이 작품은 NIH K08 EB003996과 미국 연구 재단 부여 2573의 굳는 베테랑에 의해 지원되었다.

1. 폴리머를 선택 <ol><li> 귀하의 사양에 따라 중합체 (예 : 폴리 - L - 젖산 (PLLA), polycaprolactone (PCL), 폴리스티렌 (PS) 또는 나일론) (예, 생분해성, 열가 소성 또는 교차 linkable) 그 고분자의 용매를 선택합니다. 선택에 따라 적절한 개인 보호 장비를 선택합니다. </li><li> 귀하의 신청에 따라 기판을 선택합니다 (예 : 유리, 플라스틱, 금속 또는 실리콘 웨이퍼). </li></ol> 2. 콜렉터를 선택하십시오 <ol><li> 귀하의 사양에 따라 컬렉터 지오메 트리를 선택합니다. 랜덤 섬유는 고정 접시에서 수집하실 수 있습니다. 정렬 섬유는 빠르게 회전하는 바퀴, 드럼 또는 막대, 또는 병렬 접시에에서 수집하실 수 있습니다. </li><li> 수집기는 전도성이어야하며, 그것도 인접 객체 테이블 톱 등 접지 않고 접지 수있는 것과 같은 방식으로 자사의 엑셀에서 격리되어 있어야합니다 </li></ol> 3. 경험적으로 하나 대략 중요 얽히게함 농도 <ol><li> 여러 후보 고분자 농도 (예, 4, 10, 15, 20, 30 WT %)를 준비하고 시작하는 (솔루션이 점성 액체 아니라 젤한다) 흐름 농도를 선택합니다. </li><li> electrospinning 장치 2,3,4,5를 (그림 1 참조) 설정 <ol><li> 주사기 펌프를로드하고 일각에서 지워 솔루션의 구슬 즉시 교체되는 등 펌프 속도를 설정합니다. </li><li> 지상 수집기와 도체 플레이트 (예 : 어떤 주사기 팁 protrudes 통해 알루미늄 호일과 같은 전도성 물질의 작은 사각형)에 높은 전압 와이어 클립. </li><li> 바퀴 회전을 시작합니다. </li><li> 전원 공급 장치가 그것을 켜기 전에 0으로 설정되어 있는지 확인하십시오. </li></ol></li><li> 스트림을 준수 <ol><li> 천천히 전압을 램프와 바늘 끝에 솔루션의 비드를 봐. </li><li> 길고 꾸준한 스트림을 얻을 수있는 전압을 조정합니다. 꾸준한를 얻을 수없는 경우, 폴리머 솔루션 농도를 조정합니다. 예를 들어, 표 1을 참조하십시오. </li></ol></li></ol> 4. 문제 해결 - 스트림 : <ol><li> 스트림을 보는 데 문제가 <ol><li> 어두운 매트 배경을 사용하여 뷰어 및 스트림 (그림 2 참조) 사이의 단방향 광원 (예 : 손전등 등) 장소. </li></ol></li><li> 주사기 팁에서 드리핑 <ol><li> 폴리머 솔루션 바퀴없이 매력과 함께 곧장 피가 뚝뚝 떨어지는 경우, 도체 판은 바늘 끝과 연락을하고 수집기가지면과 접촉하고있다는 점이다 있는지 확인합니다. </li><li> 주사기 끝에 폴리머 솔루션의 드롭 바퀴의 방향으로 기울고 있지만 스트림을 형성하지 않으면 전압을 높일 수 있습니다. 스트림의 품질은 꾸준한 볼 때까지 거리와 전압을 변화하여 조정할 수 있습니다. 4 % PLLA 솔루션과 8x8 cm 도체 판에 대한 해당 전압과 제안 거리 그림 3을 참조하십시오. </li></ol></li><li> 주사기 끝에 대형 globs <ol><li> 폴리머 솔루션이 아닌 전도성 스틱에 부착된 종이 타월로 글로브 떨어진 바늘, 강타의 끝에 수집하고 강화하기 시작하면. </li></ol></li><li> 요동 또는 &#39;wagging&#39;스트림 스트림이 빠르게 위아래로 wagging 및되면 전압을 낮추거나 주사기 팁과 바퀴 사이의 거리를 향상시킬 수 있습니다. 스트림이 게으름 뱅이는 폴리머의 높은 농도를 사용하거나 느린 증발과 함께 약간의 용매를 추가하는 계속하는 경우. </li><li> 단기 또는 불연속 스트림 높은 회전 속도에서 휠 세트 관찰할 수 교신 보이는 지속적인 스트림 균일 성과 정렬 최상의 품질을 얻을 수 있습니다. 스트림이 더 느린 추가 용매 증발하고, 전압이 스트림의 길이와 steadiness을 향상시킬 수 조정, 폴리머 솔루션을 증가, 짧고 불연속 때. </li></ol> 5. 문제 해결 - 섬유 형태론 6,7,8 (4 그림 참조) <ol><li> 구슬 장식 구슬이 섬유 발견되면 폴리머 솔루션을 향상시키고 도체 판은 바늘로 지속적인 연락을하고 접지 와이어 브러시는 바퀴와 함께 지속적인 접촉을하고있는 것이 있는지 확인하십시오. </li><li> 리본 및 출혈 섬유 섬유 리본으로 형성거나 함께 출혈이 경우 고분자의 높은 농도 또는 증발의 높은 속도 (더 많은 휘발성)과 용제를 사용합니다. </li><li> 소용돌이 장식이나 물결 모양의 섬유 섬유 파도 또는 curlicues을 형성하는 경우, 휠 속도를 늘리거나 수집기에서 추가로 바늘 끝을 이동합니다. 또한, 도체 판과 수집기가 진동하지 않는 확인하십시오. </li><li> 다공성 9 모공이 원하는 경우, 신속하게 증발 용제를 사용합니다. 모공이 원하는하지 않는 경우, 주요 용매보다 휘발성 공동 용매의 작은 금액을 추가해보십시오. </li><li> 정렬 10 수집기는 MOV 때낮은 RPM이나 휴식을 주입, 정렬 품질이 떨어집니다. 바퀴의 속도를 증가하여 정렬을 늘리십시오. </li></ol> 6. 대표 결과 : 전형적인 섬유 결과의 묘사 4 그림을 참조하십시오. <img src="/files/ftp_upload/2494/2494fig1.jpg" alt="그림 1" /> 그림 1. 전형적인 electrospinning 설정. 폴리머 솔루션 (파란색)은 주사기 펌프 (오렌지)에서 적절합니다. 고전압 DC 전원 공급 장치 (녹색)은 근거 정렬의 nanofibers가 수집하는쪽으로 빠르게 회전 바퀴 수집기 (회색). 주사기와 컬렉터 사이의 폴리머 제트는 꾸준한 스트리밍 세그먼트와 빠른 속도로 진동 채찍질 세그먼트로 구성되어 있습니다. <img src="/files/ftp_upload/2494/2494fig2.jpg" alt="그림 2" /> . 그림 2 스트리밍 제트는 주사기의 끝부분을 종료 볼 수 있으며, 갈기 제트기가 볼 수 너무 작습니다. PLLA의 중요한 얽히게함 농도를 Approximating <table border="1"><tbody><tr><td> PLLA (% WT / V) </td><td> 관찰 </td><td> 농도 조정 </td></tr><tr><td> 0.5 </td><td> 드리핑 없으며 어떤 흐름을 </td><td> 증가 </td></tr><tr><td> 2.0 </td><td> 작은 globs를 풍기고 없으며 어떤 흐름을 </td><td> 약간 Increse </td></tr><tr><td> 4.0 </td><td> 꾸준한 </td><td> 좋은 </td></tr><tr><td> 6.0 </td><td> 대형 globs이나 구슬를 풍기고 </td><td> 약간 감소 </td></tr><tr><td> 12.0 </td><td> 끝에 Clumping 없다; 더 스트림 </td><td> 감소 </td></tr></tbody></table> 표 1. 예는 PLLA의 중요한 얽히게함 농도의 근사치를 묘사. 다양한 폴리머 농도가 시도하고 꾸준한까지 관찰 결과 스트리밍 전투기가 얻어진다. <img src="/files/ftp_upload/2494/2494fig3.jpg" alt="그림 3" /> 그림 3. 주사기 팁 및 수집기 사이의 거리를 지속적으로 스트리밍 제트를 얻기 위해 적용된 전압 균형을해야합니다. 초과 적용 전압은 덜 잘 정렬 섬유에 결과를 산출하는 요동 또는 &#39;wagging&#39;제트가 발생합니다. 전압이 너무 낮은 경우에는 제트 형태로되지 않습니다 및 솔루션은 주사기 팁에서 똑 것입니다. 보라색 ​​음영 지역은 위에서 지속적으로 스트리밍 제트가 주사기 - 투 - 컬렉터 거리의 함수로 PLLA에 대해 얻을 수있는 이상의 전압 범위를 나타냅니다. <img src="/files/ftp_upload/2494/2494fig4.jpg" alt="그림 4" /> 그림 4. Electrospun 섬유 구슬 장식 (A), 리본 (B), curlicues (C), 다공성 globs (D), 좋은 정렬 (E)와 가난한 정렬 (F)를 포함, morphologies 다양한 전시하실 수 있습니다.

<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>

관심 없음 충돌 선언하지 않습니다.

참고 : 예제의 대부분은 폴리 - L - 젖산 (PLLA) nanofibers를 electrospinning과 함께 계약을 발표했다. PLLA 우리 연구실에서 가장 일반적으로 늘인 폴리머이기 때문에 이것은 간단합니다. 그러나, 우리는 성공적으로 다른 폴리머 (예, PLGA, PCL, PS) electrospin 여기에 제시된 기술을 쉽게 높은 분자량 폴리머 솔루션 중순에 대다수에 해당하는 믿을 이러한 메서드를 사용합니다.

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		<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>
		</table>
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electrospinning fundamentals: optimizing solution and apparatus parameters

Electrospun nanofiber의 공사장 공중 발판은 성숙을 가속 성장을 향상시키고, 체외에서 세포의 마이 그 레이션을 직접으로 표시되었습니다. Electrospinning가 부과 폴리머 제트가 접지된 수집에 수집되는 과정이며 무작위로 지향 섬유 매트에 빠르게 정렬 nanofibers의 컬렉터 결과를 회전하는 동안 정지 수집 결과. 폴리머 분사는 적용 정전기 충전이 솔루션의 표면 장력을 극복 때 형성됩니다. 주어진 중합체의 최소 농도가있다, 중요 얽히게함 농도는 안정적인 제트기를 얻을 수없는 아래 칭했다되며 nanofibers는 형태로되지 않습니다 - nanoparticles가 (전기 분무) 달성 수 있지만. 안정 제트는 두 도메인, 스트리밍 세그먼트와 세그먼트를 채찍질하고 있습니다. 채찍질 전투기가 육안으로 일반적으로 보이지 않는 반면, 스트리밍 세그먼트 적절한 조명 조건 하에서 종종 볼 수 있습니다. 스트림의 길이, 두께, 일관성 및 움직임을 관찰하는 것이 형성되는 nanofibers의 정렬과 형태를 예측하는 데 유용합니다. 짧은 아닌 유니폼, 일관성 및 / 또는 진동 스트림은 splattering 구슬 장식하고, 소용돌이 장식이나 물결 패턴, 가난한 섬유 정렬을 포함한 다양한 문제 나타내는 것입니다. 스트림 따라서 생산되고있는 섬유의 정렬과 형태를 최적화 솔루션의 구성과 electrospinning 장치의 구성을 조정하여 최적화할 수 있습니다. 이 프로토콜에서는, 우리는 기본적인 electrospinning 기기를 설정하는 경험적으로 폴리머 솔루션의 중요한 얽히게함 농도를 approximating하고 electrospinning 과정을 최적화하기위한 절차를 제시한다. 또한, 우리는 몇 가지 일반적인 문제 및 문제 해결 기술을 논의합니다.

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

Electrospinning Fundamentals: Optimizing Solution and Apparatus Parameters

기술 Electrospinning하면 조직 공학 또는 기타 응용 프로그램에 대한 nanofibrous 공사장 공중 발판의 다양한 만들 수 있습니다. 우리는 여기서 원하는 형태와 정렬로 섬유를 얻기 위해 electrospinning 솔루션 및 장치의 매개 변수를 최적화하기위한 절차를 설명합니다. 일반적인 문제 및 문제 해결 기법도 제공됩니다.

Electrospinning 기본 : 최적화 솔루션 및 장치 매개 변수

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 조회수.  University of Michigan. 기술 Electrospinning하면 조직 공학 또는 기타 응용 프로그램에 대한 nanofibrous 공사장 공중 발판의 다양한 만들 수 있습니다. 우리는 여기서 원하는 형태와 정렬로 섬유를 얻기 위해 electrospinning 솔루션 및 장치의 매개 변수를 최적화하기위한 절차를 설명합니다. 일반적인 문제 및 문제 해결 기법도 제공됩니다.

비디오: 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.

Polycaprolactone, 엘라스틴, 콜라겐을 사용하여 네이티브 아티 건축을 모방하기 위해 트라이 - 계층 Electrospinning : 예비 연구

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

연구

생체공학

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.

양적 측정 현장에서</em독립적인 수중 Velocimetry 장치 (SCUVA)을 사용하여> 흐름

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.

솔루션의 생물 고분자의 작은 및 와이드 앵글 X-레이 산란 연구

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.

섬유 공사장 공중 발판으로 마이크로 스피어를 해제 전기 방사의 성장 인자

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.

마이크로 광 및 전기 방사의 조합은 각막 재생을위한 틈새를 장착 멤브레인을 생산하는

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.

자기 조립, 분해 Thermoresponsive Hydrogels 반응 압출, 마이크로, 통해 여러 길이 가늠 자에를 조작 하 고 전기

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.

조직 공학 응용 프로그램에 대 한 제어 형태학과 3 차원 Poly(ε-caprolactone) 장비의 전기 글 녹아

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.

충돌기 제트의 두 가지 모드를 사용 하 여 패턴 고해상도: 수요와 근처-필드 전기에

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.

조직 Microcolumns 수확 용

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.

폐 정맥의 특정 매개 변수의 시각화 및 평가를 위한 3차원 심초음파 방법

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