Name: stepwise cell seeding on tessellated scaffolds to study sprouting blood vessels
Uploaded: 2021-01-14T15:00:00
Description: Watch this Scientific Journal Video about Stepwise Cell Seeding on Tessellated Scaffolds to Study Sprouting Blood Vessels at JoVE.com

This research was supported by funding from the University of Michigan - Israel Partnership for Research. The authors would like to thank Uri Merdler, Lior Debbi&#160;and Galia Ben David for their great assistance and support, Nadine Wang, Ph.D. and Pilar Herrera-Fierro, Ph.D. of the Lurie Nanofabrication Facility at the University of Michigan, as well as Luis Solorio, Ph.D. for enlightening discussions of photolithography techniques.

1. Tessellated scaffold fabrication
NOTE: Photolithography is a widespread technique that requires specialized equipment typically housed within a nanofabrication facility/laboratory. The method laid out in this protocol was generalized as much as possible for the audience; however, slight changes to procedures may be necessary depending on equipment available to the reader. We recommend performing these procedures in a clean room at a nanofabrication facility&#160;to ensure the highest process ...

<ol>
	<li>Novosel, E. C., Kleinhans, C., Kluger, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vascularization+is+the+key+challenge+in+tissue+engineering.">Vascularization is the key challenge in tissue engineering.</a> Advanced Drug Delivery Reviews. 63 (4), 300-311 (2011).</li><li>Landau, S., Guo, S., Levenberg, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Localization+of+Engineered+Vasculature+within+3D+Tissue+Constructs.">Localization of Engineered Vasculature within 3D Tissue Constructs.</a> Frontiers in Bioengineering and Biotechnology. 6, 2 (2018).</li><li>Griffith, C. K., 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=Diffusion+Limits+of+an+in+Vitro+Thick+Prevascularized+Tissue.">Diffusion Limits of an in Vitro Thick Prevascularized Tissue.</a> Tissue Engineering. 11 (12), (2005).</li><li>Potente, M., Gerhardt, H., Carmeliet, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Basic+and+therapeutic+aspects+of+angiogenesis.">Basic and therapeutic aspects of angiogenesis.</a> Cell. 146 (6), 873-887 (2011).</li><li>Landau, S., 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=Tropoelastin+coated+PLLA-PLGA+scaffolds+promote+vascular+network+formation.">Tropoelastin coated PLLA-PLGA scaffolds promote vascular network formation.</a> Biomaterials. 122, 72-82 (2017).</li><li>Lesman, 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=Engineering+vessel-like+networks+within+multicellular+fibrin-based+constructs.">Engineering vessel-like networks within multicellular fibrin-based constructs.</a> Biomaterials. 32 (31), 7856-7869 (2011).</li><li>Richards, D., Jia, J., Yost, M., Markwald, R., Mei, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3D+Bioprinting+for+Vascularized+Tissue+Fabrication.">3D Bioprinting for Vascularized Tissue Fabrication.</a> Annals of Biomedical Engineering. 45 (1), 132-147 (2017).</li><li>Levenberg, S., 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=Engineering+vascularized+skeletal+muscle+tissue.">Engineering vascularized skeletal muscle tissue.</a> Nature Biotechnology. 23 (7), 879-884 (2005).</li><li>Rouwkema, J., Khademhosseini, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vascularization+and+Angiogenesis+in+Tissue+Engineering:+Beyond+Creating+Static+Networks.">Vascularization and Angiogenesis in Tissue Engineering: Beyond Creating Static Networks.</a> Trends in Biotechnology. 34 (9), 733-745 (2016).</li><li>Miller, J. S., 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=Rapid+casting+of+patterned+vascular+networks+for+perfusable+engineered+three-dimensional+tissues.">Rapid casting of patterned vascular networks for perfusable engineered three-dimensional tissues.</a> Nature Materials. 11, (2012).</li><li>Gariboldi, M. I., Butler, R., Best, S. M., Cameron, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engineering+vasculature+Architectural+effects+on+microcapillary-like+structure+self-assembly.">Engineering vasculature Architectural effects on microcapillary-like structure self-assembly.</a> PLOS ONE. 14 (1), 1-13 (2019).</li><li>Blache, U., Guerrero, J., G&#252;ven, S., Klar, A. S., Scherberich, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microvascular+Networks+and+Models,+In+vitro+Formation.">Microvascular Networks and Models, In vitro Formation.</a> Vascularization for Tissue Engineering and Regenerative Medicine. , 1-40 (2018).</li><li>Wong, K. H. K., Chan, J. M., Kamm, R. D., Tien, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+Models+of+Vascular+Functions.">Microfluidic Models of Vascular Functions.</a> Annual Review of Biomedical Engineering. 14 (1), 205-230 (2012).</li><li>Jansen, K. A., Bacabac, R. G., Piechocka, I. K., Koenderink, G. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cells+actively+stiffen+fibrin+networks+by+generating+contractile+stress.">Cells actively stiffen fibrin networks by generating contractile stress.</a> Biophysical Journal. 105 (10), 2240-2251 (2013).</li><li>Pollet, A. M. A. O., den Toonder, J. M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recapitulating+the+vasculature+using+Organ-on-Chip+technology.">Recapitulating the vasculature using Organ-on-Chip technology.</a> Bioengineering. 7 (1), (2020).</li><li>Hasan, 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=Microfluidic+techniques+for+development+of+3D+vascularized+tissue.">Microfluidic techniques for development of 3D vascularized tissue.</a> Biomaterials. 35 (26), 7308-7325 (2014).</li><li>Jordahl, J. H., 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=3D+Jet+Writing:+Functional+Microtissues+Based+on+Tessellated+Scaffold+Architectures.">3D Jet Writing: Functional Microtissues Based on Tessellated Scaffold Architectures.</a> Advanced Materials. 30 (14), 1707196 (2018).</li><li>Gauvin, 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=Microfabrication+of+complex+porous+tissue+engineering+scaffolds+using+3D+projection+stereolithography.">Microfabrication of complex porous tissue engineering scaffolds using 3D projection stereolithography.</a> Biomaterials. 33 (15), 3824-3834 (2012).</li><li>Coscoy, S., 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=Microtopographies+control+the+development+of+basal+protrusions+in+epithelial+sheets.">Microtopographies control the development of basal protrusions in epithelial sheets.</a> Biointerphases. 13 (4), 041003 (2018).</li><li>Kaplan, B., 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=Rapid+prototyping+fabrication+of+soft+and+oriented+polyester+scaffolds+for+axonal+guidance.">Rapid prototyping fabrication of soft and oriented polyester scaffolds for axonal guidance.</a> Biomaterials. , (2020).</li><li>Steier, A., Mu&#241;iz, A., Neale, D., Lahann, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Emerging+Trends+in+Information-Driven+Engineering+of+Complex+Biological+Systems.">Emerging Trends in Information-Driven Engineering of Complex Biological Systems.</a> Advanced Materials. 31 (26), 11806898 (2019).</li><li>Szklanny, A. 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=High-Throughput+Scaffold+System+for+Studying+the+Effect+of+Local+Geometry+and+Topology+on+the+Development+and+Orientation+of+Sprouting+Blood+Vessels.">High-Throughput Scaffold System for Studying the Effect of Local Geometry and Topology on the Development and Orientation of Sprouting Blood Vessels.</a> Advanced Functional Materials. , 1901335 (2019).</li><li>Welti, J., Loges, S., Dimmeler, S., Carmeliet, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+molecular+discoveries+in+angiogenesis+and+antiangiogenic+therapies+in+cancer.">Recent molecular discoveries in angiogenesis and antiangiogenic therapies in cancer.</a> Journal of Clinical Investigation. 123 (8), 3190-3200 (2013).</li><li>Gui, L., Niklason, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vascular+Tissue+Engineering:+Building+Perfusable+Vasculature+for+Implantation.">Vascular Tissue Engineering: Building Perfusable Vasculature for Implantation.</a> Current Opinion in Chemical Engineering. 3, 68-74 (2014).</li><li>Blache, U., Ehrbar, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inspired+by+nature:+Hydrogels+as+versatile+tools+for+vascular+engineering.">Inspired by nature: Hydrogels as versatile tools for vascular engineering.</a> Advances in Wound Care. 7 (7), 232-246 (2018).</li><li>Cochrane, 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=Advanced+in+vitro+models+of+vascular+biology:+Human+induced+pluripotent+stem+cells+and+organ-on-chip+technology.">Advanced in vitro models of vascular biology: Human induced pluripotent stem cells and organ-on-chip technology.</a> Advanced Drug Delivery Reviews. 140, 68-77 (2019).</li><li>Nemani, K. V., Moodie, K. L., Brennick, J. B., Su, A., Gimi, B. <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+and+in+vivo+evaluation+of+SU-8+biocompatibility.">In vitro and in vivo evaluation of SU-8 biocompatibility.</a> Materials Science &amp; Engineering. C, Materials for Biological Applications. 33 (7), 4453-4459 (2013).</li><li>Mathew, R., Ravi Sankar, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Review+on+Surface+Stress-Based+Miniaturized+Piezoresistive+SU-8+Polymeric+Cantilever+Sensors.">A Review on Surface Stress-Based Miniaturized Piezoresistive SU-8 Polymeric Cantilever Sensors.</a> Nano-Micro Letters. 10 (2), 1-41 (2018).</li><li>Knowlton, S., Yenilmez, B., Anand, S., Tasoglu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photocrosslinking-based+bioprinting:+Examining+crosslinking+schemes.">Photocrosslinking-based bioprinting: Examining crosslinking schemes.</a> Bioprinting. 5, 10-18 (2017).</li><li>Redd, M. 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=Patterned+human+microvascular+grafts+enable+rapid+vascularization+and+increase+perfusion+in+infarcted+rat+hearts.">Patterned human microvascular grafts enable rapid vascularization and increase perfusion in infarcted rat hearts.</a> Nature Communications. 10 (1), 1-14 (2019).</li><li>Zhu, 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=SU-8+Photoresist.">SU-8 Photoresist.</a> Encyclopedia of Nanotechnology. , 2530-2543 (2012).</li><li>Zheng, F., 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=Organ-on-a-Chip+Systems:+Microengineering+to+Biomimic+Living+Systems.">Organ-on-a-Chip Systems: Microengineering to Biomimic Living Systems.</a> Small. 12 (17), 2253-2282 (2016).</li><li>Freiman, 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=Adipose-derived+endothelial+and+mesenchymal+stem+cells+enhance+vascular+network+formation+on+three-dimensional+constructs+in+vitro.">Adipose-derived endothelial and mesenchymal stem cells enhance vascular network formation on three-dimensional constructs in vitro.</a> Stem Cell Research &amp; Therapy. 7 (1), 5 (2016).</li><li>van Duinen, V., 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=Perfused+3D+angiogenic+sprouting+in+a+high-throughput+in+vitro+platform.">Perfused 3D angiogenic sprouting in a high-throughput in vitro platform.</a> Angiogenesis. 22 (1), 157-165 (2019).</li><li>Nguyen, D. -. H. 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=Biomimetic+model+to+reconstitute+angiogenic+sprouting+morphogenesis+in+vitro.">Biomimetic model to reconstitute angiogenic sprouting morphogenesis in vitro.</a> Proceedings of the National Academy of Sciences. 110 (17), 6712-6717 (2013).</li><li>Nashimoto, 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=Integrating+perfusable+vascular+networks+with+a+three-dimensional+tissue+in+a+microfluidic+device.">Integrating perfusable vascular networks with a three-dimensional tissue in a microfluidic device.</a> Integrative Biology. 9 (6), 506-518 (2017).</li><li>Rosenfeld, D., 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=Morphogenesis+of+3D+vascular+networks+is+regulated+by+tensile+forces.">Morphogenesis of 3D vascular networks is regulated by tensile forces.</a> Proceedings of the National Academy of Sciences of the United States of America. 113 (12), 3215-3220 (2016).</li><li>Neto, F., 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=and+TAZ+regulate+adherens+junction+dynamics+and+endothelial+cell+distribution+during+vascular+development.">and TAZ regulate adherens junction dynamics and endothelial cell distribution during vascular development.</a> bioRxiv. , 174185 (2017).</li></ol>

The need for a rich vasculature within embedded in engineered tissues is critical for construct survival and proper function1. Although engineering the vascular system has been the focus of a vast amount of research, much is left to investigate and understand24. In particular, when recreating a specific tissue, the microvasculature should behave and organize accordingly12. The most common approach for microvessels generation is co-seeding endothelial...

The field of tissue engineering is rapidly progressing towards the fabrication of engineered constructs to replace missing or damaged organs and tissues1. However, fully functional constructs have yet to be achieved, in part, since generating operational vascular networks for tissue nourishment remains an outstanding challenge. Without proper vascularization, engineered tissues are limited to a passive diffusion transport of oxygen and nutrients, constraining the maximum viable tissue thickness to the diffusion limit, approximately 200 &#181;m2. Such thicknesses are not suitable to repair large tissue defects or for full organ fabrication, which renders the presence of functional vascular network a mandatory characteristic for functional and implantable tissues3.
The vascular system is comprised of a wide variety of blood vessels, with different sizes, phenotypes, and organization, tightly related to the host tissue. Understanding the behavior, response and migration decisions made by the developing and sprouting vessels can instruct their integration in engineered tissues4. Currently, the most common approach for creating in vitro vascular networks is combining endothelial cells (ECs) with support cells (SCs, with the capability to differentiate into mural cells), seeded within a three-dimensional micro-environment. This environment provides chemical and physical cues to allow the cells to attach, proliferate and self-assemble into vessel networks2,5,6,7,8. When co-cultured, SCs secrete extracellular matrix (ECM) proteins while providing mechanical support to the ECs, which form the tubular structures. Furthermore, a cross-interaction between both cell types promote tubulogenesis, vessel sprouting and migration, in addition to the SCs maturation and differentiation into &#945;-smooth muscle actin-expressing (&#945;SMA) mural cells4. Vessel network development is most commonly studied in 3D environments created using hydrogels, porous polymeric scaffolds, or a combination thereof. The latter option equally provides a cell-friendly environment and the required mechanical support for both the cells and the ECM9.
A great amount of work has been carried out to study vascular development, including co-culturing the cells on hydrogels10, hydrogels-scaffold combinations11,12, 2D platforms, and microfluidic devices13. However, hydrogels can be easily deformed by the cell-exerted forces14, while 2D and microfluidics systems fail to recreate a closer-to-nature environment to obtain a more extrapolatable response15,16. Understanding how forming vessels react to their surrounding environment can provide critical insight that might allow for the fabrication of engineered environments with the capability of guiding the vessel development in a predictable manner. Understanding vascular formation phenomena is especially critical to keep pace with the rapid emergence of submicron-to-micron scale fabrication techniques, such as stereolithography, digital projection lithography, continuous liquid interface production, 3D melt-electro jetwriting, solution based 3D electro jet writing, and emerging bioprinting techniques17,18,19,20,21. Aligning the control of these micromanufacturing techniques with a deepened understanding of vascular biology is key to the creation of an appropriate engineered vasculature for a target tissue.
Here, we present a 3D system to study the response of new forming and sprouting vessels to the surrounding scaffold geometry, observing their sprout origin and subsequent migration22. By utilizing 3D scaffolds with tessellated compartment geometries, and a two-step seeding technique, we succeeded to create highly organized vascular networks in a clear and easy to analyze fashion. The tessellated geometries provide a high throughput system with individual units containing vessels that respond to their local environment. Using multicolored ECs, we tracked sprout formation origins and subsequent migration patterns, correlated to the compartment geometry and the SCs location22.
Although the proposed protocol has been prepared to analyze the effects of geometrical cues on vascularization behavior, this approach can be expanded and applied to a variety of new applications. The tessellated scaffold and the easily imageable networks allow for the straightforward analysis of different ECs and SCs interaction, the addition of specific organ cells and their interaction with the vascular networks, drug effect on vascular networks, and more. Our suggested system results very versatile and of simple fabrication and processing.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Angiotool freeware</td>
			<td>NIH-CCR</td>
			<td></td>
			<td>Free download at https://ccrod.cancer.gov/confluence/display/ROB2/Home</td>
		</tr>
		<tr>
			<td>Bovine albumin serum Probumin</td>
			<td>Millipore</td>
			<td>82-045-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Dental pulp stem cells</td>
			<td>Lonza</td>
			<td>PT-5025</td>
			<td></td>
		</tr>
		<tr>
			<td>ECM media + bullet kit</td>
			<td>Sciencell</td>
			<td>#1001</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol 96%</td>
			<td>Gadot-Group</td>
			<td>64-17-5</td>
			<td></td>
		</tr>
		<tr>
			<td>Evicel fibrin sealant</td>
			<td>Johnson&#38;Johnson</td>
			<td>EVB05IL</td>
			<td>Provides both thrombin and fibrinogen (BAC2) solutions</td>
		</tr>
		<tr>
			<td>GlutaMAX</td>
			<td>Gibco</td>
			<td>35050061</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti-mouse Cy3 antibody</td>
			<td>Jackson</td>
			<td>115-166-072</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti-rabbit Alexa-Fluor 488</td>
			<td>Thermo- Fisher Scientific</td>
			<td>A11034</td>
			<td></td>
		</tr>
		<tr>
			<td>Human adipose microvascular cells</td>
			<td>Sciencell</td>
			<td>#7200</td>
			<td></td>
		</tr>
		<tr>
			<td>Human fibronectin</td>
			<td>Sigma</td>
			<td>F0895-5MG</td>
			<td>Stock concentration: 1 mg/mL</td>
		</tr>
		<tr>
			<td>ImageJ</td>
			<td>NIH</td>
			<td></td>
			<td>Free download at https://imagej.nih.gov/ij/download.html</td>
		</tr>
		<tr>
			<td>Isopropyl alcohol</td>
			<td>Gadot-Group</td>
			<td>67-63-0</td>
			<td></td>
		</tr>
		<tr>
			<td>Lift-off reagent</td>
			<td>Kayaku Advanced Materials, Inc</td>
			<td>G112850</td>
			<td>Commercial name Omnicoat</td>
		</tr>
		<tr>
			<td>Low-glucose DMEM</td>
			<td>Biological Industries</td>
			<td>01-050-1A</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse anti-SMA antibody</td>
			<td>Dako</td>
			<td>M0851</td>
			<td></td>
		</tr>
		<tr>
			<td>NEAA</td>
			<td>Gibco</td>
			<td>11140068</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde solution 4% in PBS</td>
			<td>ChemCruz</td>
			<td>SC-281692</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin-Nystatin Solution</td>
			<td>Biological Industries</td>
			<td>03-032-1B</td>
			<td></td>
		</tr>
		<tr>
			<td>Phospate buffered saline (PBS)</td>
			<td>Sigma</td>
			<td>P5368-10PAK</td>
			<td></td>
		</tr>
		<tr>
			<td>Rabbit anti-vWF antibody</td>
			<td>Abcam</td>
			<td>ab9378</td>
			<td></td>
		</tr>
		<tr>
			<td>Silicon wafer</td>
			<td>Silicon Valley Microelectronics (SVM)</td>
			<td></td>
			<td>Wafers 4&#34;, Type N-1-10, 500-550 microns thick</td>
		</tr>
		<tr>
			<td>SU-8 2050 photoresist</td>
			<td>Kayaku Advanced Materials, Inc</td>
			<td>Y11058</td>
			<td></td>
		</tr>
		<tr>
			<td>SU-8 developer</td>
			<td>Kayaku Advanced Materials, Inc</td>
			<td>Y020100</td>
			<td></td>
		</tr>
		<tr>
			<td>Tryton-X 100</td>
			<td>BioLab LTD</td>
			<td>57836</td>
		</tr>
	</tbody>
</table>

stepwise cell seeding on tessellated scaffolds to study sprouting blood vessels

The cardiovascular system is a key player in human physiology, providing nourishment to most tissues in the body; vessels are present in different sizes, structures, phenotypes, and performance depending on each specific perfused tissue. The field of tissue engineering, which aims to repair or replace damaged or missing body tissues, relies on controlled angiogenesis to create a proper vascularization within the engineered tissues. Without a vascular system, thick engineered constructs cannot be sufficiently nourished, which may result in cell death, poor engraftment, and ultimately failure. Thus, understanding and controlling the behavior of engineered blood vessels is an outstanding challenge in the field. This work presents a high-throughput system that allows for the creation of organized and repeatable vessel networks for studying vessel behavior in a 3D scaffold environment. This two-step seeding protocol shows that vessels within the system react to the scaffold topography, presenting distinctive sprouting behaviors depending on the compartment geometry in which the vessels reside. The obtained results and understanding from this high throughput system can be applied in order to inform better 3D bioprinted scaffold construct designs, wherein fabrication of various 3D geometries cannot be rapidly assessed when using 3D printing as the basis for cellularized biological environments. Furthermore, the understanding from this high throughput system may be utilized for the improvement of rapid drug screening, the rapid development of co-cultures models, and the investigation of mechanical stimuli on blood vessel formation to deepen the knowledge of the vascular system.

The presented protocol, using stereolithography techniques, allows for the fabrication of tessellated scaffolds made of SU-8 photoresist. Scaffolds with distinct compartment geometries (squares, hexagons, and circles), and highly accurate and repeatable features were obtained (Figure 1).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/61995/61995fig01.jpg" /> 
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Watch this Scientific Journal Video about Stepwise Cell Seeding on Tessellated Scaffolds to Study Sprouting Blood Vessels at JoVE.com

Stepwise Cell Seeding on Tessellated Scaffolds to Study Sprouting Blood Vessels

Engineered tissues heavily rely on proper vascular networks to provide vital nutrients and gases and remove metabolic waste. In this work, a stepwise seeding protocol of endothelial cells and support cells creates highly organized vascular networks in a high-throughput platform for studying developing vessel behavior in a controlled 3D environment.

The cardiovascular system is a key player in human physiology, providing nourishment to most tissues in the body; vessels are present in different sizes, ...

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