The support from ERC through HealInSynergy (306990) and the FPU program AP2009-3626 are acknowledged.

1. Production of Dorsal Substrates
<ol>
	<li>Production of a flat film of PLLA by solvent casting.
	<ol>
		<li>Work in a fume hood to prepare a solution of 2% (w/v) PLLA in chloroform (2 g PLLA in 100 ml chloroform) by stirring at room temperature (RT) until completely dissolved (3 hr approximately).</li>
		<li>Place the washers on a glass Petri dish. 
		Note: Use stainless-steel washers with an inner diameter of 10.5 mm (slightly smaller than the ventral sample diameter) so that the washer is placed on top of the...

<ol>
	<li>Baker, B. M., Chen, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deconstructing+the+third+dimension:+how+3D+culture+microenvironments+alter+cellular+cues.">Deconstructing the third dimension: how 3D culture microenvironments alter cellular cues.</a> J Cell Sci. 125 (Pt 13), 3015-3024 (2012).</li><li>Weiss, 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> Rev. Mod. Phys. 31 (1), 11-20 (1959).</li><li>Ruffner, H., Lichtenberg, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3D+cell+culture+systems--towards+primary+drug+discovery+platforms:+an+interview+with+Heinz+Ruffner+(Novartis)+and+Jan+Lichtenberg+(InSphero).">3D cell culture systems--towards primary drug discovery platforms: an interview with Heinz Ruffner (Novartis) and Jan Lichtenberg (InSphero).</a> Biotechnol J. 7 (7), 833-834 (2012).</li><li>Horning, J. 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=3-D+tumor+model+for+in+vitro+evaluation+of+anticancer+drugs.">3-D tumor model for in vitro evaluation of anticancer drugs.</a> Mol Pharm. 5 (5), 849-862 (2008).</li><li>Wolf, 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=Compensation+mechanism+in+tumor+cell+migration:+mesenchymal-amoeboid+transition+after+blocking+of+pericellular+proteolysis.">Compensation mechanism in tumor cell migration: mesenchymal-amoeboid transition after blocking of pericellular proteolysis.</a> J Cell Biol. 160 (2), 267-277 (2003).</li><li>Schor, S. 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=A+novel+'sandwich'+assay+for+quantifying+chemo-regulated+cell+migration+within+3-dimensional+matrices:+wound+healing+cytokines+exhibit+distinct+motogenic+activities+compared+to+the+transmembrane+assay.">A novel 'sandwich' assay for quantifying chemo-regulated cell migration within 3-dimensional matrices: wound healing cytokines exhibit distinct motogenic activities compared to the transmembrane assay.</a> Cell Motil Cytoskeleton. 63 (5), 287-300 (2006).</li><li>Lee, E. J., Hwang, C. M., Baek, D. H., Lee, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+of+microfluidic+system+for+the+assessment+of+cell+migration+on+3D+micropatterned+substrates.">Fabrication of microfluidic system for the assessment of cell migration on 3D micropatterned substrates.</a> Conf Proc IEEE Eng Med Biol Soc. 2009 (2009), 6034-6037 (2009).</li><li>Zaman, M. 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=Migration+of+tumor+cells+in+3D+matrices+is+governed+by+matrix+stiffness+along+with+cell-matrix+adhesion+and+proteolysis.">Migration of tumor cells in 3D matrices is governed by matrix stiffness along with cell-matrix adhesion and proteolysis.</a> Proc Natl Acad Sci U S A. 103 (29), 10889-10894 (2006).</li><li>Ballester-Beltr&#225;n, J., Lebourg, M., Salmer&#243;n-S&#225;nchez, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dorsal+and+ventral+stimuli+in+sandwich-like+microenvironments.+Effect+on+cell+differentiation.">Dorsal and ventral stimuli in sandwich-like microenvironments. Effect on cell differentiation.</a> Biotechnol Bioeng. 110 (11), 3048-3058 (2013).</li><li>Ballester-Beltr&#225;n, J., Lebourg, M., Moratal, D., Salmer&#243;n-S&#225;nchez, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fibronectin-matrix+sandwich-like+microenvironments+to+manipulate+cell+fate.">Fibronectin-matrix sandwich-like microenvironments to manipulate cell fate.</a> Biomater. Sci. 2 (3), 381-389 (2014).</li><li>Ballester-Beltr&#225;n, J., Lebourg, M., Rico, P., Salmer&#243;n-S&#225;nchez, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dorsal+and+ventral+stimuli+in+cell-material+interactions:+effect+on+cell+morphology.">Dorsal and ventral stimuli in cell-material interactions: effect on cell morphology.</a> Biointerphases. 7 (1-4), 39 (2012).</li><li>Ballester-Beltr&#225;n, J., Lebourg, M., Rico, P., Salmer&#243;n-S&#225;nchez, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+migration+within+confined+sandwich-like+nanoenvironments.">Cell migration within confined sandwich-like nanoenvironments.</a> Nanomedicine. , (2015).</li><li>Gla&#223;, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+Migration+Analysis:+Segmenting+Scratch+Assay+Images+with+Level+Sets+and+Support+Vector+Machines.">Cell Migration Analysis: Segmenting Scratch Assay Images with Level Sets and Support Vector Machines.</a> Pattern Recogn. 45 (9), 3154-3165 (2012).</li><li>Cukierman, E., Pankov, R., Stevens, D. R., Yamada, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Taking+cell-matrix+adhesions+to+the+third+dimension.">Taking cell-matrix adhesions to the third dimension.</a> Science. 294 (5547), 1708-1712 (2001).</li><li>Huebsch, N., Arany, P. R., Mao, A. 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=Harnessing+traction-mediated+manipulation+of+the+cell/matrix+interface+to+control+stem-cell+fate.">Harnessing traction-mediated manipulation of the cell/matrix interface to control stem-cell fate.</a> Nat. Mater. 9 (6), 518-526 (2010).</li><li>Petrie, R. J., Gavara, N., Chadwick, R. S., Yamada, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonpolarized+signaling+reveals+two+distinct+modes+of+3D+cell+migration.">Nonpolarized signaling reveals two distinct modes of 3D cell migration.</a> J Cell Biol. 197 (3), 439-455 (2012).</li><li>Mao, Y., Schwarzbauer, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stimulatory+effects+of+a+three-dimensional+microenvironment+on+cell-mediated+fibronectin+fibrillogenesis.">Stimulatory effects of a three-dimensional microenvironment on cell-mediated fibronectin fibrillogenesis.</a> J Cell Sci. 118 (Pt 19), 4427-4436 (2005).</li></ol>

Nowadays, 3D culture is an important topic for the pharmaceutical and biotechnological industry as well as research in cell biology, including cancer and stem cells. As a consequence several 3D culture systems have been developed. Unfortunately, differences between the 3D systems usually result in different cell behavior, hindering the understanding of cell fate. Besides, experimental procedures are usually not as straightforward as for 2D culture systems. Hence developing new culture systems seeking to overcome some of ...

Traditionally, cell culture has been carried out on bi-dimensional (2D) substrates, though most of the in vivo cellular microenvironments have a three-dimensional (3D) nature. This unnatural 2D environment triggers changes in cell behavior as a way of self-adaptation to a flat world, which directly impacts cell fate1,2. Hence, results obtained on 2D cell cultures are not always reproducible in vivo. This has encouraged the development of new relevant culture systems seeking to provide more physiological-like conditions to get further insights into any dimension-dependent biological mechanism3,4.
One of the main differences between 2D culture and the 3D in vivo environment is the distribution of cell receptors anchored to the extracellular matrix (ECM): whereas on 2D substrates cells adhere ventrally, the majority of cells in vivo are completely surrounded by the ECM and thus cell adhesion occurs through a 3D distribution of receptors. This triggers different cell adhesion signaling pathways thereby modulating important processes such as cell growth, cell differentiation and gene expression. During the last decades, many different 3D culture systems have been established5-8, though their variability and complexity hinder their standardization in common cell culture procedures. Moreover 3D systems are usually not easy to handle and current experimental procedures on 2D substrates cannot be easily established for 3D cultures. In addition, literature rarely compares 3D cultures with the equivalent 2D condition or other 3D systems, hindering the proper understanding of cell behavior in these models.
Once having the cells adhered on a 2D substrate, the excitation of the dorsal receptors &#8212; by overlaying a film of a new material (sandwich-like culture)&#160;&#8212; can trigger cell responses alike 3D environments. The reason behind this is the simultaneous activation of both dorsal and ventral receptors to adhere and spread within the sandwich environment (Figure 1)9,10. As a consequence, cells undergo important changes with respect to 2D cultures11,12. Thus, cell fate is determined during assembly because of the sandwich culture, since the dorsal stimulation triggers changes in key cellular pathways. Therefore, the cell fate is highly determined by the time when the sandwich-like culture is assembled11.
Due to the nature of the system, a sandwich-like culture is a simple and versatile tool that allows the study of different parameters in cell/material interactions such as chemistry, topography, stiffness and protein coatings at both the ventral and dorsal sides. This offers a higher degree of versatility compared to other 3D systems (Figure 2) due to the independent dorsal and ventral combination of a wide variety of surface conditions. Additionally, different cell lines and different times to assemble the sandwich-like culture can be studied, increasing the wide spectra of possibilities.
A standard protocol of the sandwich-like culture is detailed below using either poly-L-lactic acid (PLLA) electrospun fibers or films as dorsal substrates, glass coverslip as ventral substrate and fibronectin as protein coating. Sandwich-like cultures were assembled just after cell seeding or after 3 hr of 2D culture. However, note that other material systems and proteins could be used; likewise the sandwich-like culture can be assembled at different time points.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Ploy(lactic acid)</td>
			<td>NatureWorks</td>
			<td>4042D</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Cover glasses (12 mm&#216;)</td>
			<td>Marienfeld</td>
			<td>631-0666</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Chloroform</td>
			<td>Scharlab</td>
			<td>CL0200</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>1,1,1,3,3,3-Hexafluoro-2-propanol (HFIP)</td>
			<td>Sigma</td>
			<td>105228</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Syringe (1mL)</td>
			<td>Henke Sass Wolf</td>
			<td>4010-200V0</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Syringe pump</td>
			<td>New Era Pump Systems</td>
			<td>NE1000</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>High Voltage DC Power Supply</td>
			<td>Glassman High Voltage</td>
			<td>Series FC</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Incubator</td>
			<td>Hucoa-Herl&#246;s</td>
			<td>3111</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Laminar flow&#160; hood</td>
			<td>Telstar</td>
			<td>AV30/70</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Human Fibronectin</td>
			<td>Sigma</td>
			<td>F2006</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>RNeasy Micro Kit</td>
			<td>Qiagen</td>
			<td align="right">74004</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Inverted microscope</td>
			<td>Leica Microsystems</td>
			<td>DMI 6000</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma-Aldrich</td>
			<td>T8787</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Albumin</td>
			<td>Sigma-Aldrich</td>
			<td>A7409</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Tween 20</td>
			<td>Sigma-Aldrich</td>
			<td>P2287</td>
			<td>Reagent</td>
		</tr>
	</tbody>
</table>

sandwich-like microenvironments to harness cell/material interactions

Cell culture has been traditionally carried out on bi-dimensional (2D) substrates where cells adhere using ventral receptors to the biomaterial surface. However in vivo, most of the cells are completely surrounded by the extracellular matrix (ECM), resulting in a three-dimensional (3D) distribution of receptors. This may trigger differences in the outside-in signaling pathways and thus in cell behavior.
This article shows that stimulating the dorsal receptors of cells already adhered to a 2D substrate by overlaying a film of a new material (a sandwich-like culture) triggers important changes with respect to standard 2D cultures. Furthermore, the simultaneous excitation of ventral and dorsal receptors shifts cell behavior closer to that found in 3D environments. Additionally, due to the nature of the system, a sandwich-like culture is a versatile tool that allows the study of different parameters in cell/material interactions, e.g., topography, stiffness and different protein coatings at both the ventral and dorsal sides. Finally, since sandwich-like cultures are based on 2D substrates, several analysis procedures already developed for standard 2D cultures can be used normally, overcoming more complex procedures needed for 3D systems.

The stimulation of dorsal receptors within the sandwich-like culture triggers changes in cell morphology, cell adhesion and intracellular signaling pathways (e.g. focal adhesion kinase, FAK)10-12. As an example, fibroblasts cultured within the sandwich-like system overexpressed the &#945;5 integrin subunit compared to the 2D, as observed for other 3D cultures15,16.
Cell fate is highly dependent on the time when the dorsal receptors are stimulated and b...

Watch this Scientific Journal Video about Sandwich-like Microenvironments to Harness Cell/Material Interactions at JoVE.com

Sandwich-like Microenvironments to Harness Cell/Material Interactions

The following protocol describes the procedure to assemble sandwich-like cultures to be used as an intermediate stage between bi-dimensional (2D) and three-dimensional (3D) cellular environments. The engineered systems can have applications in microscopy, biomechanics, biochemistry and cell biology assays.

Cell culture has been traditionally carried out on bi-dimensional (2D) substrates where cells adhere using ventral receptors to the biomaterial surface. ...

sandwich-like-microenvironments-to-harness-cellmaterial-interactions

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Bioengineering

7.5K Views.  Universitat Politècnica de València. The following protocol describes the procedure to assemble sandwich-like cultures to be used as an intermediate stage between bi-dimensional (2D) and three-dimensional (3D) cellular environments. The engineered systems can have applications in microscopy, biomechanics, biochemistry and cell biology assays.