We acknowledge financial support from the American Heart Association Scientist Development Grant, 13SDG14670062 (PWA) and the University of Minnesota Doctoral Dissertation Fellowship (ESH). We also acknowledge the microfabrication resources of the Minnesota Nano Center (MNC) and the image processing resources of the University Imaging Centers (UIC), both at the University of Minnesota. Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from NSF through the MRS program.

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The authors have nothing to disclose.

여기서 우리는 만성 혈관 질환 경로 1,23,24의 확장 된 실험 시간은 전형적인 수 있도록 이전에 개발 된 vMTF 기술을 기반으로 구축하는 프로토콜을 제시한다. 이를 위해, 우리는 이전 MTF 수축력 실험에 사용하기위한 개선 된 혈관 조직 생존력과 엔지니어링 동맥 박편을 수득 미세 증착 기술을 이용하여 PDMS 기판 (11)의 장기간의 작용을 제공하는 것으로 나타났다 genipin를 미세 패턴. 매케인 등. 관련 MTF 모델 25 몇 주 동안 설계 심장 조직의 확장 된 문화에 대한 대안 micromolded 젤라틴 하이드로 겔 기판을 개발했다. 이 프로토콜은 성공적으로 2 주에 걸쳐 동맥 라멜라 구조 (그림 2)과 기능 (그림 3) 모방 vMTFs을 얻었다. 제시된 프로토콜을 성공적으로 완료하여 원하는 해상도를 얻을 수 있지만질병 관련 시간 코스에 대한 확장 된 문화 시간의 ULT (예를 들어, 최대 14 일 26 지속 뇌 혈관 경련의 병리학 적 효과), 일반적으로 다음과 같은 몇 가지 함정이 발생한다. 장치에 지사의 일부 또는 전체 차단 될 수 있습니다 해로운 손상에 PDMS 미세 유체 장치 결과의 반복 사용. 따라서, 새로운 디바이스는 각각의 실험을 위해 사용되어야한다. 또 다른 문제는, 일반적인하지는 않지만, 조직의 예상치와 일치 박리입니다. 이 사건은 발생 자연에서 무작위 드문 것 같았다. 관찰에 의해, 조직은 얇은 막으로 분리하기 전에 arch- 또는 루멘 같은 구조를 형성한다. 우리는 또한 미세 접촉 프린팅 기술을 사용하여 제작 된 조직에서이 동작을 관찰했다. 따라서, 우리는이 문제가 오버 파종 또는 표현형 비정상적인 행동 결과 배양 된 혈관 평활근 세포의 스위치가 아니라 여기에 제시된 제조 방법의 직접적인 결과 중 하나의 결과로 생각합니다. 현재 마이크로 유체IC 설계 선형 흐름 패턴을 필요로하며, 같은 하나의 주 배향 방향과 조직에 한정된다. 이러한 심실 심근 구조 (27)의 &quot;벽돌 벽&quot;패턴으로 더 복잡한 패턴을 필요로하는 조직에 응용 프로그램은보다 정교한 미세 유체 설계가 필요합니다. 우리는 다른 세포 유형으로 genipin 수정 기판을 접종하지 않았습니다. 그러나 Genchi 외. genipin 수정 PDMS 11 등방성 골격 근육의 생존 능력을 확장했다. 따라서, 우리는이 프로토콜의 최소한의 수정 버전이 기관 - 온 - 어 - 칩 기술의 미래 발전에 다른 기관 시스템에 광범위하게 적용이 있는지 확신. 이전의 방법 (8)에 기초 vMTFs위한 응력 계산 방법은 박막의 조직에서의 상대적으로 수축 및 대응 절단 길이에 의해 제한된다. 너무 오래 잘라 경우, 영화 자체에 컬합니다. 너무 짧게 잘라 경우, 필름은되지 않습니다차. 어느 경우는 제한을 모델에 따라 수축 특성의 적절한 분석을 방지 할 수 있습니다. 적절한 절단 길이는 반복 실험을 통해 정제해야한다. 아가 왈 등으로하는 레이저 조각 시스템의 구현은,., 반복성과 MTF (28)의 절단 품질을 개선 할 수있다. 더 단단히 통제되는 자 급식 실험 시스템에서 네이티브 조직의 구조와 기능을 요점을 되풀이하는 능력은 생물 공학 분야에서의 키 추적이다. 이 추구는 기본적인 생리 학적 및 기관계 29,30의 병리학 동작의 이해를 증진, 여러 시험 관내 조직 모방 다기능 아직 단순화 된 모델 기관 온어 칩의 개발을 유도 하였다. PDMS 기판 상 genipin 증착을 사용하여, 2 주간에 걸쳐 연장 된 세포 생존 및 혈관 평활근 기능의 유지를 증명 하였다. 이것은 이전 제조 TECHN 비해 상당한 개선이다배양 19 7 일, 및보다 강력한 동맥 온칩 방법 개발에 도움이있다 - 조직 및 4 후의 세포 죽음의 박리를 초래할 수 iques. 때문에 대부분의 혈관 질환의 만성적 인 특성으로,이 사전은 특정 혈관 병변에 관련된 수축 메커니즘으로 미래 연구의 다양한 프레임 워크를 제공합니다.

이러한 뇌 혈관 경련, 2, 3, 고혈압, 동맥 경화증 및 4와 같은 혈관 질환은 서서히 발전 전형적으로 사실상 만성적이며, 혈관 평활근 세포 (혈관 평활근 세포)로 역기능 힘 발생을 수반한다. 우리의 생체 내 모델보다 실험 조건의 미세한 제어 체외 방법에서 사용이 느리게 진행 혈관 장애를 연구하는 것을 목표로하고 있습니다. 시험관의 기능 수축력을 측정하는 우리는 이전에 개발 한 혈관 근육 박막 (vMTFs)은 심장 혈관 조직 (5)를 설계하지만,이 방법은 상대적으로 단기 연구에 제한되어있다. 여기서는 장기 측정 이전 vMTF 기술을 확장 기판 개질 기술을 제시한다. 혈관 내피 세포는 전체 기능에도 중요하지만, 설계 라멜라 동맥 혈관의 변화를 평가하는데 유용한 모델 시스템을 제공하는질병의 진행 동안 수축. 기능적인 혈관 질환 조직 모델 구조 및 동맥 라멜라의 기능을 모두 엔지니어, 용기의 기본 수축 부, 고 충실도로 효과적으로 요약되어야한다. 동맥 라멜라 6 엘라스틴의 시트로 구분 수축 혈관 평활근 세포의 동심, 원주 방향으로 정렬 시트입니다. 폴리 디메틸 실록산 (PDMS) 기판 상에 세포 외 기질 (ECM) 단백질의 마이크로 콘택트 프린팅 이전 심혈관 조직 5,7-10 정렬 모방 조직 조직 유도 신호를 제공하기 위해 사용되어왔다. 그러나 조직은 만성 연구에서 자신의 적용을 제한, 문화 3-4 일 후에 무결성을 잃을 수 미세 접촉 인쇄를 사용하여 패턴. 이 프로토콜은 새로운 미세 증착 기술로 기존 미세 접촉 인쇄 기술로 대체함으로써이 문제에 대한 해결책을 제공한다. genipin와 f와 Genchi 등. 수정 된 PDMS 기판운드, 문화 (11)에 1 개월 심근 세포의 생존을 연장. 여기서는 PDMS에 패터닝 된 혈관 평활근 세포의 배양을 확장하는 유사한 접근법을 사용한다. Genipin, 치자 나무 열매의 천연 가수 유도체는 유사한 가교제 및 조직 복구 12,13 및 ECM 수식 (14)의 분야에서 생체 재료로서의 사용이 증가에 비해 인해 비교적 낮은 독성 기판 변형위한 바람직한 후보 15. 이 프로토콜에서, 피브로넥틴은 이전 미세 접촉 인쇄 방법에서와 같이, 셀 안내 큐로서 이용되고; 그러나 genipin 피브로넥틴은 패터닝 이전에 PDMS 기판 상에 증착된다. 세포가 패턴 매트릭스 저하로 따라서, 첨부 된 혈관 평활근 세포에서 새로 합성 된 ECM은 genipin 코팅 된 PDMS 기판에 바인딩 할 수 있습니다. 이 프로토콜은 두 단계 genipin과 ECM 증착을위한 미세 유체 전달 장치를 이용한다. 미세 유체 장치 모방 microco의 디자인이전의 연구 (16)에서 설계 동맥 박편에 사용 ntact 인쇄 패턴. 따라서,이 프로토콜이 성공적으로 구조 및 생체 동맥 박편의 수축 기능에 고도로 정렬 요점을 되풀이 동맥 라멜라 모방을 수득 할 것으로 예상. 우리는 또한 genipin 시험관 혈관 질환 모델에서 장기에 적합한 기판 수정 화합물 확인하기 위해 조직의 수축력을 평가.

<table><tbody><tr><td>Coverslip staining rack</td><td>Electron Microscopy Sciences</td><td>&lt;a href=&quot;http://www.emsdiasum.com/&quot;&gt;www.emsdiasum.com/&lt;/a&gt;</td><td>72239-04</td></tr><tr><td>Microscope cover glass - 25 mm</td><td>Fisher Scientific, Inc.</td><td>&lt;a href=&quot;http://www.fishersci.com/&quot;&gt;www.fishersci.com&lt;/a&gt;</td><td>12-545-102</td></tr><tr><td>Poly(N-iso-propylacrylamide) (PIPAAm)</td><td>Polysciences, Inc.</td><td>&lt;a href=&quot;http://www.polysciences.com/&quot;&gt;www.polysciences.com/&lt;/a&gt;</td><td>#21458</td></tr><tr><td>1-butanol</td><td>Sigma-Aldrich</td><td>&lt;a href=&quot;http://www.sigmaaldrich.com/&quot;&gt;www.sigmaaldrich.com&lt;/a&gt;</td><td>360465</td></tr><tr><td>Spincoater</td><td>Specialty Coating Systems, Inc.</td><td>&lt;a href=&quot;http://www.scscoatings.com/&quot;&gt;www.scscoatings.com&lt;/a&gt;</td><td></td></tr><tr><td>Polydimethylsiloxane (PDMS)</td><td>Ellsworth Adhesives (Dow Corning)</td><td>&lt;a href=&quot;http://www.ellsworth.com/&quot;&gt;www.ellsworth.com&lt;/a&gt;</td><td>184 SIL ELAST KIT 0.5KG</td></tr><tr><td>Fluorescent microbeads</td><td>Polysciences, Inc.</td><td>&lt;a href=&quot;http://www.polysciences.com/&quot;&gt;www.polysciences.com/&lt;/a&gt;</td><td>17151</td></tr><tr><td>Silicon wafers</td><td>Wafer World, Inc.</td><td>&lt;a href=&quot;http://www.waferworld.com/&quot;&gt;www.waferworld.com&lt;/a&gt;</td><td>2398</td></tr><tr><td>Photoresist&amp;nbsp;</td><td>MicroChem Corp.</td><td>&lt;a href=&quot;http://www.microchem.com/&quot;&gt;www.microchem.com&lt;/a&gt;</td><td></td></tr><tr><td>Contact mask aligner</td><td>Suss MicroTec</td><td>&lt;a href=&quot;http://www.suss.com/&quot;&gt;www.suss.com&lt;/a&gt;</td><td></td></tr><tr><td>Developer</td><td>MicroChem Corp.</td><td>&lt;a href=&quot;http://www.microchem.com/&quot;&gt;www.microchem.com&lt;/a&gt;</td><td></td></tr><tr><td>Tridecafluro-trichlorosilane</td><td>UCT Specialties, Inc.</td><td>&lt;a href=&quot;http://www.unitedchem.com/&quot;&gt;www.unitedchem.com&lt;/a&gt;</td><td>T2492</td></tr><tr><td>Surgical biopsy punch</td><td>Integra LifeSciences Corp.</td><td>&lt;a href=&quot;http://www.miltex.com/&quot;&gt;www.miltex.com&lt;/a&gt;</td><td>33-31AA-P/25</td></tr><tr><td>Genipin</td><td>Cayman Chemical</td><td>&lt;a href=&quot;http://www.caymanchem.com/&quot;&gt;www.caymanchem.com&lt;/a&gt;</td><td>10010622</td></tr><tr><td>1X phosphate buffered saline</td><td>Mediatech, Inc.</td><td>&lt;a href=&quot;http://www.cellgro.com/&quot;&gt;www.cellgro.com&lt;/a&gt;</td><td>21-031-CV</td></tr><tr><td>Fibronectin</td><td>Corning, Inc.</td><td>&lt;a href=&quot;http://www.corning.com/&quot;&gt;www.corning.com&lt;/a&gt;</td><td>356008</td></tr><tr><td>Penicillin/streptomycin</td><td>Life Technologies, Inc.</td><td>&lt;a href=&quot;http://www.lifetechnologies.com/&quot;&gt;www.lifetechnologies.com&lt;/a&gt;</td><td>15140-122</td></tr><tr><td>Umbillical artery smooth muscle cells</td><td>Lonza</td><td>&lt;a href=&quot;http://www.lonza.com/&quot;&gt;www.lonza.com&lt;/a&gt;</td><td>CC-2579</td></tr><tr><td>Tyrode&#039;s solution components</td><td>Sigma-Aldrich</td><td>&lt;a href=&quot;http://www.sigmaaldrich.com/&quot;&gt;www.sigmaaldrich.com&lt;/a&gt;</td><td>various</td></tr><tr><td>Stereomicroscope</td><td>Zeiss</td><td>&lt;a href=&quot;http://www.zeiss.com/&quot;&gt;www.zeiss.com&lt;/a&gt;</td><td>4350020000000000</td></tr><tr><td>Temperature-controlled platform</td><td>Warner Instruments</td><td>&lt;a href=&quot;http://www.warneronline.com/&quot;&gt;www.warneronline.com&lt;/a&gt;</td><td>641659; 640352; 641922</td></tr><tr><td>Endothelin-1</td><td>Sigma-Aldrich</td><td>&lt;a href=&quot;http://www.sigmaaldrich.com/&quot;&gt;www.sigmaaldrich.com&lt;/a&gt;</td><td>E7764-50UG</td></tr><tr><td>HA-1077</td><td>Sigma-Aldrich</td><td>&lt;a href=&quot;http://www.sigmaaldrich.com/&quot;&gt;www.sigmaaldrich.com&lt;/a&gt;</td><td>H139-10MG</td></tr></tbody></table>

microfluidic genipin deposition technique for extended culture of micropatterned vascular muscular thin films

The chronic nature of vascular disease progression requires the development of experimental techniques that simulate physiologic and pathologic vascular behaviors on disease-relevant time scales. Previously, microcontact printing has been used to fabricate two-dimensional functional arterial mimics through patterning of extracellular matrix protein as guidance cues for tissue organization. Vascular muscular thin films utilized these mimics to assess functional contractility. However, the microcontact printing fabrication technique used typically incorporates hydrophobic PDMS substrates. As the tissue turns over the underlying extracellular matrix, new proteins must undergo a conformational change or denaturing in order to expose hydrophobic amino acid residues to the hydrophobic PDMS surfaces for attachment, resulting in altered matrix protein bioactivity, delamination, and death of the tissues.
Here, we present a microfluidic deposition technique for patterning of the crosslinker compound genipin. Genipin serves as an intermediary between patterned tissues and PDMS substrates, allowing cells to deposit newly-synthesized extracellular matrix protein onto a more hydrophilic surface and remain attached to the PDMS substrates. We also show that extracellular matrix proteins can be patterned directly onto deposited genipin, allowing dictation of engineered tissue structure. Tissues fabricated with this technique show high fidelity in both structural alignment and contractile function of vascular smooth muscle tissue in a vascular muscular thin film model. This technique can be extended using other cell types and provides the framework for future study of chronic tissue- and organ-level functionality.

이 작품의 주요 목표는 소수성 PDMS 기판에 미세 패턴 혈관 평활근 세포의 생존을 연장했다. 이 패턴 genipin 및 PDMS에 피브로넥틴 (그림 1) 입금 미세 유체 전달 시스템을 통합하여 수행되었다. 미세 유체 전달을 사용하여 ECM 단백질의 침착 genipin 및 피브로넥틴 (그림 1D)의 선 사이의 벌거 벗은 PDMS와 채널 패턴의 높은 충실도 전송을 얻었다. 이전의 마이크로 콘택트 인쇄 법 5,10,16 유사한 동맥의 라멜라 구조를 생체 모방 부착 세포 (도 1E) 형태 합류 단층 (도 2). 이러한 조직은 그의 응력 vMTF 기술을 사용하여 측정 하였다 (도 3)에 응답하여, 수축성 구조체를 수득 하였다. 이주의 과정을 통해 조직의 생존 능력의 질적 평가는 genipin - 후 변형에 최소한의 악화를 보였다에드 기판 (그림 2A). 조직 합류 및 정렬 2 주 (그림 2B, 2C 및 2D) 이상 유지되었다. 두 가지 주요 스트레스 값은 모든 vMTF 계산 하였다 :. 1) 기초 톤, 2) 유도 수축 (그림 3C 및 3D)이 기저 톤 평형 비자극 혈관 평활근 세포에 의해 유지되는 스트레스입니다. 수축력이 유도 된 엔도 텔린 1 자극에 의​​해 유도 된 부가적인 응력이다. 기저 톤 유도 수축성 모두 (도 3E 및 3F)에 걸쳐 혈관 활성 조직을 보여주는 2 주 시간 걸쳐 일관된 동작을 나타내었다. 혈청 결핍 혈관 평활근 세포 증식을 19 않기 때문에 분석의 끝에 수축성 조직에 약간의 감소는, 조직을 구성하는 세포의 감소 된 수의 직접적인 결과이다. 배지에 혈청의 최소 기저 수준의 첨가는 향후 연구에서이 결과를 완화 할 수있다. <imgALT = &quot;그림 2&quot;SRC = &quot;/ 파일 / ftp_upload / 52971 / 52971fig2.jpg&quot;/&gt; 그림 2. 조직이 성공적으로 Genipin 수정 기판에 2 주 동안 모방 생체 동맥 강철 구조 유력한 남아 이주의 과정을 통해 희생 시점에서 조직의 (A) 대표 위상차 이미지 (스케일 바 : 200 μm의).. F-액틴 필라멘트, 파란색 : 핵 (세포의 존재를 확립하는 것으로), 스케일 바 혈청 기아 (녹색 후 (B) 1 일 고정 genipin 수정 기판에 제작 된 조직의 대표 면역 이미지, 4 일 및 10 일째 .. - 7) (D) 조직 정렬 F - 굴지 방향 순서 매개 변수 (OOP에 의해 측정) (22) (오차 막대 표준 오차, N = 3 : F - 굴지 범위 (오차 막대에 의해 측정 된 100 ㎛) (C) 비율 합류 : 표준 오차, N = 3-7). © 안압 PublishiNG. 재현 및 / 또는 허가를 수정했습니다. 판권 소유. 모든 권리 보유. (19)는 <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/52971/52971fig2large.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> <img alt="그림 3" src="/files/ftp_upload/52971/52971fig3.jpg" /> 그림 3. 조직 수축성은 2 주에 걸쳐 유지된다. (A) 대표 vMTF 절단 방식. (B) 컷 vMTF의 개략도. 32 ° C 이하로 냉각되면, PIPAAm 용해는 vMTF 해제. 현재 셀 층에서 스트레스는 구부리 수동 PDMS 층됩니다. 돌출 길이의 측정이 Grosberg의 방법에 따른 곡률 반경으로 변환 할 수 등. (8)의 곡률 반경은 조직의 평균 단면 응력을 계산하는 데 사용된다. (C) 순차 송신 LIG대표 수축력 분석의 HT 이미지 (스케일 바 : 1mm). 조직은 평형에 도달 완전한 휴식을 할 수 있도록 엔도 텔린-1, 다음 HA-1077 치료로 자극한다. 아래 :. 수축력 분석을위한 분석의 과정에서 이상적인 조직의 사이드 뷰의 도식 (D) 대표 스트레스 곡선. 두 가지 주요 스트레스 값이 계산됩니다. 기저 톤 평형 응력 상태와 이완 응력 상태 사이의 차이이다. 유도 수축은 엔도 텔린 -1 자극 상태로 평형 상태에서 응력의 변화이다 (E) 기저 톤 (오차 막대 : 표준 오차, N = 5-12) (F) 유도 수축 (오차 막대 :.. 표준 오차, N = 5-12). © 안압 출판. 재현 및 / 또는 허가를 수정했습니다. 모든 권리 보유. (19) <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/52971/52971fig3large.jpg" target="_blank">의 더 큰 버전을 보려면 여기를 클릭하십시오</a>이 그림.

Watch this Scientific Journal Video about Microfluidic Genipin Deposition Technique for Extended Culture of Micropatterned Vascular Muscular Thin Films at JoVE.com

Microfluidic Genipin Deposition Technique for Extended Culture of Micropatterned Vascular Muscular Thin Films

We present a method for microfluidic deposition of patterned genipin and fibronectin on PDMS substrates, allowing extended viability of vascular smooth muscle cell-dense tissues. This tissue fabrication method is combined with previous vascular muscular thin film technology to measure vascular contractility over disease-relevant time courses.

미세 패턴 혈관 근육 박막의 확장 문화 미세 유체 Genipin 증착 기술

The chronic nature of vascular disease progression requires the development of experimental techniques that simulate physiologic and pathologic vascular ...

microfluidic-genipin-deposition-technique-for-extended-culture

Universidad San Sebastian

Research

JoVE Journal

Bioengineering

7.6K 조회수.  University of Minnesota. We present a method for microfluidic deposition of patterned genipin and fibronectin on PDMS substrates, allowing extended viability of vascular smooth muscle cell-dense tissues. This tissue fabrication method is combined with previous vascular muscular thin film technology to measure vascular contractility over disease-relevant time courses.

비디오: Microfluidic Genipin Deposition Technique for Extended Culture of Micropatterned Vascular Muscular Thin Films

Microfabricated Platforms for Mechanically Dynamic Cell Culture

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or fundamental cell biology studies is limited by current bioreactor technologies, which cannot simultaneously apply a variety of mechanical stimuli to cultured cells. In order to address this issue, we have developed a series of microfabricated platforms designed to screen for the effects of mechanical stimuli in a high-throughput format. In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and further demonstrate how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

기계 다이나믹 셀 문화 Microfabricated 플랫폼

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or ...

연구

생체공학

Fabrication of Micropatterned Hydrogels for Neural Culture Systems using Dynamic Mask Projection Photolithography

Increasingly, patterned cell culture environments are becoming a relevant technique to study cellular characteristics, and many researchers believe in the need for 3D environments to represent in vitro experiments which better mimic in vivo qualities 1-3. Studies in fields such as cancer research 4, neural engineering 5, cardiac physiology 6, and cell-matrix interaction7,8have shown cell behavior differs substantially between traditional monolayer cultures and 3D constructs.
Hydrogels are used as 3D environments because of their variety, versatility and ability to tailor molecular composition through functionalization 9-12. Numerous techniques exist for creation of constructs as cell-supportive matrices, including electrospinning13, elastomer stamps14, inkjet printing15, additive photopatterning16, static photomask projection-lithography17, and dynamic mask microstereolithography18. Unfortunately, these methods involve multiple production steps and/or equipment not readily adaptable to conventional cell and tissue culture methods. The technique employed in this protocol adapts the latter two methods, using a digital micromirror device (DMD) to create dynamic photomasks for crosslinking geometrically specific poly-(ethylene glycol) (PEG) hydrogels, induced through UV initiated free radical polymerization. The resulting "2.5D" structures provide a constrained 3D environment for neural growth. We employ a dual-hydrogel approach, where PEG serves as a cell-restrictive region supplying structure to an otherwise shapeless but cell-permissive self-assembling gel made from either Puramatrix or agarose. The process is a quick simple one step fabrication which is highly reproducible and easily adapted for use with conventional cell culture methods and substrates.
Whole tissue explants, such as embryonic dorsal root ganglia (DRG), can be incorporated into the dual hydrogel constructs for experimental assays such as neurite outgrowth. Additionally, dissociated cells can be encapsulated in the photocrosslinkable or self polymerizing hydrogel, or selectively adhered to the permeable support membrane using cell-restrictive photopatterning. Using the DMD, we created hydrogel constructs up to ~1mm thick, but thin film (&lt;200 &mu;m) PEG structures were limited by oxygen quenching of the free radical polymerization reaction. We subsequently developed a technique utilizing a layer of oil above the polymerization liquid which allowed thin PEG structure polymerization.
In this protocol, we describe the expeditious creation of 3D hydrogel systems for production of microfabricated neural cell and tissue cultures. The dual hydrogel constructs demonstrated herein represent versatile in vitro models that may prove useful for studies in neuroscience involving cell survival, migration, and/or neurite growth and guidance. Moreover, as the protocol can work for many types of hydrogels and cells, the potential applications are both varied and vast.

Simple techniques are described for the rapid production of microfabricated neural culture systems using a digital micromirror device for dynamic mask projection lithography on regular cell culture substrates. These culture systems may be more representative of natural biological architecture, and the techniques described could be adapted for numerous applications.

동적 마스크 프로젝션 석판술를 사용하여 신경 문화 시스템의 Micropatterned Hydrogels의 제작

Increasingly, patterned cell culture environments are becoming a relevant technique to study cellular characteristics, and many researchers believe in the ...

Endothelialized Microfluidics for Studying Microvascular Interactions in Hematologic Diseases

Advances in microfabrication techniques have enabled the production of inexpensive and reproducible microfluidic systems for conducting biological and biochemical experiments at the micro- and nanoscales 1,2. In addition, microfluidics have also been specifically used to quantitatively analyze hematologic and microvascular processes, because of their ability to easily control the dynamic fluidic environment and biological conditions3-6. As such, researchers have more recently used microfluidic systems to study blood cell deformability, blood cell aggregation, microvascular blood flow, and blood cell-endothelial cell interactions6-13.However, these microfluidic systems either did not include cultured endothelial cells or were larger than the sizescale relevant to microvascular pathologic processes. A microfluidic platform with cultured endothelial cells that accurately recapitulates the cellular, physical, and hemodynamic environment of the microcirculation is needed to further our understanding of the underlying biophysical pathophysiology of hematologic diseases that involve the microvasculature.
Here, we report a method to create an "endothelialized" in vitro model of the microvasculature, using a simple, single mask microfabrication process in conjunction with standard endothelial cell culture techniques, to study pathologic biophysical microvascular interactions that occur in hematologic disease. This "microvasculature-on-a-chip" provides the researcher with a robust assay that tightly controls biological as well as biophysical conditions and is operated using a standard syringe pump and brightfield/fluorescence microscopy. Parameters such as microcirculatory hemodynamic conditions, endothelial cell type, blood cell type(s) and concentration(s), drug/inhibitory concentration etc., can all be easily controlled. As such, our microsystem provides a method to quantitatively investigate disease processes in which microvascular flow is impaired due to alterations in cell adhesion, aggregation, and deformability, a capability unavailable with existing assays.

A method to culture an endothelial cell monolayer throughout the entire inner 3D surface of a microfluidic device with microvascular-sized channels (&lt;30 &mu;m) is described. This in vitro microvasculature model enables the study of biophysical interactions between blood cells, endothelial cells, and soluble factors in hematologic diseases.

Hematologic 질환의 Microvascular 상호 작용 유학을위한 Endothelialized Microfluidics

Advances in  microfabrication techniques have enabled the production of inexpensive and  reproducible microfluidic systems for conducting biological and ...

Procedure for the Development of Multi-depth Circular Cross-sectional Endothelialized Microchannels-on-a-chip

Efforts have been focused on developing in vitro assays for the study of microvessels because in vivo animal studies are more time-consuming, expensive, and observation and quantification are very challenging. However, conventional in vitro microvessel assays have limitations when representing in vivo microvessels with respect to three-dimensional (3D) geometry and providing continuous fluid flow. Using a combination of photolithographic reflowable photoresist technique, soft lithography, and microfluidics, we have developed a multi-depth circular cross-sectional endothelialized microchannels-on-a-chip, which mimics the 3D geometry of in vivo microvessels and runs under controlled continuous perfusion flow. A positive reflowable photoresist was used to fabricate a master mold with a semicircular cross-sectional microchannel network. By the alignment and bonding of the two polydimethylsiloxane (PDMS) microchannels replicated from the master mold, a cylindrical microchannel network was created. The diameters of the microchannels can be well controlled. In addition, primary human umbilical vein endothelial cells (HUVECs) seeded inside the chip showed that the cells lined the inner surface of the microchannels under controlled perfusion lasting for a time period between 4 days to 2 weeks.

A microchannels-on-a-chip platform was developed by the combination of photolithographic reflowable photoresist technique, soft lithography, and microfluidics. The endothelialized microchannels platform mimics the three-dimensional (3D) geometry of in vivo microvessels, runs under controlled continuous perfusion flow, allows for high-quality and real-time imaging&#160;and can be applied for microvascular research.

멀티 깊이 원형 단면 Endothelialized 마이크로 채널 - 온 - 칩의 개발을위한 절차

Efforts have been focused on developing in vitro assays for the study of microvessels because in vivo animal studies are more time-consuming, expensive, ...

Layer-by-layer Collagen Deposition in Microfluidic Devices for Microtissue Stabilization

Although microfluidics provides exquisite control of the cellular microenvironment, culturing cells within microfluidic devices can be challenging. 3D culture of cells in collagen type I gels helps to stabilize cell morphology and function, which is necessary for creating microfluidic tissue models in microdevices. Translating traditional 3D culture techniques for tissue culture plates to microfluidic devices is often difficult because of the limited channel dimensions. In this method, we describe a technique for modifying native type I collagen to generate polycationic and polyanionic collagen solutions that can be used with layer-by-layer deposition to create ultrathin collagen assemblies on top of cells cultured in microfluidic devices. These thin collagen layers stabilize cell morphology and function, as shown using primary hepatocytes as an example cell, allowing for the long term culture of microtissues in microfluidic devices.

The creation of functional microtissues within microfluidic devices requires the stabilization of cell phenotypes by adapting traditional cell culture techniques to the limited spatial dimensions in microdevices. Modification of collagen allows the layer-by-layer deposition of ultrathin collagen assemblies that can stabilize primary cells, such as hepatocytes, as microfluidic tissue models.

Microtissue 안정화를위한 미세 유체 장치에서 레이어별로 층 콜라겐 증착

Although microfluidics provides exquisite control of the cellular microenvironment, culturing cells within microfluidic devices can be challenging. 3D ...

Micropatterning and Assembly of 3D Microvessels

In vitro platforms to study endothelial cells and vascular biology are largely limited to 2D endothelial cell culture, flow chambers with polymer or glass based substrates, and hydrogel-based tube formation assays. These assays, while informative, do not recapitulate lumen geometry, proper extracellular matrix, and multi-cellular proximity, which play key roles in modulating vascular function. This manuscript describes an injection molding method to generate engineered vessels with diameters on the order of 100 &#181;m. Microvessels are fabricated by seeding endothelial cells in a microfluidic channel embedded within a native type I collagen hydrogel. By incorporating parenchymal cells within the collagen matrix prior to channel formation, specific tissue microenvironments can be modeled and studied. Additional modulations of hydrodynamic properties and media composition allow for control of complex vascular function within the desired microenvironment. This platform allows for the study of perivascular cell recruitment, blood-endothelium interactions, flow response, and tissue-microvascular interactions. Engineered microvessels offer the ability to isolate the influence from individual components of a vascular niche and precisely control its chemical, mechanical, and biological properties to study vascular biology in both health and disease.

This manuscript presents an injection molding method to engineer microvessels that recapitulate physiological properties of endothelium. The microfluidic-based process creates patent 3D vascular networks with tailorable conditions, such as flow, cellular composition, geometry, and biochemical gradients. The fabrication process and examples of potential applications are described.

미세화 및 3D 미세 혈관의 조립

In vitro platforms to study endothelial cells and vascular biology are largely limited to 2D endothelial cell culture, flow chambers with polymer or glass ...

Image-guided, Laser-based Fabrication of Vascular-derived Microfluidic Networks

This detailed protocol outlines the implementation of image-guided, laser-based hydrogel degradation for the fabrication of vascular-derived microfluidic networks embedded in PEGDA hydrogels. Here, we describe the creation of virtual masks that allow for image-guided laser control; the photopolymerization of a micromolded PEGDA hydrogel, suitable for microfluidic network fabrication and pressure head-driven flow; the setup and use of a commercially available laser scanning confocal microscope paired with a femtosecond pulsed Ti:S laser to induce hydrogel degradation; and the imaging of fabricated microfluidic networks using fluorescent species and confocal microscopy. Much of the protocol is focused on the proper setup and implementation of the microscope software and microscope macro, as these are crucial steps in using a commercial microscope for microfluidic fabrication purposes that contain a number of intricacies. The image-guided component of this technique allows for the implementation of 3D image stacks or user-generated 3D models, thereby allowing for creative microfluidic design and for the fabrication of complex microfluidic systems of virtually any configuration. With an expected impact in tissue engineering, the methods outlined in this protocol could aid in the fabrication of advanced biomimetic microtissue constructs for organ- and human-on-a-chip devices. By mimicking the complex architecture, tortuosity, size, and density of in vivo vasculature, essential biological transport processes can be replicated in these constructs, leading to more accurate in vitro modeling of drug pharmacokinetics and disease.

This protocol outlines the implementation of image-guided, laser-based hydrogel degradation to fabricate vascular-derived, biomimetic microfluidic networks embedded in poly(ethylene glycol) diacrylate (PEGDA) hydrogels. These biomimetic microfluidic systems may be useful for tissue engineering applications, generation of in vitro disease models, and fabrication of advanced "on-a-chip" devices.

혈관 유래 미세 유체 네트워크의 이미지 유도, 레이저 기반의 제조

This detailed protocol outlines the implementation of image-guided, laser-based hydrogel degradation for the fabrication of vascular-derived microfluidic ...

Microfluidic Bioprinting for Engineering Vascularized Tissues and Organoids

Engineering vascularized tissue constructs and organoids has been historically challenging. Here we describe a novel method based on microfluidic bioprinting to generate a scaffold with multilayer interlacing hydrogel microfibers. To achieve smooth bioprinting, a core-sheath microfluidic printhead containing a composite bioink formulation extruded from the core flow and the crosslinking solution carried by the sheath flow, was designed and fitted onto the bioprinter. By blending gelatin methacryloyl (GelMA) with alginate, a polysaccharide that undergoes instantaneous ionic crosslinking in the presence of select divalent ions, followed by a secondary photocrosslinking of the GelMA component to achieve permanent stabilization, a microfibrous scaffold could be obtained using this bioprinting strategy. Importantly, the endothelial cells encapsulated inside the bioprinted microfibers can form the lumen-like structures resembling the vasculature over the course of culture for 16 days. The endothelialized microfibrous scaffold may be further used as a vascular bed to construct a vascularized tissue through subsequent seeding of the secondary cell type into the interstitial space of the microfibers. Microfluidic bioprinting provides a generalized strategy in convenient engineering of vascularized tissues at high fidelity.

We provide a generalized protocol based on a microfluidic bioprinting strategy for engineering a microfibrous vascular bed, where a secondary cell type could be further seeded into the interstitial space of this microfibrous structure to generate vascularized tissues and organoids.

공학에 대 한 미세 Bioprinting 나가도록 조직 및 Organoids

Engineering vascularized tissue constructs and organoids has been historically challenging. Here we describe a novel method based on microfluidic ...

Perfusable Vascular Network with a Tissue Model in a Microfluidic Device

A spheroid (a multicellular aggregate) is regarded as a good model of living tissues in the human body. Despite the significant advancement in the spheroid cultures, a perfusable vascular network in the spheroids remains a critical challenge for long-term culture required to maintain and develop their functions, such as protein expressions and morphogenesis. The protocol presents a novel method to integrate a perfusable vascular network within the spheroid in a microfluidic device. To induce a perfusable vascular network in the spheroid, angiogenic sprouts connected to microchannels were guided to the spheroid by utilizing angiogenic factors from human lung fibroblasts cultured in the spheroid. The angiogenic sprouts reached the spheroid, merged with the endothelial cells co-cultured in the spheroid, and formed a continuous vascular network. The vascular network could perfuse the interior of the spheroid without any leakage. The constructed vascular network may be further used as a route for supply of nutrients and removal of waste products, mimicking blood circulation in vivo. The method provides a new platform in spheroid culture toward better recapitulation of living tissues.

The protocol describes how to engineer a perfusable vascular network in a spheroid. The spheroid's surrounding microenvironment is devised to induce angiogenesis and connect the spheroid to the microchannels in a microfluidic device. The method allows the perfusion of the spheroid, which is a long-awaited technique in three-dimensional cultures.

미세 소자에서 조직 모델 perfusable 혈관 네트워크

A spheroid (a multicellular aggregate) is regarded as a good model of living tissues in the human body. Despite the significant advancement in the ...

Microfluidic Model to Mimic Initial Event of Neovascularization

Neovascularization is usually initialized from an existing normal vasculature and the biomechanical microenvironment of endothelial cells (ECs) in the initial stage varies dramatically from the following process of neovascularization. Although there are plenty of models to simulate different stages of neovascularization, an in vitro 3D model that capitulates the initial process of neovascularization under the corresponding stimulations of normal vasculature microenvironments is still lacking. Here, we reconstructed an in vitro 3D model that mimics the initial event of neovascularization (MIEN). The MIEN model contains a microfluidic sprouting chip and an automatic control, highly efficient circulation system. A functional, perfusable microchannel coated with endothelium was formed and the process of sprouting was simulated in the microfluidic sprouting chip. The initially physiological microenvironment of neovascularization was recapitulated with the microfluidic control system, by which ECs would be exposed to high luminal shear stress, physiological transendothelial flow, and various vascular endothelial growth factor (VEGF) distributions simultaneously. The MIEN model can be readily applied to the study of neovascularization mechanism and holds a potential promise as a low-cost platform for drug screening and toxicology applications.

Here, we provide a microfluidic chip and an automatically controlled, highly efficient circulation microfluidic system that recapitulates the initial microenvironment of neovascularization, allowing endothelial cells (ECs) to be stimulated by high luminal shear stress, physiological level of transendothelial flow, and various vascular endothelial growth factor (VEGF) distribution simultaneously.

뇌혈관화의 초기 이벤트를 모방하는 미세 유체 모델

Neovascularization is usually initialized from an existing normal vasculature and the biomechanical microenvironment of endothelial cells (ECs) in the ...