Name: wet-spinning-based molding process of gelatin for tissue regeneration
Uploaded: 2019-03-07T14:15:00
Description: Watch this Scientific Journal Video about Wet-spinning-based Molding Process of Gelatin for Tissue Regeneration at JoVE.com

这项研究得到了国防部的支持 (mab-105-070);ma6-106-077;ma6-107-032;maba-107-065), 科技部 (最低 107-2320-b016-016), 三科总医院, 国防医疗中心, 台湾 (tgh-c106-046;tgh-c106-115;tgh-c107-041), 和成新总医院和国防医疗中心合作 (ch-ndmc-107-8)。

这些脂肪组织是经台湾台北市三服务总医院机构审查委员会认证的骨科手术中获得的, 涉及动物主体的程序已得到国家动物护理委员会的批准国防医疗中心, 台湾 (r. c.)
1. 湿法纺纱工艺
<ol><li>
解决方案准备
	<ol>
<li>将5克明胶粉溶解在100毫升的双蒸馏水中, 得到 5% (w v) 溶液浓度。</li>
		<li>在60-70°c 下一夜慢慢搅拌混合物, 以实现完全均匀的分散, 而不会产生任何气?...

<ol>
	<li>Bagnall, A. M., Jones, L., Duffy, S., Riemsima, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spinal+fixation+surgery+for+acute+traumatic+spinal+cord+injury.">Spinal fixation surgery for acute traumatic spinal cord injury.</a> Cochrane Database of Systematic Reviews. 1, 004725 (2008).</li><li>Fehlings, M. G., Perrin, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+and+timing+of+early+decompression+for+cervical+spinal+cord+injury:+update+with+a+review+of+recent+clinical+evidence.">The role and timing of early decompression for cervical spinal cord injury: update with a review of recent clinical evidence.</a> Injury. 36, 13-26 (2005).</li><li>Yang, L., Jones, N. R., Stoodley, M. A., Blumbergs, P. C., Brown, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Excitotoxic+model+of+post-traumatic+syringomyelia+in+the+rat.">Excitotoxic model of post-traumatic syringomyelia in the rat.</a> Spine. 26, 1842-1849 (2001).</li><li>Rolls, A., 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=Two+faces+of+chondroitin+sulfate+proteoglycan+in+spinal+cord+repair:+a+role+in+microglia/macrophage+activation.">Two faces of chondroitin sulfate proteoglycan in spinal cord repair: a role in microglia/macrophage activation.</a> PLoS Medicine. 5, 1262-1277 (2008).</li><li>Properzi, F., Asher, R. A., Fawcett, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chondroitin+sulphate+proteoglycans+in+the+central+nervous+system:+changes+and+synthesis+after+injury.">Chondroitin sulphate proteoglycans in the central nervous system: changes and synthesis after injury.</a> Biochemical Society Transactions. 31, 335-336 (2003).</li><li>Fawcett, J. W., Asher, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+glial+scar+and+central+nervous+system+repair.">The glial scar and central nervous system repair.</a> Brain Research Bulletin. 49, 377-391 (1999).</li><li>Yang, Z., Mo, L., Duan, H., Li, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+chitosan/collagen+substrates+on+the+behavior+of+rat+neural+stem+cells.">Effects of chitosan/collagen substrates on the behavior of rat neural stem cells.</a> Science China Life Sciences. 53, 215-222 (2010).</li><li>Chawla, K. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Fibrous Materials. , (1998).</li><li>Pickering, K. L., Aruan Efendy, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+recent+developments+in+natural+fibre+composites+and+their+mechanical+performance.">A review of recent developments in natural fibre composites and their mechanical performance.</a> Composites Part A-Applied Science and Manufacturing. 83, 98-112 (2016).</li><li>Lundgren, H. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthetic+fibers+made+from+proteins.">Synthetic fibers made from proteins.</a> Advances in Protein Chemistry. 5, 305-351 (1954).</li><li>Radishevskii, M. B., Serkov, A. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coagulation+mechanism+in+wet+spinning+of+fibres.">Coagulation mechanism in wet spinning of fibres.</a> Fibre Chemistry. 37, 266-271 (2005).</li><li>Yannas, I. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collagen+and+gelatin+in+the+solid+state.">Collagen and gelatin in the solid state.</a> Journal of Macromolecular Science Part C Polymer Reviews. 7, 49-106 (1972).</li><li>Baer, E., Cassidy, J. J., Hiltner, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hierarchical+structure+of+collagen+composite+Systems:+lessons+from+biology.">Hierarchical structure of collagen composite Systems: lessons from biology.</a> Pure and Applied Chemistry. 6, 961-973 (2009).</li><li>Harrington, W. F., Von Hippel, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+structure+of+collagen+and+gelatin.">The structure of collagen and gelatin.</a> Advances in Protein Chemistry. 16, 1-138 (1961).</li><li>Veis, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Macromolecular Chemistry of Gelatin. , (1994).</li><li>Freyman, T. M., Yannas, I. V., Gibson, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+materials+as+porous+scaffolds+for+tissue+engineering.">Cellular materials as porous scaffolds for tissue engineering.</a> Progress in Materials Science. 46, 273-282 (2001).</li><li>Michalczyk, K., Ziman, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nestin+structure+and+predicted+function+in+cellular+cytoskeletal+organization.">Nestin structure and predicted function in cellular cytoskeletal organization.</a> Histology and Histopathology. 20, 665-671 (2005).</li></ol>

我们介绍了明胶基生物材料的发展, 使用简单的湿法纺丝技术, 可用于研究天然聚合物的组织再生。这项工作证明了明胶制造作为一个伟大的蛋白质来源, 而无需添加其他来源的可能性, 目的是优化明胶本身的性能。基于明胶的生物材料的开发完全是在室温 (22-26°c) 下进行的。温和的溶液制备是协议中的关键一步, 因为保持精确的溶液浓度和非常平稳地搅拌溶液以避免任何气泡也是如此。溶液中气泡...

组织再生的最新发展涉及组织工程的应用, 这对改进医疗新的治疗策略提出了挑战。例如, 在受伤或疾病之后, 神经系统再生的潜力有限, 在全世界造成了严重的健康问题。由于与神经系统相关的病理生理过程的复杂性, 传统的自体移植或稳定手术的实施已被证明在功能结果方面有好处, 但没有有力的证据表明脊柱固定手术的效果 1,2。受损部位的组织丢失, 取而代之的是肥大诱导的星形胶质细胞3, 最终形成致密的胶质瘢痕 4,5。这个基质作为一个屏障, 阻止恢复神经功能6, 7, 因此, 极大地阻碍了再生。因此, 通过保持受损区域的完整性, 以及通过直接替换神经细胞和电路, 以促进轴突再生。
聚合物生物材料被首选为组织再生治疗的支架, 基于调节细胞或轴突行为和组织进展, 通过自然细胞外基质 (ecm) 的支持。纤维格式通常被认为是各种材料的组成部分, 因为它是一维结构8。纤维一般可以通过熔体挤出或湿法纺丝获得;然而, 设备的大尺寸和成本以及执行这些方法的难度是具有挑战性的。此外, 与聚合物纤维相关的大部分工作都集中在合成材料或复合材料上。天然聚合物作为生物材料的来源, 为人体提供了更好的生物相容性。然而, 要获得天然聚合物纤维的对齐是相对困难的比合成聚合物来源9。因此, 将天然聚合物作为丰富的蛋白质来源转化为生物材料纤维是一项重要的策略--不仅可以直接从原料中分离出生物材料纤维, 从而避免不必要地转化为单体, 而且蛋白质纤维也具有良好的外观和良好的特性10。
在这方面, 我们通过湿法纺丝的基本概念描述了一种制造天然聚合物纤维的廉价加工方法, 该方法可在组织工程的实验室规模上实施。湿法纺丝是通过将聚合物溶液挤压和凝固成合适的聚合物非溶剂来进行的。适当的粘性溶液掺杂到凝固介质中, 会使聚合物分子溶解。通过相变, 细丝失去其溶解度,并以固体聚合物11相的形式沉淀。参照这一概念, 我们通过成型工艺将明胶的发展扩展到管形, 这被认为适合组织再生应用。此外, 本质上, 我们还可以开发任何形状的材料从明胶纤维 (例如, 明胶导管卷起从几个明胶纤维), 为其他所需的应用。
明胶是一种可生物降解的天然聚合物, 由变性和水解胶原蛋白形成, 包括胶原蛋白12的任何半晶、无定形或三重螺旋状态.众所周知, 胶原蛋白是脊椎动物和无脊椎动物13,14的所有结缔组织中必不可少的结构蛋白, 这类似于诱导神经生长的主要 ecm 的蛋白质结构,同时, 取代脊髓损伤过程中分泌的大量糖胺多糖。因此, 使用明胶作为来源将是一个伟大的选择, 任何医疗车辆。除了是一个廉价的来源, 明胶也是生物降解和细胞兼容和临床证明是一个临时缺陷填充 15.在这里描述的体外和体内测试中发展成一种管状,表明明胶具有优异的生物相容性, 适合未来的组织工程应用。明胶管利用人脂肪干细胞培养, 以阳性 nestin 染色为神经细胞标记, 改善细胞分化为神经祖细胞的作用。此外, 明胶作为填充间隙材料, 由本研究中建立的方法, 预计将是可控和安全的, 并大大有利于组织工程师谁目前正在开发相关的天然聚合物, 以增强组织再生策略。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td colspan="4">Solution preparation:</td>
		</tr>
		<tr>
			<td>Gelatin type B (porcine)</td>
			<td>Ferak</td>
			<td>Art. -Nr. 10733</td>
			<td>500 g vial</td>
		</tr>
		<tr>
			<td>Wet spinning process:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Peristaltic pump</td>
			<td>Gilson</td>
			<td>Model M312</td>
			<td>Minipuls*3</td>
		</tr>
		<tr>
			<td>Plastic tube connector</td>
			<td>World Precision Instruments</td>
			<td>14011</td>
			<td>1 box</td>
		</tr>
		<tr>
			<td>Syringe</td>
			<td>Sterican</td>
			<td>5A06258541</td>
			<td>26Gx1/2&#34;(0.45 x 12mm)</td>
		</tr>
		<tr>
			<td>Acetone</td>
			<td>Ferak</td>
			<td>Art. -Nr. 00010</td>
			<td>2.5 L vial</td>
		</tr>
		<tr>
			<td>Polycaprolactone CAPA 6500</td>
			<td>Perstorp</td>
			<td>24980-41-4</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Dichloromethane&#160;</td>
			<td>Scharlau</td>
			<td>CL03421000</td>
			<td>1 L vial</td>
		</tr>
		<tr>
			<td>Glass Pasteur pipette</td>
			<td>Fisher Scientific</td>
			<td>13-678-20A</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Hemostat</td>
			<td>Shinetec instruments</td>
			<td>ST-B021</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Peripheral venous catheter (Introcan Certo)</td>
			<td>B. Braun</td>
			<td>1B03258241</td>
			<td>24Gx3/4&#34;(0.7 x 19mm)</td>
		</tr>
		<tr>
			<td colspan="4">Morphology of the gelatin tube:</td>
		</tr>
		<tr>
			<td>Ion sputter coater machine&#160;</td>
			<td>Hitachi</td>
			<td>e1010</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Scanning electron microscopy</td>
			<td>Hitachi</td>
			<td>S-3000N</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Cultivation of cells on the gelatin tube:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin-EDTA</td>
			<td>Gibco</td>
			<td>488625</td>
			<td>100 mL vial</td>
		</tr>
		<tr>
			<td>Fetal bovine serum</td>
			<td>Gibco</td>
			<td>923119</td>
			<td>500 mL vial</td>
		</tr>
		<tr>
			<td>Dulbecco&#39;s modified Eagle&#39;s medium&#160;</td>
			<td>Gibco</td>
			<td>31600-034</td>
			<td>Powder</td>
		</tr>
		<tr>
			<td>Keratinocyte-SFM medium</td>
			<td>Gibco</td>
			<td>10744-019</td>
			<td>500 mL vial</td>
		</tr>
		<tr>
			<td>T25 culture flask</td>
			<td>TPP</td>
			<td>90025</td>
			<td>VENT type</td>
		</tr>
		<tr>
			<td>6-well plate</td>
			<td>Falcon</td>
			<td>1209938</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Immunocytochemistry:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Phospate-buffered saline</td>
			<td>Gibco</td>
			<td>654471</td>
			<td>500 mL vial</td>
		</tr>
		<tr>
			<td>Acetic acid glacial</td>
			<td>Ferak</td>
			<td>Art. -Nr. 00697</td>
			<td>500 mL vial</td>
		</tr>
		<tr>
			<td>NP-40 surfactant (Tergitol solution)</td>
			<td>Sigma</td>
			<td>056K0151</td>
			<td>500 mL vial</td>
		</tr>
		<tr>
			<td>Normal goat serum</td>
			<td>Vector Laboratories</td>
			<td>S-1000-20</td>
			<td>20 mL vial, concentrate</td>
		</tr>
		<tr>
			<td>Nestin (primary antibody)</td>
			<td>Santa Cruz Biotechnology</td>
			<td>SC-23927</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Donkey anti-mouse-fluorescein isothiocyanate (secondary antibody)</td>
			<td>Santa Cruz Biotechnology</td>
			<td>SC-2099</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Hoechst 33342</td>
			<td>Anaspec</td>
			<td>AS-83218</td>
			<td>5 mL vial</td>
		</tr>
		<tr>
			<td>In vivo biocompatibility test:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tiletamine+zolazepam&#160;</td>
			<td>Virbac</td>
			<td>BC91</td>
			<td>5 mL vial</td>
		</tr>
		<tr>
			<td>Xylazine</td>
			<td>Bayer korea</td>
			<td>KR03227</td>
			<td>10 mL vial</td>
		</tr>
		<tr>
			<td>Ketoprofen</td>
			<td>Astar</td>
			<td>1406232</td>
			<td>2 mL vial</td>
		</tr>
		<tr>
			<td>Povidone-iodine solution</td>
			<td>Everstar</td>
			<td>HA161202</td>
			<td>4 L barrel</td>
		</tr>
		<tr>
			<td>Cefazolin</td>
			<td>China Chemical &#38; Pharmaceutical</td>
			<td>18P909</td>
			<td>1 g vial</td>
		</tr>
		<tr>
			<td>Scalpel blade</td>
			<td>Shinetec instruments</td>
			<td>ST-B021</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Surgical scissor</td>
			<td>Shinetec instruments</td>
			<td>ST-B021</td>
			<td>-</td>
		</tr>
	</tbody>
</table>

wet-spinning-based molding process of gelatin for tissue regeneration

本文提出了一种廉价的方法, 以制备明胶, 作为一种天然聚合物, 成单丝纤维或其他适当的形式。通过湿法纺丝法, 在合适的凝固介质中, 通过光滑挤压生产明胶纤维。为了增加这些明胶纤维的功能表面和它们模仿组织特征的能力, 明胶可以通过参考这个概念被塑造成一个管状。通过体外和体内试验, 明胶管在组织工程中具有巨大的应用潜力。明胶管作为合适的填充间隙材料, 可用于替代受损区域 (如神经或心血管系统) 的组织, 并通过直接替代干细胞和神经电路来促进再生。该协议提供了一个基于天然聚合物的生物材料的详细过程, 其实施有望极大地有利于相关天然聚合物的开发, 这有助于实现组织再生策略。

在这项研究中, 我们成功地将明胶开发成纤维 (图 2a) 和管 (图 2b, c), 通过用户友好的湿纺概念。这些基于明胶的材料可作为任何医疗工具使用, 具体取决于其形状。考虑到这种材料的功能表面和框架更适合组织再生, 我们通过体外和体内试验来检测明胶管的生物相容性。
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Watch this Scientific Journal Video about Wet-spinning-based Molding Process of Gelatin for Tissue Regeneration at JoVE.com

Wet-spinning-based Molding Process of Gelatin for Tissue Regeneration

我们开发并描述了一种基于湿法纺纱概念的协议, 用于构建用于组织工程应用的明胶基生物材料。

明胶湿纺成型工艺促进组织再生

This article presents an inexpensive method to fabricate gelatin, as a natural polymer, into monofilament fibers or other appropriate forms. Through the ...

该协议改进了湿纺的基本概念，将材料从单个纤维条开发成各种条状材料，可用于任何首选医疗应用。该技术简单、价格低廉，无需添加合成聚合物，将天然聚合物定制为感兴趣的材料的蛋白质资源。该技术可推广至生物材料开发，用于杀死感冒治疗，如中枢或外周神经系统治疗、血管置换或直接尿路重建。此方法用于医疗应用，包括作为组织神经化或再生医学的策略。这种技术可以很容易地由初学者实现。请注意，经过几次成型重复后，应始终检查溶液的质量，以保持最佳形成。要形成湿纺管，首先将一个 24 表由三英寸外周静脉导管浸入新鲜准备的明胶溶液中三秒钟，然后浸入新鲜准备的丙酮溶液中浸泡一分钟。重复这些步骤 20 次。最后一次丙酮浸入后，让成型管在室温下干燥五分钟，并使用 hemostat 小心地将明胶管从导管转移到玻璃巴斯德移液器中，并采用 2.5%聚丙酮二氯甲烷溶液，在室温下进行过夜下浸渍孵化。第二天早上，在紫外线下对明胶进行两个小时的消毒，然后短暂地将管子淹没在75%乙醇中。然后用干细胞培养器清洗管两次，去除残留乙醇。要培养与细胞培养的明胶管，用一毫升0.25%的三氯丁二和5%的二氧化碳，将培养方的人类脂肪干细胞的末端替换为0.25%的三氯丁二。当细胞分离后，用一毫升胎儿牛血清停止反应，将细胞悬浮液转移到微离心管中。通过离心收集细胞，将颗粒重新塞在一毫升干细胞培养中等物中。然后将明胶管放在含有三毫升干细胞培养的六井板的一个井中。在计算细胞后，将四倍十至四分之一的人类脂肪干细胞植入管中，在细胞培养箱中孵化两周。在确认适当的水平的解合后，对雌性8周大的Sprague Dawley大鼠的"手趾捏"反应不足，剃掉梯形区域的头发，用波维酮碘溶液对暴露的皮肤进行消毒。用无菌手术窗帘盖住大鼠，以减少手术部位的细菌污染，并使用手术剪刀制作浅两厘米长的皮肤切口。将明胶管直接放入筋膜和肌肉之间的层中，并使用尼龙缝合线关闭伤口。然后用波维酮碘溶液对切口进行消毒。通过肌肉注射酮普罗芬和西法佐林诱导大鼠，并在无菌条件下保持动物七天。这种用户友好的湿纺概念可用于将明胶开发成纤维和管。通过扫描电子显微镜对明胶管进行形态学观察，发现表面不太光滑，内径大于200微米，厚度约为20微米。为神经细胞标记表达而染色人类脂肪干细胞培养明胶管，表明标记物的正染色以及多个检测到的核表明细胞可以穿透并粘附在明胶管上，并分化成神经祖细胞。将明胶管植入筋膜层可证实其安全性和生物相容性，因为在局部组织内未观察到发红、肿胀或其他炎症症状的迹象，且管内被发育良好的结缔组织包围。在尝试两点一的这一步骤时，确保模具在每个溶液的特定涂层时间浸入，对于建立精确的管形非常重要。按照这个程序，我们的实验利用人类疾病的动物模型可以进行，以准确调查生物材料的结果，组织再生策略。该技术开发后，为研究人员将简单的相关性质聚合物开发成任何类型的材料，用于确定的医疗应用铺平了道路。在正常使用条件下，聚丙酮二氯甲烷溶液被认为对环境危害最小，但不要忘记在适当的生物安全柜中对这种化学品执行任何步骤。

wet-spinning-based-molding-process-of-gelatin-for-tissue-regeneration

Research

JoVE Journal

Bioengineering

Expression, Isolation, and Purification of Soluble and Insoluble Biotinylated Proteins for Nerve Tissue Regeneration

Recombinant protein engineering has utilized Escherichia coli (E. coli) expression systems for nearly 4 decades, and today E. coli is still the most widely used host organism. The flexibility of the system allows for the addition of moieties such as a biotin tag (for streptavidin interactions) and larger functional proteins like green fluorescent protein or cherry red protein. Also, the integration of unnatural amino acids like metal ion chelators, uniquely reactive functional groups, spectroscopic probes, and molecules imparting post-translational modifications has enabled better manipulation of protein properties and functionalities. As a result this technique creates customizable fusion proteins that offer significant utility for various fields of research. More specifically, the biotinylatable protein sequence has been incorporated into many target proteins because of the high affinity interaction between biotin with avidin and streptavidin. This addition has aided in enhancing detection and purification of tagged proteins as well as opening the way for secondary applications such as cell sorting. Thus, biotin-labeled molecules show an increasing and widespread influence in bioindustrial and biomedical fields. For the purpose of our research we have engineered recombinant biotinylated fusion proteins containing nerve growth factor (NGF) and semaphorin3A (Sema3A) functional regions. We have reported previously how these biotinylated fusion proteins, along with other active protein sequences, can be tethered to biomaterials for tissue engineering and regenerative purposes. This protocol outlines the basics of engineering biotinylatable proteins at the milligram scale, utilizing&#160; a T7 lac inducible vector and E. coli expression hosts, starting from transformation to scale-up and purification.

Developing biotinylatable fusion proteins has many potential applications in various fields of research. Recombinant protein engineering is a straight forward procedure that is cost-effective, providing high yields of custom-designed proteins.

表达，分离，纯化可溶性和不溶性蛋白质生物素对神经组织再生

Recombinant protein engineering has utilized Escherichia coli (E. coli) expression systems for nearly 4 decades, and today E. coli is still the most ...

科研

生物工程

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

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

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

医疗器械的使用3D印刷模具的液体注射成型快速，低成本原型

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

Engineering 3D Cellularized Collagen Gels for Vascular Tissue Regeneration

Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. Collagen has been extensively used for a wide range of biomedical applications and is considered a valid alternative to synthetic materials due to its inherent biocompatibility (i.e., low antigenicity, inflammation, and cytotoxic responses). However, the limited mechanical properties and the related low hand-ability of collagen gels have hampered their use as scaffold materials for vascular tissue engineering. Therefore, the rationale behind this work was first to engineer cellularized collagen gels into a tubular-shaped geometry and second to enhance smooth muscle cells driven reorganization of collagen matrix to obtain tissues stiff enough to be handled.
The strategy described here is based on the direct assembling of collagen and smooth muscle cells (construct) in a 3D cylindrical geometry with the use of a molding technique. This process requires a maturation period, during which the constructs are cultured in a bioreactor under static conditions (without applied external dynamic mechanical constraints) for 1 or 2 weeks. The &#8220;static bioreactor&#8221; provides a monitored and controlled sterile environment (pH, temperature, gas exchange, nutrient supply and waste removal) to the constructs. During culture period, thickness measurements were performed to evaluate the cells-driven remodeling of the collagen matrix, and glucose consumption and lactate production rates were measured to monitor the cells metabolic activity. Finally, mechanical and viscoelastic properties were assessed for the resulting tubular constructs. To this end, specific protocols and a focused know-how (manipulation, gripping, working in hydrated environment, and so on) were developed to characterize the engineered tissues.

In this work, we present a technique for the rapid fabrication of living vascular tissues by direct culturing of collagen, smooth muscle cells and endothelial cells. In addition, a new protocol for the mechanical characterization of engineered vascular tissues is described.

工程三维细胞化胶原凝胶的血管组织再生

Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. ...

Adapting the Electrospinning Process to Provide Three Unique Environments for a Tri-layered In Vitro Model of the Airway Wall

Electrospinning is a highly adaptable method producing porous 3D fibrous scaffolds that can be exploited in in vitro cell culture. Alterations to intrinsic parameters within the process allow a high degree of control over scaffold characteristics including fiber diameter, alignment and porosity. By developing scaffolds with similar dimensions and topographies to organ- or tissue-specific extracellular matrices (ECM), micro-environments representative to those that cells are exposed to in situ can be created. 
The airway bronchiole wall, comprised of three main micro-environments, was selected as a model tissue. Using decellularized airway ECM as a guide, we electrospun the non-degradable polymer, polyethylene terephthalate (PET), by three different protocols to produce three individual electrospun scaffolds optimized for epithelial, fibroblast or smooth muscle cell-culture. Using a commercially available bioreactor system, we stably co-cultured the three cell-types to provide an in vitro model of the airway wall over an extended time period.
This model highlights the potential for such methods being employed in in vitro diagnostic studies investigating important inter-cellular cross-talk mechanisms or assessing novel pharmaceutical targets, by providing a relevant platform to allow the culture of fully differentiated adult cells within 3D, tissue-specific environments.

Adapting the Electrospinning Process to Provide Three Unique Environments for a Tri-layered In Vitro Model of the Airway Wall

Advancements in biomaterial technologies enable the development of three-dimensional multi-cell-type constructs. We have developed electrospinning protocols to produce three individual scaffolds to culture the main structural cells of the airway to provide a 3D in vitro model of the airway bronchiole wall.

适应静电过程中提供三个独特的环境为一个三层次<em&gt;在体外</em&gt;的气道壁模型

Electrospinning is a highly adaptable method producing porous 3D fibrous scaffolds that can be exploited in in vitro cell culture. Alterations to ...

Qualitative Characterization of the Aqueous Fraction from Hydrothermal Liquefaction of Algae Using 2D Gas Chromatography with Time-of-flight Mass Spectrometry

Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry is a powerful tool for identifying and quantifying chemical components in complex mixtures. It is often used to analyze gasoline, jet fuel, diesel, bio-diesel and the organic fraction of bio-crude/bio-oil. In most of those analyses, the first dimension of separation is non-polar, followed by a polar separation. The aqueous fractions of bio-crude and other aqueous samples from biofuels production have been examined with similar column combinations. However, sample preparation techniques such as derivatization, solvent extraction, and solid-phase extraction were necessary prior to analysis. In this study, aqueous fractions obtained from the hydrothermal liquefaction of algae were characterized by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry without prior sample preparation techniques using a polar separation in the first dimension followed by a non-polar separation in the second. Two-dimensional plots from this analysis were compared with those obtained from the more traditional column configuration. Results from qualitative characterization of the aqueous fractions of algal bio-crude are discussed in detail. The advantages of using a polar separation followed by a non-polar separation for characterization of organics in aqueous samples by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry are highlighted.

A two-dimensional gas chromatography-time-of-flight mass spectrometry method is described for characterization of the aqueous fraction of bio-crude produced from hydrothermal liquefaction of algae. This protocol can also be employed to analyze the aqueous fraction of liquid products from fast pyrolysis, catalytic fast pyrolysis, catalytic deoxygenation and hydro-treating.

从藻类水热液化使用二维气相色谱时间飞行质谱法水提取部分的定性鉴定

Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry is a powerful tool for identifying and quantifying chemical components in ...

Alternating Magnetic Field-Responsive Hybrid Gelatin Microgels for Controlled Drug Release

Magnetically-responsive nano/micro-engineered biomaterials that enable a tightly controlled, on-demand drug delivery have been developed as new types of smart soft devices for biomedical applications. Although a number of magnetically-responsive drug delivery systems have demonstrated efficacies through either in vitro proof of concept studies or in vivo preclinical applications, their use in clinical settings is still limited by their insufficient biocompatibility or biodegradability. Additionally, many of the existing platforms rely on sophisticated techniques for their fabrications. We recently demonstrated the fabrication of biodegradable, gelatin-based thermo-responsive microgel by physically entrapping poly(N-isopropylacrylamide-co-acrylamide) chains as a minor component within a three-dimensional gelatin network. In this study, we present a facile method to fabricate a biodegradable drug release platform that enables a magneto-thermally triggered drug release. This was achieved by incorporating superparamagnetic iron oxide nanoparticles and thermo-responsive polymers within gelatin-based colloidal microgels, in conjunction with an alternating magnetic field application system.

We present a facile method to fabricate a biodegradable gelatin-based drug release platform that is magneto-thermally responsive. This was achieved by incorporating superparamagnetic iron oxide nanoparticles and poly(N-isopropylacrylamide-co-acrylamide) within a spherical gelatin micro-network crosslinked by genipin, in conjunction with an alternating magnetic field application system.

交变磁场敏感的混合明胶微凝胶药物控释

Magnetically-responsive nano/micro-engineered biomaterials that enable a tightly controlled, on-demand drug delivery have been developed as new types of ...

A Paired Bead and Magnet Array for Molding Microwells with Variable Concave Geometries

A spheroid culture is a useful tool for understanding cellular behavior in that it provides an in vivo-like three-dimensional environment. Various spheroid production methods such as non-adhesive surfaces, spinner flasks, hanging drops, and microwells have been used in studies of cell-to-cell interaction, immune-activation, drug screening, stem cell differentiation, and organoid generation. Among these methods, microwells with a three-dimensional concave geometry have gained the attention of scientists and engineers, given their advantages of uniform-sized spheroid generation and the ease with which the responses of individual spheroids can be monitored. Even though cost-effective methods such as the use of flexible membranes and ice lithography have been proposed, these techniques incur serious drawbacks such as difficulty in controlling the pattern sizes, achievement of high aspect ratios, and production of larger areas of microwells. To overcome these problems, we propose a robust method for fabricating concave microwells without the need for complex high-cost facilities. This method utilizes a 30 x 30 through-hole array, several hundred micrometer-order steel beads, and magnetic force to fabricate 900 microwells in a 3 cm x 3 cm polydimethylsiloxane (PDMS) substrate. To demonstrate the applicability of our method to cell biological applications, we cultured adipose stem cells for 3 days and successfully produced spheroids using our microwell platform. In addition, we performed a magnetostatic simulation to investigate the mechanism, whereby magnetic force was used to trap the steel beads in the through-holes. We believe that the proposed microwell fabrication method could be applied to many spheroid-based cellular studies such as drug screening, tissue regeneration, stem cell differentiation, and cancer metastasis.

This manuscript introduces a robust method of fabricating concave microwells without the need for complex high-cost facilities. Using magnetic force, steel beads, and a through-hole array, several hundred microwells were formed in a 3 cm x 3 cm polydimethylsiloxane (PDMS) substrate.

变凹形形状 Microwells 的配对磁珠和磁体阵列

A spheroid culture is a useful tool for understanding cellular behavior in that it provides an in vivo-like three-dimensional environment. Various ...

Three-dimensional Tissue Engineered Aligned Astrocyte Networks to Recapitulate Developmental Mechanisms and Facilitate Nervous System Regeneration

Neurotrauma and neurodegenerative disease often result in lasting neurological deficits due to the limited capacity of the central nervous system (CNS) to replace lost neurons and regenerate axonal pathways. However, during nervous system development, neuronal migration and axonal extension often occur along pathways formed by other cells, referred to as &#34;living scaffolds&#34;. Seeking to emulate these mechanisms and to design a strategy that circumvents the inhibitory environment of the CNS, this manuscript presents a protocol to fabricate tissue engineered astrocyte-based &#34;living scaffolds&#34;. To create these constructs, we employed a novel biomaterial encasement scheme to induce astrocytes to self-assemble into dense three-dimensional bundles of bipolar longitudinally-aligned somata and processes. First, hollow hydrogel micro-columns were assembled, and the inner lumen was coated with collagen extracellular-matrix. Dissociated cerebral cortical astrocytes were then delivered into the lumen of the cylindrical micro-column and, at a critical inner diameter of &#60;350 &#181;m, spontaneously self-aligned and contracted to produce long fiber-like cables consisting of dense bundles of astrocyte processes and collagen fibrils measuring &#60;150 &#181;m in diameter yet extending several cm in length. These engineered living scaffolds exhibited &#62;97% cell viability and were virtually exclusively comprised of astrocytes expressing a combination of the intermediate filament proteins glial-fibrillary acidic protein (GFAP), vimentin, and nestin. These aligned astrocyte networks were found to provide a permissive substrate for neuronal attachment and aligned neurite extension. Moreover, these constructs maintain integrity and alignment when extracted from the hydrogel encasement, making them suitable for CNS implantation. These preformed constructs structurally emulate key cytoarchitectural elements of naturally occurring glial-based &#34;living scaffolds&#34; in vivo. As such, these engineered living scaffolds may serve as test-beds to study neurodevelopmental mechanisms in vitro or facilitate neuroregeneration by directing neuronal migration and/or axonal pathfinding following CNS degeneration in vivo.

We showcase the development of self-assembled, three-dimensional bundles of longitudinally aligned astrocytic somata and processes within a novel biomaterial encasement. These engineered &#34;living scaffolds&#34;, exhibiting micron-scale diameter yet extending centimeters in length, may serve as test-beds to study neurodevelopmental mechanisms or facilitate neuroregeneration by directing neuronal migration and/or axonal pathfinding.

三维组织工程化排列的星形胶质细胞网络, 以概括发展机制和促进神经系统再生

Neurotrauma and neurodegenerative disease often result in lasting neurological deficits due to the limited capacity of the central nervous system (CNS) to ...

Patterning the Geometry of Human Embryonic Stem Cell Colonies on Compliant Substrates to Control Tissue-Level Mechanics

Human embryonic stem cells demonstrate a unique ability to respond to morphogens in vitro by self-organizing patterns of cell fate specification that correspond to primary germ layer formation during embryogenesis. Thus, these cells represent a powerful tool with which to examine the mechanisms that drive early human development. We have developed a method to culture human embryonic stem cells in confined colonies on compliant substrates that provides control over both the geometry of the colonies and their mechanical environment in order to recapitulate the physical parameters that underlie embryogenesis. The key feature of this method is the ability to generate polyacrylamide hydrogels with defined patterns of extracellular matrix ligand at the surface to promote cell attachment. This is achieved by fabricating stencils with the desired geometric patterns, using these stencils to create patterns of extracellular matrix ligand on glass coverslips, and transferring these patterns to polyacrylamide hydrogels during polymerization. This method is also compatible with traction force microscopy, allowing the user to measure and map the distribution of cell-generated forces within the confined colonies. In combination with standard biochemical assays, these measurements can be used to examine the role mechanical cues play in fate specification and morphogenesis during early human development.

Extracellular matrix ligands can be patterned onto polyacrylamide hydrogels to enable the culture of human embryonic stem cells in confined colonies on compliant substrates. This method can be combined with traction force microscopy and biochemical assays to examine the interplay between tissue geometry, cell-generated forces, and fate specification.

在符合标准的基质上对人类胚胎干细胞菌落的几何结构进行模式化，以控制组织级力学

Human embryonic stem cells demonstrate a unique ability to respond to morphogens in vitro by self-organizing patterns of cell fate specification that ...

Protocols of 3D Bioprinting of Gelatin Methacryloyl Hydrogel Based Bioinks

Gelatin methacryloyl (GelMA) has become a popular biomaterial in the field of bioprinting. The derivation of this material is gelatin, which is hydrolyzed from mammal collagen. Thus, the arginine-glycine-aspartic acid (RGD) sequences and target motifs of matrix metalloproteinase (MMP) remain on the molecular chains, which help achieve cell attachment and degradation. Furthermore, formation properties of GelMA are versatile. The methacrylamide groups allow a material to become rapidly crosslinked under light irradiation in the presence of a photoinitiator. Therefore, it makes great sense to establish suitable methods for synthesizing three-dimensional (3D) structures with this promising material. However, its low viscosity restricts GelMA's printability. Presented here are methods to carry out 3D bioprinting of GelMA hydrogels, namely the fabrication of GelMA microspheres, GelMA fibers, GelMA complex structures, and GelMA-based microfluidic chips. The resulting structures and biocompatibility of the materials as well as the printing methods are discussed. It is believed that this protocol may serve as a bridge between previously applied biomaterials and GelMA as well as contribute to the establishment of GelMA-based 3D architectures for biomedical applications.

Presented here is a method for the 3D bioprinting of gelatin methacryloyl.

明胶美沙克里洛醇水凝胶生物油墨3D生物印刷方案

Gelatin methacryloyl (GelMA) has become a popular biomaterial in the field of bioprinting. The derivation of this material is gelatin, which is hydrolyzed ...