微京尼平沉积技术的微模式化血管肌肉薄膜的扩展文化
Summary
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.
Abstract
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.
Introduction
血管疾病，如脑血管痉挛1,2，高血压3，和动脉粥样硬化4，发展缓慢，在性质上通常是慢性的，并且通过血管平滑肌细胞（VSMCs）涉及功能失调力代。我们的目标是研究用体外方法与实验条件下比在体内模型更精确的控制，这些缓慢进展的血管功能障碍。我们以前曾开发血管肌薄膜（vMTFs），用于测量的体外功能收缩工程心血管组织5，但这种方法已被限制于相对短期研究。在这里，我们提出了扩大我们以前vMTF技术长期测量底物改性技术。
而内皮也是很关键的整体血管功能，设计动脉薄片提供了一个有用的模型系统，用于评估变化血管在疾病进展期间的收缩。工程师的官能血管疾病组织模型，二者的结构和动脉瓣的功能，该船只的基本收缩单元，必须概括以高的保真度。动脉薄片是同心，周向排列的弹性由6张分离收缩血管平滑肌细胞的表。细胞外基质（ECM）蛋白的微接触印刷到聚二甲基硅氧烷（PDMS）衬底先前已用于提供指导线索为组织机构，以模仿对齐心血管组织5,7-10。然而，组织使用微接触印刷在培养3-4天会失去诚信，限制了其应用在慢性研究构图。这个协议提供了通过用一个新的微流体沉积技术代替以往的微接触印刷技术的解决这个问题。
现地等改性PDMS基板与京尼平以及found延长细胞的存活长达一个月中培养11。在这里，我们使用类似的方法来延长图案的血管平滑肌细胞的培养上PDMS。京尼平，栀子果实的自然水解衍生物，是一种理想的候选衬底修改由于其相对低的毒性相比类似的交联剂和其越来越多地使用作为在组织修复12,13和ECM变形例14中的字段的生物材料， 15。在这个协议中，纤连蛋白被用作细胞指导线索，如在前面的微接触印刷法;然而，京尼平沉积到之前纤连图案的PDMS衬底。因此，当细胞降解的图案矩阵，从附着的VSMC新合成的细胞外基质可以结合到京尼平涂覆PDMS衬底。
这个协议利用两步京尼平和ECM沉积的微流体输送装置。微流体装置模拟microco的设计ntact印刷图案在以前的研究中16用于改造动脉片状结晶。因此，我们预计该协议产生动脉薄片模仿，成功地概括了高度一致的体内结构和动脉薄片的收缩功能。我们还评估组织收缩，以确认京尼平是用于长期体外血管疾病模型合适的基材变形化合物。
Protocol
Representative Results
Discussion
在这里，我们提出了一个协议，建立在先前开发vMTF技术，允许延长试验时间比较典型的慢性血管疾病的途径1,23,24。要做到这一点，我们微图案京尼平，这已被证明可以提供的PDMS基板11的长期功能化，使用微流体沉积技术以产生工程改造动脉薄片具有改善血管组织的生存力为在MTF收缩实验。麦凯恩等人 。开发工程心脏组织的扩展文化替代的微成形的明胶凝胶基质几个星期在…
Divulgations
The authors have nothing to disclose.
Acknowledgements
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.
Materials
| Coverslip staining rack | Electron Microscopy Sciences | www.emsdiasum.com/ | 72239-04 | Alternative coverslip rack may be used |
| Microscope cover glass – 25 mm | Fisher Scientific, Inc. | www.fishersci.com | 12-545-102 | Alternative brand and size may be used; Microscope slides may also be substituted as substrate base |
| Poly(N-iso-propylacrylamide) (PIPAAm) | Polysciences, Inc. | www.polysciences.com/ | #21458 | Sigma-Aldrich makes an alternate compound, but we have not tested it for use with this protocol; Compound gives strong odor, use proper ventilation |
| 1-butanol | Sigma-Aldrich | www.sigmaaldrich.com | 360465 | Hazard: flammable (store stock solution in flammable cabinet); flash point is 37 °C, avoid heating; alternative product may be used |
| Spincoater | Specialty Coating Systems, Inc. | www.scscoatings.com | SCS G3P8 Model; Alternative brand and/or model may be used | |
| Polydimethylsiloxane (PDMS) | Ellsworth Adhesives (Dow Corning) | www.ellsworth.com | 184 SIL ELAST KIT 0.5KG | Alternative distributor may be used |
| Fluorescent microbeads | Polysciences, Inc. | www.polysciences.com/ | 17151 | Alternative brand and/or larger size may be used |
| Silicon wafers | Wafer World, Inc. | www.waferworld.com | 2398 | Alternative brand and/or size may be used |
| Photoresist | MicroChem Corp. | www.microchem.com | SU-8 3025 allows 20-25-µm feature height | |
| Contact mask aligner | Suss MicroTec | www.suss.com | MA6 contact mask aligner; alternative brand and/or model may be used for wafer exposure | |
| Developer | MicroChem Corp. | www.microchem.com | SU-8 Developer; Hazard: flammable | |
| Tridecafluro-trichlorosilane | UCT Specialties, Inc. | www.unitedchem.com | T2492 | Silane for non-stick coating of patterned silicon wafers (CAUTION: Tridecafluro-trichlorosilane is a flammable and corrosive liquid. Proper personal protective equipment and local exhaust is necessary for use. ) |
| Surgical biopsy punch | Integra LifeSciences Corp. | www.miltex.com | 33-31AA-P/25 | Alternative brand and/or size may be used |
| Genipin | Cayman Chemical | www.caymanchem.com | 10010622 | Sigma-Aldrich (G4796-25MG) makes an alternate compound, but we have not tested it for use with this protocol |
| 1X phosphate buffered saline | Mediatech, Inc. | www.cellgro.com | 21-031-CV | Alternative brand may be used |
| Fibronectin | Corning, Inc. | www.corning.com | 356008 | Sigma-Aldrich (F1056) makes an alternate compound, but we have not tested it for use with this protocol |
| Penicillin/streptomycin | Life Technologies, Inc. | www.lifetechnologies.com | 15140-122 | Alternative brand and/or size may be used, as long as concentration is the same |
| Umbillical artery smooth muscle cells | Lonza | www.lonza.com | CC-2579 | Alternative cell types may be used for alternative applications. Media should be modified accordingly |
| Tyrode's solution components | Sigma-Aldrich | www.sigmaaldrich.com | various | Alternative brand may be used for mixing solution |
| Stereomicroscope | Zeiss | www.zeiss.com | 4350020000000000 | SteREOLumar V12; Alternative brand/type of stereomicroscope may be used |
| Temperature-controlled platform | Warner Instruments | www.warneronline.com | 641659; 640352; 641922 | |
| Endothelin-1 | Sigma-Aldrich | www.sigmaaldrich.com | E7764-50UG | Alternative amount may be purchased, as long as treatment concentration is maintained |
| HA-1077 | Sigma-Aldrich | www.sigmaaldrich.com | H139-10MG | Alternative amount may be purchased, as long as treatment concentration is maintained |
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