The authors would like to acknowledge Drs. Jonathan Reichner and Angle Byrd for cell experiment insight. The National Science Foundation Graduate Research Fellowship Program (GRFP) supported this work.

1. 3D Mold Design and Parts
<ol>
	<li>Mold
	<ol>
		<li>Before working, obtain a silicone elastomer kit, a live cell imaging chamber, a 22 mm glass coverslip, and a machined aluminum metal cube with dimensions 10.07 mm x 3.95 mm x 5.99 mm. Prepare the live cell imaging chamber for molding by placing the coverslip in the bottom holder and assembling the rest of the chamber as directed by the vendor.</li>
		<li>Next, using forceps, place the machined aluminum metal cube in the middle of the live cell imaging chamber housi...

<ol>
	<li>Adzick, N. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Molecular+and+Cellular+Biology+of+Wound+Repair.">The Molecular and Cellular Biology of Wound Repair.</a> Ann Surg. 225 (2), 236 (1997).</li><li>Reddi, A. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bone+morphogenetic+proteins:+an+unconventional+approach+to+isolation+of+first+mammalian+morphogens.">Bone morphogenetic proteins: an unconventional approach to isolation of first mammalian morphogens.</a> Cytokine Growth F. R. 8 (1), 11-20 (1997).</li><li>Coussens, , Werb, Z, L. M., Werb, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inflammation+and+cancer.">Inflammation and cancer.</a> Nature. 420 (6917), 860-867 (2002).</li><li>Vital-Lopez, F. G., Armaou, A., Hutnik, M., Maranas, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+the+effect+of+chemotaxis+on+glioblastoma+tumor+progression.">Modeling the effect of chemotaxis on glioblastoma tumor progression.</a> AIChE J. 57 (3), 778-792 (2011).</li><li>Hughes-Alford, S. K., Lauffenburger, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+analysis+of+gradient+sensing:+towards+building+predictive+models+of+chemotaxis+in+cancer.">Quantitative analysis of gradient sensing: towards building predictive models of chemotaxis in cancer.</a> Curr. Opin. Cell Biol. 24 (2), 284-291 (2012).</li><li>Friedl, P., Gilmour, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collective+cell+migration+in+morphogenesis,+regeneration+and+cancer.">Collective cell migration in morphogenesis, regeneration and cancer.</a> Nat. Rev. Mol Cell Bio. 10 (7), 445-457 (2009).</li><li>Cristini, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphologic+Instability+and+Cancer+Invasion.">Morphologic Instability and Cancer Invasion.</a> Clin. Cancer Res. 11 (19), 6772-6779 (2005).</li><li>Lammermann, 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=Rapid+leukocyte+migration+by+integrin-independent+flowing+and+squeezing.">Rapid leukocyte migration by integrin-independent flowing and squeezing.</a> Nature. 453 (7191), 51-55 (2008).</li><li>Parent, C. A., Devreotes, P. N. <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's+sense+of+direction.">A cell's sense of direction.</a> Science. 284 (5415), 765-770 (1999).</li><li>Boyden, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+chemotactic+effect+of+mixtures+of+antibody+and+antigen+on+polymorphonuclear+leucocytes.">The chemotactic effect of mixtures of antibody and antigen on polymorphonuclear leucocytes.</a> J. Exp. Med. 115, 453-466 (1962).</li><li>Nelson, R. D., Quie, P. G., Simmons, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemotaxis+under+agarose:+a+new+and+simple+method+for+measuring+chemotaxis+and+spontaneous+migration+of+human+polymorphonuclear+leukocytes+and+monocytes.">Chemotaxis under agarose: a new and simple method for measuring chemotaxis and spontaneous migration of human polymorphonuclear leukocytes and monocytes.</a> J. Immunol. 115 (6), 1650-1656 (1975).</li><li>Rosoff, W. J., McAllister, R., Esrick, M. A., Goodhill, G. J., Urbach, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generating+controlled+molecular+gradients+in+3D+gels.">Generating controlled molecular gradients in 3D gels.</a> Biotechnol. Bioeng. 91 (6), 754-759 (2005).</li><li>Wells, A., Kassis, J., Solava, J., Turner, T., Lauffenburger, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth+factor-induced+cell+motility+in+tumor+invasion.">Growth factor-induced cell motility in tumor invasion.</a> Acta Oncol. 41 (2), 124-130 (2002).</li><li>Wilkinson, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assays+of+leukocyte+locomotion+and+chemotaxis.">Assays of leukocyte locomotion and chemotaxis.</a> J. Immunol. Methods. 216 (1-2), 139-153 (1998).</li><li>Bonvin, C., Overney, J., Shieh, A. C., Dixon, J. B., Swartz, M. 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+multichamber+fluidic+device+for+3D+cultures+under+interstitial+flow+with+live+imaging:+development,+characterization,+and+applications.">A multichamber fluidic device for 3D cultures under interstitial flow with live imaging: development, characterization, and applications.</a> Biotechnol. Bioeng. 105 (5), 982-991 (2010).</li><li>Noo, L. J., 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=Neutrophil+chemotaxis+in+linear+and+complex+gradients+of+interleukin-8+formed+in+a+microfabricated+device.">Neutrophil chemotaxis in linear and complex gradients of interleukin-8 formed in a microfabricated device.</a> Nat. Biotechnol. 20 (8), 826-830 (2002).</li><li>Shao, J., 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=Integrated+microfluidic+chip+for+endothelial+cells+culture+and+analysis+exposed+to+a+pulsatile+and+oscillatory+shear+stress.">Integrated microfluidic chip for endothelial cells culture and analysis exposed to a pulsatile and oscillatory shear stress.</a> Lab Chip. 9 (21), 3118-3125 (2009).</li><li>Haessler, U., Kalinin, Y., Swartz, M. A., Wu, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+agarose-based+microfluidic+platform+with+a+gradient+buffer+for+3D+chemotaxis+studies.">An agarose-based microfluidic platform with a gradient buffer for 3D chemotaxis studies.</a> Biomed. Microdevices. 11 (4), 827-835 (2009).</li><li>Friedl, P., Wolf, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumour-cell+invasion+and+migration:+diversity+and+escape+mechanisms.">Tumour-cell invasion and migration: diversity and escape mechanisms.</a> Nat. Rev. Cancer. 3 (5), 362-374 (2003).</li><li>Sixt, M., Lammermann, T. <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+analysis+of+chemotactic+leukocyte+migration+in+3D+environments.">In vitro analysis of chemotactic leukocyte migration in 3D environments.</a> Methods Mol. Biol. 769, 149-165 (2011).</li><li>Zigmond, 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=Ability+of+polymorphonuclear+leukocytes+to+orient+in+gradients+of+chemotactic+factors.">Ability of polymorphonuclear leukocytes to orient in gradients of chemotactic factors.</a> J. Cell Biol. 75 (2 Pt 1), 606-616 (1977).</li><li>Zicha, D., Dunn, G. A., Brown, A. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+direct-viewing+chemotaxis+chamber.">A new direct-viewing chemotaxis chamber.</a> J. Cell. Sci. 99 (Pt 4), 769-775 (1991).</li><li>Gilbert, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macromolecular+diffusion+through+collagen+membranes.">Macromolecular diffusion through collagen membranes.</a> Int. J. Pharm. 47 (1-3), 79-88 (1988).</li><li>Ramanujan, 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=Diffusion+and+convection+in+collagen+gels:+implications+for+transport+in+the+tumor+interstitium.">Diffusion and convection in collagen gels: implications for transport in the tumor interstitium.</a> Biophys. J. 83 (3), 1650-1660 (2002).</li><li>Weadock, K., Silver, F. H., Wolff, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diffusivity+of+125I-calmodulin+through+collagen+membranes:+effect+of+source+concentration+and+membrane+swelling+ratio.">Diffusivity of 125I-calmodulin through collagen membranes: effect of source concentration and membrane swelling ratio.</a> Biomaterials. 7 (4), 263-267 (1986).</li><li>Erikson, A., Andersen, H. N., Naess, S. N., Sikorski, P., Davies, C. d. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physical+and+chemical+modifications+of+collagen+gels:+impact+on+diffusion.">Physical and chemical modifications of collagen gels: impact on diffusion.</a> Biopolymers. 89 (2), 135-143 (2008).</li><li>Moghe, P. V., Nelson, R. D., Tranquillo, R. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytokine-stimulated+chemotaxis+of+human+neutrophils+in+a+3-D+conjoined+fibrin+gel+assay.">Cytokine-stimulated chemotaxis of human neutrophils in a 3-D conjoined fibrin gel assay.</a> J. Immunol. Methods. 180 (2), 193-211 (1995).</li><li>Sundd, 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=Live+cell+imaging+of+paxillin+in+rolling+neutrophils+by+dual-color+quantitative+dynamic+footprinting.">Live cell imaging of paxillin in rolling neutrophils by dual-color quantitative dynamic footprinting.</a> Microcirculation. 18 (5), 361-372 (2011).</li><li>Sanders, E. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aseptic+Laboratory+Techniques:+Volume+Transfers+with+Serological+Pipettes+and+Micropipettors.">Aseptic Laboratory Techniques: Volume Transfers with Serological Pipettes and Micropipettors.</a> J. Vis. Exp. (63), 2754 (2012).</li><li>Stephenson, F. 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> Calculations for Molecular Biology and Biotechnology: A Guide to Mathematics in the Laboratory 2e. , (2010).</li><li>Bar-Kochba, E., Toyjanova, J., Andrews, E., Kim, K., Franck, 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+Fast+Iterative+Digital+Volume+Correlation+Algorithm+for+Large+Deformations.">A Fast Iterative Digital Volume Correlation Algorithm for Large Deformations.</a> Exp. Mech. In press, (2014).</li><li>Shenoy, V., Rosenblatt, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diffusion+of+Macromolecules+in+Collagen+and+Hyaluronic+Acid,+Rigid-Rod-Flexible+Polymer+Composite+Matrixes.">Diffusion of Macromolecules in Collagen and Hyaluronic Acid, Rigid-Rod-Flexible Polymer Composite Matrixes.</a> Macromolecules. 28 (26), 8751-8758 (1995).</li><li>Leddy, H., Guilak, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Site-Specific+Molecular+Diffusion+in+Articular+Cartilage+Measured+using+Fluorescence+Recovery+after+Photobleaching.">Site-Specific Molecular Diffusion in Articular Cartilage Measured using Fluorescence Recovery after Photobleaching.</a> Ann. Biomed. Eng. 31 (7), 753-760 (2003).</li></ol>

The authors declare that they have no competing financial interests.

The most critical steps for successful diffusion experiments with or without cells are: correctly setting up the mold assembly; developing the necessary manual dexterity to prevent damage during extraction of hydrophobic coverslips; ensuring to find a very good linear starting line to correctly calculate the diffusion coefficient; correct experimental calculations of both collagen and chemoattractant; correctly use of live cell imaging system to ensure matrix does not dry out; and maintaining a sterile, healthy culture.<...

The preferred movement of cells towards a concentration gradient, known as chemotaxis, plays an important role in pathological and physiological processes in the body. Such examples are skin and mucosa wound healing1, morphogenesis2, inflammation3, and tumor growth4,5. It has also been shown that cancer cells can migrate through both individual and collective cell-migration strategies6. Moreover, diffusional instability mechanisms can induce the separation of single or clustered cells from a tumorous body/object and then can immigrate towards a source of nutrients and thus invade wider areas and tissues7.
Furthermore, it has been shown that diverse migration mechanisms can be active in 2D and in 3D, due to different roles of adhesion molecules8. Therefore, a move to physiologically relevant in vitro assays to investigate cell motility in a measureable and simple way is of significance in understanding cell movement phenomena9. Unfortunately, the difficulty in analyzing cell migration, a comprehensive quantifiable chemotaxis assay usually requires a long laborious method, founded on the measurement of impartial cell motility and transport phenomena models.
Past experimental approaches to investigate cell chemotaxis include the Boyden chamber10 and the under agarose assay11. However, within these early assays, cell migration experiments did not monitor the movement in respect to time. More, importantly, the concentration gradients used for the experiments were not well defined or completely understood while only sustaining the signaling for no more than a few hr. Furthermore, early chemotaxis chamber attempts restricted cell migration to two dimensions and did not allow one to monitor the kinetics of migration12. Looking at the Boyden chamber, an endpoint assay would not allow the researcher to observe migration visually and could not directly differentiate chemotaxis (directional movement) from chemokinesis (random movement). Additionally, several variables&#8212;differences in the pore size and thickness of membranes&#8212;made the chamber very difficult to easily reproduce and concealed the migrant reaction of cells to chemokines13,14.
With the new understanding of microfluidics, new chambers and micro-devices have been investigated as an instrument to investigate cell locomotion under interstitial flow conditions or chemotaxis15,16. Under these new devices, new cell metrics were introduced and investigated, like the effect of shear stress on a cell17,18. Unfortunately, past and current microfluidic chemotaxis chambers limited studies of cell migration to 2D substrates&#8212;an important setback since many biological processes, including tumor cell invasion and metastasis, and immune cell migration, involve 3D migration.
Direct observation chambers&#8212;where a chemoattractant solution is in contact with a 3D gel containing cells have also been also reported19,20. These chambers have two compartments, one containing a chemoattractant and one containing cells, are joined beside one another horizontally21 or as concentric rings22. These systems are pointed in the right direction, but do not keep a chemotaxis system for an extended period of time.
Furthermore, researchers have also examined diffusivity through collagen membranes in dialysis cells, as well as the diffusion of tracer molecules through collagen samples subjected to hydrostatic pressure23-25. Some diffusion experiments in collagen gels rely on physical and chemical modifications of the gel using magnetic fields and chemical incorporation26. A popular method for modeling diffusivity in collagenous tissues relies on the fluorescence imaging of continuous point photobleaching. This method has revealed anisotropy in the diffusion coefficients of macromolecules in oriented collagenous tissues. Yet, photobleaching has been used in articular cartilage and not collagen matrices. While similar, the necessary modeling experiments must be carried through specifically understanding the diffusion coefficient of collagen gels. More importantly, the systems do not utilize a method for measuring cell force generation.
Unfortunately, most systems seem to be missing one or two key elements for an ideal system: the allowing of cell tracking, a diffusion gradient understanding with a chemotactic factor through the matrix, a relatively simple set up with an ease of reproducibility, the minimization of cell-cell interactions, and the ability to measure dimensional units for quantification (i.e., velocity, force, specific concentration). Moghe et al.27 proposed a system that fulfilled most of these requirements in which cells were initially dispersed throughout the gel rather than concentrated on the filter surface, but was difficult to measure forces that the cell generates.
To this purpose, we present a planar gradient diffusion system to investigate chemotaxis in a 3D collagen matrix, which allows one to overcome modern diffusion chamber limitations of existing assays, which is based on time-lapse microscopy, coupled with image analysis techniques to measure cell forces in a 3D environment. This protocol provides a simple, yet innovative way of creating a simple 3D diffusion chamber that can be used to investigate 3D chemotaxis in different cells.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Silicone elastomer kit</td>
			<td>Dow Corning Corp</td>
			<td>182 SIL ELAST KIT .5KG</td>
			<td>a two-part misture with a 10:1 mix</td>
		</tr>
		<tr>
			<td>Live cell imaging chamber</td>
			<td>Live Cell Instrument</td>
			<td>CM-B18-1</td>
			<td>CMB for 18mm round coverslips</td>
		</tr>
		<tr>
			<td>22mm Glass Coverslip</td>
			<td>Fisher Scientific</td>
			<td>NC0180281</td>
			<td>Neuvitro Corp. cover slip 22mm 1.5</td>
		</tr>
		<tr>
			<td>Machined aluminum metal cube</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hobby utility knife</td>
			<td>X-Acto</td>
			<td>X3201</td>
			<td></td>
		</tr>
		<tr>
			<td>3-(aminopropyl) trimethoxysilane</td>
			<td>Sigma-Aldrich</td>
			<td>281778-5ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Glutaraldehyde</td>
			<td>Polysciences, Inc</td>
			<td>00216A-10</td>
			<td>Glutaraldehyde, EM Grade, 8%</td>
		</tr>
		<tr>
			<td>50 ml tube</td>
			<td>Fisher Scientific</td>
			<td>14-432-22</td>
			<td>Standard floor model and tabletop centrifuges</td>
		</tr>
		<tr>
			<td>Glass petri dish</td>
			<td>Fisher Scientific</td>
			<td>08-747A</td>
			<td>Reusable Petri Dishes: Complete (60 x 15mm)</td>
		</tr>
		<tr>
			<td>Forceps</td>
			<td>Fisher Scientific</td>
			<td>22-327-379</td>
			<td>Fine Point Forceps</td>
		</tr>
		<tr>
			<td>Cover glasses</td>
			<td>Fisher Scientific</td>
			<td>12-518-105A</td>
			<td>Rectangle; 30 x 22mm; Thickness No. 1</td>
		</tr>
		<tr>
			<td>Tridecafluoro-1,1,2,2-tetrahydrooctyl</td>
			<td>Gelest</td>
			<td>SIT8174.0</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic acid</td>
			<td>Sigma-Aldrich</td>
			<td>320099</td>
			<td>Acetic acid ACS reagent, &#8805;99.7%</td>
		</tr>
		<tr>
			<td>Hexane</td>
			<td>Sigma-Aldrich</td>
			<td>296090</td>
			<td>Hexane</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>anhydrous, 95%</td>
		</tr>
		<tr>
			<td>Ethyl alcohol</td>
			<td>Sigma-Aldrich</td>
			<td>E7023</td>
			<td>200 proof, for molecular biology</td>
		</tr>
		<tr>
			<td>High-precision diamond scribing tool</td>
			<td>Lunzer</td>
			<td>PV-081-3</td>
			<td>Straight extended tip scribe, .020&#34; (.50mm) diameter by .200&#34; (5.0mm) tip length</td>
		</tr>
		<tr>
			<td>Vacuum grease</td>
			<td>Dow Corning</td>
			<td>14-635-5C</td>
			<td>High-Vacuum Grease</td>
		</tr>
		<tr>
			<td>15 ml tube</td>
			<td>Fisher Scientific</td>
			<td>14-959-49D</td>
			<td>15 ml conical centrifuge tubes with hydrophobic, biologically inert surface</td>
		</tr>
		<tr>
			<td>10X phosphate buffered solution</td>
			<td>Fisher Scientific</td>
			<td>BP399-500</td>
			<td>1.37 M Sodium Chloride, 0.027 M Potassium Chloride, and 0.119 M Phosphate Buffer</td>
		</tr>
		<tr>
			<td>1N sodium hydroxide</td>
			<td>Sigma-Aldrich</td>
			<td>38215</td>
			<td>Sodium hydroxide concentrate</td>
		</tr>
		<tr>
			<td>Collagen I, rat tail</td>
			<td>BD Biosciences</td>
			<td>354236</td>
			<td>Rat tail&#160;</td>
		</tr>
		<tr>
			<td>Micro centrifuge tube</td>
			<td>Fisher Scientific</td>
			<td>02-681-332</td>
			<td>Volume: 2.0 ml; O.D. x L: 13 x 40 mm; sterile; single-wrapped</td>
		</tr>
		<tr>
			<td>Carboxylate-modified microspheres</td>
			<td>Invitrogen</td>
			<td>&#160;F-8813</td>
			<td>Carboxylate-modified microspheres, 0.5 &#181;m, yellow-green fluorescent (505/515), 2% solids</td>
		</tr>
		<tr>
			<td>Rhodamine</td>
			<td>Sigma-Aldrich</td>
			<td>83689</td>
			<td>Rhodamine B for fluorescence</td>
		</tr>
	</tbody>
</table>

planar gradient diffusion system to investigate chemotaxis in a 3d collagen matrix

The importance of cell migration can be seen through the development of human life. When cells migrate, they generate forces and transfer these forces to their surrounding area, leading to cell movement and migration. In order to understand the mechanisms that can alter and/or affect cell migration, one can study these forces. In theory, understanding the fundamental mechanisms and forces underlying cell migration holds the promise of effective approaches for treating diseases and promoting cellular transplantation. Unfortunately, modern chemotaxis chambers that have been developed are usually restricted to two dimensions (2D) and have complex diffusion gradients that make the experiment difficult to interpret. To this end, we have developed, and describe in this paper, a direct-viewing chamber for chemotaxis studies, which allows one to overcome modern chemotaxis chamber obstacles able to measure cell forces and specific concentration within the chamber in a 3D environment to study cell 3D migration. More compelling, this approach allows one to successfully model diffusion through 3D collagen matrices and calculate the coefficient of diffusion of a chemoattractant through multiple different concentrations of collagen, while keeping the system simple and user friendly for traction force microscopy (TFM) and digital volume correlation (DVC) analysis.

The ability of this assay to accurately assess the migration of the cell relies upon a good setup of the system. Therefore, it is critical for make sure to design the diffusion system mold accurately and take great care in placing both hydrophobic and hydrophilic coverslips, as illustrated in Figure 1. If the system is properly designed and during the diffusion modeling stage ensuring to find a very good linear starting line, one is able to achieve nice fluoresces images, as depicted in Figure 2<...

Watch this Scientific Journal Video about Planar Gradient Diffusion System to Investigate Chemotaxis in a 3D Collagen Matrix at JoVE.com

Planar Gradient Diffusion System to Investigate Chemotaxis in a 3D Collagen Matrix

Cell migration is an important part of human development and life. In order to understand the mechanisms that can alter cell migration, we present a planar gradient diffusion system to investigate chemotaxis in a 3D collagen matrix, which allows one to overcome modern diffusion chamber limitations of existing assays.

The importance of cell migration can be seen through the development of human life. When cells migrate, they generate forces and transfer these forces to ...

planar-gradient-diffusion-system-to-investigate-chemotaxis-3d

Research

JoVE Journal

Bioengineering

8.4K visualizações.  California State University, Long Beach. Cell migration is an important part of human development and life. In order to understand the mechanisms that can alter cell migration, we present a planar gradient diffusion system to investigate chemotaxis in a 3D collagen matrix, which allows one to overcome modern diffusion chamber limitations of existing assays.