连续到分散的流量比率14,19。但是, 这些方法对于粘度高得多的流体来说是不切实际的, 因为它们会显著降低生产速率, 同时显著提高挥发性溶剂或连续相的消耗。在百货商店, 据报道, 一些高粘度聚合物溶液与η > 1 Pa·s 仍然没有分解成水滴与上述方法17,19。
还有几种改进的微流控装置的设计, 将第三阶段的流体引入到系统中, 从而促进了高粘度滴的产生。创新包括: 引入气泡将喷射螺纹切割成水滴21, 一种具有中等粘度的不溶做伴流体, 引入 dipsersed 相和连续相18之间的中间相, 并微反应器介绍了从两个低粘度前体生成高粘度的小水滴 21, 22, 23.然而, 随着这个过程中的一个流体越来越多, 这个系统变得更加复杂, 而这些装置通常在比生成单乳液滴的典型装置更窄的流动机制中工作。
为了直接从高粘度流体中产生单分散液滴与η > 1 Pa·s, 研究了表面控相反演方法的24。由于低黏度水滴的产生比高粘度水滴容易得多12, 高粘度连续相的细长低黏度水滴首先使用典型的共流结构产生, 然后被分解为在共流结构的下游表面润湿性的变化。释放的低粘度流体将下游高粘度流体封装成水滴, 从而完成了相位反演。根据相变机理, 单分散高粘度液滴可根据典型的共流装置产生, 而该共流装置的出口被处理为由低粘度流体润湿, 然后连接到更宽的管24 ,25。

<table>
	<tbody>
		<tr>
			<td>VitroTubes Glass Tubing</td>
			<td>VitroCom</td>
			<td>8240</td>
			<td>Square - Miniature Hollow Glass Tubing, I.D.=0.4mm, OD=0.8mm</td>
		</tr>
		<tr>
			<td>VitroTubes Glass Tubing</td>
			<td>VitroCom</td>
			<td>CV2033</td>
			<td>Round - Miniature Hollow Glass Tubing, I.D.=0.2mm, O.D.=0.33mm</td>
		</tr>
		<tr>
			<td>VitroTubes Glass Tubing</td>
			<td>VitroCom</td>
			<td>CV1017</td>
			<td>Round - Miniature Hollow Glass Tubing, I.D.=0.1mm, O.D.=0.17mm</td>
		</tr>
		<tr>
			<td>VitroTubes Glass Tubing</td>
			<td>VitroCom</td>
			<td>Q14606</td>
			<td>Square - Miniature Hollow Glass Tubing, I.D.=1.05mm+0.1/-0, OD=1.5mm</td>
		</tr>
		<tr>
			<td>Standard Glass Capillaries</td>
			<td>WPI</td>
			<td>1B100-6</td>
			<td>Round - Glass Tubing, I.D.=0.58mm, O.D.=1.00mm</td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>Sinopharm Chemical Reagent Beijing</td>
			<td>10010618</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraffin Liquid</td>
			<td>Sinopharm Chemical Reagent Beijing</td>
			<td>30139828</td>
			<td></td>
		</tr>
		<tr>
			<td>Poly(vinyl alcohol), PVA-124</td>
			<td>Sinopharm Chemical Reagent Beijing</td>
			<td>30153084</td>
			<td></td>
		</tr>
		<tr>
			<td>Span 80</td>
			<td>Sigma-Aldrich</td>
			<td>85548</td>
			<td></td>
		</tr>
		<tr>
			<td>Starch</td>
			<td>Sigma-Aldrich</td>
			<td>S9765</td>
			<td></td>
		</tr>
		<tr>
			<td>Trichloro(octadecyl)silane</td>
			<td>Sigma-Aldrich</td>
			<td>104817</td>
			<td></td>
		</tr>
		<tr>
			<td>Toluidine Blue O</td>
			<td>Sigma-Aldrich</td>
			<td>T3260</td>
			<td></td>
		</tr>
		<tr>
			<td>Honey</td>
			<td></td>
			<td></td>
			<td>Chaste tree honey, common food product purchased from supermarket</td>
		</tr>
		<tr>
			<td>DEVCON 5 Minute Epoxy</td>
			<td>ITW&#160;</td>
			<td></td>
			<td>Epoxy glue</td>
		</tr>
		<tr>
			<td>Blunt Tip Stainless Steel Dispensing Needles (Luer Lock)</td>
			<td>Suzhou Lanbo Needle, China</td>
			<td>LTA820050</td>
			<td>20G x 1/2&#34;&#160;</td>
		</tr>
		<tr>
			<td>Tungsten/Carbide Scriber</td>
			<td>Ullman</td>
			<td>1830</td>
			<td>For cutting glass tubing</td>
		</tr>
		<tr>
			<td>Microscope Slides</td>
			<td>Sail Brand</td>
			<td>7101</td>
			<td>76.2 mm x 25.4 mm, Thickness 1 - 1.2 mm</td>
		</tr>
		<tr>
			<td>Polyethylene Tubing</td>
			<td>Scientific Commodities</td>
			<td>BB31695-PE/5</td>
			<td>I.D. = 0.86 mm, O.D. = 1.32 mm</td>
		</tr>
		<tr>
			<td>Syringe Pumps</td>
			<td>Longer Pump, China</td>
			<td>LSP01-1A</td>
			<td>3 pumps needed for the experiments</td>
		</tr>
	</tbody>
</table>

fabricating high-viscosity droplets using microfluidic capillary device with phase-inversion co-flow structure

高粘度的单分散液滴的产生一直是液滴微流体的挑战。在这里, 我们演示了一个相逆共流装置, 以产生均匀的高粘度液滴在低粘度流体。微流控毛细管装置有一个共同的共流结构, 其出口连接到一个更宽的管。低粘度流体的细长滴液首先由高粘度流体在共流结构中封装。当细长的低粘度水滴流过出口时, 被低粘度流体所润湿, 然后通过低粘度水滴与出口尖端的粘附来诱导相反转, 从而导致随后的反高粘度流体的封装。通过将低粘度流体的流速比转化为高粘度流体, 可以调节产生的高粘度水滴的大小。我们展示了几个典型的例子, 产生高粘度的水滴, 粘度高达 11.9 Pas, 如甘油, 蜂蜜, 淀粉和聚合物溶液。该方法提供了一种简单而直接的方法来生成单分散高粘度滴, 可用于各种液滴的应用, 如材料合成, 药物输送, 细胞化验, 生物工程和食品工程。

采用相反转、共流结构的微流控毛细管装置, 设计成单分散水性高粘度水滴, 如图 1A所示。在图 1中, 高粘度水相是甘油, 其黏度为ηw = 1.4 Pas;低粘度油相为液体石蜡, 其粘度为ηo = 0.029 Pas;两个阶段之间的表面张力为γ = 27.7 锰/米。在中间管, 拉长的油滴可以由甘油封装在一个良好控制的滴水模式<sup cla...

Watch this Scientific Journal Video about Fabricating High-viscosity Droplets using Microfluidic Capillary Device with Phase-inversion Co-flow Structure at JoVE.com

Fabricating High-viscosity Droplets using Microfluidic Capillary Device with Phase-inversion Co-flow Structure

反相共流微流控毛细管装置制备高粘度水滴的方法

本文展示了一种反相共流装置, 以产生单分散高粘度在 1 Pas 以上的液滴, 在液滴微流体中难以实现。

The generation of monodisperse droplets with high viscosity has always been a challenge in droplet microfluidics. Here, we demonstrate a phase-inversion ...

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10.2K 次观看.  University of Science and Technology Beijing. 本文展示了一种反相共流装置, 以产生单分散高粘度在 1 Pas 以上的液滴, 在液滴微流体中难以实现。

视频: Fabricating High-viscosity Droplets using Microfluidic Capillary Device with Phase-inversion Co-flow Structure

Fabricating Nanogaps by Nanoskiving

There are several methods of fabricating nanogaps with controlled spacings, but the precise control over the sub-nanometer spacing between two electrodes-and generating them in practical quantities-is still challenging. The preparation of nanogap electrodes using nanoskiving, which is a form of edge lithography, is a fast, simple and powerful technique. This method is an entirely mechanical process which does not include any photo- or electron-beam lithographic steps and does not require any special equipment or infrastructure such as clean rooms. Nanoskiving is used to fabricate electrically addressable nanogaps with control over all three dimensions; the smallest dimension of these structures is defined by the thickness of the sacrificial layer (Al or Ag) or self-assembled monolayers. These wires can be manually positioned by transporting them on drops of water and are directly electrically-addressable; no further lithography is required to connect them to an electrometer.

The fabrication of electrically addressable, high-aspect-ratio (> 1000:1) metal nanowires separated by gaps of single nanometers using either sacrificial layers of aluminum and silver or self-assembled monolayers as templates is described. These nanogap structures are fabricated without a clean room or any photo- or electron-beam lithographic processes by a form of edge lithography known as nanoskiving.

制造由Nanoskiving Nanogaps的

There are several methods of fabricating nanogaps with controlled spacings, but the precise control over the sub-nanometer spacing between two ...

科研

化学

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR

Copper (I) binding by metallochaperone transport proteins prevents copper oxidation and release of the toxic ions that may participate in harmful redox reactions. The Cu (I) complex of the peptide model of a Cu (I) binding metallochaperone protein, which includes the sequence MTCSGCSRPG (underlined is conserved), was determined in solution under inert conditions by NMR spectroscopy.
NMR is a widely accepted technique for the determination of solution structures of proteins and peptides. Due to difficulty in crystallization to provide single crystals suitable for X-ray crystallography, the NMR technique is extremely valuable, especially as it provides information on the solution state rather than the solid state. Herein we describe all steps that are required for full three-dimensional structure determinations by NMR. The protocol includes sample preparation in an NMR tube, 1D and 2D data collection and processing, peak assignment and integration, molecular mechanics calculations, and structure analysis. Importantly, the analysis was first conducted without any preset metal-ligand bonds, to assure a reliable structure determination in an unbiased manner.

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR

The NMR-solution structure of a metallochaperone model peptide with Cu (I) was determined, and a detailed protocol from sample preparation and 1D and 2D data collection to a three-dimensional structure is described.

Copper (I) binding by metallochaperone transport proteins prevents copper oxidation and release of the toxic ions that may participate in harmful redox ...

Capillary Electrophoresis to Monitor Peptide Grafting onto Chitosan Films in Real Time

Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. Compared to other analytical separation techniques, such as chromatography, CE is cheap, robust and effectively requires no sample preparation (for a number of complex natural matrices or polymeric samples). CE is fast and can be used to follow the evolution of mixtures in real time (e.g., chemical reaction kinetics), as the signals observed for the separated compounds are directly proportional to their quantity in solution.
Here, the efficiency of CE is demonstrated for monitoring the covalent grafting of peptides onto chitosan films for subsequent biomedical applications. Chitosan&#39;s antimicrobial and biocompatible properties make it an attractive material for biomedical applications such as cell growth substrates. Covalently grafting the peptide RGDS (arginine - glycine - aspartic acid - serine) onto the surface of chitosan films aims at improving cell attachment. Historically, chromatography and amino acid analysis have been used to provide a direct measurement of the amount of grafted peptide. However, the fast separation and absence of sample preparation provided by CE enables equally accurate yet real-time monitoring of the peptide grafting process. CE is able to separate and quantify the different components of the reaction mixture: the (non-grafted) peptide and the chemical coupling agents. In this way the use of CE results in improved films for downstream applications.
The chitosan films were characterized through solid-state NMR (nuclear magnetic resonance) spectroscopy. This technique is more time-consuming and cannot be applied in real time, but yields a direct measurement of the peptide and thus validates the CE technique.

Free solution capillary electrophoresis is a fast, cheap and robust analytical method that enables the quantitative monitoring of chemical reactions in real time. Its utility for rapid, convenient and precise analysis is demonstrated here through analysis of covalent peptide grafting onto chitosan films for improved cell adhesion.

毛细管电泳监视肽接枝壳聚糖膜实时

Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. ...

Using Capillary Electrophoresis to Quantify Organic Acids from Plant Tissue: A Test Case Examining Coffea arabica Seeds

Carboxylic acids are organic acids containing one or more terminal carboxyl (COOH) functional groups. Short chain carboxylic acids (SCCAs; carboxylic acids containing three to six carbons), such as malate and citrate, are critical to the proper functioning of many biological systems, where they function in cellular respiration and can serve as indicators of cell health. In foods, organic acid content can have significant impact on taste, with increased SCCA levels resulting in a sour or &#34;acid&#34; taste. Because of this, methods for the rapid analysis of organic acid levels are of particular interest to the food and beverage industries. Unfortunately, however, most methods used for SCCA quantification are dependent on time-consuming protocols requiring the derivatization of samples with hazardous reagents, followed by costly chromatographic and/or mass spectrometric analyses. This method details an alternate method for the detection and quantification of organic acids from plant material and food samples using free zonal capillary electrophoresis (CZE), sometimes simply referred to as capillary electrophoresis (CE). CZE provides a cost-effective method for measuring SCCAs with a low limit of detection (0.005 mg/ml). This article details the extraction and quantification of SCCAs from plant samples. While the method provided focuses on measurement of SCCAs from coffee beans, the method provided can be applied to multiple plant-based food materials.

Using Capillary Electrophoresis to Quantify Organic Acids from Plant Tissue: A Test Case Examining Coffea arabica Seeds

This article presents a method for the detection and quantification of organic acids from plant material using free zonal capillary electrophoresis. An example of the potential application of this method, determining the effects of a secondary fermentation on organic acid levels in coffee seeds, is provided.

利用毛细管电泳从植物组织量化有机酸:一个测试用例检查<em&gt;小粒种咖啡</em&gt;种子

Carboxylic acids are organic acids containing one or more terminal carboxyl (COOH) functional groups. Short chain carboxylic acids (SCCAs; carboxylic ...

Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering

We demonstrate a protocol to effectively monitor the gelation process of a high concentration solution of conjugated polymer both in the presence and absence of white light exposure. By instituting a controlled temperature ramp, the gelation of these materials can be precisely monitored as they proceed through this structural evolution, which effectively mirrors the conditions experienced during the solution deposition phase of organic electronic device fabrication. Using small angle neutron scattering (SANS) and ultra-small angle neutron scattering (USANS) along with appropriate fitting protocols we quantify the evolution of select structural parameters throughout this process. Thorough analysis indicates that continued light exposure throughout the gelation process significantly alters the structure of the ultimately formed gel. Specifically, the aggregation process of poly(3-hexylthiophene-2,5-diyl) (P3HT) nano-scale aggregates is negatively affected by the presence of illumination, ultimately resulting in the retardation of growth in conjugated polymer microstructures and the formation of smaller scale macro-aggregate clusters.

A protocol for the analysis of gels formed from the optoelectronic conjugated polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) using small and ultra-small angle neutron scattering in both the presence and absence of illumination is presented.

利用中子散射监测光照对共轭高分子凝胶结构的影响

We demonstrate a protocol to effectively monitor the gelation process of a high concentration solution of conjugated polymer both in the presence and ...

Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils

In this article, we have demonstrated a method for producing hollow particles and microcapsules using oil droplets consisting of hydrocarbon oil (styrene) and fluorocarbon oil (perfluoro-n-octane, PFO) in aqueous surfactant (sodium dodecylsulfate, SDS) solutions. Since fluorocarbon oils are immiscible with hydrocarbon oils, the two oils are separated. Emulsions are prepared by stirring styrene/PFO/aqueous SDS solution mixtures at 80 &#176;C. The type of emulsions and the morphology of droplets in the emulsions are observed by light microscope and scanning confocal fluorescence microscope. It is found that oil droplets with Janus-type morphologies consisting of mutually immiscible styrene and PFO are formed in aqueous SDS solutions. Polystyrene particles are fabricated by radical polymerization of the ternary mixtures of styrene/PFO/aqueous SDS solution at 80 &#176;C. The morphologies of the polystyrene are confirmed by scanning electron microscopy and scanning transmission electron microscopy observations. These observations show the preparation of hollow polystyrene particles with a single hole on the surface. To our knowledge, this method is a novel strategy using the immiscibility of hydrocarbon and fluorocarbon oils. The hollow particles can also be applied to the preparation of microcapsules.

A protocol for the fabrication of hollow polymer particles and microcapsules by radical polymerization using emulsions consisting of styrene, perfluoro-n-octane, and aqueous SDS (sodium dodecylsulfate) solution is presented.

由烃类和氟碳油组成的同液滴的自由基聚合制备空心聚苯乙烯颗粒和微胶囊

In this article, we have demonstrated a method for producing hollow particles and microcapsules using oil droplets consisting of hydrocarbon oil (styrene) ...

Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy

Water/solid interfaces are ubiquitous and play a key role in many environmental, biophysical, and technological processes. Resolving the internal structure and probing the hydrogen-bond (H-bond) dynamics of the water molecules adsorbed on solid surfaces are fundamental issues of water science, which remains a great challenge owing to the light mass and small size of hydrogen. Scanning tunneling microscopy (STM) is a promising tool for attacking these problems, thanks to its capabilities of sub-&#197;ngstr&#246;m spatial resolution, single-bond vibrational sensitivity, and atomic/molecular manipulation. The designed experimental system consists of a Cl-terminated tip and a sample fabricated by dosing water molecules in situ onto the Au(111)-supported NaCl(001) surfaces. The insulating NaCl films electronically decouple the water from the metal substrates, so the intrinsic frontier orbitals of water molecules are preserved. The Cl-tip facilitates the manipulation of the single water molecules, as well as gating the orbitals of water to the proximity of Fermi level (EF) via tip-water coupling. This paper outlines the detailed methods of submolecular resolution imaging, molecular/atomic manipulation, and single-bond vibrational spectroscopy of interfacial water. These studies open up a new route for investigating the H-bonded systems at the atomic scale.

Here, we present a protocol to investigate the structure and dynamics of interfacial water at the atomic scale, in terms of submolecular resolution imaging, molecular manipulation, and single-bond vibrational spectroscopy.

用扫描隧穿显微镜和光谱法探讨界面水的结构和动力学

Water/solid interfaces are ubiquitous and play a key role in many environmental, biophysical, and technological processes. Resolving the internal ...

Synthesis and Structure Determination of &#181;-Conotoxin PIIIA Isomers with Different Disulfide Connectivities

Peptides with a high number of cysteines are usually influenced regarding the three-dimensional structure by their disulfide connectivity. It is thus highly important to avoid undesired disulfide bond formation during peptide synthesis, because it may result in a completely different peptide structure, and consequently altered bioactivity. However, the correct formation of multiple disulfide bonds in a peptide is difficult to obtain by using standard self-folding methods such as conventional buffer oxidation protocols, because several disulfide connectivities can be formed. This protocol represents an advanced strategy required for the targeted synthesis of multiple disulfide-bridged peptides which cannot be synthesized via buffer oxidation in high quality and quantity. The study demonstrates the application of a distinct protecting group strategy for the synthesis of all possible 3-disulfide-bonded peptide isomers of &#181;-conotoxin PIIIA in a targeted way. The peptides are prepared by Fmoc-based solid phase peptide synthesis using a protecting group strategy for defined disulfide bond formation. The respective pairs of cysteines are protected with trityl (Trt), acetamidomethyl (Acm), and tert-butyl (tBu) protecting groups to make sure that during every oxidation step only the required cysteines are deprotected and linked. In addition to the targeted synthesis, a combination of several analytical methods is used to clarify the correct folding and generation of the desired peptide structures. The comparison of the different 3-disulfide-bonded isomers indicates the importance of accurate determination and knowledge of the disulfide connectivity for the calculation of the three-dimensional structure and for interpretation of the biological activity of the peptide isomers. The analytical characterization includes the exact disulfide bond elucidation via tandem mass spectrometry (MS/MS) analysis which is performed with partially reduced and alkylated derivatives of the intact peptide isomer produced by an adapted protocol. Furthermore, the peptide structures are determined using 2D nuclear magnetic resonance (NMR) experiments and the knowledge obtained from MS/MS analysis.

Cysteine-rich peptides fold into distinct three-dimensional structures depending on their disulfide connectivity. Targeted synthesis of individual disulfide isomers is required when buffer oxidation does not lead to the desired disulfide connectivity. The protocol deals with the selective synthesis of 3-disulfide-bonded peptides and their structural analysis using NMR and MS/MS studies.

不同二硫 Connectivities µ-芋螺毒素 PIIIA 异构体的合成与结构测定

Peptides with a high number of cysteines are usually influenced regarding the three-dimensional structure by their disulfide connectivity. It is thus ...

Large-scale Top-down Proteomics Using Capillary Zone Electrophoresis Tandem Mass Spectrometry

Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) has been recognized as a useful tool for top-down proteomics that aims to characterize proteoforms in complex proteomes. However, the application of CZE-MS/MS for large-scale top-down proteomics has been impeded by the low sample-loading capacity and narrow separation window of CZE. Here, a protocol is described using CZE-MS/MS with a microliter-scale sample-loading volume and a 90-min separation window for large-scale top-down proteomics. The CZE-MS/MS platform is based on a linear polyacrylamide (LPA)-coated separation capillary with extremely low electroosmotic flow, a dynamic pH-junction-based online sample concentration method with a high efficiency for protein stacking, an electro-kinetically pumped sheath flow CE-MS interface with extremely high sensitivity, and an ion trap mass spectrometer with high mass resolution and scan speed. The platform can be used for the high-resolution characterization of simple intact protein samples and the large-scale characterization of proteoforms in various complex proteomes. As an example, a highly efficient separation of a standard protein mixture and a highly sensitive detection of many impurities using the platform is demonstrated. As another example, this platform can produce over 500 proteoform and 190 protein identifications from an Escherichia coli proteome in a single CZE-MS/MS run.

A detailed protocol is described for the separation, identification, and characterization of proteoforms in protein samples using capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS). The protocol can be used for the high-resolution characterization of proteoforms in simple protein samples and the large-scale identification of proteoforms in complex proteome samples.

利用毛细管区电泳串联质谱技术进行大尺度自上而下蛋白质组学

Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) has been recognized as a useful tool for top-down ...

High-throughput and Comprehensive Drug Surveillance Using Multisegment Injection-Capillary Electrophoresis-Mass Spectrometry

New analytical methods are urgently needed to enable high-throughput, yet comprehensive drug screening, given an alarming opioid and prescription drug crisis in public health. Conventional urine drug testing based on a two-tier immunoassay screen followed by a gas chromatography-tandem mass spectrometry (GC-MS/MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS) method are expensive and prone to bias while being limited to targeted panels of known drugs of abuse (DoA). Herein, we outline an improved method for drug surveillance that allows for the resolution and detection of an expanded panel of DoA and their metabolites when using multisegment injection-capillary electrophoresis-mass spectrometry (MSI-CE-MS). Multiplexed separations of ten urine samples with a quality control by CE (&lt; 3 min/sample) in conjunction with full-scan data acquisition using a time-of-flight mass spectrometer (TOF-MS) under positive ion mode detection allows for the identification and quantification of DoA above recommended cut-off levels. An excellent resolution of drug isomers and isobars, including background interferences, are achieved when using MSI-CE-MS with an electrokinetic spacer between sample segments, where accurate mass/molecular formula together with the comigration of a matching deuterated internal standard and the detection of one or more bio-transformed metabolites facilitate DoA identification over a wider detection window. Additionally, urine samples can be analyzed directly without enzyme deconjugation for the rapid screening without complicated sample workup. MSI-CE-MS enables the surveillance of a broad spectrum of DoA that is required for the treatment monitoring of high-risk patients, including confirming prescribed drug adherence, revealing illicit drug use/substitution, and evaluating optimal dosage regimes as required for new advances in precision medicine.

Here we describe a high-throughput method for comprehensive drug surveillance that allows for the improved resolution and detection of large panels of drugs of abuse and their metabolites, with quality control based on multisegment injection-capillary electrophoresis-mass spectrometry.

采用多段注射-毛细管电泳质谱法进行高通量和综合药物监测

New analytical methods are urgently needed to enable high-throughput, yet comprehensive drug screening, given an alarming opioid and prescription drug ...

反相共流微流控毛细管装置制备高粘度水滴的方法

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