The authors thank Tyra Witt, Cheri Mueske, Brant Newman and Dr. Peter J. Psaltis, MBBS, PhD for their valuable contributions. This study was financially supported by European Regional Development Fund &#8211; FNUSA-ICRC (No. CZ.1.05/1.100/02.0123), American Heart Association Scientist Development Grant (AHA #06-35185N), National Institutes of Health (T32HL007111) and The Grainger Innovation Fund &#8211; Grainger Foundation.

모든 동물 실험은 메이요 클리닉에서 기관 동물 관리 및 이용위원회 (IACUC)에 의해 승인되었다. 2205 스테인레스 스틸 스텐트 1. 설계 및 분석 <ol><li> CAD를 사용하여 베어 메탈 스텐트 설계 <ol><li> 스텐트 스트럿 두께와 같은 벽 두께와 &#39;돌출 보스 /베이스&#39;기능을 선택하여 압출 중공 실린더를 확인합니다. </li><li> 압출 실린더 접선 다른 스케치 평면에 스텐트 패턴을 디자인합니다. 압출 중공 원통의 원주에 일치하도록 평면 패턴의 폭을 만든다. </li><li> 랩 기능을 사용하여 중공 실린더에 플랫 패턴 디자인을 전송합니다. </li><li> 네이티브 형식으로도 FEA에 대한 수출 될 ACIS 형식으로 파트를 저장합니다. </li></ol></li><li> 스텐트 모델의 유한 요소 해석 <ol><li> 더 분​​석가에 대한 유한 요소 해석 소프트웨어의 일부 모듈에 ACIS 형식으로 저장 솔리드 형상을 가져 오기이다. </li><li> FEA 소프트웨어의 일부 모델러의 스텐트에 동축 2 분석 실린더 모델입니다. 외측 실린더는 크림 퍼 시뮬레이션 스텐트의 직경보다 큰 직경을 갖는 초기 및 내측 실린더는 인플레이션 풍선을 시뮬레이트하도록 1mm의 초기 직경을 갖는다. </li><li> 위를 조립하는 어셈블리 모델러의 &#39;인스턴스&#39;트리 항목을 더블 클릭 상대 위치에 부품을 말했다. </li><li> 감소 통합 20 노드 육면체 요소로서 요소 유형을 지정 FEA 소프트웨어 메쉬 모듈을 사용하여 소자의 크기를 지정하고, 상기 스텐트 메쉬. </li><li> 스텐트 및 모델 트리의 &#39;상호 작용의 특성&#39;에 각각 두 개의 실린더 사이의 마찰 강성 접촉 쌍을 지정합니다. </li><li> 스텐트 모델로 2205 스테인레스 스틸의 탄소 성 응력 - 변형 동작을 지정합니다. </li><li> 우선 C 시뮬레이션 1mm로 외통 압착하는 경계 조건을 정의스텐트의 rimping. 압착 스텐트의 휴식을 시뮬레이션하기 위해 외부 실린더를 제거합니다. 확장을 시뮬레이션 3mm로 내부 실린더를 확장하고 마지막으로, 스텐트의 반동을 시뮬레이션 할 수있는 내부 실린더를 제거합니다. </li><li> &#39;분석&#39;모델 트리 항목에 할당 된 프로세서와 RAM의 양의 수를 포함한 시뮬레이션 매개 변수를 정의하고 시뮬레이션을 실행합니다. </li><li> 시뮬레이션이 완료되면, 주 균주를 연구 결과 결과 파일 (filename.odb) 및 후 처리를 열고 반복적 재료의 파괴​​ 한도보다 작은 20 %의 주요 스트레인을 달성하기 위해 스텐트 디자인을 향상 . </li></ol></li></ol> 압착 및 확장 2. 스텐트 제조 및 테스트 <ol><li> 스텐트 제조 <ol><li> 이러한 개척자의 액션 정밀 제품으로 정밀 가공 회사에서 총 시추 및 정밀 연삭 바 원재료로 2205 스테인레스 스틸 튜브를 확보,OH. </li><li> 레이저 절단 및 전해에 대해 같은 워키 건, 일리노이 Laserage 기술 공사로 스텐트 절단 회사에 정밀 연마 튜브 및 플랫 패턴 스텐트 디자인을 전송합니다. </li><li> 또 다른 10 분 동안베이스 (10 %의 NaHCO3) 다음에 10 분 동안 강산 (50 % 염산)에 의해 그들을 담근다 전해 스텐트의 표면을 패시베이션. 주의 : 적절한 보호 장비와 흄 후드에서 화학 물질을 처리합니다. 마지막으로, 에틸 알코올 및 탈 이온수로 스텐트를 씻는다. 이 프로세스는 산세 불린다. </li></ol></li><li> 압착 및 확장을위한 제조 된 스텐트의 시험 <ol><li> 도구를 압착 개최 손을 사용하여 3 중 풍선에 스텐트를 압착. 스텐트와 압착 공구의 3 중 풍선을 잡으십시오. 방사상으로 풍선에 압착 할 수있는 스텐트를 변형 핸들을 누릅니다. </li><li> 균일 압착에 대한 현미경에 의한 구조의 실패의 흔적을 사용하여 압착 스텐트를 검사소성 변형. </li><li> 물 3 중 풍선을 가압하여 3mm의 설계 직경을 확장합니다. 미세 골절 균일 확장을위한 확장 된 스텐트를 검사합니다. </li></ol></li></ol> 잉여금 자기장에 대한 스텐트 3. 특성 주 : 2 인치 직경 1 인치의 높이의 원통 자석을이 연구에 사용 하였다. 자석의 극 축을 따라 정렬됩니다. 자석의 표면 자속 밀도는 약 1 T. <ol><li> 강한 네오디뮴 자석을 사용하여 직경 방향 또는 축 방향으로 자화 된 스텐트. 자화 약 1 분 동안 강한 자석에 가까운 스텐트를 잡습니다. </li><li> 직경 자기 또는 축 방향으로 자화 자기장 라인을 따라 축과 원통면 옆에 스텐트를 보유 할 자력선을 따라 직경이 평탄면 중 하나에 상기 스텐트를 잡아. 잉여금 자기 한 느낌스텐트의 D는 적어도 24 시간 동안 안정하지만, 자화 후 가능한 빨리 스텐트를 사용하는 것으로 확인되었다. </li><li> 유리 맨드릴 상에 개별적으로 스텐트를 장착 한 다음 자기 프로빙 조명기의 정밀 척에 유리 맨드릴 마운트. 자성 마이크로 센서 프로브 정확하게 XYZ가 자기 프로빙 어셈블리의 조명기를 사용하여 스테이지면 (도 4)를 만지지 않고 스텐트 부근에 위치 될 수있다. </li><li> 멀리 스텐트에서 자성 마이크로 센서의 기준선 판독을 측정하고 자기 프로빙 조명기의 XYZ 스테이지를 사용하여 프로브를 위치시킴으로써 상기 스텐트의 표면에 잔류 자기장을 측정한다. </li></ol> 4. 자기 세포 캡처 연구 <ol><li> 얻기 세포, 형광 염료와 SPION 및 염색 라벨 <ol><li> 5,7에 기재된 돼지의 말초 혈액으로부터 내피 세포 생장 (EOC)를 도출. unti했다 T-75 플라스크 문화L 약 80 %의 합류 (5 × 6 6 8X10에 세포). </li><li> 10 nm의 직경 마그네타이트 FE (3 O 4) 8,9에 기재된 바와 같이 50 nm 두께의 폴리 (락트산 - 코 - 글리콜 산) (PLGA) 쉘에 의해 둘러싸인 코어로서 SPIONs 합성. </li><li> O 37 ℃에서 16 시간 동안 세포 배양 배지의 200 μg / ml의 농도로 유도 SPION EOC 부화 </li><li> 부드럽게 세포 배양 배지를 흡인. 부드럽게 플라스크에 인산 완충 식염수 (PBS) 10 ㎖를 첨가 요동하고 PBS를 흡입하여 세포를 세척한다. </li><li> 실험 중 시각화 형광 염료 (CM-DII)와 세포를 얼룩. 이는 5 μL / ㎖의 농도로 세포 배양 배지 10 ㎖에 염료를 첨가하여 37 ℃에서 30 분 동안 세포와 함께 배양하여 제조사의 지침에 따라 수행된다. </li><li> 단계 4.1.4에서와 같이 PBS로 세포를 세척하고 37 ℃에서 5 분 동안 0.25 % 트립신 EDTA 용액 3 ㎖로 배양플라스크에서 세포를 올립니다. </li><li> 5 분 세포 펠렛을 형성하기 위해 500 XG에 PBS로, 15ml의 원뿔형 튜브에 가기를 세포 현탁액을 전송하고, 원심 분리기. </li><li> 1-2x10 106 세포 / ml의 농도로 PBS에 세포 펠렛을 다시 중지하고 수회와 원추형 튜브의 피펫 팅하여 잘 혼합한다. </li></ol></li><li> 체외 세포 연구 <ol><li> 설계 및 제작합니다 (예를 들어, 3D 인쇄) 단지 유리 커버 슬립의 표면 위의 스텐트를 유지하는 간단한기구. </li><li> 전자기 자기야을 이용한 스텐트 탈자 또는 강한 네오디뮴 자석을 사용하여 직경 방향 또는 축 방향으로 자화 스텐트. </li><li> 축 방향으로 자화 된 직경 자기 또는 비 착자 제어 스텐트를 포함하는 접시로 PBS에 현탁 SPION 라벨링 EOC 피펫. 이미지 반전 형광 현미경을 사용하여 즉시 형광을 위해 PBS에 현탁 EOC와 스텐트. </li></ol></li></ol><p클래스 = &quot;jove_title&quot;&gt; 5. 인 - 생체 내 동물 연구 <ol><li> 스텐트 시술 <ol><li> 4 건강한 요크셔 돼지에서 말초 혈액을 그립니다 - 5,7에 설명 된대로 삼주 전에 각각 주입 스텐트 문화 EOC하기 - 약 50 kg의 무게. </li><li> (매일 아스피린 325 밀리그램과 클로피도그렐 75 mg)을 수술 3 일전부터 항 혈소판 약물을 관리합니다. </li><li> 스텐트 시술 당일, 근육 Telazol, 크 실라와 아트로핀과 돼지를 마취 (5 / 2-3 / 0.05 밀리그램 / 각각 ㎏) 해당 기관의 동물 관리 및 사용 지침에 명시된대로. </li><li> 삽관 및 1-2.5 % 아이소 플루 란 마취의 흡입에 돼지를 놓습니다. </li><li> 돼지의 복부 목 영역을 면도하고 일반 멸균 조건의 절차를 실시하고 있습니다. </li><li> 임플란트 (1) 및 기준 자화 심장 도관 기술을 이용하여 우측 관상 동맥 (RCA)에 1 비자 성 스텐트. <ol><li> Cathete동물의 rization은 훈련 중재 심장 전문의에 의해 수행되어야한다. 9 프랑스어 칼집과 오른쪽 경동맥에 액세스 할 수 있습니다. </li><li> 목표 관상 동맥 Cannulate 및 투시 화상을 얻기 위해 요오드화 조영제를 주입. </li><li> 동맥에서 0.014 인치 표준 관상 동맥 가이드 와이어를 놓습니다. 풍선을 사전이 가이드 와이어를 이용하여 스텐트 3-3.5 mm 직경의 혈관에 스텐트를 배포합니다. </li></ol></li><li> 와이어 풍선 위에를 사용하여 이식 된 스텐트에 대한 RCA 근위 내의 혈류를 폐색하고 2 분 동안 중심 카테터를 통해 PBS 4 mL에 현탁 SPION 표지 약 2 × 6자가 EOC을 제공한다. </li><li> 추가 폐색의 2 분 후 RCA 혈액의 흐름을 복원합니다. </li><li> 회복실에 동물을 전송하고이 의식을 회복 할 때까지 밀접하게 동물을 모니터링 할 수 있습니다. </li><li> 항 혈소판 약물을 투여 계속 (아스피린 325 밀리그램과 클로피도그렐 75mg)을 희생 할 때까지 작동 가능 게시합니다. </li></ol></li><li> 스텐트 이식편 및 조직학 <ol><li> 이전에 설명한 바와 같이 첫 번째 동물을 마취하여 동물에게 수술 후 7 일 안락사 후 정맥 적용 기관 동물 관리 및 사용 지침에 따라 나트륨 펜 토바 비탈 (100 ㎎ / ㎏)의 치사량을 관리 할 수​​ 있습니다. </li><li> 수술 스텐트 동맥 세그먼트를 수확. 30 분 이상 동안 10 % 포르말린 버퍼 외식 동맥 수정. 또한 조직 학적 분석을 위해 포르말린 버퍼에 샘플을 남겨주세요. </li><li> 금속 스텐​​트 조직학을 수행 할 수있는 설비에 고정 된 샘플을 아웃소싱. 이 처리 중에, 샘플은, 메틸에 포함되는 횡단 및 철 입자 러시안 블루 염색으로 염색 된 Mallory의 기법을 사용하여 조직 학적 분석. </li></ol></li></ol>

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J., 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=Nanoparticles+of+magnetic+ferric+oxides+encapsulated+with+poly(D,L+latide-co-glycolide)+and+their+applications+to+magnetic+resonance+imaging+contrast+agent.">Nanoparticles of magnetic ferric oxides encapsulated with poly(D,L latide-co-glycolide) and their applications to magnetic resonance imaging contrast agent.</a> J Magn Magn Mater. 272 (3 Special Issue), 2432-2433 (2004).</li><li>Lee, S. J., 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=Magnetic+enhancement+of+iron+oxide+nanoparticles+encapsulated+with+poly(D,L-latide-co-glycolide).">Magnetic enhancement of iron oxide nanoparticles encapsulated with poly(D,L-latide-co-glycolide).</a> Colloid Surface A. (1-3), 255-251 (1016).</li><li>Forbes, Z. G., 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=Locally+targeted+drug+delivery+to+magnetic+stents+for+therapeutic+applications.">Locally targeted drug delivery to magnetic stents for therapeutic applications.</a> Computer Architectures for Machine Perception, 2003 IEEE International Workshop on. , 1-6 (2003).</li><li>Rathel, T., 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=Magnetic+Stents+Retain+Nanoparticle-Bound+Antirestenotic+Drugs+Transported+by+Lipid+Microbubbles.">Magnetic Stents Retain Nanoparticle-Bound Antirestenotic Drugs Transported by Lipid Microbubbles.</a> Pharm Res-Dordr. 29 (5), 1295-1307 (2012).</li><li>Gunn, J., Cumberland, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stent+coatings+and+local+drug+delivery+-+state+of+the+art.">Stent coatings and local drug delivery - state of the art.</a> Eur Heart J. 20 (23), 1693-1700 (1999).</li><li>Lu, A., Jia, G., Gao, G., Wang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+magnetic+stent+on+coronary+restenosis+after+percutaneous+transluminal+coronary+angioplasty+in+dogs.">The effect of magnetic stent on coronary restenosis after percutaneous transluminal coronary angioplasty in dogs.</a> Chin Med J (Engl. 114 (8), 821-823 (2001).</li><li>Kempe, H., Kempe, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+magnetite+nanoparticles+for+implant-assisted+magnetic+drug+targeting+in+thrombolytic+therapy.">The use of magnetite nanoparticles for implant-assisted magnetic drug targeting in thrombolytic therapy.</a> Biomaterials. 31 (36), 9499-9510 (2010).</li><li>Chorny, M., 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=Targeting+stents+with+local+delivery+of+paclitaxel-loaded+magnetic+nanoparticles+using+uniform+fields.">Targeting stents with local delivery of paclitaxel-loaded magnetic nanoparticles using uniform fields.</a> P Natl Acad Sci USA. 107 (18), 8346-8351 (2010).</li><li>Polyak, B., Friedman, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+targeting+for+site-specific+drug+delivery:+applications+and+clinical+potential.">Magnetic targeting for site-specific drug delivery: applications and clinical potential.</a> Expert Opin Drug Del. 6 (1), 53-70 (2009).</li><li>Liu, J. Y., 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=Magnetic+stent+hyperthermia+for+esophageal+cancer:+an+in+vitro+investigation+in+the+ECA-109+cell+line.">Magnetic stent hyperthermia for esophageal cancer: an in vitro investigation in the ECA-109 cell line.</a> Oncol Rep. 27 (3), 791-797 (2012).</li><li>Gunn, J., Cumberland, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Does+stent+design+influence+restenosis.">Does stent design influence restenosis.</a> Eur Heart J. 20 (14), 1009-1013 (1999).</li><li>Aviles, M. O., 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=In+vitro+study+of+ferromagnetic+stents+for+implant+assisted-magnetic+drug+targeting.">In vitro study of ferromagnetic stents for implant assisted-magnetic drug targeting.</a> J Magn Magn Mater. 311 (1), 306-311 (2007).</li><li>Mardinoglu, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Theoretical+modelling+of+physiologically+stretched+vessel+in+magnetisable+stent+assisted+magnetic+drug+targeting+application.">Theoretical modelling of physiologically stretched vessel in magnetisable stent assisted magnetic drug targeting application.</a> J Magn Magn Mater. 323 (3-4), 324-329 (2011).</li><li>Liu, Z. Y., 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=Stress+corrosion+cracking+of+2205+duplex+stainless+steel+in+H2S-CO2+environment.">Stress corrosion cracking of 2205 duplex stainless steel in H2S-CO2 environment.</a> J Mater Sci. 44 (16), 4228-4234 (2009).</li><li>Alverez-Armas, I., Degallaix-Moreuill, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Duplex stainless steels. , (2009).</li><li>Tefft, B. J., 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=Magnetizable+Duplex+Steel+Stents+Enable+Endothelial+Cell+Capture.">Magnetizable Duplex Steel Stents Enable Endothelial Cell Capture.</a> Ieee T Magn. 49 (1), 463-466 (2013).</li><li>Pelton, A. R., 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=Fatigue+and+durability+of+Nitinol+stents.">Fatigue and durability of Nitinol stents.</a> J Mech Behav Biomed Mater. 1 (2), 153-164 (2008).</li><li>Knowles, M., 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=Finite+element+analysis+of+a+balloon-expandable+stent+and+superior+mesenteric+arterial+wall+interaction.">Finite element analysis of a balloon-expandable stent and superior mesenteric arterial wall interaction.</a> J Vasc Surg. 60 (6), 1722-1723 (2014).</li><li>Veeram Reddy, S. R., 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=A+novel+biodegradable+stent+applicable+for+use+in+congenital+heart+disease:+bench+testing+and+feasibility+results+in+a+rabbit+model.">A novel biodegradable stent applicable for use in congenital heart disease: bench testing and feasibility results in a rabbit model.</a> Catheter Cardiovasc Interv. 83 (3), 448-456 (2014).</li><li>Shellock, F. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MR+imaging+of+metallic+implants+and+materials:+a+compilation+of+the+literature.">MR imaging of metallic implants and materials: a compilation of the literature.</a> AJR Am J Roentgenol. 151 (4), 811-814 (1988).</li><li>Lopic, N., 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=Quantitative+determination+of+magnetic+force+on+a+coronary+stent+in+MRI.">Quantitative determination of magnetic force on a coronary stent in MRI.</a> J Magn Reson Imaging. 37 (2), 391-397 (2013).</li></ol>

The authors declare that they have no competing financial interests.

우리는 베어 메탈 스텐트의 기능을 할 수 있으며 SPION 표지 내피 세포를 유치 할 수있는 자기 스텐트를 개발했다. 자기 스텐트와 관련된 이전 연구에서 연구팀은 (는) 강자성 스텐트 5,10-14의 불가능에 자성 재료로 만든 니켈 코팅 된 상업 스텐트 및 코일 또는 메쉬를 사용했습니다. 다른 그룹은 나노 입자로드 내피 세포 3을 대상으로 시판 304 등급의 스테인레스 스틸 스텐트의 상자?...

Patients implanted with vascular stents manufactured from thrombogenic materials like stainless steel, cobalt chromium, and platinum chromium &#8211; both bare metal stents (BMS) and drug eluting stents (DES) &#8211; need anti-platelet therapy to prevent thrombus formation. BMS heal rapidly, but are subject to late stage restenosis due to incomplete healing. DES require long term anti-platelet therapy due to delayed healing. Anti-platelet therapy administered to avoid thrombosis as a result of incomplete or delayed healing leads to increased bleeding risk and may not be suitable for certain patients1,2. An ideal stent will heal completely and quickly thus avoiding long-term anti-platelet therapy and late stage restenosis. This complete healing can only be achieved if the stent is rapidly coated with a monolayer of endothelial cells after implantation. Coating the stents with biocompatible materials such as gold or other biopolymers has been shown to improve thrombo-resistance, but none of these techniques achieved ideal blood compatibility as may be possible by coating with endothelial cells3,4.
A stent can be coated with endothelial cells post implantation by attracting circulating progenitor cells. This self-seeding technique can be achieved by utilizing ligands and antibodies. But this technique is limited by the low number of circulating endothelial progenitor cells. A promising strategy is to deliver cells directly to the stent immediately following implantation during a short period of blood flow occlusion3,5. This strategy requires a technique for rapidly capturing cells and retaining them on the stent even after restoring blood flow. We have developed a technique in which a magnetic stent is used to attract and retain magnetically-labeled endothelial cells delivered post implantation. To achieve this, a functional BMS with sufficient magnetic properties to capture and retain magnetically-labeled endothelial cells is required6.
In this paper, we discuss the methods for designing, manufacturing, and testing a 2205 stainless steel stent. The stents were designed using CAD and FEA. The manufactured stents were magnetized using a neodymium magnet and the retained magnetic field was measured using a magneto-resistance microsensor probe. We then tested the stents for magnetically-labeled cell capture in a culture dish during our in-vitro experiments. Finally, the stents were tested in-vivo by implanting magnetic and non-magnetic stents in 4 pigs and histologically analyzing the stented arteries.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>2205 Stainless steel</td>
			<td>Carpenter Technology Corporation</td>
			<td>N/A</td>
			<td>Round bar stock material</td>
		</tr>
		<tr>
			<td>Abaqus</td>
			<td>Dassault systems</td>
			<td>N/A</td>
			<td>Software</td>
		</tr>
		<tr>
			<td>Atropine</td>
			<td></td>
			<td></td>
			<td>Prescription drug.</td>
		</tr>
		<tr>
			<td>Clopidogrel</td>
			<td></td>
			<td></td>
			<td>Commercial name: Plavix. Prescription drug.</td>
		</tr>
		<tr>
			<td>CM-DiI</td>
			<td>Life Technologies</td>
			<td>V-22888</td>
			<td>Molecular Probes, Eugene, OR</td>
		</tr>
		<tr>
			<td>Endothelial growth medium-2</td>
			<td>Lonza</td>
			<td>CC-3162</td>
			<td></td>
		</tr>
		<tr>
			<td>Hand Held Crimping tool</td>
			<td>Blockwise engineering</td>
			<td>M1-RMC</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrochloric acid (HCl)</td>
			<td>Sigma Aldrich</td>
			<td>MFCD00011324</td>
			<td>CAUTION: wear proptective equipment and handle under fume hood</td>
		</tr>
		<tr>
			<td>Isoflurane anesthesia</td>
			<td>Piramal Critical Care, Inc.&#160;</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isopropyl alcohol</td>
			<td>Sigma Aldrich</td>
			<td>MFCD00011674</td>
			<td></td>
		</tr>
		<tr>
			<td>NdFeB magnet 2&#34; Dia x 1&#34; thick</td>
			<td>Amazing magnets</td>
			<td>D1000P</td>
			<td>Axially magnetized disc magnet with poles on flat faces</td>
		</tr>
		<tr>
			<td>Over-The-Wire trifold balloon</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Any commercially available OTW trifold balloon can be used</td>
		</tr>
		<tr>
			<td>Phosphate buffered saline</td>
			<td>Life Technologies</td>
			<td>10010-023</td>
			<td>Commonly known as PBS</td>
		</tr>
		<tr>
			<td>Sodium Bicarbonate (NaHCO3)</td>
			<td>Sigma Aldrich</td>
			<td>MFCD00003528</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium pentobarbital</td>
			<td>Zoetis</td>
			<td></td>
			<td>Commercial Name: Sleepaway (26%), FatalPlus, Beuthanasi.&#160; Controlled substance to be ordered only by licensed veternarian</td>
		</tr>
		<tr>
			<td>SolidWorks</td>
			<td>Dassault systems</td>
			<td>N/A</td>
			<td>Software</td>
		</tr>
		<tr>
			<td>SpinTJ-020 micro sensor</td>
			<td>MicroMagneitcs Sensible Solutions</td>
			<td>N/A</td>
			<td>Long probe STJ-020 microsensor</td>
		</tr>
		<tr>
			<td>SPION</td>
			<td>Mayo Clinic</td>
			<td>N/A</td>
			<td>Nanoparticles synthesized internally (Ref: Lee, S. J. et al. Nanoparticles of magnetic ferric oxides encapsulated with poly(D,L latide-co-glycolide) and their applications to magnetic resonance imaging contrast agent. J Magn Magn Mater 272, 2432-2433, doi:DOI 10.1016/j.jmmm.2003.12.416 (2004))</td>
		</tr>
		<tr>
			<td>Telazol</td>
			<td>Zoetis</td>
			<td></td>
			<td>Controlled substance to be ordered only by licensed veternarian</td>
		</tr>
		<tr>
			<td>Trypsin EDTA</td>
			<td>Life Technologies</td>
			<td>25200-056</td>
			<td>Gibco, Grand Island, NY</td>
		</tr>
		<tr>
			<td>Xylazine</td>
			<td>Bayer Animal Health</td>
			<td></td>
			<td>Commercial name: Rompun. Controlled sunstance to be ordered only by a licensed veternarian</td>
		</tr>
	</tbody>
</table>

ferromagnetic bare metal stent for endothelial cell capture and retention

심혈관 스텐트에 내피 세포가 급속 스텐트 혈전증을 감소시키고 출혈 위험을 줄일 수있는 항 혈소판 요법을 피하기 위해 필요하다. 초 상자성 산화철 나노 입자 (SPION)로 표지 내피 세포 생장 (EOC)를 캡쳐하고 유지하기 위해 자력을 이용의 가능성은 이미 밝혀졌다. 그러나이 기술은 빠른에 내피 증명 시험관 내 및 생체 내 시험 하였다 자기 및 생체 물질로부터 기계적 작용 성 스텐트의 개발이 필요하다. 우리는 컴퓨터 이용 설계 (CAD)를 이용하여 2,205 듀플렉스 스테인레스 약하게 강자성 스텐트를 개발하고 설계는 또한 유한 요소 해석 (FEA)을 사용하여 정제 하였다. 스텐트의 최종 설계는 기계적 권축과 팽창시에 재료의 파단 한계 이하 주 변형률을 나타냈다. 백 스텐트를 제작하고, 그 중 일부는 기계적 시험, RET에 사용 된ained 자기장 측정 시험관 세포 캡처 연구 및 생체 내 주입 연구. 텐 스텐트은 실패없이 사이클을 압착 및 확장 입었 있는지 확인하기 위해 배포를 테스트 하였다. 다른 스텐트 (10)는 강한 네오디뮴 자석을 이용하고, 그들의 자화 유지 자기장을 측정 하였다. 스텐트는 유지 자기가 우리의 시험관 연구에서 SPION 표지 EOC를 캡처하기에 충분한 것으로 나타났다. SPION 표지 EOC 캡처 및 보유 1 자화 스텐트 4 돼지의 각 1 비 자화 제어 스텐트를 주입하여 큰 동물 모델에서 확인되었다. 스텐트 동맥 7 일 이후 외식 및 조직 학적으로 분석 하였다. 본 연구에서 개발 된 약하게 자기 스텐트 유치와 빠른 치유를 촉진 할 수 SPION 표지 내피 세포를 보유 할 수 있었다.

<html> FEA (도 1)에 기초하여 반복적 스텐트 디자인은 압착 및 30 %의 궁극적 인 스트레인 미만 20 %의 주요 균주 스텐트 확장 할 수 있었다. 압착 및 확장 테스트 (그림 2) 골절의 징후를 보이지 않았다. 변형 된 스텐트의 사진은 FEA 계산 변형와 잘 일치를 보였다 또한 현미경 사진은 골절을 (그림 3)가 없었다. 유지 자기장 측정 (그림 4 및 5)에서 예상대?...

Watch this Scientific Journal Video about Ferromagnetic Bare Metal Stent for Endothelial Cell Capture and Retention at JoVE.com

Ferromagnetic Bare Metal Stent for Endothelial Cell Capture and Retention

우리의 목표는 설계, 제조 및 내피 세포 캡처를위한 강자성 스텐트를 테스트했다. 열 스텐트 파괴에 대해 시험하고, 10 이상이 유지 자성 스텐트에 대해 시험 하였다. 마지막으로, 10 스텐트는 시험관 시험하고 8 개의 스텐트는 세포 캡처 및 보존을 보여 4 돼지에 이식했다.

내피 세포 캡처 및 유지에 대한 강자성 베어 메탈 스텐트

Rapid endothelialization of cardiovascular stents is needed to reduce stent thrombosis and to avoid anti-platelet therapy which can reduce bleeding risk. ...

ferromagnetic-bare-metal-stent-for-endothelial-cell-capture

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Bioengineering

11.4K 조회수.  Mayo Clinic.  우리의 목표는 설계, 제조 및 내피 세포 캡처를위한 강자성 스텐트를 테스트했다. 열 스텐트 파괴에 대해 시험하고, 10 이상이 유지 자성 스텐트에 대해 시험 하였다. 마지막으로, 10 스텐트는 시험관 시험하고 8 개의 스텐트는 세포 캡처 및 보존을 보여 4 돼지에 이식했다. 

비디오: Ferromagnetic Bare Metal Stent for Endothelial Cell Capture and Retention

Autologous Endothelial Progenitor Cell-Seeding Technology and Biocompatibility Testing For Cardiovascular Devices in Large Animal Model

Implantable cardiovascular devices are manufactured from artificial materials (e.g. titanium (Ti), expanded polytetrafluoroethylene), which pose the risk of thromboemboli formation1,2,3. We have developed a method to line the inside surface of Ti tubes with autologous blood-derived human or porcine endothelial progenitor cells (EPCs)4. By implanting Ti tubes containing a confluent layer of porcine EPCs in the inferior vena cava (IVC) of pigs, we tested the improved biocompatibility of the cell-seeded surface in the prothrombotic environment of a large animal model and compared it to unmodified bare metal surfaces5,6,7 (Figure 1). This method can be used to endothelialize devices within minutes of implantation and test their antithrombotic function in vivo. 
Peripheral blood was obtained from 50 kg Yorkshire swine and its mononuclear cell fraction cultured to isolate EPCs4,8. Ti tubes (9.4 mm ID) were pre-cut into three 4.5 cm longitudinal sections and reassembled with heat-shrink tubing. A seeding device was built, which allows for slow rotation of the Ti tubes. 
We performed a laparotomy on the pigs and externalized the intestine and urinary bladder. Sharp and blunt dissection was used to skeletonize the IVC from its bifurcation distal to the right renal artery proximal. The Ti tubes were then filled with fluorescently-labeled autologous EPC suspension and rotated at 10 RPH x 30 min to achieve uniform cell-coating9. After administration of 100 USP/ kg heparin, both ends of the IVC and a lumbar vein were clamped. A 4 cm veinotomy was performed and the device inserted and filled with phosphate-buffered saline. As the veinotomy was closed with a 4-0 Prolene running suture, one clamp was removed to de-air the IVC. At the end of the procedure, the fascia was approximated with 0-PDS (polydioxanone suture), the subcutaneous space closed with 2-0 Vicryl and the skin stapled closed. 
After 3 - 21 days, pigs were euthanized, the device explanted en-block and fixed. The Ti tubes were disassembled and the inner surfaces imaged with a fluorescent microscope.
We found that the bare metal Ti tubes fully occluded whereas the EPC-seeded tubes remained patent. Further, we were able to demonstrate a confluent layer of EPCs on the inside blood-contacting surface.
Concluding, our technology can be used to endothelialize Ti tubes within minutes of implantation with autologous EPCs to prevent thrombosis of the device. Our surgical method allows for testing the improved biocompatibility of such modified devices with minimal blood loss and EPC-seeded surface disruption.

A method for seeding titanium blood-contacting biomaterials with autologous cells and testing biocompatibility is described. This method uses endothelial progenitor cells and titanium tubes, seeded within minutes of surgical implantation into porcine venae cavae. This technique is adaptable to many other implantable biomedical devices.

Autologous 내피 전구 세포 - 심는 기술 및 대형 동물 모델에서 순환기 장치에 대한 Biocompatibility 테스트

Implantable cardiovascular devices are manufactured from artificial materials (e.g. titanium (Ti), expanded polytetrafluoroethylene), which pose the risk ...

연구

생체공학

Monitoring the Wall Mechanics During Stent Deployment in a Vessel

Clinical trials have reported different restenosis rates for various stent designs1. It is speculated that stent-induced strain concentrations on the arterial wall lead to tissue injury, which initiates restenosis2-7. This hypothesis needs further investigations including better quantifications of non-uniform strain distribution on the artery following stent implantation. A non-contact surface strain measurement method for the stented artery is presented in this work. ARAMIS stereo optical surface strain measurement system uses two optical high speed cameras to capture the motion of each reference point, and resolve three dimensional strains over the deforming surface8,9. As a mesh stent is deployed into a latex vessel with a random contrasting pattern sprayed or drawn on its outer surface, the surface strain is recorded at every instant of the deformation. The calculated strain distributions can then be used to understand the local lesion response, validate the computational models, and formulate hypotheses for further in vivo study.

Stent-induced arterial strain distributions are characterized using an optical surface strain measurement system. This visualization technique is used to gain insights into the impact of stent implantation on the host vessel.

선박의 스텐 트를 배포하는 동안 벽 역학 모니터링

Clinical trials have reported different restenosis rates for various stent designs1. It is speculated that stent-induced strain concentrations on the ...

Electric Cell-substrate Impedance Sensing for the Quantification of Endothelial Proliferation, Barrier Function, and Motility

Electric Cell-substrate Impedance Sensing (ECIS) is an in vitro impedance measuring system to quantify the behavior of cells within adherent cell layers. To this end, cells are grown in special culture chambers on top of opposing, circular gold electrodes. A constant small alternating current is applied between the electrodes and the potential across is measured. The insulating properties of the cell membrane create a resistance towards the electrical current flow resulting in an increased electrical potential between the electrodes. Measuring cellular impedance in this manner allows the automated study of cell attachment, growth, morphology, function, and motility. Although the ECIS measurement itself is straightforward and easy to learn, the underlying theory is complex and selection of the right settings and correct analysis and interpretation of the data is not self-evident. Yet, a clear protocol describing the individual steps from the experimental design to preparation, realization, and analysis of the experiment is not available. In this article the basic measurement principle as well as possible applications, experimental considerations, advantages and limitations of the ECIS system are discussed. A guide is provided for the study of cell attachment, spreading and proliferation; quantification of cell behavior in a confluent layer, with regard to barrier function, cell motility, quality of cell-cell and cell-substrate adhesions; and quantification of wound healing and cellular responses to vasoactive stimuli. Representative results are discussed based on human microvascular (MVEC) and human umbilical vein endothelial cells (HUVEC), but are applicable to all adherent growing cells.

This protocol reviews Electric Cell-substrate Impedance Sensing, a method to record and analyze the impedance spectrum of adherent cells for the quantification of cell attachment, proliferation, motility, and cellular responses to pharmacological and toxic stimuli. Detection of endothelial permeability and assessment of cell-cell and cell-substrate contacts are emphasized.

전기 세포 기판 임피던스 내피 증식, 장벽 기능의 정량화에 대한 감지 및 운동성

Electric Cell-substrate Impedance Sensing (ECIS) is an in vitro impedance measuring system to quantify the behavior of cells within adherent cell layers. ...

Fabrication of Mechanically Tunable and Bioactive Metal Scaffolds for Biomedical Applications

Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness and low bioactivity of metals. In this study, we have developed a new method towards fabricating a new type of bioactive and mechanically reliable porous metal scaffolds-densified porous Ti scaffolds. The method consists of two fabrication processes, 1) the fabrication of porous Ti scaffolds by dynamic freeze casting, and 2) coating and densification of the porous scaffolds. The dynamic freeze casting method to fabricate porous Ti scaffolds allowed the densification of porous scaffolds by minimizing the chemical contamination and structural defects. The densification process is distinctive for three reasons. First, the densification process is simple, because it requires a control of only one parameter (degree of densification). Second, it is effective, as it achieves mechanical enhancement and sustainable release of biomolecules from porous scaffolds. Third, it has broad applications, as it is also applicable to the fabrication of functionally graded porous scaffolds by spatially varied strain during densification.

Bioactive and mechanically reliable metal scaffolds have been fabricated through a method which consists of two processes, dynamic freeze casting for the fabrication of porous Ti, and coating and densification of the Ti scaffolds. The densification process is simple, effective and applicable to the fabrication of functionally graded scaffolds.

Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness ...

Co-transplantation of Human Ovarian Tissue with Engineered Endothelial Cells: A Cell-based Strategy Combining Accelerated Perfusion with Direct Paracrine Delivery

Infertility is a frequent side effect of chemotherapy and/or radiotherapy and for some patients, cryopreservation of oocytes or embryos is not an option. As an alternative, an increasing number of these patients are choosing to cryopreserve ovarian tissue for autograft following recovery and remission. Despite improvements in outcomes among patients undergoing auto-transplantation of cryopreserved ovarian tissue, efficient revascularization of grafted tissue remains a major obstacle. To mitigate ischemia and thus improve outcomes in patients undergoing auto-transplantation, we developed a vascular cell-based strategy for accelerating perfusion of ovarian tissue. We describe a method for co-transplantation of exogenous endothelial cells (ExECs) with cryopreserved ovarian tissue in a mouse xenograft model. We extend this approach to employ ExECs that have been engineered to constitutively express Anti-Mullerian hormone (AMH), thus enabling sustained paracrine signaling input to ovarian grafts. Co-transplantation with ExECs increased follicular volume and improved antral follicle development, and AMH-expressing ExECs promoted retention of quiescent primordial follicles. This combined strategy may be a useful tool for mitigating ischemia and modulating follicular activation in the context of fertility preservation and/or infertility at large.

For some patients, the only option for fertility preservation is cryopreservation of ovarian tissue. Unfortunately, delayed revascularization undermines follicular viability. Here, we present a protocol to co-transplant human ovarian tissue with endothelial cells for utilization as a cell-based strategy combining accelerated perfusion with a direct paracrine delivery of bioactive molecules.

공동 설계 된 내 피 세포와 인간 난소 조직 이식: 세포 기반 전략 결합 가속 직접 Paracrine 배달 관류

Infertility is a frequent side effect of chemotherapy and/or radiotherapy and for some patients, cryopreservation of oocytes or embryos is not an option. ...

Immobilization of Live Caenorhabditis elegans Individuals Using an Ultra-thin Polydimethylsiloxane Microfluidic Chip with Water Retention

Radiation is widely used for biological applications and for ion-beam breeding, and among these methods, microbeam irradiation represents a powerful means of identifying radiosensitive sites in living organisms. This paper describes a series of on-chip immobilization methods developed for the targeted microbeam irradiation of live individuals of Caenorhabditis elegans. Notably, the treatment of the polydimethylsiloxane (PDMS) microfluidic chips that we previously developed to immobilize C. elegans individuals without the need for anesthesia is explained in detail. This chip, referred to as a worm sheet, is resilient to allow the microfluidic channels to be expanded, and the elasticity allows animals to be enveloped gently. Also, owing to the self-adsorption capacity of the PDMS, animals can be sealed in the channels by covering the surface of the worm sheet with a thin cover film, in which animals are not pushed into the channels for enclosure. By turning the cover film over, we can easily collect the animals. Furthermore, the worm sheet shows water retention and allows C. elegans individuals to be subjected to microscopic observation for long periods under live conditions. In addition, the sheet is only 300 &#181;m thick, allowing heavy ions such as carbon ions to pass through the sheet enclosing the animals, thus allowing the ion particles to be detected and the applied radiation dose to be measured accurately. Because selection of the cover films used for enclosing the animals is very important for successful long-term immobilization, we conducted the selection of the suitable cover films and showed a recommended one among some films. As an application example of the chip, we introduced imaging observation of muscular activities of animals enclosing the microfluidic channel of the worm sheet, as well as the microbeam irradiation. These examples indicate that the worm sheets have greatly expanded the possibilities for biological experiments.

Immobilization of Live Caenorhabditis elegans Individuals Using an Ultra-thin Polydimethylsiloxane Microfluidic Chip with Water Retention

A series of immobilization methods has been established to allow the targeted irradiation of live Caenorhabditis elegans individuals using a recently developed ultra-thin polydimethylsiloxane microfluidic chip with water retention. This novel on-chip immobilization is also adequate for imaging observations. The detailed treatment and application examples of the chip are explained.

물 유지와 울트라입니다 미세 칩을 사용 하 여 라이브 꼬마 선 충 의 동원 정지

Radiation is widely used for biological applications and for ion-beam breeding, and among these methods, microbeam irradiation represents a powerful means ...

Growth of Human and Sheep Corneal Endothelial Cell Layers on Biomaterial Membranes

Corneal endothelial cell cultures have a tendency to undergo epithelial-to-mesenchymal transition (EMT) after loss of cell-to-cell contact. EMT is deleterious for the cells as it reduces their ability to form a mature and functional layer. Here, we present a method for establishing and subculturing human and sheep corneal endothelial cell cultures that minimizes the loss of cell-to-cell contact. Explants of corneal endothelium/Descemet&#39;s membrane are taken from donor corneas and placed into tissue culture under conditions that allow the cells to collectively migrate onto the culture surface. Once a culture has been established, the explants are transferred to fresh plates to initiate new cultures. Dispase II is used to gently lift clumps of cells off tissue culture plates for subculturing. Corneal endothelial cell cultures that have been established using this protocol are suitable for transferring to biomaterial membranes to produce tissue-engineered cell layers for transplantation in animal trials. A custom-made device for supporting biomaterial membranes during tissue culture is described and an example of a tissue-engineered graft composed of a layer of corneal endothelial cells and a layer of corneal stromal cells on either side of a collagen type I membrane is presented.

This protocol describes the critical steps required to establish and grow corneal endothelial cell cultures from explants of human or sheep tissue. A method for subculturing corneal endothelial cells on membranous biomaterials is also presented.

생체 재료 멤브레인에 인간과 양 각막 내피 세포 층의 성장

Corneal endothelial cell cultures have a tendency to undergo epithelial-to-mesenchymal transition (EMT) after loss of cell-to-cell contact. EMT is ...

Mitigation of Blood Borne Cell Attachment to Metal Implants through CD47-Derived Peptide Immobilization

The key complications associated with bare metal stents and drug eluting stents are in-stent restenosis and late stent thrombosis, respectively. Thus, improving the biocompatibility of metal stents remains a significant challenge. The goal of this protocol is to describe a robust technique of metal surface modification by biologically active peptides to increase biocompatibility of blood contacting medical implants, including endovascular stents. CD47 is an immunological species-specific marker of self and has anti-inflammatory properties. Studies have shown that a 22 amino acid peptide corresponding to the Ig domain of CD47 in the extracellular region (pepCD47), has anti-inflammatory properties like the full-length protein. In vivo studies in rats, and ex vivo studies in rabbit and human blood experimental systems from our lab have demonstrated that pepCD47 immobilization on metals improves their biocompatibility by preventing inflammatory cell attachment and activation. This paper describes the step-by step protocol for the functionalization of metal surfaces and peptide attachment. The metal surfaces are modified using polyallylamine bisphosphate with latent thiol groups (PABT) followed by deprotection of thiols and amplification of thiol-reactive sites via reaction with polyethyleneimine installed with pyridyldithio groups (PEI-PDT). Finally, pepCD47, incorporating terminal cysteine residues connected to the core peptide sequence through a dual 8-amino-3,6-dioxa-octanoyl spacer, are attached to the metal surface via disulfide bonds. This methodology of peptide attachment to metal surface is efficient and relatively inexpensive and thus can be applied to improve biocompatibility of several metallic biomaterials.

Presented here is a protocol for appending peptide CD47 (pepCD47) to metal stents using polybisphosphonate chemistry. Functionalization of metal stents using pepCD47 prevents the attachment and activation of inflammatory cells thus improving their biocompatibility.

CD47 유래 펩타이드 고정화를 통해 금속 임플란트에 대한 혈액 매개 세포 부착 완화

The key complications associated with bare metal stents and drug eluting stents are in-stent restenosis and late stent thrombosis, respectively. Thus, ...

Segmenting Growth of Endothelial Cells in 6-Well Plates on an Orbital Shaker for Mechanobiological Studies

Shear stress imposed on the arterial wall by the flow of blood affects endothelial cell morphology and function. Low magnitude, oscillatory and multidirectional shear stresses have all been postulated to stimulate a pro-atherosclerotic phenotype in endothelial cells, whereas high magnitude and unidirectional or uniaxial shear are thought to promote endothelial homeostasis. These hypotheses require further investigation, but traditional in vitro techniques have limitations, and are particularly poor at imposing multidirectional shear stresses on cells. 
One method that is gaining increasing use is to culture endothelial cells in standard multi-well plates on the platform of an orbital shaker; in this simple, low-cost, high-throughput and chronic method, the swirling medium produces different patterns and magnitudes of shear, including multidirectional shear, in different parts of the well. However, it has a significant limitation: cells in one region, exposed to one type of flow, may release mediators into the medium that affect cells in other parts of the well, exposed to different flows, hence distorting the apparent relation between flow and phenotype. 
Here we present an easy and affordable modification of the method that allows cells to be exposed only to specific shear stress characteristics. Cell seeding is restricted to a defined region of the well by coating the region of interest with fibronectin, followed by passivation using passivating solution. Subsequently, the plates can be swirled on the shaker, resulting in exposure of cells to well-defined shear profiles such as low magnitude multidirectional shear or high magnitude uniaxial shear, depending on their location. As before, the use of standard cell-culture plasticware allows straightforward further analysis of the cells. The modification has already allowed the demonstration of soluble mediators, released from endothelium under defined shear stress characteristics, that affect cells located elsewhere in the well.

This protocol describes a coating method to restrict endothelial cell growth to a specific region of a 6-well plate for shear stress application using the orbital shaker model.

메카노생물학적 연구를 위한 궤도 셰이커에 6웰 플레이트에서 내피 세포의 분할 성장

Shear stress imposed on the arterial wall by the flow of blood affects endothelial cell morphology and function. Low magnitude, oscillatory and ...

A Microphysiological System to Study Leukocyte-Endothelial Cell Interaction during Inflammation

Leukocyte-endothelial cell interactions play an important role in inflammatory diseases such as sepsis. During inflammation, excessive migration of activated leukocytes across the vascular endothelium into key organs can lead to organ failure. A physiologically relevant biomimetic microfluidic assay (bMFA) has been developed and validated using several experimental and computational techniques, which can reproduce the entire leukocyte rolling/adhesion/migration cascade to study leukocyte-endothelial cell interactions. Microvascular networks obtained from in vivo images in rodents were digitized using a Geographic Information System (GIS) approach and microfabricated with polydimethylsiloxane (PDMS) on a microscope slide. To study the effect of shear rate and vascular topology on leukocyte-endothelial cell interactions, a Computational Fluid Dynamics (CFD) model was developed to generate a corresponding map of shear rates and velocities throughout the network. The bMFA enables the quantification of leukocyte-endothelial cells interactions, including rolling velocity, number of adhered leukocytes in response to different shear rates, number of migrated leukocytes, endothelial cell permeability, adhesion molecule expression and other important variables. Furthermore, by using human-related samples, such as human endothelial cells and leukocytes, bMFA provides a tool for rapid screening of potential therapeutics to increase their clinical translatability.

In this protocol, a biomimetic microfluid assay, which can reproduce a physiologically relevant microvascular environment and reproduce the entire leukocyte adhesion/migration cascade, is employed to study leukocyte-endothelial cell interactions in inflammatory disease.

염증 중 백혈구-내피 세포 상호작용을 연구하는 미생리학적 시스템

Leukocyte-endothelial cell interactions play an important role in inflammatory diseases such as sepsis. During inflammation, excessive migration of ...