这项工作是支持K08 EB003996由美国国立卫生研究院和美国研究基金会赠款2573瘫痪退伍军人。

1。选择一种聚合物<ol><li>选择一种聚合物（如聚- L -乳酸（PLLA），聚己内酯（PCL），聚苯乙烯（PS）或尼龙）根据您的规格（例如，可生物降解的热塑性或交联）和溶剂，聚合物。选择合适的个人防护设备，根据您的选择。 </li><li>选择根据您的应用程序基材（如玻璃，塑料，金属或硅晶片）。 </li></ol> 2。选择收集器<ol><li>选择集热器的几何形状，根据您的要求。随机的纤维可收集固定板。不结盟的纤维可以被收集在快速旋转的车轮，鼓或棒，或平行板。 </li><li>集热器必须是导电性和孤立的，它可以不也接地相邻的对象，表的顶部，等接地必须保持在这样一种方式阿克塞尔</li></ol> 3。接近临界纠缠浓度实证1 <ol><li>准备几个候选聚合物浓度（例如，4，10，15，20，30％）和流动（的解决方案应该是一种粘性液体，但没有一种凝胶体）开始，选择浓度。 </li><li>设置电设备2,3,4,5（见图1） <ol><li>装入注射器泵和泵的转速，如珠，任何解决方案的提示消灭立即更换。 </li><li>地面的收藏家和剪辑的高压电线的导体板（导电材料，如铝箔通过注射器尖端突出的一个小广场）。 </li><li>启动车轮旋转。 </li><li>确保电源在开机前零。 </li></ol></li><li>观察数据流<ol><li>斜坡电压慢慢看解决针尖珠。 </li><li>调整电压，以获得长期稳定的流。如果不能获得源源不断，调整了聚合物溶液的浓度。一个例子，请参阅表1。 </li></ol></li></ol> 4。疑难解答 - 流： <ol><li>无法查看流<ol><li>使用的是深色亚光的背景下，地方一个单向的光源（如手电筒）之间的浏览器和流（见图2）。 </li></ol></li><li>滴水注射器针尖<ol><li>如果聚合物溶液滴落，没有车轮的吸引力直线下降，确保导体板与针尖接触和收藏家正与地面接触。 </li><li>如果注射器尖端的聚合物溶液的下降是靠在车轮的方向，但没有形成一个流，增加电压。可以调整不同的距离和电压，直到源源不断流的质量。提出相应的电压为4％，PLLA的解决方案和一个8x8厘米的导体板距离，参见图3。 </li></ol></li><li>在注射器针尖大的水珠<ol><li>当聚合物溶液开始收集和变硬，尖的针，轻扫连接到一个非导电棒纸巾的​​glob。 </li></ol></li><li>振荡或“摆”流 当流是摆起来，迅速下降，降低电压或增加注射器针尖与车轮之间的距离。如果流继续WAG使用的聚合物浓度较高或较慢的蒸发增加一个小的溶剂。 </li><li>短期或间断流 可见观察的接触轮在高速旋转速度的稳定流产量最高质量的统一性和调整。当流是短期和间断，增加聚合物溶液，添加更多的缓慢蒸发溶剂，调整电压将提高流的长度和稳定性。 </li></ol> 5。疑难解答-纤维形态6,7,8（参见图4） <ol><li>卷边 当珠发现在纤维，增加聚合物溶液，并确保导体板用针不断接触和接地线刷轮连续接触。 </li><li>丝带和止血纤维 纤维形成色带或出血一起时，使用浓度较高的聚合物或溶剂的蒸发率较高（更不稳定）。 </li><li>花饰或波浪状的纤维 当纤维形成波浪或curlicues，增加车轮的转速或移动针尖进一步从集电极。此外，检查，导体板和收藏家不振动。 </li><li>孔隙率9 如果毛孔都需要，使用迅速蒸发溶剂。如果不希望毛孔，尝试添加少量助溶剂，是低于主要溶剂挥发。 </li><li>对齐10 当集热器是MOVING在低转速或休息时，对齐质量差。增加车轮的速度增加对齐。 </li></ol> 6。代表性的成果： 请参考图4描绘典型的光纤结果。 <img src="/files/ftp_upload/2494/2494fig1.jpg" alt="图1" /> 图1一个典型的静电设置。聚合物溶液（蓝色）免除从注射泵（橙色）。一个高压直流电源（绿色）的理由一个快速旋转的轮子器（灰色）对齐纤维收集到。聚合物喷射注射器和集电极之间由一个稳定的流段和快速振荡的鞭打段。 <img src="/files/ftp_upload/2494/2494fig2.jpg" alt="图2" /> 图2流喷射可见退出注射器尖端;鞭刑喷气是太小，无法看到。 逼近的关键纠缠浓度的PLLA <table border="1"><tbody><tr><td> 聚乳酸（％WT / V） </td><td> 观察 </td><td> 浓度调整 </td></tr><tr><td> 0.5 </td><td>滴水;没有流</td><td>增加</td></tr><tr><td> 2.0 </td><td>随地吐痰的小水珠，没有流</td><td> Increse略有</td></tr><tr><td> 4.0 </td><td>川流不息</td><td>好</td></tr><tr><td> 6.0 </td><td>随地吐痰的大水珠或珠</td><td>略有下降</td></tr><tr><td> 12.0 </td><td>聚集在一角;没有流</td><td>减少</td></tr></tbody></table> 表1。一个例子描绘逼近的关键纠缠浓度的PLLA。各种聚合物浓度都试过了，和由此产生的流，直到源源不断观察喉获得。 <img src="/files/ftp_upload/2494/2494fig3.jpg" alt="图3" /> 图3。注射器针尖和集电极之间的距离必须与外加电压的平衡，以获得稳定的的流喷射。多余施加电压使振荡或“摆”喷气对齐纤维少，结果形成。当电压过低，没有飞机将形成从注射器尖端的解决方案只会滴。上面紫色的阴影区域代表一个稳定的流喷射注射器 - 集电极距离的函数，可用于聚乳酸获得的电压范围。 <img src="/files/ftp_upload/2494/2494fig4.jpg" alt="图4" /> 图4。纤维可以表现出各种形态，包括（一）串珠，缎带（二），curlicues（三），（四）多孔水珠，良好的对齐（E）和贫困对齐（F）的。

<ol>
	<li>Shenoy, S. L., Bates, W. D., Frisch, H. L., Wnek, G. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+chain+entanglements+on+fiber+formation+during+electrospinning+of+polymer+solutions:+good+solvent,+non-specific+polymer-polymer+interaction+limit.">Role of chain entanglements on fiber formation during electrospinning of polymer solutions: good solvent, non-specific polymer-polymer interaction limit.</a> Polymer. 46, 3372-3384 (2005).</li><li>Gertz, C. C., Leach, M. K., Birrel, L. K., Martin, D. C., Feldman, E. L., Corey, 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=Accelerated+neuritogenesis+and+maturation+of+primary+spinal+motor+neurons+in+response+to+nanofibers.">Accelerated neuritogenesis and maturation of primary spinal motor neurons in response to nanofibers.</a> Dev. Neurobiol. 70, 589-603 (2010).</li><li>Lin, D. Y., Johnson, M. A., Vohden, R. A., Chen, D., Martin, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tailored+nanofiber+morphologies+using+modulated+electrospinning+for+biomedical+applications.">Tailored nanofiber morphologies using modulated electrospinning for biomedical applications.</a> Mat. Res. Soc. Symp. Proc. 736, D3.8.1-D3.8.6 (2003).</li><li>Corey, J. M., Gertz, C. C., Wang, B. S., Birrell, L. K., Johnson, S. L., Martin, D. C., Feldman, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+design+of+electrospun+PLLA+nanofiber+scaffolds+compatible+with+serum-free+growth+of+primary+motor+and+sensory+neurons.">The design of electrospun PLLA nanofiber scaffolds compatible with serum-free growth of primary motor and sensory neurons.</a> Acta. Biomater. 4, 863-875 (2008).</li><li>Corey, J. M., Lin, D. Y., Mycek, K. B., Chen, Q., Samuel, S., Feldman, E. L., Martin, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aligned+electrospun+nanofibers+specify+the+direction+of+dorsal+root+ganglia+neurite+growth.">Aligned electrospun nanofibers specify the direction of dorsal root ganglia neurite growth.</a> J. Biomed. Mater. Res. A. 83, 636-645 (2007).</li><li>Tan, S. -. H., Kotaki, M., Ramakrishna, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systematic+parameter+study+for+ultra-fine+fiber+fabrication+via+electrospinning+process.">Systematic parameter study for ultra-fine fiber fabrication via electrospinning process.</a> Polymer. 46, 6128-6134 (2005).</li><li>Yang, F., Murugan, R., Wang, S., Ramakrishna, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrospinning+of+nano/micro+scale+poly(L-lactic+acid)+aligned+fibers+and+their+potential+in+neural+tissue+engineering.">Electrospinning of nano/micro scale poly(L-lactic acid) aligned fibers and their potential in neural tissue engineering.</a> Biomaterials. 26, 2603-2610 (2005).</li><li>Li, W., Laurencin, C. T., Caterson, E. J., Tuan, R. S., Ko, F. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrospun+nanofibrous+structure:+A+novel+scaffold+for+tissue+engineering.">Electrospun nanofibrous structure: A novel scaffold for tissue engineering.</a> J. Biomed. Mater. Res. A. 60, 613-621 (2002).</li><li>Kim, C. H., Jung, Y. H., Kim, H. Y., Lee, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+collector+temperature+on+the+porous+structure+of+electrospun+fibers.">Effect of collector temperature on the porous structure of electrospun fibers.</a> Macromol. Res. 14, 59-65 (2006).</li><li>Wang, H. B., Mullins, M. E., Cregg, J. M., Hurtado, A., Oudega, M., Trombley, M. T., Gilbert, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Creation+of+highly+aligned+electrospun+poly-L-lactic+acid+fibers+for+nerve+regeneration+applications.">Creation of highly aligned electrospun poly-L-lactic acid fibers for nerve regeneration applications.</a> J. Neural Eng. 6, (2009).</li></ol>

注意：这里大多数的例子介绍静电聚- L -乳酸（PLLA）纤维的处理。这完全是因为聚乳酸是在我们的实验室中最常用的纺聚合物。但是，我们也成功地使用这些方法来electrospin其他聚合物（如的PLGA，PCL，PS），并认为这里介绍的技术很容易适用于大多数中旬高分子量聚合物溶液。

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		<div>
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		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>High voltage DC power supply</td>
<td>&nbsp;</td>
<td>Gamma High Voltage</td>
<td>ES40P-5W</td>
<td>&nbsp;</td>
<tr>
<td>Syringe pump</td>
<td>&nbsp;</td>
<td>KD Scientific</td>
<td>KDS100</td>
<td>&nbsp;</td>
<tr>
<td>Aluminum foil</td>
<td>&nbsp;</td>
<td>Reynolds</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Blunt metal tips, 23ga</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>13-850-102 </td>
<td>&nbsp;</td>
<tr>
<td>Polypropylene syringe</td>
<td>&nbsp;</td>
<td>BD</td>
<td>309585</td>
<td>&nbsp;</td>
<tr>
<td>Rotating or stationary collector</td>
<td>&nbsp;</td>
<td>Custom built</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Various alligator clips and wires</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Dimethylformamide</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>AC11622-0010</td>
<td>&nbsp;</td>
<tr>
<td>Chloroform</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>AC42355-0040 </td>
<td>&nbsp;</td>
<tr>
<td>PLLA</td>
<td>&nbsp;</td>
<td>Boehringer Ingelheim</td>
<td>Resomer L210</td>
<td>&nbsp;</td>
<tr>
<td>PLGA 85:15</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>43471</td>
<td>&nbsp;</td>
<tr>
<td>Carbon tape</td>
<td>&nbsp;</td>
<td>Ted Pella</td>
<td>13073-1</td>
<td>&nbsp;</td>		</tbody>
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electrospinning fundamentals: optimizing solution and apparatus parameters

静电纳米纤维支架已经证明，加速成熟，提高增长，和直接的细胞在体外的迁移。静电是一个充电的聚合物喷射是接地的收藏家收集的过程;一个快速旋转对齐纤维收藏家的结果，而固定的收藏家在随机取向的纤维毡结果。聚合物喷射时形成一个应用的静电电荷克服了溶液的表面张力。是一个给定的聚合物的最低浓度，称为临界缠结浓度，低于不能达到一个稳定的飞机，没有纤维的形式 - 虽然纳米粒子可能会实现（电）。一个稳定的飞机有两个域，一个流段和段鞭笞。虽然鞭刑喷气机通常是肉眼看不到，流段通常是可见的，适当的照明条件下。观测流的长度，厚度，一致性和运动是有用的预测的路线和正在形成的纳米纤维的形态。短，不统一，不一致，和/或振荡流显示的各种问题，包括贫穷的光纤对准，钉珠，飞溅，花饰或波浪形图案。流可以通过调整解决方案的组成和电设备的配置进行了优化，从而优化路线和正在生产的纤维形态。在这个协议中，我们目前的程序，设立一个基本的静电设备，经验近似的聚合物解决方案的关键纠缠浓度和优化的静电纺丝的过程。此外，我们将讨论一些常见问题和故障排除技术。

Watch this Scientific Journal Video about Electrospinning Fundamentals: Optimizing Solution and Apparatus Parameters at JoVE.com

Electrospinning Fundamentals: Optimizing Solution and Apparatus Parameters

静电技术，可以创建各种组织工程或其他应用程序的纳米纤维支架。我们在这里描述的程序，以优化电的解决方案和设备的参数，以获得所需的形态和排列的纤维。还介绍了常见问题和故障排除技术。

静电基础：优化解决方案和设备参数

Electrospun nanofiber scaffolds have been shown to accelerate the maturation, improve the growth, and direct the migration of cells in vitro. ...

electrospinning-fundamentals-optimizing-solution-apparatus

Research

JoVE Journal

Bioengineering

64.6K 次观看.  University of Michigan. 静电技术，可以创建各种组织工程或其他应用程序的纳米纤维支架。我们在这里描述的程序，以优化电的解决方案和设备的参数，以获得所需的形态和排列的纤维。还介绍了常见问题和故障排除技术。

视频: Electrospinning Fundamentals: Optimizing Solution and Apparatus Parameters

Tri-layered Electrospinning to Mimic Native Arterial Architecture using Polycaprolactone, Elastin, and Collagen: A Preliminary Study

Throughout native artery, collagen and elastin play an important role, providing a mechanical backbone, preventing vessel rupture, and promoting recovery under pulsatile deformations. The goal of this study was to mimic the structure of native artery by fabricating a multi-layered electrospun conduit composed of poly(caprolactone) (PCL) with the addition of elastin and collagen with blends of 45-45-10, 55-35-10, and 65-25-10 PCL-ELAS-COL to demonstrate mechanical properties indicative of native arterial tissue, while remaining conducive to tissue regeneration. Whole grafts and individual layers were analyzed using uniaxial tensile testing, dynamic compliance, suture retention, and burst strength. Compliance results revealed that changes to the middle/medial layer changed overall graft behavior with whole graft compliance values ranging from 0.8 - 2.8 % / 100 mmHg, while uniaxial results demonstrated an average modulus range of 2.0 - 11.8 MPa. Both modulus and compliance data displayed values within the range of native artery. Mathematical modeling was implemented to show how changes in layer stiffness affect the overall circumferential wall stress, and as a design aid to achieve the best mechanical combination of materials. Overall, the results indicated that a graft can be designed to mimic a tri-layered structure by altering layer properties.

The aim of this study was to mimic the native three layered architecture of the arterial wall. To accomplish this, electrospinning was employed with the use of a 3-1 (input-output) nozzle and blends of polycaprolactone, elastin, and collagen.

三层次的静电，以模仿母语动脉结构采用聚己内酯，弹性和胶原的初步研究

Throughout native artery, collagen and elastin play an important role, providing a mechanical backbone, preventing vessel rupture, and promoting recovery ...

科研

生物工程

Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus (SCUVA)

The ability to directly measure velocity fields in a fluid environment is necessary to provide empirical data for studies in fields as diverse as oceanography, ecology, biology, and fluid mechanics. Field measurements introduce practical challenges such as environmental conditions, animal availability, and the need for field-compatible measurement techniques. To avoid these challenges, scientists typically use controlled laboratory environments to study animal-fluid interactions. However, it is reasonable to question whether one can extrapolate natural behavior (i.e., that which occurs in the field) from laboratory measurements. Therefore, in situ quantitative flow measurements are needed to accurately describe animal swimming in their natural environment.
We designed a self-contained, portable device that operates independent of any connection to the surface, and can provide quantitative measurements of the flow field surrounding an animal. This apparatus, a self-contained underwater velocimetry apparatus (SCUVA), can be operated by a single scuba diver in depths up to 40 m. Due to the added complexity inherent of field conditions, additional considerations and preparation are required when compared to laboratory measurements. These considerations include, but are not limited to, operator motion, predicting position of swimming targets, available natural suspended particulate, and orientation of SCUVA relative to the flow of interest. The following protocol is intended to address these common field challenges and to maximize measurement success.

Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus SCUVA

This protocol provides instructions on how to use a self-contained underwater velocimetry apparatus (SCUVA), which is designed for quantification of in situ animal-generated flows. In addition, this protocol addresses challenges posed by field conditions, and includes operator motion, predicting position of animals, and orientation of SCUVA.

定量测量原位流动，使用一个自包含的水下测速仪（SCUVA）

The ability to directly measure velocity fields in a fluid environment is necessary to provide empirical data for studies in fields as diverse as ...

Small and Wide Angle X-Ray Scattering Studies of Biological Macromolecules in Solution

In this paper, Small and Wide Angle X-ray Scattering (SWAXS) analysis of macromolecules is demonstrated through experimentation. SWAXS is a technique where X-rays are elastically scattered by an inhomogeneous sample in the nm-range at small angles (typically 0.1 - 5&deg;) and wide angles (typically &gt; 5&deg;). This technique provides information about the shape, size, and distribution of macromolecules, characteristic distances of partially ordered materials, pore sizes, and surface-to-volume ratio. Small Angle X-ray Scattering (SAXS) is capable of delivering structural information of macromolecules between 1 and 200 nm, whereas Wide Angle X-ray Scattering (WAXS) can resolve even smaller Bragg spacing of samples between 0.33 nm and 0.49 nm based on the specific system setup and detector. The spacing is determined from Bragg's law and is dependent on the wavelength and incident angle.
In a SWAXS experiment, the materials can be solid or liquid and may contain solid, liquid or gaseous domains (so-called particles) of the same or another material in any combination. SWAXS applications are very broad and include colloids of all types: metals, composites, cement, oil, polymers, plastics, proteins, foods, and pharmaceuticals. For solid samples, the thickness is limited to approximately 5 mm.
Usage of a lab-based SWAXS instrument is detailed in this paper. With the available software (e.g., GNOM-ATSAS 2.3 package by D. Svergun EMBL-Hamburg and EasySWAXS software) for the SWAXS system, an experiment can be conducted to determine certain parameters of interest for the given sample. One example of a biological macromolecule experiment is the analysis of 2 wt% lysozyme in a water-based aqueous buffer which can be chosen and prepared through numerous methods. The preparation of the sample follows the guidelines below in the Preparation of the Sample section. Through SWAXS experimentation, important structural parameters of lysozyme, e.g. the radius of gyration, can be analyzed.

The demonstration of the small and wide angle X-ray scattering (SWAXS) procedure has become instrumental in the study of biological macromolecules. Through the use of the instrumentation and procedures of specific angle methods and preparation, the experimental data from the SWAXS displays the atomic and nano-scale characterization of macromolecules.

小型和广角X-射线散射研究生物大分子的解决方案

In this paper, Small and Wide Angle X-ray Scattering (SWAXS) analysis of macromolecules is demonstrated through experimentation. SWAXS is a technique ...

Electrospinning Growth Factor Releasing Microspheres into Fibrous Scaffolds

This procedure describes a method to fabricate a multifaceted substrate to direct nerve cell growth. This system incorporates mechanical, topographical, adhesive and chemical signals. Mechanical properties are controlled by the type of material used to fabricate the electrospun fibers. In this protocol we use 30% methacrylated Hyaluronic Acid (HA), which has a tensile modulus of ~500 Pa, to produce a soft fibrous scaffold. Electrospinning on to a rotating mandrel produces aligned fibers to create a topographical cue. Adhesion is achieved by coating the scaffold with fibronectin. The primary challenge addressed herein is providing a chemical signal throughout the depth of the scaffold for extended periods. This procedure describes fabricating&#160;poly(lactic-co-glycolic acid) (PLGA) microspheres that contain Nerve Growth Factor (NGF) and directly impregnating the scaffold with these microspheres during the electrospinning process. Due to the harsh production environment, including high sheer forces and electrical charges, protein viability is measured after production. The system provides protein release for over 60 days and has been shown to promote primary nerve cell growth.

This protocol combines electrospinning and microspheres to develop tissue engineered scaffolds to direct neurons. Nerve growth factor was encapsulated within PLGA microspheres and electrospun into Hyaluronic Acid (HA) fibrous scaffolds. The protein bioactivity was tested by seeding the scaffolds with primary chick Dorsal Root Ganglia and culturing for 4-6 days.

静电生长因子释放到微纤维支架

This procedure describes a method to fabricate a multifaceted substrate to direct nerve cell growth.  This system incorporates mechanical, topographical, ...

Combination of Microstereolithography and Electrospinning to Produce Membranes Equipped with Niches for Corneal Regeneration

Corneal problems affect millions of people worldwide reducing their quality of life significantly. Corneal disease can be caused by illnesses such as Aniridia or Steven Johnson Syndrome as well as by external factors such as chemical burns or radiation. Current treatments are (i) the use of corneal grafts and (ii) the use of stem cell expanded in the laboratory and delivered on carriers (e.g., amniotic membrane); these treatments are relatively successful but unfortunately they can fail after 3-5 years. There is a need to design and manufacture new corneal biomaterial devices able to mimic in detail the physiological environment where stem cells reside in the cornea. Limbal stem cells are located in the limbus (circular area between cornea and sclera) in specific niches known as the Palisades of Vogt. In this work we have developed a new platform technology which combines two cutting-edge manufacturing techniques (microstereolithography and electrospinning) for the fabrication of corneal membranes that mimic to a certain extent the limbus. Our membranes contain artificial micropockets which aim to provide cells with protection as the Palisades of Vogt do in the eye.

We report a technique for the fabrication of micropockets within electrospun membranes in which to study cell behavior. Specifically, we describe a combination of microstereolithography and electrospinning for the production of PLGA (Poly(lactide-co-glycolide)) corneal biomaterial devices equipped with microfeatures.

Microstereolit​​hography和静电结合，以产生膜配备有利基的角膜再生

Corneal problems affect millions of people worldwide reducing their quality of life significantly. Corneal disease can be caused by illnesses such as ...

Fabricating Degradable Thermoresponsive Hydrogels on Multiple Length Scales via Reactive Extrusion, Microfluidics, Self-assembly, and Electrospinning

While various smart materials have been explored for a variety of biomedical applications (e.g., drug delivery, tissue engineering, bioimaging, etc.), their ultimate clinical use has been hampered by the lack of biologically-relevant degradation observed for most smart materials. This is particularly true for temperature-responsive hydrogels, which are almost uniformly based on polymers that are functionally non-degradable (e.g., poly(N-isopropylacrylamide) (PNIPAM) or poly(oligoethylene glycol methacrylate) (POEGMA)). As such, to effectively translate the potential of thermoresponsive hydrogels to the challenges of remote-controlled or metabolism-regulated drug delivery, cell scaffolds with tunable cell-material interactions, theranostic materials with the potential for both imaging and drug delivery, and other such applications, a method is required to render the hydrogels (if not fully degradable) at least capable of renal clearance following the required lifetime of the material. To that end, this protocol describes the preparation of hydrolytically-degradable hydrazone-crosslinked hydrogels on multiple length scales based on the reaction between hydrazide and aldehyde-functionalized PNIPAM or POEGMA oligomers with molecular weights below the renal filtration limit. Specifically, methods to fabricate degradable thermoresponsive bulk hydrogels (using a double barrel syringe technique), hydrogel particles (on both the microscale through the use of a microfluidics platform facilitating simultaneous mixing and emulsification of the precursor polymers and the nanoscale through the use of a thermally-driven self-assembly and cross-linking method), and hydrogel nanofibers (using a reactive electrospinning strategy) are described. In each case, hydrogels with temperature-responsive properties similar to those achieved via conventional free radical cross-linking processes can be achieved, but the hydrazone cross-linked network can be degraded over time to re-form the oligomeric precursor polymers and enable clearance. As such, we anticipate these methods (which may be generically applied to any synthetic water-soluble polymer, not just smart materials) will enable easier translation of synthetic smart materials to clinical applications.

Protocols are described for the fabrication of degradable thermoresponsive hydrogels based on hydrazone cross-linking of polymeric oligomers on the bulk scale, microscale, and nanoscale, the latter for preparation of both gel nanoparticles and nanofibers.

通过反应挤出、微流体、自组装和电纺丝制备多长尺度可降解 Thermoresponsive 水凝胶

While various smart materials have been explored for a variety of biomedical applications (e.g., drug delivery, tissue engineering, bioimaging, etc.), ...

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.

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

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 ...

High-resolution Patterning Using Two Modes of Electrohydrodynamic Jet: Drop on Demand and Near-field Electrospinning

Electrohydrodynamic (EHD) jet printing has drawn attention in various fields because it can be used as a high-resolution and low-cost direct patterning tool. EHD printing uses a fluidic supplier to maintain the extruded meniscus by pushing the ink out of the nozzle tip. The electric field is then used to pull the meniscus down to the substrate to produce high-resolution patterns. Two modes of EHD printing have been used for fine patterning: continuous near-field electrospinning (NFES) and dot-based drop-on-demand (DOD) EHD printing. According to the printing modes, the requirements for the printing equipment and ink viscosity will differ. Even though two different modes can be implemented with a single EHD printer, the realization methods significantly differ in terms of ink, fluidic system, and driving voltage. Consequently, without a proper understanding of the jetting requirements and limitations, it is difficult to obtain the desired results. The purpose of this paper is to present a guideline so that inexperienced researchers can reduce the trial and error efforts to use the EHD jet for their specific research and development purposes. To demonstrate the fine-patterning implementation, we use Ag nanoparticle ink for the conductive patterning in the protocol. In addition, we also present the generalized printing guidelines that can be used for other types of ink for various fine-patterning applications.

Here, we present a protocol to produce high-resolution conductive patterns using electrohydrodynamic (EHD) jet printing. The protocol includes two modes of EHD jet printing: the continuous near-field electrospinning (NFES) and the dot-based drop-on-demand (DOD) EHD printing.

采用两种 Electrohydrodynamic 射流的高分辨率模式: 需求下降和近场静电纺丝

Electrohydrodynamic (EHD) jet printing has drawn attention in various fields because it can be used as a high-resolution and low-cost direct patterning ...

Apparatus for Harvesting Tissue Microcolumns

This manuscript describes the production process for a laboratory apparatus, made from off-the-shelf components, that can be used to collect microcolumns of full-thickness skin tissue. The small size of the microcolumns allows donor sites to heal quickly without causing donor site scarring, while harvesting full-thickness tissue enables the incorporation of all cellular and extracellular components of skin tissue, including those associated with deeper dermal regions and the adnexal skin structures, which have yet to be successfully reproduced using conventional tissue engineering techniques. The microcolumns can be applied directly into skin wounds to augment healing, or they can be used as the autologous cell/tissue source for other tissue engineering approaches. The harvesting needles are made by modifying standard hypodermic needles, and they can be used alone for harvesting small amounts of tissue or coupled with a simple suction-based collection system (also made from commonly available laboratory supplies) for high-volume harvesting to facilitate studies in large animal models.

Here we describe a protocol for producing harvesting needles that can be used to collect full-thickness skin tissue without causing donor site scarring. The needles can be combined with a simple collection system to achieve high-volume harvesting.

水样组织的采集装置

This manuscript describes the production process for a laboratory apparatus, made from off-the-shelf components, that can be used to collect microcolumns ...

Three-Dimensional Echocardiographic Method for the Visualization and Assessment of Specific Parameters of the Pulmonary Veins

The dimensions of the pulmonary veins are important parameters when planning pulmonary vein isolation (PVI), especially with the cryoballoon ablation technique. Acknowledging the dimensions and anatomical variations of the pulmonary veins (PVs) may improve the outcome of the intervention. Conventional 2D transoesophageal echocardiography can only provide limited data about the dimensions of the PVs; however, 3D echocardiography can further evaluate relevant diameters and areas of the PVs, as well as their spatial relationship to surrounding structures. In previous literature data, parameters influencing the success rate of PVI have already been identified. These are the left lateral ridge, the intervenous ridge, the ostial area of the PVs and the ovality index of the ostium. Proper imaging of the PVs by 3D echocardiography is a technically challenging method. One crucial step is the collection of images. Three individual transducer positions are necessary to visualize the important structures; these are the left lateral ridge, the ostium of the PVs and the intervenous ridge of the left and right PVs. Next, 3D images are acquired and saved as digital loops. These datasets are cropped, which result in the en face views displaying spatial relationships. This step can also be employed to determine the anatomical variations of the PVs. Finally, multiplanar reconstructions are created to measure each individual parameter of the PVs.
Optimal quality and orientation of the acquired images are paramount for the appropriate assessment of PV anatomy. In the present work, we examined the 3D visibility of the PVs and the suitability of the above method in 80 patients. The aim was to provide a detailed outline of the essential steps and potential pitfalls of PV visualization and assessment with 3D echocardiography.

The dimensions of the pulmonary veins (PV) are important parameters when planning pulmonary vein isolation. 2D transoesophageal echocardiography can only provide limited data about the PVs; however, 3D echocardiography can evaluate relevant diameters and areas of the PVs, as well as their spatial relationship to surrounding structures.

用于肺静脉特定参数可视化和评估的三维超声心动图方法

The dimensions of the pulmonary veins are important parameters when planning pulmonary vein isolation (PVI), especially with the cryoballoon ablation ...