Name: bioprintable alginate/gelatin hydrogel 3d in vitro model systems induce cell spheroid formation
Uploaded: 2018-07-02T14:30:00
Description: Watch this Scientific Journal Video about Bioprintable Alginate/Gelatin Hydrogel 3D In Vitro Model Systems Induce Cell Spheroid Formation at JoVE.com

Tao Jiang thanks the China Scholarship Council (201403170354) and McGill Engineering Doctoral Award (90025) for their scholarship funding. Jose G. Munguia-Lopez thanks CONACYT (250279, 290936 and 291168) and FRQNT (258421) for their scholarship funding. Salvador Flores-Torres thanks CONACYT for their scholarship funding (751540). Joseph M. Kinsella thanks the National Science and Engineering Research Council, the Canadian Foundation for Innovation, the Townshend-Lamarre Family Foundation, and McGill University for their funding. We would like to thank Allen Ehrlicher for allowing us to use his rheometer, Dan Nicolau for allowing us to use his confocal microscope, and Morag Park for granting us access to fluorescently labeled cell lines.

1. Preparation of the Materials, Hydrogel, and Cell Culture Materials
<ol>
	<li>Material and solution preparation
	<ol>
		<li>Wash and dry 250 mL and 100 mL glass beakers, magnetic stirrers, spatulas, 10 mL cartridges, 25 G cylindrical nozzles (with a length of 0.5 in and an inner diameter of 250 &#181;m). Sterilize the materials by autoclaving them at 121 &#176;C/15 min/1 atm. Keep the materials under sterile conditions until use. 
		Note: Refer to the Table of Materials for vend...

<ol>
	<li>Cui, X., Hartanto, Y., Zhang, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advances+in+multicellular+spheroids+formation.">Advances in multicellular spheroids formation.</a> Journal of the Royal Society Interface. 14 (127), (2017).</li><li>Yip, D., Cho, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+multicellular+3D+heterospheroid+model+of+liver+tumor+and+stromal+cells+in+collagen+gel+for+anti-cancer+drug+testing.">A multicellular 3D heterospheroid model of liver tumor and stromal cells in collagen gel for anti-cancer drug testing.</a> Biochemical and Biophysical Research Communications. 433 (3), 327-332 (2013).</li><li>Breslin, S., O'Driscoll, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+relevance+of+using+3D+cell+cultures,+in+addition+to+2D+monolayer+cultures,+when+evaluating+breast+cancer+drug+sensitivity+and+resistance.">The relevance of using 3D cell cultures, in addition to 2D monolayer cultures, when evaluating breast cancer drug sensitivity and resistance.</a> Oncotarget. 7 (29), 45745-45756 (2016).</li><li>Yue, X., Lukowski, J. K., Weaver, E. M., Skube, S. B., Hummon, A. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+proteomic+and+phosphoproteomic+comparison+of+2D+and+3D+colon+cancer+cell+culture+models.">Quantitative proteomic and phosphoproteomic comparison of 2D and 3D colon cancer cell culture models.</a> Journal of Proteome Research. 15 (12), 4265-4276 (2016).</li><li>Priwitaningrum, D. L., 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=Tumor+stroma-containing+3D+spheroid+arrays:+a+tool+to+study+nanoparticle+penetration.">Tumor stroma-containing 3D spheroid arrays: a tool to study nanoparticle penetration.</a> Journal of Controlled Release. 244 (Pt B), 257-268 (2016).</li><li>Hong, 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=Cellular+behavior+in+micropatterned+hydrogels+by+bioprinting+system+depended+on+the+cell+types+and+cellular+interaction.">Cellular behavior in micropatterned hydrogels by bioprinting system depended on the cell types and cellular interaction.</a> Journal of Bioscience and Bioengineering. 116 (2), 224-230 (2013).</li><li>Dolati, 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=In+vitro+evaluation+of+carbon-nanotube-reinforced+bioprintable+vascular+conduits.">In vitro evaluation of carbon-nanotube-reinforced bioprintable vascular conduits.</a> Nanotechnology. 25 (14), 145101 (2014).</li><li>Murphy, S. V., Atala, A. <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+of+tissues+and+organs.">3D bioprinting of tissues and organs.</a> Nature Biotechnology. 32 (8), 773-785 (2014).</li><li>Kang, H. W., 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+3D+bioprinting+system+to+produce+human-scale+tissue+constructs+with+structural+integrity.">A 3D bioprinting system to produce human-scale tissue constructs with structural integrity.</a> Nature Biotechnology. 34 (3), 312-319 (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 (9), 768-774 (2012).</li><li>Jia, W., 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=Direct+3D+bioprinting+of+perfusable+vascular+constructs+using+a+blend+bioink.">Direct 3D bioprinting of perfusable vascular constructs using a blend bioink.</a> Biomaterials. 106, 58-68 (2016).</li><li>Kolesky, D. B., Homan, K. A., Skylar-Scott, M. A., Lewis, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+bioprinting+of+thick+vascularized+tissues.">Three-dimensional bioprinting of thick vascularized tissues.</a> Proceedings of the National Academy of Sciences of the United States of America. 113 (12), 3179-3184 (2016).</li><li>Lee, 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=Design+and+fabrication+of+human+skin+by+three-dimensional+bioprinting.">Design and fabrication of human skin by three-dimensional bioprinting.</a> Tissue Engineering Part C: Methods. 20 (6), 473-484 (2014).</li><li>Jiang, 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=Directing+the+self-assembly+of+tumour+spheroids+by+bioprinting+cellular+heterogeneous+models+within+alginate/gelatin+hydrogels.">Directing the self-assembly of tumour spheroids by bioprinting cellular heterogeneous models within alginate/gelatin hydrogels.</a> Scientific Reports. 7 (1), 4575 (2017).</li><li>Knowlton, S., Onal, S., Yu, C. H., Zhao, J. J., 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=Bioprinting+for+cancer+research.">Bioprinting for cancer research.</a> Trends in Biotechnology. 33 (9), 504-513 (2015).</li><li>Derby, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Printing+and+prototyping+of+tissues+and+scaffolds.">Printing and prototyping of tissues and scaffolds.</a> Science. 338 (6109), 921-926 (2012).</li><li>Nair, 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=Characterization+of+cell+viability+during+bioprinting+processes.">Characterization of cell viability during bioprinting processes.</a> Biotechnology Journal. 4 (8), 1168-1177 (2009).</li><li>Costa, E. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3D+tumor+spheroids:+an+overview+on+the+tools+and+techniques+used+for+their+analysis.">3D tumor spheroids: an overview on the tools and techniques used for their analysis.</a> Biotechnology Advances. 34 (8), 1427-1441 (2016).</li><li>Zhao, 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=Three-dimensional+printing+of+Hela+cells+for+cervical+tumor+model+in+vitro.">Three-dimensional printing of Hela cells for cervical tumor model in vitro.</a> Biofabrication. 6 (3), 035001 (2014).</li><li>Ling, 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=Bioprinting-based+high-throughput+fabrication+of+three-dimensional+MCF-7+human+breast+cancer+cellular+spheroids.">Bioprinting-based high-throughput fabrication of three-dimensional MCF-7 human breast cancer cellular spheroids.</a> Engineering. 1 (2), 269-274 (2015).</li><li>Liang, 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=A+cell-instructive+hydrogel+to+regulate+malignancy+of+3D+tumor+spheroids+with+matrix+rigidity.">A cell-instructive hydrogel to regulate malignancy of 3D tumor spheroids with matrix rigidity.</a> Biomaterials. 32 (35), 9308-9315 (2011).</li><li>Szot, C. S., Buchanan, C. F., Freeman, J. W., Rylander, M. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3D+in+vitro+bioengineered+tumors+based+on+collagen+I+hydrogels.">3D in vitro bioengineered tumors based on collagen I hydrogels.</a> Biomaterials. 32 (31), 7905-7912 (2011).</li><li>Carey, S. P., Kraning-Rush, C. M., Williams, R. M., Reinhart-King, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biophysical+control+of+invasive+tumor+cell+behavior+by+extracellular+matrix+microarchitecture.">Biophysical control of invasive tumor cell behavior by extracellular matrix microarchitecture.</a> Biomaterials. 33 (16), 4157-4165 (2012).</li><li>Hospodiuk, M., Dey, M., Sosnoski, D., Ozbolat, I. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+bioink:+a+comprehensive+review+on+bioprintable+materials.">The bioink: a comprehensive review on bioprintable materials.</a> Biotechnology Advances. 35 (2), 217-239 (2017).</li><li>Caliari, S. R., Burdick, J. 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+practical+guide+to+hydrogels+for+cell+culture.">A practical guide to hydrogels for cell culture.</a> Nature Methods. 13 (5), 405-414 (2016).</li><li>Bhutani, U., Laha, A., Mitra, K., Majumdar, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sodium+alginate+and+gelatin+hydrogels:+viscosity+effect+on+hydrophobic+drug+release.">Sodium alginate and gelatin hydrogels: viscosity effect on hydrophobic drug release.</a> Materials Letters. 164, 76-79 (2016).</li><li>Biswal, 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=Effect+of+mechanical+and+electrical+behavior+of+gelatin+hydrogels+on+drug+release+and+cell+proliferation.">Effect of mechanical and electrical behavior of gelatin hydrogels on drug release and cell proliferation.</a> Journal of the Mechanical Behavior of Biomedical Materials. 53, 174-186 (2016).</li><li>Rowley, J. A., Madlambayan, G., Mooney, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alginate+hydrogels+as+synthetic+extracellular+matrix+materials.">Alginate hydrogels as synthetic extracellular matrix materials.</a> Biomaterials. 20 (1), 45-53 (1999).</li><li>Djabourov, M., Leblond, J., Papon, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gelation+of+aqueous+gelatin+solutions.+I.+Structural+investigation.">Gelation of aqueous gelatin solutions. I. Structural investigation.</a> Journal de Physique (France). 49 (2), 319-332 (1988).</li><li>Djabourov, M., Leblond, J., Papon, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gelation+of+aqueous+gelatin+solutions.+II.+Rheology+of+the+sol-gel+transition.">Gelation of aqueous gelatin solutions. II. Rheology of the sol-gel transition.</a> Journal de Physique (France). 49 (2), 333-343 (1988).</li><li>Coussot, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Rheometry of Pastes, Suspensions, and Granular Materials: Applications in Industry and Environment. , (2005).</li><li>Ouyang, L., Yao, R., Zhao, Y., Sun, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+bioink+properties+on+printability+and+cell+viability+for+3D+bioplotting+of+embryonic+stem+cells.">Effect of bioink properties on printability and cell viability for 3D bioplotting of embryonic stem cells.</a> Biofabrication. 8 (3), 035020 (2016).</li><li>Michon, C., Cuvelier, G., Launay, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concentration+dependence+of+the+critical+viscoelastic+properties+of+gelatin+at+the+gel+point.">Concentration dependence of the critical viscoelastic properties of gelatin at the gel point.</a> Rheologica Acta Rheologica Acta: An International Journal of Rheology. 32 (1), 94-103 (1993).</li><li>Mouser, V. 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=Yield+stress+determines+bioprintability+of+hydrogels+based+on+gelatin-methacryloyl+and+gellan+gum+for+cartilage+bioprinting.">Yield stress determines bioprintability of hydrogels based on gelatin-methacryloyl and gellan gum for cartilage bioprinting.</a> Biofabrication. 8 (3), 035003 (2016).</li><li>Benbow, J. J., Oxley, E. W., Bridgwater, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+extrusion+mechanics+of+pastes-the+influence+of+paste+formulation+on+extrusion+parameters.">The extrusion mechanics of pastes-the influence of paste formulation on extrusion parameters.</a> Chemical Engineering Science. 42 (9), 2151-2162 (1987).</li><li>Bingham, E. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Fluidity and plasticity. , (1922).</li><li>Horrobin, D. J., Nedderman, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Die+entry+pressure+drops+in+paste+extrusion.">Die entry pressure drops in paste extrusion.</a> Chemical Engineering Science. 53 (18), 3215-3225 (1998).</li><li>Soman, P., 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=Cancer+cell+migration+within+3D+layer-by-layer+microfabricated+photocrosslinked+PEG+scaffolds+with+tunable+stiffness.">Cancer cell migration within 3D layer-by-layer microfabricated photocrosslinked PEG scaffolds with tunable stiffness.</a> Biomaterials. 33 (29), 7064-7070 (2012).</li><li>Asghar, W., 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+cancer+microenvironments+for+in+vitro+3-D+tumor+models.">Engineering cancer microenvironments for in vitro 3-D tumor models.</a> Materials Today. 18 (10), 539-553 (2015).</li><li>Lin, R. Z., Chang, H. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+in+three-dimensional+multicellular+spheroid+culture+for+biomedical+research.">Recent advances in three-dimensional multicellular spheroid culture for biomedical research.</a> Biotechnology Journal. 3 (9-10), 1172-1184 (2008).</li><li>Akasov, 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=Formation+of+multicellular+tumor+spheroids+induced+by+cyclic+RGD-peptides+and+use+for+anticancer+drug+testing+in+vitro.">Formation of multicellular tumor spheroids induced by cyclic RGD-peptides and use for anticancer drug testing in vitro.</a> International Journal of Pharmaceutics. 506 (1-2), 148-157 (2016).</li></ol>

Cell-laden structures can be compromised if contamination (biological or chemical) occurs at any point in the process. Usually, biological contamination is seen after two or three days of culture as a color change in the culture media or the bioprinted structure. Therefore, the sterilization (physical and chemical disinfection) is a key step for all the cell-related processes. Noteworthy, autoclaving gelatin changes its gelling properties, which made it gel slower in the trials we conducted. Therefore, we sterilized the ...

Although 2D cell culture is widely used in cancer research, limitations exist as the cells are grown in a monolayer format with a uniform concentration of nutrients and oxygen. These cultures lack important cell-cell and cell-matrix interactions present in the native tumor microenvironment (TME). Consequently, these models poorly recapitulate physiological conditions, resulting in aberrant cell behaviors, including unnatural morphologies, irregular receptor organization, membrane polarization, and abnormal gene expression, among other conditions1,2,3,4. On the other hand, 3D cell culture, where cells are expanded in a volumetric space as aggregates, spheroids, or organoids, offers an alternative technique to create more accurate in vitro environments to study fundamental cell biology and physiology. 3D cell culture models can also encourage cell-ECM interactions that are critical physiological characteristics of the native TME in vitro1,4,5. The emerging 3D bioprinting technology provides possibilities to build models that mimic the heterogeneous TME.
3D bioprinting is derived from rapid prototyping and enables the fabrication of 3D microstructures that are capable of mimicking some of the complexities of living tissue samples6,7. The current bioprinting methods include inkjet, extrusion, and laser-assisted printing8. Among them, the extrusion method allows the heterogeneity to be controlled within the printed matrices by precisely positioning distinct types of materials at different initial locations. Therefore, it is the best approach to fabricate heterogeneous in vitro models involving multiple types of cells or matrices. Extrusion bioprinting has been successfully used to build auricular shaped scaffolds9, vascular structures10,11,12, and skin tissues13, resulting in high printing fidelity and cell viability. The technology also features versatile material selections, the ability to deposit materials with cells embedded with a known density, and high reproducibility14,15,16,17. Natural and synthetic hydrogels are frequently used as bioinks for 3D bioprinting due to their biocompatibility, bioactivity, and their hydrophilic networks that can be engineered to structurally resemble the ECM7,18,19,20,21,22,23.Hydrogels are also advantageous since they can include adhesive sites for cells, structural elements, permeability for nutrients and gases, and the appropriate mechanical properties to encourage cell development24. For instance, collagen hydrogels offer integrin anchorage sites that cells can use to attach to the matrix. Gelatin, denatured collagen, retains similar cell adhesion sites. In contrast, alginate is bioinert but provides mechanical integrity by forming crosslinks with divalent ions25,26,27,28.
In this work, we developed a composite hydrogel as a bioink, comprised of alginate and gelatin, with similarities to the microscopic architecture of a native tumor stroma. Breast cancer cells and fibroblasts were embedded in the hydrogels and printed via an extrusion-based bioprinter to create a 3D model that mimics the in vivo microenvironment. The engineered 3D environment allows cancer cells to form multicellular tumor spheroids (MCTS) with a high viability for long periods of cell culture (&#62; 30 days). This protocol demonstrates the methodologies of synthesizing composite hydrogels, characterizing the materials&#39; microstructure and printability, bioprinting cellular heterogeneous models, and observing the formation of MCTS. These methodologies can be applied to other bioinks in extrusion bioprinting as well as to different designs of heterogeneous tissue models with potential applications in drug screening, cell migration assays, and studies that focus on fundamental cell physiological functions.

<table border="0" cellpadding="0" cellspacing="0" width="925">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Sodium alginate</td>
			<td style="width:213px;">FMC BioPolymer</td>
			<td style="width:173px;">CAS-No: 9005-38-3</td>
			<td style="width:167px;">Protanal LF 10/60 FT</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Gelatin</td>
			<td style="width:213px;">Sigma-Aldrich</td>
			<td style="width:173px;">G9391</td>
			<td>Type B gelatin from bovine skin</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Dubelcco&#39;s phosphate buffered saline (DPBS 1X)</td>
			<td style="width:213px;">Gibco</td>
			<td style="width:173px;">LS14190136</td>
			<td>1&#215;, w/o calcium, w/o magnesium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Magnetic hotplate</td>
			<td style="width:213px;">Corning&#160;</td>
			<td style="width:173px;">N/A</td>
			<td>Stirrer/hot plate model PC-420</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">50 mL centrifuge tubes</td>
			<td style="width:213px;">Corning</td>
			<td style="width:173px;">352098</td>
			<td>Falcon&#174; 50mL High Clarity PP Centrifuge Tube, Conical Bottom, Sterile</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Centrifuge</td>
			<td style="width:213px;">GMI</td>
			<td style="width:173px;">N/A</td>
			<td>Sorvall RT6000D, GMI, USA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Calcium chloride anhydrous</td>
			<td style="width:213px;">Sigma-Aldrich</td>
			<td>C1016</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">MilliQ water</td>
			<td style="width:213px;">Millipore</td>
			<td style="width:173px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Millipore 0.22 &#181;m filters</td>
			<td style="width:213px;">Millipore</td>
			<td style="width:173px;">SLGS033SB</td>
			<td>Millex-GS Syringe Filter Unit, 0.22&#160;&#181;m, mixed cellulose esters, 33&#160;mm, ethylene oxide sterilized</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Oscillation rheometer MCR 302</td>
			<td style="width:213px;">Anton Paar</td>
			<td style="width:173px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Rheometer measuring tool CP25</td>
			<td style="width:213px;">Anton Paar</td>
			<td style="width:173px;">79038</td>
			<td>Conical plate geometry for rheometer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">RheoCompass</td>
			<td style="width:213px;">Anton Paar</td>
			<td style="width:173px;">N/A</td>
			<td>Software controlling rheometer MCR 302</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Scanning electron microscope</td>
			<td style="width:213px;">Hitachi</td>
			<td style="width:173px;">N/A</td>
			<td>SEM, Hitachi SU-3500 Variable Pressure</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Paraformaldehyde, 96%, extra pure</td>
			<td style="width:213px;">Acros Organics</td>
			<td style="width:173px;">416785000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Dulbecco modified eagle medium (DMEM)</td>
			<td style="width:213px;">Gibco</td>
			<td>11965092</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Antibiotic/Antimycotic solution (100X) stabilized</td>
			<td style="width:213px;">Sigma</td>
			<td>A5955</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fetal bovine serum</td>
			<td>Wisent Bioproducts</td>
			<td style="width:173px;">080-150</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:372px;">Cell culture T-75 flasks</td>
			<td style="width:213px;">Sigma-Aldrich</td>
			<td style="width:173px;">CLS430641</td>
			<td>75 cm2 TC-Treated surface treatment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">3D bioprinter BioScaffolder 3.1</td>
			<td style="width:213px;">GeSiM</td>
			<td style="width:173px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">GeSim software</td>
			<td style="width:213px;">GeSiM</td>
			<td style="width:173px;">N/A</td>
			<td>Software controlling BioScaffolder 3.1</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">10cc cartridge UV resist</td>
			<td>EFD Nordson</td>
			<td>7012126</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">End cap</td>
			<td>EFD Nordson</td>
			<td>7014472</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Tip cap</td>
			<td>EFD Nordson</td>
			<td>7014469</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Piston&#160;</td>
			<td>EFD Nordson</td>
			<td>7012182</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Stainless nozzle G25</td>
			<td>EFD Nordson</td>
			<td>7018345</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Water bath</td>
			<td style="width:213px;">VWR</td>
			<td style="width:173px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Agarose</td>
			<td style="width:213px;">Sigma-Aldrich</td>
			<td style="width:173px;">A9539</td>
			<td>Bioreagent, for molecular biology</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Costar 6-well plates&#160;</td>
			<td style="width:213px;">Corning</td>
			<td style="width:173px;">3516</td>
			<td>TC-Treated Multiple Well Plates, Individually Wrapped, Sterile&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Confocal spinning disk inverted microscope</td>
			<td style="width:213px;">Olympus Life Science</td>
			<td style="width:173px;">N/A</td>
			<td>Olympus IX83</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">MTS assay kit</td>
			<td style="width:213px;">Promega</td>
			<td style="width:173px;">G3582</td>
			<td>CellTiter 96&#174; AQueous&#160;One Solution Cell Proliferation Assay&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Live/Dead viability cytotoxicity kit</td>
			<td>Molecular Probes,ThermoFisher Scientific</td>
			<td>L3224</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Trypsin 0.25/EDTA 1X</td>
			<td>Gibco</td>
			<td>25200-072</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Corning 96-well plate</td>
			<td style="width:213px;">Corning</td>
			<td style="width:173px;">3595</td>
			<td>Clear Flat Bottom Polystyrene TC-Treated Microplate, Individually Wrapped, with Low Evaporation Lid, Sterile</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Autoclave Tuttnauer</td>
			<td style="width:213px;">Heidolph Brinkmann</td>
			<td style="width:173px;">N/A</td>
			<td>Heidolph Tuttnauer 2540E Autoclave Sterilizer Electronic Model with 4 Stainless Steel Trays, 23L Capacity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Trypan blue</td>
			<td style="width:213px;">Invitrogen&#160;</td>
			<td style="width:173px;">T10282</td>
			<td>0.4% solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Ethanol</td>
			<td style="width:213px;">Commercial Alcohols</td>
			<td style="width:173px;">P016EA95</td>
			<td>Greenfield Speciality Alcohols</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:372px;">CO2 Incubator</td>
			<td style="width:213px;">Panasonic</td>
			<td style="width:173px;">N/A</td>
			<td>MCO 19AIC-PA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">Lyophilizer&#160;</td>
			<td style="width:213px;">SP Scientific</td>
			<td style="width:173px;">N/A</td>
			<td>Virtis Sentry 2.0</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">SolidWorks</td>
			<td style="width:213px;">Dassault Systems</td>
			<td style="width:173px;">N/A</td>
			<td>A CAD software used to build demostrative propeller-like model</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:372px;">MATLAB</td>
			<td style="width:213px;">The MathWorks</td>
			<td style="width:173px;">N/A</td>
			<td>A programming software used to generate G-code for BioScaffolder 3.1</td>
		</tr>
	</tbody>
</table>

bioprintable alginate/gelatin hydrogel 3d in vitro model systems induce cell spheroid formation

The cellular, biochemical, and biophysical heterogeneity of the native tumor microenvironment is not recapitulated by growing immortalized cancer cell lines using conventional two-dimensional (2D) cell culture. These challenges can be overcome by using bioprinting techniques to build heterogeneous three-dimensional (3D) tumor models whereby different types of cells are embedded. Alginate and gelatin are two of the most common biomaterials employed in bioprinting due to their biocompatibility, biomimicry, and mechanical properties. By combining the two polymers, we achieved a bioprintable composite hydrogel with similarities to the microscopic architecture of a native tumor stroma. We studied the printability of the composite hydrogel via rheology and obtained the optimal printing window. Breast cancer cells and fibroblasts were embedded in the hydrogels and printed to form a 3D model mimicking the in vivo microenvironment. The bioprinted heterogeneous model achieves a high viability for long-term cell culture (&#62; 30 days) and promotes the self-assembly of breast cancer cells into multicellular tumor spheroids (MCTS). We observed the migration and interaction of the cancer-associated fibroblast cells (CAFs) with the MCTS in this model. By using bioprinted cell culture platforms as co-culture systems, it offers a unique tool to study the dependence of tumorigenesis on the stroma composition. This technique features a high-throughput, low cost, and high reproducibility, and it can also provide an alternative model to conventional cell monolayer cultures and animal tumor models to study cancer biology.

The temperature sweep shows a distinct difference of the A3G7 precursor at 25 &#176;C and 37 &#176;C. The precursor is liquid at 37 &#176;C and has a complex viscosity of 1938.1 &#177; 84.0 mPa x s, which is validated by a greater G&#34; over G&#39;. As the temperature decreases, the precursor undergoes physical gelation due to the spontaneous physical entanglement of the gelatin molecules into a tri-helix formation29,30. Both the...

Watch this Scientific Journal Video about Bioprintable Alginate/Gelatin Hydrogel 3D In Vitro Model Systems Induce Cell Spheroid Formation at JoVE.com

Bioprintable Alginate/Gelatin Hydrogel 3D In Vitro Model Systems Induce Cell Spheroid Formation

We developed a heterogeneous breast cancer model consisting of immortalized tumor and fibroblast cells embedded in a bioprintable alginate/gelatin bioink. The model recapitulates the in vivo tumor microenvironment and facilitates the formation of multicellular tumor spheroids, yielding insight into the mechanisms driving tumorigenesis.

Bioprintable Alginate/Gelatin Hydrogel 3D In Vitro Model Systems Induce Cell Spheroid Formation

The cellular, biochemical, and biophysical heterogeneity of the native tumor microenvironment is not recapitulated by growing immortalized cancer cell ...

Research

JoVE Journal

Bioengineering

Eye Irritation Test (EIT) for Hazard Identification of Eye Irritating Chemicals using Reconstructed Human Cornea-like Epithelial (RhCE) Tissue Model

Eye Irritation Test EIT for Hazard Identification of Eye Irritating Chemicals using Reconstructed Human Cornea-like Epithelial RhCE Tissue Model

To comply with the Seventh Amendment to the EU Cosmetics Directive and EU REACH legislation, validated non-animal alternative methods for reliable and ...

Modeling Ovarian Cancer Multicellular Spheroid Behavior in a Dynamic 3D Peritoneal Microdevice

Ovarian cancer is characterized by extensive peritoneal metastasis, with tumor spheres commonly found in the malignant ascites. This is associated with ...

Improved 3D Hydrogel Cultures of Primary Glial Cells for In Vitro Modelling of Neuroinflammation

Improved 3D Hydrogel Cultures of Primary Glial Cells for In Vitro Modelling of Neuroinflammation

In the central nervous system, numerous acute injuries and neurodegenerative disorders, as well as implanted devices or biomaterials engineered to enhance ...

3D Analysis of Multi-cellular Responses to Chemoattractant Gradients

Various limitations of 2D cell culture systems have sparked interest in 3D cell culture and analysis platforms, which would better mimic the spatial and ...

3D Printed Porous Cellulose Nanocomposite Hydrogel Scaffolds

This work demonstrates the use of three-dimensional (3D) printing to produce porous cubic scaffolds using cellulose nanocomposite hydrogel ink, with ...

A Human 3D Extracellular Matrix-Adipocyte Culture Model for Studying Matrix-Cell Metabolic Crosstalk

The extracellular matrix (ECM) plays a central role in regulating tissue homeostasis, engaging in crosstalk with cells and regulating multiple aspects of ...

Protocols of 3D Bioprinting of Gelatin Methacryloyl Hydrogel Based Bioinks

Gelatin methacryloyl (GelMA) has become a popular biomaterial in the field of bioprinting. The derivation of this material is gelatin, which is hydrolyzed ...

Using Multilayered Hydrogel Bioink in Three-Dimensional Bioprinting for Homogeneous Cell Distribution

During the extrusion-based three-dimensional bioprinting process, liquid-like bioinks with low viscosity can protect cells from membrane damage induced by ...

Advanced 3D Liver Models for In vitro Genotoxicity Testing Following Long-Term Nanomaterial Exposure

Due to the rapid development and implementation of a diverse array of engineered nanomaterials (ENM), exposure to ENM is inevitable and the development of ...

3D Printing of In Vitro Hydrogel Microcarriers by Alternating Viscous-Inertial Force Jetting

3D Printing of In Vitro Hydrogel Microcarriers by Alternating Viscous-Inertial Force Jetting

Microcarriers are beads with a diameter of 60-250 &#181;m and a large specific surface area, which are commonly used as carriers for large-scale cell ...