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

64.7K 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 ...

Optimizing Attachment of Human Mesenchymal Stem Cells on Poly(&#949;-caprolactone) Electrospun Yarns

Research into biomaterials and tissue engineering often includes cell-based in vitro investigations, which require initial knowledge of the starting cell number. While researchers commonly reference their seeding density this does not necessarily indicate the actual number of cells that have adhered to the material in question. This is particularly the case for materials, or scaffolds, that do not cover the base of standard cell culture well plates. This study investigates the initial attachment of human mesenchymal stem cells seeded at a known number onto electrospun poly(&#949;-caprolactone) yarn after 4 hr in culture. Electrospun yarns were held within several different set-ups, including bioreactor vessels rotating at 9 rpm, cell culture inserts positioned in low binding well plates and polytetrafluoroethylene (PTFE) troughs placed within petri dishes. The latter two were subjected to either static conditions or positioned on a shaker plate (30 rpm). After 4 hr incubation at 37&#160;oC, 5% CO2, the location of seeded cells was determined by cell DNA assay. Scaffolds were removed from their containers and placed in lysis buffer. The media fraction was similarly removed and centrifuged &#8211; the supernatant discarded and pellet broken up with lysis buffer. Lysis buffer was added to each receptacle, or well, and scraped to free any cells that may be present. The cell DNA assay determined the percentage of cells present within the scaffold, media and well fractions. Cell attachment was low for all experimental set-ups, with greatest attachment (30%) for yarns held within cell culture inserts and subjected to shaking motion. This study raises awareness to the actual number of cells attaching to scaffolds irrespective of the stated cell seeding density.

This article describes a range of set-ups for seeding human mesenchymal stem cells onto materials, in this case electrospun yarns, that do not cover the base of standard culture well plates in order to maximize and quantify the number of cells that initially attach compared to the known seeding density.

폴리 (ε 카프로 락톤) 전기 방사 원사에 인간 중간 엽 줄기 세포의 첨부 파일을 최적화

Research into biomaterials and tissue engineering often includes cell-based in vitro investigations, which require initial knowledge of the starting cell ...

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.

전기 방사를 적응하는 것은 트라이 계층에 대한 세 가지 독특한 환경을 제공하기 위해<em&gt; 체외</em&gt;기도 벽의 모델

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

Custom-designed Laser-based Heating Apparatus for Triggered Release of Cisplatin from Thermosensitive Liposomes with Magnetic Resonance Image Guidance

Liposomes have been employed as drug delivery systems to target solid tumors through exploitation of the enhanced permeability and retention (EPR) effect resulting in significant reductions in systemic toxicity. Nonetheless, insufficient release of encapsulated drug from liposomes has limited their clinical efficacy. Temperature-sensitive liposomes have been engineered to provide site-specific release of drug in order to overcome the problem of limited tumor drug bioavailability. Our lab has designed and developed a heat-activated thermosensitive liposome formulation of cisplatin (CDDP), known as HTLC, to provide triggered release of CDDP at solid tumors. Heat-activated delivery in vivo was achieved in murine models using a custom-built laser-based heating apparatus that provides a conformal heating pattern at the tumor site as confirmed by MR thermometry (MRT). A fiber optic temperature monitoring device was used to measure the temperature in real-time during the entire heating period with online adjustment of heat delivery by alternating the laser power. Drug delivery was optimized under magnetic resonance (MR) image guidance by co-encapsulation of an MR contrast agent (i.e.,&#160;gadoteridol) along with CDDP into the thermosensitive liposomes as a means to validate the heating protocol and to assess tumor accumulation. The heating protocol consisted of a preheating period of 5 min prior to administration of HTLC and 20 min heating post-injection. This heating protocol resulted in effective release of the encapsulated agents with the highest MR signal change observed in the heated tumor in comparison to the unheated tumor and muscle. This study demonstrated the successful application of the laser-based heating apparatus for preclinical thermosensitive liposome development and the importance of MR-guided validation of the heating protocol for optimization of drug delivery.

AN MRI-compatible&#160;custom-designed laser-based heating apparatus has been developed to provide local heating of subcutaneous tumors in order to activate release of agents from thermosensitive liposomes specifically at the tumor region.

자기 공명 이미지 지침에 열성 리포좀에서 시스플라틴의 트리거 된 릴리스를위한 맞춤 설계 레이저 기반의 가열 장치

Liposomes have been employed as drug delivery systems to target solid tumors through exploitation of the enhanced permeability and retention (EPR) effect ...

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo

We demonstrate a superior method of 2D spectral-spatial imaging of stable radical reporter molecules at 250 MHz using rapid-scan electron-paramagnetic-resonance (RS-EPR), which can provide quantitative information under in vivo conditions on oxygen concentration, pH, redox status and concentration of signaling molecules (i.e., OH&#8226;, NO&#8226;). The RS-EPR technique has a higher sensitivity, improved spatial resolution (1 mm), and shorter acquisition time in comparison to the standard continuous wave (CW) technique. A variety of phantom configurations have been tested, with spatial resolution varying from 1 to 6 mm, and spectral width of the reporter molecules ranging from 16 &#181;T (160 mG) to 5 mT (50 G). A cross-loop bimodal resonator decouples excitation and detection, reducing the noise, while the rapid scan effect allows more power to be input to the spin system before saturation, increasing the EPR signal. This leads to a substantially higher signal-to-noise ratio than in conventional CW EPR experiments.

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo

A new electron paramagnetic resonance (EPR) method, rapid scan EPR (RS-EPR), is demonstrated for 2D spectral spatial imaging which is superior to the traditional continuous wave (CW) technique and opens new venues for in vivo imaging. Results are demonstrated at 250 MHz, but the technique is applicable at any frequency.

빠른 스캔 전자 스핀 공명 이미징 생리 학적으로 중요 매개 변수에 대한 새로운 길을 엽니 다<em&gt; 생체</em

We demonstrate a superior method of 2D spectral-spatial imaging of stable radical reporter molecules at 250 MHz using rapid-scan ...

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.), ...

Electrospinning 기본 : 최적화 솔루션 및 장치 매개 변수

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