이 작품은 모두 실험실 창업 펀드 (J. Capadona), 그리고 메드 트로닉 대학원 원정대 (K. 포터)를 통해 케이스 웨스턴 리저브 대학의 생명 공학과에 의해 지원되었다. 본 연구에 대한 추가 자금 지원에 의해 부분적으로 지원되었다 NSF 부여 ECS-0621984 (C. Zorman), 케이스 동창회 (C. Zorman), 공로 검토 수상 (B7122R)를 통해 보훈뿐만 아니라, 고급 플랫폼 기술 센터 (C3819C).

1. 샘플 준비 <ol><li> 솔루션 주조 및 압축 기술 10-12을 사용하여 25-100 ㎛의 범위에서 두께 PVAC-NC 필름을 준비합니다. </li><li> 영화와 웨이퍼 사이의 친밀한 접촉을 촉진하기 위해 70 ° C (유리 전이 온도 이상) 두 분 핫 플레이트에 가열하여 실리콘 웨이퍼에 필름을 준수합니다. 이 단계는 준비된 필름 평면 마이크로 프로세스에 필요한 실리콘 웨이퍼를 평평하고 고정 유지되도록합니다. </li><li> 레이저 미세 가공 (VLS 3.50, VersaLASER)에 의해 시료 형상으로 본 영화. 1.0 %의 전력 (0.5 W), 4.0 % 속도 (56mm / s)로, 그리고 인치 13,16 1,000 펄스 CO 2 직접 쓰기 레이저 미세 매개 변수를 설정합니다. </li><li> 측면 패드 크기 1.5 × 1.5 mm 2, 희미한 측면 빔 dogbone 모양의 구조로 환경 조건 ( &quot;설치 샘플&quot;)을 설정하는 데 사용되는 패턴 샘플두께가 일치 ensions 300 X 3,000 μm의 2에 걸쳐 필름 (그림 2)의. </li><li> 두께는 그 영화의 일치 패턴 생체 실험 샘플 ( &quot;임플란트 샘플&quot;) 빔에 300 μm의 X 6 mm의. </li><li> 조심스럽게 면도날과 핀셋을 사용하여 웨이퍼에서 샘플을 놓습니다. </li><li> 샘플 처리를 위해, microtensile 테스터 그립 시스템의 일부로 사용할 수 있도록 설계 맞춤 가공 아크릴 홀더를 준비합니다. 레이저 에칭 표시는 홀더의 중심선 끝에서 1.5 mm를 보여줍니다. 아크릴 홀더의 중심선에 시아 노 아크릴 레이트 겔 기반의 접착제의 작은 금액을 놓고 조심 홀더에 임플란트 샘플 1.5 mm의 길이를 준수하고 표시된 중심선 (그림 3) 겹칩니다. 각 임플란트 샘플은 하나의 아크릴 홀더가 필요합니다. 접착제 젤은 ACR을 준수하는 PVAC-NC의 1.5 mm의 길이에 따라 남아 있는지 확인해야합니다ylic 홀더. 그렇지 않으면, 접착제 젤은 샘플의 기계적 작동을 방해 할 수 있습니다. </li><li> 적어도 24 시간 동안 건조기에서 그들을 배치하여 모든 시료에서 수분을 제거합니다. </li><li> 길이, 너비 및 광학 현미경을 사용하여 샘​​플의 두께 치수를 측정한다. </li></ol> 2. 환경 조건을 설정 <ol><li> 먼저 고정 그립 사이에 다음, 모바일 그립 사이에 체결, microtensile 테스터 (그림 4 참조)에 건조 설정 샘플을로드합니다. </li><li> microtensile 샘플 향하는 노즐, 고정 된 위치에 물이 채워진 탱크와 에어 브러시를 장착합니다. 플라스틱 튜브를 통해 공기 압축기 에어 브러쉬를 연결합니다. 에어 브러쉬 노즐이 완전히 폐쇄, 공기 압축기의 전원을 켭니다. </li><li> 인장 변형 (긍정적 변형)와 t에 적용되는 압축 응력 (음의 변형) 교대 순환 microtensile 테스트 절차를 시작그 샘플은, 응력 - 변형 그래프의 선형 탄성 영역 내에 남아있는. PVAC-NC 경우, 적용 변형은 2 % 이하로 제한됩니다. 그 긴장을 달성하는 데 필요한 힘을 측정하는 동안이 실험에 사용 된 사용자 정의 microtensile 테스터에서 변형률 속도를 제어 하였다. 또한, 다른 설정은 결과 변형률을 측정하는 동안 가해진 힘을 제어 포함 할 수 있습니다. </li><li> 점차적으로 에어 브러시 노즐의 흐름을 증가하고, 에어 브러시에서 흐름의 양의 함수로 응력 - 변형 그래프의 기울기를 모니터링합니다. 60 초에 걸쳐 탄성 계수의 의미 (&gt; 10 %) 감소를 일으키지 않는 최대 유량은 생체 실험에 사용되는 수준입니다. 이 시점에서, 습도 조건 (따라서 탄성 계수의 감소에 기여) 건조 샘플을 적시하지 않으며, 또한 생체 내 생물학적 체액에 노출 된 후 건조 샘플 ESTA했습니다 최소화 할 것blished. </li><li> 샘플 근처의 온도를 측정한다. 이상적인 설정은 디지털 판독과 열전대를 포함 할 것, 그리고 에어 브러시가 작동하는 동안 수행 할 수. 시료 온도는 37 ° C, 생리적 조건에 일치하는 일까지 개최되는 등 복사 열원의 강도와 거리를 설정합니다. </li></ol> 3. 환경 제어 비 환경 컨트롤 비교 <ol><li> 인산 적어도 30 분 동안 담가 설정 샘플은 식염수 버퍼. 이 시간 후, 시료가 완전히 포화되고 주어진 온도에서의 최소 탄성 계수로 감​​소되었습니다. </li><li> 빨리 microtensile 테스터로 샘플을로드하고 주기적 microtensile 테스트를 시작, 오프 에어 브러쉬로, 샘플을 건조하는 동안. 이 비 통제 된 조건 하에서 얼마나 빨리 샘플 건조를 결정합니다. </li><li> microtensile 테스터에 두 번째 PBS 포화 설정 샘플을로드하고 주기적 microtensile 테스트를 시작합니다에 에어 브러쉬. 이 통제 된 환경 조건에서 얼마나 빨리 샘플 건조를 결정합니다. </li></ol> 4. 프로브 주입 및 Explantation <ol><li> micromanipulator에 클램프 및 대뇌 피질의 조직에 직교하는 위치에 임플란트 샘플을 첨부합니다. </li><li> 삽입하기 전에, 조직 역학의 균일 성을 보장하기 위해 식염수 조직이 충분히 촉촉한 유지합니다. </li><li> micromanipulator에 손 컨트롤을 사용하여 피질에 고분자 샘플을 낮 춥니 다. 일반적으로 1 ~ 30 분 사이, 대상 임플란트 때까지 대뇌 피질의 조직 샘플을 둡니다. 가볍게 5 분, DAB를 통해 시간 포인트를 건조로부터 조직을 방지하기 위해 조직을 생리 식염수에 적신 면봉을 사용하여 매 5 분. </li><li> 프로브가 피질에 이식되는 동안 고정 된 샘플 클램프에서 3.0 mm의 제로 변위의 위치에 드라이브로드를 설정하여 현재 이식 샘플을로드하기 위해 microtensile 테스터를 준비합니다. 또한, 에어 브러쉬 노즐을 설정유량 설정하고 적절한 강도 2.4 단계에서 확인하는 복사열 소스. </li><li> 지정된 임플란트 시간의 끝에, micromanipulator에 손 컨트롤을 사용하여 피질의 프로브를 올립니다. 즉시 조심스럽게 micromanipulator에 클램프에서 샘플을 제거하고 단계 5.2에서 자세히 설명 microtensile 테스터로로드합니다. </li></ol> 5. 임플란트 샘플의 Microtensile 테스트 <ol><li> explantation 후 시간을 절약하기 위해, microtensile 테스터로 단계 4.4에서 설명한 사전에 주입하는 임플란트 샘플을 받아 완전히 준비가되어 있는지 확인합니다. </li><li> 즉시 explantation 후, microtensile 테스터 클램프의 두 세트 사이의 샘플을로드합니다. 샘플이 하나의 클램프의 상단 역할을하도록 설계 아크릴 홀더에 장착되어 있기 때문에, 아래로 이동 그립 샘플 측의 임플란트 샘플 어셈블리를 배치합니다. 그것은 샘플이 설치되어 있는지 확인하는 것이 중요하다되도록 변형 APPL입니다만 테스트하는 동안 시료에 토크를 적용 피하기 위해 프로브의 길이를 따라 이었죠. 같은 샘플은 각 클램프의 중앙에 장착해야하며, 클램프 서로에 대해 수준이어야합니다. </li><li> 클램프 사이의 거리가 3.0 mm, 그리고 프로브가 고정 클램프에 배치됩니다의 끝 그러한 샘플의 위치를​​ 조정합니다. 클램프 사이 3.0 mm 길이는 샘플의 게이지 길이, 샘플의 변형을 결정하기 위해 나중에 계산에 사용됩니다. </li><li> 즉시 두 클램프 사이의 샘플을 확보 한 후 동시에 측정하고를 기록하는 동안, 그리고 신경 조직에서 explantation의 2 분 이내에, 일정한 속도 (여기에 사용 된 10 ㎛ / 초)에서 샘플을 연장하는 인장 방향으로 모터를 작동 샘플의 신장과 샘플을 변형하는 데 필요한 관련 인력 (로드 셀, 트랜스 듀서 기술 MDB-2.5 사용) (변위 표시, Mitutoyu 543-561 사용). </li><lI&gt; 기계 샘플의 실패하거나 드라이브 막대 범위의 끝에 도달시 microtensile 테스트를 중지합니다. 수집 된 데이터를 내보내고, 데이터 분석을 수행 할 수 있습니다. </li><li> 각 샘플 및 / 또는 상태 (즉, 삽입 시간)의 각 집합에 대한 microtensile 테스트를 반복합니다. </li></ol> 6. 데이터 분석 <ol><li> ε는, t는 시간을 적용 변형입니다 수학 식 1에서 설명한 최초의 게이지 길이에 의해 신장의 거리를 나누어 이식 샘플 응용 공학 변형에 원시 신장 데이터를 변환, D는 마이크로 미터에 의해 측정 된 변위 표시기 및 L 0는 샘플의 초기 게이지 길이 : <img src="/files/ftp_upload/50078/50078eq1.jpg" alt="식 1" fo:src="/files/ftp_upload/50078/50078eq1highres.jpg"/> (1) </li><li> TRA에 의해, 힘 (뉴턴)으로 나누어 시료의 엔지니어링 스트레스에 원시 힘 데이터를 변환수학 식 2에 설명 된 nsverse 단면적 : <img src="/files/ftp_upload/50078/50078eq2.jpg" alt="식 2" fo:src="/files/ftp_upload/50078/50078eq2highres.jpg"/> (2) 샘플 응력 σ 여기서, F는로드 셀 (뉴턴)에 의해 측정 된 힘이다, W 0 샘플의 초기 폭, 그리고 t 0 샘플의 초기 두께입니다. </li><li> 스트레스를 줄거리 ([t]를 σ) 대 변형 (ε [T]) Microsoft Excel과 같은 컴퓨터 프로그램을 사용하여 각 샘플에 대한 곡선. </li><li> 플롯의 선형 탄성 부분을 분리하고이 부분에 가장 적합한 라인을 찾기 위해 소프트웨어 기반의 커브 피팅 도구를 사용합니다. 가장 적합한 직선의 기울기는 시료의 탄성 계수에 해당합니다. 음모의 고립 된 부분은 적어도 10 응력 - 변형 점을 포함해야하며, 기울기가 큰 인 플롯의 부분에서주의해야한다. </li><li> 주기적인 테스트의 탄성 계수는​​ 각 사이클에 대해 결정해야합니다. 이것은 자동 또는 수동으로 수행 할 수 있습니다. </li><li> 대 시간 각 사이클의주기 테스트, 플롯의 탄성 계수. 이 설정 샘플은 적시거나 건조 얼마나 빨리 나타내는 것입니다 시간이 어떻게 측정 계수의 변화를 나타냅니다. </li><li> 임플란트 샘플, 임플란트의 각 샘플 및 시간주기 검사의 단일 사이클에 해당합니다. 각 임플란트 샘플 위에서 설명한 절차를 사용하여의 탄성 계수를 측정한다. </li><li> 탄성 계수 대 임플란트 시간을 플롯합니다. 이 시점에서 비교는 벤치 탑 조사 등을 만들 수 있습니다 </li></ol>

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R., Shanmuganathan, K., Tyler, D. J., Rowan, S. J., Weder, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stimuli-Responsive+Polymer+Nanocomposites+Inspired+by+the+Sea+Cucumber+Dermis.">Stimuli-Responsive Polymer Nanocomposites Inspired by the Sea Cucumber Dermis.</a> Science. 319, 1370-1374 (2008).</li><li>Shanmuganathan, K., Capadona, J. R., Rowan, S. J., Weder, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stimuli-Responsive+Mechanically+Adaptive+Polymer+Nanocomposites.">Stimuli-Responsive Mechanically Adaptive Polymer Nanocomposites.</a> ACS Applied Materials &amp; Interfaces. 2, 165-174 (2009).</li><li>Shanmuganathan, K., Capadona, J. R., Rowan, S. J., Weder, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bio-inspired+mechanically-adaptive+nanocomposites+derived+from+cotton+cellulose+whiskers.">Bio-inspired mechanically-adaptive nanocomposites derived from cotton cellulose whiskers.</a> Journal of Materials Chemistry. 20, 180 (2010).</li><li>Hess, A., Capadona, J., Shanmuganathan, K., Hsu, L., Rowan, S., Weder, C., Tyler, D., Zorman, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+stimuli-responsive+polymer+nanocomposite+toward+biologically+optimized,+MEMS-based+neural+probes.">Development of a stimuli-responsive polymer nanocomposite toward biologically optimized, MEMS-based neural probes.</a> Journal of Micromechanics and Microengineering. 21, 054009 (2011).</li><li>Capadona, J. R., Tyler, D. J., Zorman, C. A., Rowan, S. J., Weder, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanically+adaptive+nanocomposites+for+neural+interfacing.">Mechanically adaptive nanocomposites for neural interfacing.</a> Materials Research Society Bulletin. 37, 581-589 (2012).</li><li>Ophir, J., Cespedes, I., Garra, B., Ponnekanti, H., Huang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elastography:+ultrasonic+imaging+of+tissue+strain+and+elastic+modulus+in+vivo.">Elastography: ultrasonic imaging of tissue strain and elastic modulus in vivo.</a> European journal of ultrasound. 3, 49-70 (1996).</li><li>Hess, A., Shanmuganathan, K., Capadona, J., Hsu, L., Rowan, S., Weder, C., Tyler, D., Zorman, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micro+Electro+Mechanical+Systems+(MEMS).">Micro Electro Mechanical Systems (MEMS).</a> , 453-456 (2011).</li><li>Harris, J. P., Hess, A. E., Rowan, S. J., Weder, C., Zorman, C. A., Tyler, D. J., Capadona, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+deployment+of+mechanically+adaptive+nanocomposites+for+intracortical+microelectrodes.">In vivo deployment of mechanically adaptive nanocomposites for intracortical microelectrodes.</a> Journal of Neural Engineering. 8, 046010 (2011).</li><li>Shanmuganathan, 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> Bio-inspired Stimuli-responsive Mechanically Dynamic Nanocomposites. , (2010).</li><li>Rousche, P. J., Pellinen, D. S., Pivin, D. P., Williams, J. C., Vetter, R. J., Kipke, 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=Flexible+polyimide-based+intracortical+electrode+arrays+with+bioactive+capability.">Flexible polyimide-based intracortical electrode arrays with bioactive capability.</a> IEEE Transactions on Biomedical Engineering. 48, 361-371 (2001).</li><li>Norlin, P., Kindlundh, M., Mouroux, A., Yoshida, K., Hofmann, U. 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+32-site+neural+recording+probe+fabricated+by+DRIE+of+SOI+substrates.">A 32-site neural recording probe fabricated by DRIE of SOI substrates.</a> Journal of Micromechanics and Microengineering. 12, 414 (2002).</li><li>Ward, M. P., Rajdev, P., Ellison, C., Irazoqui, P. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toward+a+comparison+of+microelectrodes+for+acute+and+chronic+recordings.">Toward a comparison of microelectrodes for acute and chronic recordings.</a> Brain Research. 1282, 183-200 (2009).</li><li>Lin, J. M., Chang, P. 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+Novel+Remote+Health+Monitor+with+Replaceable+Non-Fragile+Bio-Probes+on+RFID+Tag.">A Novel Remote Health Monitor with Replaceable Non-Fragile Bio-Probes on RFID Tag.</a> Applied Mechanics and Materials. 145, 415-419 (2012).</li><li>Kunzelman, K. S., Cochran, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress/strain+characteristics+of+porcine+mitral+valve+tissue:+parallel+versus+perpendicular+collagen+orientation.">Stress/strain characteristics of porcine mitral valve tissue: parallel versus perpendicular collagen orientation.</a> Journal of Cardiac Surgery. 7, 71-78 (1992).</li><li>Snedeker, J., Niederer, P., Schmidlin, F., Farshad, M., Demetropoulos, C., Lee, J., Yang, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strain-rate+dependent+material+properties+of+the+porcine+and+human+kidney+capsule.">Strain-rate dependent material properties of the porcine and human kidney capsule.</a> Journal of Biomechanics. 38, 1011-1021 (2005).</li><li>Ahn, S., Kasi, R. M., Kim, S. C., Sharma, N., Zhou, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stimuli-responsive+polymer+gels.">Stimuli-responsive polymer gels.</a> Soft Matter. 4, 1151-1157 (2008).</li><li>Stuart, M. A. C., 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=Emerging+applications+of+stimuli-responsive+polymer+materials.">Emerging applications of stimuli-responsive polymer materials.</a> Nature Materials. 9, 101-113 (2010).</li></ol>

우리는 공개 아무것도 없어.

생물학적 시스템과 상호 작용하기위한 이식 생체 미세 전자 기계 시스템 (bioMEMS)의 발전은 고도로 맞춤 특성을 가진 새로운 재료의 개발 동기를 부여하고 있습니다. 이러한 물질 중 일부는 생리적 환경에서 발견 된 자극에 대한 응답으로 재료 특성의 변화를 전시하기 위해 설계되었습니다. 물자의 한개 최근에 개발 된 클래스는 수소 결합을 형성하는 액체 (예 : 물)과 크기 10,11,18 세...

<table border="1">
	<tbody>
		<tr>
			<td>Name of Reagent/Material</td>
			<td>Company</td>
			<td>Catalogue Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Silicon wafer</td>
			<td>University Wafer</td>
			<td>&nbsp;</td>
			<td>Mechanical grade</td>
		</tr>
		<tr>
			<td>Extruded acrylic sheet</td>
			<td>Professional Plastics</td>
			<td>SACR 062EF</td>
			<td>Thickness 0.062"</td>
		</tr>
		<tr>
			<td>Razor blade</td>
			<td>McMaster-Carr</td>
			<td>3962A3</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Tweezers</td>
			<td>McMaster-Carr</td>
			<td>8384A47</td>
			<td>#5 tip</td>
		</tr>
		<tr>
			<td>Super Glue Gel</td>
			<td>Loctite</td>
			<td>130380</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Air Brush</td>
			<td>Snap-on Industrial</td>
			<td>BF175TA</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Air Compressor</td>
			<td>Paasche</td>
			<td>B002YKN8YO</td>
			<td>D500</td>
		</tr>
		<tr>
			<td>Thermocouple</td>
			<td>Omega</td>
			<td>HH12A</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Hot plate</td>
			<td>Cimarec</td>
			<td>SP131325Q</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>CO2 direct-write laser</td>
			<td>VersaLaser</td>
			<td>3.5</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Dessicator</td>
			<td>Fisher Scientific</td>
			<td>08-595</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Lamp</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>custom-built</td>
		</tr>
		<tr>
			<td>Microtensile tester</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>custom-built</td>
		</tr>
	</tbody>
</table>

environmentally-controlled microtensile testing of mechanically-adaptive polymer nanocomposites for ex vivo characterization

이식 할 수있는 초소형 디바이스는 여러 생물 의학 응용 1-4에 상당한 관심을 얻고있다. 이러한 장치는 재료 자체의 장점과 단점 5,6을 제공하는 각각의 범위에서 변경되었습니다. 가장 눈에 띄게, 마이크로 디바이스 크기 때문에, 높은 계수는 살아있는 조직으로 주입을 용이하게하기 위해 필요합니다. 반대로, 장치의 강성에 의한 지역의 긴장 7-9을 최소화하기 위해 주변 조직과 일치해야합니다. 따라서, 우리는 최근 기계적 물성 10-14의 변화와 환경 자극에 응답하여 이러한 요구 사항을 충족하는 바이오 영감 재료의 새로운 종류를 개발했다. 물과 높은 온도 (예를 들면 체온)에 노출되었을 때, 특히 우리의 폴리 (비닐 아세테이트) 기반의 나노 복합체 (PVAC-NC)는 강성의 감소를 표시합니다. 불행히도, 몇 가지 방법은 생체 내 15에있는 재료의 강성 및 기계화를 정량화하기 위해 존재생리적 환경 외부 anical 테스트는 종종 이식에 대한 큰 샘플 부적절한 필요합니다. 또한, 자극 - 반응 자료는 신속하게 explantation 후 초기 강성을 복구 할 수 있습니다. 따라서, 우리는 이식 microsamples의 기계적 특성이 생체 측정 할 수있는 방법을 개발했습니다, 시뮬레이션 생리적 조건 습기와 온도 제어 13,16,17를 사용하여 유지. 이를 위해, 사용자 정의 microtensile 테스터는 영의 계수를 (10 MPa의 5 GPa의 범위) 널리 변화와 마이크로 샘플에게 13,17을 수용 할 수 있도록 설계되었습니다. 우리의 관심은 생물학적 적응 신경 프로브 기판 마이크로에서 시료의 기계적 특성 필요하다고 할 수있는 도구로 PVAC-NC의 응용 프로그램입니다.로 이 도구는 건조 및 17 냉각 샘플을 최소화 습도와 온도 제어를 제공하기 위해 적응했다. 그 결과, 기계공explanted 시료의 알 특성은 밀접하게 explantation 직전에 샘플들을 반영한다. 이 방법의 전반적인 목표는 정량적 자극 - 반응, 기계적 적응 고분자 기반 소재의 생체 기계적 성질, 특히의 탄성 계수에 평가하는 것입니다. 이 첫 번째 이식의 결과가 독립적으로 강성의 감소에 기여하지 않고 explantation 후에 견본 기계적 특성의 변화를 최소화 할 수있는 환경 조건을 설정하여 수행됩니다. 샘플은 다음 주입, 처리 및 테스트 (그림 1A)를위한 준비가되어 있습니다. 각 샘플은 지정된 기간 동안 explanted 쥐의 두뇌 (그림 1B)로 여기에 표시됩니다 쥐의 대뇌 피질에 이식된다. 이 시점에서, 샘플 (그림 explanted 즉시로드 microtensile 테스터로하고 인장 시험을 받는다1C). 이후 데이터 분석은 대뇌 피질의 환경에서 이러한 혁신적인 재료의 기계적 거동에 대한 통찰력을 제공합니다.

우리 PVAC-NC를 포함한 거의 모든 고분자 재료의 기계적 특성은 환경 조건에 노출에 따라 달라집니다. 특히, 이러한 열이나 습기에 노출이 (가) 있습니다. 재료 인해 수분의 흡수에 가소, 또는 온도 변화를 겪게되면 탄성 계수의 감소를 표시합니다. 습기 및 생체 시료 기계적 특성에 대한 온도 제어 환경을 준비, 그것은 기계적 테스트 중에 microtensile 테스터뿐만 아니라에 샘플을로드하는 동안 ...

Watch this Scientific Journal Video about Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization at JoVE.com

Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization

방법을 논의하는<em&gt; 생체 내</em자극 - 반응 자료&gt; 기계 동작은 시간의 함수로 모니터링됩니다. 샘플 테스트<em&gt; 생체</em&gt; 생리적 환경을 시뮬레이션하기 위해 환경 관리와 microtensile 테스터를 사용하여. 이 작품은 더 이해 촉진<em&gt; 생체 내</em우리의 물자의&gt; 행동.

에 대한 기계적 적응 고분자 나노 복합 재료의 환경 제어 Microtensile 테스트<em&gt; 생체</em&gt; 특성

Implantable microdevices are gaining significant attention for several biomedical applications1-4. Such devices have been made from a range of materials, ...

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Research

JoVE Journal

Bioengineering

Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization

10.1K 조회수.  Louis Stokes Cleveland Department of Veterans Affairs Medical Center. 방법을 논의하는 생체 내 기계 동작은 시간의 함수로 모니터링됩니다. 샘플 테스트 생체 생리적 환경을 시뮬레이션하기 위해 환경 관리와 microtensile 테스터를 사용하여. 이 작품은 더 이해 촉진 생체 내 행동.

비디오: Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic valve leaflets are composed of interstitial cells suspended within an extracellular matrix (ECM) and are lined with an endothelial cell monolayer. The valve withstands a harsh, dynamic environment and is constantly exposed to shear, flexion, tension, and compression. Research has shown calcific lesions in diseased valves occur in areas of high mechanical stress as a result of endothelial disruption or interstitial matrix damage1-3. Hence, it is not surprising that epidemiological studies have shown high blood pressure to be a leading risk factor in the onset of aortic valve disease4. 
The only treatment option currently available for valve disease is surgical replacement of the diseased valve with a bioprosthetic or mechanical valve5. Improved understanding of valve biology in response to physical stresses would help elucidate the mechanisms of valve pathogenesis. In turn, this could help in the development of non-invasive therapies such as pharmaceutical intervention or prevention. Several bioreactors have been previously developed to study the mechanobiology of native or engineered heart valves6-9. Pulsatile bioreactors have also been developed to study a range of tissues including cartilage10, bone11 and bladder12. The aim of this work was to develop a cyclic pressure system that could be used to elucidate the biological response of aortic valve leaflets to increased pressure loads. 
The system consisted of an acrylic chamber in which to place samples and produce cyclic pressure, viton diaphragm solenoid valves to control the timing of the pressure cycle, and a computer to control electrical devices. The pressure was monitored using a pressure transducer, and the signal was conditioned using a load cell conditioner. A LabVIEW program regulated the pressure using an analog device to pump compressed air into the system at the appropriate rate. The system mimicked the dynamic transvalvular pressure levels associated with the aortic valve; a saw tooth wave produced a gradual increase in pressure, typical of the transvalvular pressure gradient that is present across the valve during diastole, followed by a sharp pressure drop depicting valve opening in systole. The LabVIEW program allowed users to control the magnitude and frequency of cyclic pressure. The system was able to subject tissue samples to physiological and pathological pressure conditions. This device can be used to increase our understanding of how heart valves respond to changes in the local mechanical environment.

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

A cyclic pressure bioreactor capable of subjecting heart valve tissue to physiological and pathological pressure conditions has been designed. A LabVIEW program allows users to control pressure magnitude, amplitude and frequency. This device can be used to study the mechanobiology of heart valve tissue or isolated cells.

의 순환 압력 생물 반응기 설계 예 VIVO</em대동맥 심장 밸브> 학습

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic ...

연구

생체공학

Ex vivo Mimicry of Normal and Abnormal Human Hematopoiesis

Hematopoietic stem cells require a unique microenvironment in order to sustain blood cell formation1; the bone marrow (BM) is a complex three-dimensional (3D) tissue wherein hematopoiesis is regulated by spatially organized cellular microenvironments termed niches2-4. The organization of the BM niches is critical for the function or dysfunction of normal or malignant BM5. Therefore a better understanding of the in vivo microenvironment using an ex vivo mimicry would help us elucidate the molecular, cellular and microenvironmental determinants of leukemogenesis6.
Currently, hematopoietic cells are cultured in vitro in two-dimensional (2D) tissue culture flasks/well-plates7 requiring either co-culture with allogenic or xenogenic stromal cells or addition of exogenous cytokines8. These conditions are artificial and differ from the in vivo microenvironment in that they lack the 3D cellular niches and expose the cells to abnormally high cytokine concentrations which can result in differentiation and loss of pluripotency9,10.
Herein, we present a novel 3D bone marrow culture system that simulates the in vivo 3D growth environment and supports multilineage hematopoiesis in the absence of exogenous growth factors. The highly porous scaffold used in this system made of polyurethane (PU), facilitates high-density cell growth across a higher specific surface area than the conventional monolayer culture in 2D11. Our work has indicated that this model supported the growth of human cord blood (CB) mononuclear cells (MNC)12 and primary leukemic cells in the absence of exogenous cytokines. This novel 3D mimicry provides a viable platform for the development of a human experimental model to study hematopoiesis and to explore novel treatments for leukemia.

Ex vivo Mimicry of Normal and Abnormal Human Hematopoiesis

A 3D culture system for hematopoiesis is described using human cord blood and leukemic bone marrow cells. The method is based on the use of a porous synthetic polyurethane scaffold coated with extracellular matrix proteins. This scaffold is adaptable to accommodate a wide range of cells.

정상과 비정상적인 인간 조혈의 전직 생체내 흉내

Hematopoietic stem cells require a unique microenvironment in order to sustain blood cell formation1; the bone marrow (BM) is a complex three-dimensional ...

Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model

Decades ago the human placenta was thought to be an impenetrable barrier between mother and unborn child. However, the discovery of thalidomide-induced birth defects and many later studies afterwards proved the opposite. Today several harmful xenobiotics like nicotine, heroin, methadone or drugs as well as environmental pollutants were described to overcome this barrier. With the growing use of nanotechnology, the placenta is likely to come into contact with novel nanoparticles either accidentally through exposure or intentionally in the case of potential nanomedical applications. Data from animal experiments cannot be extrapolated to humans because the placenta is the most species-specific mammalian organ 1. Therefore, the ex vivo dual recirculating human placental perfusion, developed by Panigel et al. in 1967 2 and continuously modified by Schneider et al. in 1972 3, can serve as an excellent model to study the transfer of xenobiotics or particles.
Here, we focus on the ex vivo dual recirculating human placental perfusion protocol and its further development to acquire reproducible results.
The placentae were obtained after informed consent of the mothers from uncomplicated term pregnancies undergoing caesarean delivery. The fetal and maternal vessels of an intact cotyledon were cannulated and perfused at least for five hours. As a model particle fluorescently labelled polystyrene particles with sizes of 80 and 500 nm in diameter were added to the maternal circuit. The 80 nm particles were able to cross the placental barrier and provide a perfect example for a substance which is transferred across the placenta to the fetus while the 500 nm particles were retained in the placental tissue or maternal circuit. The ex vivo human placental perfusion model is one of few models providing reliable information about the transport behavior of xenobiotics at an important tissue barrier which delivers predictive and clinical relevant data.

Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model

The ex vivo dual recirculating human placental perfusion model can be used to investigate the transfer of xenobiotics and nanoparticles across the human placenta. In this video protocol we describe the equipment and techniques required for a successful execution of a placenta perfusion.

태반의 맞은 편에 생체이 물과 나노 물질의 전송 속도의 결정을 사용하여<em&gt; 생체</em&gt; 인간 태반 관류 모델

Decades ago the human placenta was thought to be an impenetrable barrier between mother and unborn child. However, the discovery of thalidomide-induced ...

Imaging Denatured Collagen Strands In vivo and Ex vivo via Photo-triggered Hybridization of Caged Collagen Mimetic Peptides

Collagen is a major structural component of the extracellular matrix that supports tissue formation and maintenance. Although collagen remodeling is an integral part of normal tissue renewal, excessive amount of remodeling activity is involved in tumors, arthritis, and many other pathological conditions. During collagen remodeling, the triple helical structure of collagen molecules is disrupted by proteases in the extracellular environment. In addition, collagens present in many histological tissue samples are partially denatured by the fixation and preservation processes. Therefore, these denatured collagen strands can serve as effective targets for biological imaging. We previously developed a caged collagen mimetic peptide (CMP) that can be photo-triggered to hybridize with denatured collagen strands by forming triple helical structure, which is unique to collagens. The overall goals of this procedure are i)&#160;to image denatured collagen strands resulting from normal remodeling activities in vivo, and ii) to visualize collagens in ex vivo tissue sections using the photo-triggered caged CMPs. To achieve effective hybridization and successful in vivo and ex vivo imaging, fluorescently labeled caged CMPs are either photo-activated immediately before intravenous injection, or are directly activated on tissue sections. Normal skeletal collagen remolding in nude mice and collagens in prefixed mouse cornea tissue sections are imaged in this procedure. The imaging method based on the CMP-collagen hybridization technology presented here could lead to deeper understanding of the tissue remodeling process, as well as allow development of new diagnostics for diseases associated with high collagen remodeling activity.

Imaging Denatured Collagen Strands In vivo and Ex vivo via Photo-triggered Hybridization of Caged Collagen Mimetic Peptides

This procedure demonstrates in vivo near IR fluorescence imaging of collagen remodeling activities in mice as well as ex vivo staining of collagens in tissue sections using caged collagen mimetic peptides that can be photo-triggered to hybridize with denatured collagen strands.

변성 콜라겐 물가 이미징<em&gt; 생체 내</em&gt;와<em&gt; 예 생체 내</em&gt; 리테이너 타입 콜라겐 미메시스 펩티드의 사진 트리거 하이브리드를 통해

Collagen is a major structural component of the extracellular matrix that supports tissue formation and maintenance. Although collagen remodeling is an ...

Biomechanical Characterization of Human Soft Tissues Using Indentation and Tensile Testing

Regenerative medicine aims to engineer materials to replace or restore damaged or diseased organs. The mechanical properties of such materials should mimic the human tissues they are aiming to replace; to provide the required anatomical shape, the materials must be able to sustain the mechanical forces they will experience when implanted at the defect site. Although the mechanical properties of tissue-engineered scaffolds are of great importance, many human tissues that undergo restoration with engineered materials have not been fully biomechanically characterized. Several compressive and tensile protocols are reported for evaluating materials, but with large variability it is difficult to compare results between studies. Further complicating the studies is the often destructive nature of mechanical testing. Whilst an understanding of tissue failure is important, it is also important to have knowledge of the elastic and viscoelastic properties under more physiological loading conditions.
This report aims to provide a minimally destructive protocol to evaluate the compressive and tensile properties of human soft tissues. As examples of this technique, the tensile testing of skin and the compressive testing of cartilage are described. These protocols can also be directly applied to synthetic materials to ensure that the mechanical properties are similar to the native tissue. Protocols to assess the mechanical properties of human native tissue will allow a benchmark by which to create suitable tissue-engineered substitutes.

Tissue biomechanics is important for maintaining cell shape and function and for determining phenotype. This report demonstrates non-destructive mechanical protocols for characterizing elastic and viscoelastic properties of human soft tissues, which can be directly applied to tissue-engineered substrates to allow a close matching of engineered materials to native tissue.

들여 쓰기 및 인장 시험을 사용하여 인간의 부드러운 조직의 생체 역학적 특성

Regenerative medicine aims to engineer materials to replace or restore damaged or diseased organs. The mechanical properties of such materials should ...

A New Ex Vivo Model for the Evaluation of Endoscopic Submucosal Injection Material Performance

Increasing the performance of submucosal injection materials (SIMs) is important for endoscopic therapy of early gastrointestinal cancer. It is essential to establish an ex vivo model that can evaluate SIM performance accurately, for developing high-performance SIMs. In our previous study, we developed a new ex vivo model that can be used to evaluate the performance of various SIMs in detail by applying constant tension to the specimen&#39;s ends. We also confirmed that the proposed new ex vivo model allows accurate submucosal elevation height (SEH) measurement under uniform conditions and detailed comparisons of the performances of various types of SIMs. Here, we describe the new ex vivo model and explain the detailed setup methodology of this model. Since all parts of the new model were easy to obtain, the setup of the new model could be completed quickly. SEH of various SIMs could be measured more accurately by using the new model. The critical factor that determines SIM performance can be identified using the new model. SIM development speed will drastically increase after the factor has been identified.

A New Ex Vivo Model for the Evaluation of Endoscopic Submucosal Injection Material Performance

We developed a new ex vivo model that applies constant tension to the porcine gastric specimen. This development made it possible to evaluate the performance (the height and duration of the submucosal elevation) of various SIMs accurately.&#160; The detailed setup methodology of this new model is explained.

내 시경 Submucosal 주입 재료 성능 평가 대 한 새로운 Ex Vivo 모델

Increasing the performance of submucosal injection materials (SIMs) is important for endoscopic therapy of early gastrointestinal cancer. It is essential ...

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate (LAL) Assays

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause inflammation, fever, hypo- or hypertension, and, in extreme cases, can lead to tissue and organ damage that may become fatal. The amounts of endotoxin in pharmaceutical products, therefore, are strictly regulated. Among the methods available for endotoxin detection and quantification, the Limulus Amoebocyte Lysate (LAL) assay is commonly used worldwide. While any pharmaceutical product can interfere with the LAL assay, nano-formulations represent a particular challenge due to their complexity. The purpose of this paper is to provide a practical guide to researchers inexperienced in estimating endotoxins in engineered nanomaterials and nanoparticle-formulated drugs. Herein, practical recommendations for performing three LAL formats including turbidity, chromogenic and gel-clot assays are discussed. These assays can be used to determine endotoxin contamination in nanotechnology-based drug products, vaccines, and adjuvants.

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate LAL Assays

Detection of endotoxins in engineered nanomaterials represents one of the grand challenges in the field of nanomedicine. Here, we present a case study that describes the framework composed of three different LAL formats to estimate potential endotoxin contamination in nanoparticles.

나노 제형에도 Limulus Amoebocyte Lysate (LAL) 분석 실험을 사용 하 여

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause ...

Methods for In Vivo Biomechanical Testing on Brachial Plexus in Neonatal Piglets

Neonatal brachial plexus palsy (NBPP) is a stretch injury that occurs during the birthing process in nerve complexes located in the neck and shoulder regions, collectively referred to as the brachial plexus (BP). Despite recent advances in obstetrical care, the problem of NBPP continues to be a global health burden with an incidence of 1.5 cases per 1,000 live births. More severe types of this injury can cause permanent paralysis of the arm from the shoulder down. Prevention and treatment of NBPP warrants an understanding of the biomechanical and physiological responses of newborn BP nerves when subjected to stretch. Current knowledge of the newborn BP is extrapolated from adult animal or cadaveric BP tissue instead of in vivo neonatal BP tissue. This study describes an in vivo mechanical testing device and procedure to conduct in vivo biomechanical testing in neonatal piglets. The device consists of a clamp, actuator, load cell, and camera system that apply and monitor in vivo strains and loads until failure. The camera system also allows monitoring of the failure location during rupture. Overall, the presented method allows for a detailed biomechanical characterization of neonatal BP when subjected to stretch.

Methods for In Vivo Biomechanical Testing on Brachial Plexus in Neonatal Piglets

Presented here are methods to perform in vivo biomechanical testing on brachial plexus in a neonatal piglet model.

신생아 돼지의 상수 신경총에 생체 역학 테스트 방법

Neonatal brachial plexus palsy (NBPP) is a stretch injury that occurs during the birthing process in nerve complexes located in the neck and shoulder ...

Synthesis of Graphene-Hydroxyapatite Nanocomposites for Potential Use in Bone Tissue Engineering

Developing novel materials for bone tissue engineering is one of the most important thrust areas of nanomedicine. Several nanocomposites have been fabricated with hydroxyapatite to facilitate cell adherence, proliferation, and osteogenesis. In this study, hybrid nanocomposites were successfully developed using graphene nanoribbons (GNRs) and nanoparticles of hydroxyapatite (nHAPs), that when employed in bioactive scaffolds may potentially improve bone tissue regeneration. These nanostructures can be biocompatible. Here, two approaches were used for preparing the novel materials. In one approach, a co-functionalization strategy was used where nHAP was synthesized and conjugated to GNRs simultaneously, resulting in nanohybrids of nHAP on GNR surfaces (denoted as nHAP/GNR). High-resolution transmission electron microscopy (HRTEM) confirmed that the nHAP/GNR composite is comprised of slender, thin structures of GNRs (maximum length of 1.8 &#181;m) with discrete patches (150-250 nm) of needle-like nHAP (40-50 nm in length). In the other approach, commercially available nHAP was conjugated with GNRs forming GNR-coated nHAP (denoted as GNR/nHAP) (i.e., with an opposite orientation relative to the nHAP/GNR nanohybrid). The nanohybrid formed using the latter method exhibited nHAP nanospheres with a diameter ranging from 50 nm to 70 nm covered with a network of GNRs on the surface. Energy dispersive spectra, elemental mapping, and Fourier transform infrared (FTIR) spectra confirmed the successful integration of nHAP and GNRs in both nanohybrids. Thermogravimetric analysis (TGA) indicated that the loss at elevated heating temperatures due to the presence of GNRs was 0.5% and 0.98% for GNR/nHAP and nHAP/GNR, respectively. The nHAP-GNR nanohybrids with opposite orientations represent significant materials for use in bioactive scaffolds to potentially promote cellular functions for improving bone tissue engineering applications.

Novel nanocomposites of graphene nanoribbons and hydroxyapatite nanoparticles were prepared using solution-phase synthesis. These hybrids when employed in bioactive scaffolds can exhibit potential applications in tissue engineering and bone regeneration.

뼈 조직 공학에 잠재적 인 사용을위한 그래핀 - 히드 록시 아파타이트 나노 복합체의 합성

Developing novel materials for bone tissue engineering is one of the most important thrust areas of nanomedicine. Several nanocomposites have been ...

클린룸 환경을 위한 미생물 제어 및 모니터링 전략

Microbial Control and Monitoring Strategies for Cleanroom Environments and Cellular Therapies

A well-validated and holistic program that incorporates robust gowning, cleaning, environmental monitoring, and personnel monitoring measures is critical for minimizing the microbial bioburden in cellular therapy manufacturing suites and the corresponding testing laboratories to ensure that the facilities are operating in a state of control. Ensuring product safety via quality control measures, such as sterility testing, is a regulatory requirement for both minimally manipulated (section 361) and more than minimally manipulated (section 351) human cells, tissues, and cellular and tissue-based products (HCT/Ps). In this video, we provide a stepwise guide for how to develop and incorporate the best aseptic practices for operating in a cleanroom environment, including gowning, cleaning, staging of materials, environmental monitoring, process monitoring, and product sterility testing using direct inoculation, provided by the United States Pharmacopeia (USP&lt;71&gt;) and the National Institutes of Health (NIH) Alternative Sterility Testing Method. This protocol is intended as a reference guide for establishments expected to meet current good tissue practices (cGTP) and current good manufacturing practices (cGMP).

저자 스포트라이트: 클린룸 환경 및 세포 치료를 위한 미생물 제어 및 모니터링 전략  

The protocol summarizes the best practices to minimize microbial bioburden in a cleanroom environment and includes strategies such as environmental monitoring, process monitoring, and product sterility testing. It is relevant for manufacturing and testing facilities that are required to meet current good tissue practice standards and current good manufacturing practice standards.

클린룸 환경 및 세포 치료를 위한 미생물 제어 및 모니터링 전략

A well-validated and holistic program that incorporates robust gowning, cleaning, environmental monitoring, and personnel monitoring measures is critical ...