Name: establishing single-cell based co-cultures in a deterministic manner with a microfluidic chip
Uploaded: 2019-09-27T14:30:00
Description: Watch this Scientific Journal Video about Establishing Single-Cell Based Co-Cultures in a Deterministic Manner with a Microfluidic Chip at JoVE.com

This work was supported by a grant from the Ministry of Science and Technology (105-2628-E-400-001-MY2), and the Ph.D. Program in Tissue Engineering and Regenerative Medicine, National Chung Hsing University and National Health Research Institutes.

1. Fabrication of a wafer mold by soft lithography
NOTE: Mask pattern data is available in our previous publication14.
<ol>
	<li>Dehydrate a 4-inch silicon wafer in a 120 &#176;C oven for 15 min.</li>
	<li>Spin coat 4 g of SU-8 2 negative photoresist onto a 4-inch silicon wafer at 1,000 rpm for 30 s to create a 5 &#181;m thick layer (layer #1).</li>
	<li>Soft bake layer #1 on a 65 &#176;C hotplate for 1 min and then transfer layer #1 to a 95 &#176;C hotplate for 3 min...

<ol>
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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=A+high-throughput+platform+for+stem+cell+niche+co-cultures+and+downstream+gene+expression+analysis.">A high-throughput platform for stem cell niche co-cultures and downstream gene expression analysis.</a> Nature Cell Biology. 17 (3), 340 (2015).</li><li>Tumarkin, E., 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+combinatorial+cell+co-culture+using+microfluidics.">High-throughput combinatorial cell co-culture using microfluidics.</a> Integrative Biology. 3 (6), 653-662 (2011).</li><li>Hong, S., Pan, Q., Lee, L. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-cell+level+co-culture+platform+for+intercellular+communication.">Single-cell level co-culture platform for intercellular communication.</a> Integrative Biology. 4 (4), 374-380 (2012).</li><li>Chung, M. T., N&#250;&#241;ez, D., Cai, D., Kurabayashi, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deterministic+droplet-based+co-encapsulation+and+pairing+of+microparticles+via+active+sorting+and+downstream+merging.">Deterministic droplet-based co-encapsulation and pairing of microparticles via active sorting and downstream merging.</a> Lab on a Chip. 17 (21), 3664-3671 (2017).</li><li>Chen, Y. 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=Paired+single+cell+co-culture+microenvironments+isolated+by+two-phase+flow+with+continuous+nutrient+renewal.">Paired single cell co-culture microenvironments isolated by two-phase flow with continuous nutrient renewal.</a> Lab on a Chip. 14 (16), 2941-2947 (2014).</li><li>Hong, S., Lee, L. P., Pan, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-cell+level+co-culture+platform+for+intercellular+communication.">Single-cell level co-culture platform for intercellular communication.</a> Integrative Biology. 4 (4), 374-380 (2012).</li><li>Segaliny, A. I., 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=Functional+TCR+T+cell+screening+using+single-cell+droplet+microfluidics.">Functional TCR T cell screening using single-cell droplet microfluidics.</a> Lab on a Chip. 18 (24), 3733-3749 (2018).</li><li>He, C. K., Chen, Y. W., Wang, S. H., Hsu, 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=Hydrodynamic+shuttling+for+deterministic+high-efficiency+multiple+single-cell+capture+in+a+microfluidic+chip.">Hydrodynamic shuttling for deterministic high-efficiency multiple single-cell capture in a microfluidic chip.</a> Lab on a Chip. 19 (8), 1370-1377 (2019).</li><li>Wang, S. 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=Tumour+cell-derived+WNT5B+modulates+in+vitro+lymphangiogenesis+via+induction+of+partial+endothelial-mesenchymal+transition+of+lymphatic+endothelial+cells.">Tumour cell-derived WNT5B modulates in vitro lymphangiogenesis via induction of partial endothelial-mesenchymal transition of lymphatic endothelial cells.</a> Oncogene. 36, 1503 (2016).</li><li>Strober, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trypan+Blue+Exclusion+Test+of+Cell+Viability.">Trypan Blue Exclusion Test of Cell Viability.</a> Current Protocols in Immunology. 111 (1), A3.B.1-A3.B.3 (2015).</li><li>Kim, J. B., Stein, R., O'hare, 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=Three-dimensional+in+vitro+tissue+culture+models+of+breast+cancer-a+review.">Three-dimensional in vitro tissue culture models of breast cancer-a review.</a> Breast Cancer Research and Treatment. 85 (3), 281-291 (2004).</li><li>Shin, 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=Microfluidic+assay+for+simultaneous+culture+of+multiple+cell+types+on+surfaces+or+within+hydrogels.">Microfluidic assay for simultaneous culture of multiple cell types on surfaces or within hydrogels.</a> Nature Protocols. 7 (7), 1247-1259 (2012).</li><li>Wu, M. H., Huang, S. B., Lee, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+cell+culture+systems+for+drug+research.">Microfluidic cell culture systems for drug research.</a> Lab on a Chip. 10 (8), 939-956 (2010).</li><li>Hong, J. W., Song, S., Shin, J. 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+novel+microfluidic+co-culture+system+for+investigation+of+bacterial+cancer+targeting.">A novel microfluidic co-culture system for investigation of bacterial cancer targeting.</a> Lab on a Chip. 13 (15), 3033-3040 (2013).</li></ol>

The intercellular interactions of various cells in the tumor microenvironment play an important role in the progression of the tumor17. In order to understand the mechanism of cell-cell interactions, co-culture systems are used as a common analytical method. However, multiple cell types and the heterogeneity of the cells themselves have led to experimental complexity and analytical difficulties.
The hydrodynamic shuttling chip allows multiple single-cell loading in the ...

Efficient capture of different types of single cells and providing sufficient culture space are needed for single cell co-culture experiments of multiple types of single cells1. Limiting dilution is the most commonly used method to prepare the single cells for such experiments, due to the low cost of equipment required. However, due to the Poisson distribution limitation, the maximum single cell acquisition probability is only 37%, making the experimental operation laborious and time-consuming2. In contrast, using fluorescence activated cell sorting (FACS) can overcome the Poisson distribution limitation to high-efficiently prepare single cells3. However, FACS may not be accessible to some laboratories due to expensive instrumentation and maintenance cost. Microfabricated devices have been recently developed for single cell trapping4, single cell pairing5, and single cell culture applications. These devices are advantageous based on their ability to accurately manipulate single cells6, perform high-throughput experiments, or reduce sample and reagent consumption. However, performing single-cell co-culture experiments with multiple cell types with the current microfluidic devices is still challenging due the limitation of Poisson distribution1,7,8, or inability of the devices to capture more than two types of single cells4,5,6,9,10.
For example, Yoon et al. reported a microfluidic device for cell-cell interaction study11. This device uses the probabilistic method to pair cells in one chamber. However, it can only achieve the pairing of two different cell types due to geometric restrictions in the device structure. Another report from Lee et al. demonstrated a deterministic method to capture and pair single cells12. This device is increases pairing efficiency by the deterministic method but it is limited by the prolonged operation time required to pair cells. Specifically, the second cell capture can only be performed after the first captured cell is attached to the surface after 24 h. Zhao et al. reported a droplet-based microfluidic device to capture two types of a single cell13. We can found that the droplet-based microfluidic device is still limited to the Poisson distribution and can only be used on non-attached cells, and it is not possible to change the culture solution during the cultivation process.
Previously, we have developed a microfluidic &#34;hydrodynamic shuttling chip&#34; that utilizes deterministic hydrodynamic forces to capture multiple types of single-cell into the culture chamber and can subsequently perform cell co-culture experiment to analyze individual cell migration behavior under cell-cell interactions14. The hydrodynamic shuttling chip comprises an arrayed sets of units that each contains a serpentine by-pass channel, a capture-site, and a culture chamber. By using the difference in flow resistance between the serpentine by-pass channel and the culture chamber, and a specially designed operation procedure, different types of single cells can be repeatedly captured into the culture chamber. Notably, the ample space of the culture chamber can not only prevent the cell from being flushed during cell capture out but also provide sufficient space for the cells to spread, proliferate and migrate, allowing for observing of live single-cell interactions. In this article, we focus on the production of this device and detailed protocol steps.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>3M Advanced Polyolefin Diagnostic Microfluidic Medical Tape</td>
			<td>3M Company</td>
			<td>9795R</td>
			<td></td>
		</tr>
		<tr>
			<td>Antibiotics</td>
			<td>Biowest</td>
			<td>L0014-100</td>
			<td>Glutamine-Penicillin-Streptomycin</td>
		</tr>
		<tr>
			<td>AutoCAD software</td>
			<td>Autodesk</td>
			<td>AutoCAD LT 2011</td>
			<td>Part No. 057C1-74A111-1001</td>
		</tr>
		<tr>
			<td>CellTracke Blue CMAC Dye</td>
			<td>Invitrogen</td>
			<td>C2110</td>
			<td></td>
		</tr>
		<tr>
			<td>CellTracker Green CMFDA Dye</td>
			<td>Invitrogen</td>
			<td>C7025</td>
			<td></td>
		</tr>
		<tr>
			<td>Conventional oven</td>
			<td>YEONG-SHIN company</td>
			<td>ovp45</td>
			<td></td>
		</tr>
		<tr>
			<td>Desiccator</td>
			<td>Bel-Art Products</td>
			<td>F42020-0000</td>
			<td>Space saver vacuum desiccator 190 mm white base</td>
		</tr>
		<tr>
			<td>DiIC12(3) cell membrane dye</td>
			<td>BD Biosciences</td>
			<td>354218</td>
			<td>Used as a cell tracker</td>
		</tr>
		<tr>
			<td>DMEM-F12 medium</td>
			<td>Gibco</td>
			<td>11320-082</td>
			<td></td>
		</tr>
		<tr>
			<td>Endothelial Cell Growth Medium MV 2</td>
			<td>PromoCell</td>
			<td>C-22022</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal bovine serum Hyclone</td>
			<td>Thermo</td>
			<td>SH30071.03HI</td>
			<td></td>
		</tr>
		<tr>
			<td>Hamilton 700 series Glass syringe ( 0.1 ml )</td>
			<td>Hamilton</td>
			<td>80630</td>
			<td>100 &#181;L, Model 710 RN SYR, Small Removable NDL, 22s ga, 2 in, point style 2</td>
		</tr>
		<tr>
			<td>Harris Uni-Core puncher</td>
			<td>Ted Pella Inc.</td>
			<td>15075</td>
			<td>with 1.5mm inner-diameter</td>
		</tr>
		<tr>
			<td>Harris Uni-Core puncher</td>
			<td>Ted Pella Inc.</td>
			<td>15071</td>
			<td>with 0.5mm inner-diameter</td>
		</tr>
		<tr>
			<td>Hotplate</td>
			<td>YOTEC company</td>
			<td>YS-300S</td>
			<td></td>
		</tr>
		<tr>
			<td>Msak aligner</td>
			<td>Deya Optronic CO.</td>
			<td>A1K-5-MDA</td>
			<td></td>
		</tr>
		<tr>
			<td>Oxygen plasma</td>
			<td>NORDSON MARCH</td>
			<td>AP-300</td>
			<td></td>
		</tr>
		<tr>
			<td>Plasma cleaner</td>
			<td>Nordson</td>
			<td>AP-300</td>
			<td>Bench-Top Plasma Treatment System</td>
		</tr>
		<tr>
			<td>Polydimethylsiloxane (PDMS) kit</td>
			<td>Dow corning</td>
			<td>Sylgard 184</td>
			<td></td>
		</tr>
		<tr>
			<td>Poly-tetrafluoroethene (PTFE)</td>
			<td>Ever Sharp Technology, Inc.</td>
			<td>TFT-23T</td>
			<td>inner diameter, 0.51 mm; outer diameter, 0.82 mm</td>
		</tr>
		<tr>
			<td>Removable tape</td>
			<td>3M Company</td>
			<td>Scotch Removable Tape 811</td>
			<td></td>
		</tr>
		<tr>
			<td>Silicon wafer</td>
			<td>Eltech corperation</td>
			<td>SPE0039</td>
			<td></td>
		</tr>
		<tr>
			<td>Spin coater</td>
			<td>Synrex Co., Ltd.</td>
			<td>SC-HMI 2&#34; ~ 6&#34;</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereomicroscope</td>
			<td>Leica Microsystems</td>
			<td>Leica E24</td>
			<td></td>
		</tr>
		<tr>
			<td>SU-8 10 negative photoresist</td>
			<td>MicroChem</td>
			<td>Y131259</td>
			<td></td>
		</tr>
		<tr>
			<td>SU-8 2 negative photoresist</td>
			<td>MicroChem</td>
			<td>Y131240</td>
			<td></td>
		</tr>
		<tr>
			<td>SU-8 2050 negative photoresist</td>
			<td>MicroChem</td>
			<td>Y111072</td>
			<td></td>
		</tr>
		<tr>
			<td>SU-8 developer</td>
			<td>Grand Chemical Companies</td>
			<td>GP5002-000000-72GC</td>
			<td>Propylene glycol monomethyl ether acetate</td>
		</tr>
		<tr>
			<td>Syringe pump</td>
			<td>Harvard Apparatus</td>
			<td>703007</td>
			<td></td>
		</tr>
		<tr>
			<td>Trichlorosilane</td>
			<td>Gelest, Inc</td>
			<td>SIT8174.0</td>
			<td>Tridecafluoro-1,1,2,2-tetrahydrooctyl. Hazardous. Corrosive to the respiratory tract, reacts violently with water.</td>
		</tr>
		<tr>
			<td>Trypsin Neutralizer Solution</td>
			<td>Gibco</td>
			<td>R-002-100</td>
			<td></td>
		</tr>
	</tbody>
</table>

establishing single-cell based co-cultures in a deterministic manner with a microfluidic chip

Cell co-culture assays have been widely used for studying cell-cell interactions between different cell types to better understand the biology of diseases including cancer. However, it is challenging to clarify the complex mechanism of intercellular interactions in highly heterogeneous cell populations using conventional co-culture systems because the heterogeneity of the cell subpopulation is obscured by the average values; the conventional co-culture systems can only be used to describe the population signal, but are incapable of tracking individual cells behavior. Furthermore, conventional single-cell experimental methods have low efficiency in cell manipulation because of the Poisson distribution. Microfabricated devices are an emerging technology for single-cell studies because they can accurately manipulate single cells at high-throughput and can reduce sample and reagent consumption. Here, we describe the concept and application of a microfluidic chip for multiple single-cell co-cultures. The chip can efficiently capture multiple types of single cells in a culture chamber (~46%) and has a sufficient culture space useful to study the cells&#39; behavior (e.g., migration, proliferation, etc.) under cell-cell interaction at the single-cell level. Lymphatic endothelial cells and oral squamous cell carcinoma were used to perform a single-cell co-culture experiment on the microfluidic platform for live multiple single-cell interaction studies.

The device has a three-layer structure as shown by the cross-section photograph of a cut PDMS device (Figure 1A). The first layer contains a capture-site (6.0 &#181;m in width and 4.6 &#181;m in height) that connects the culture chamber and the by-pass channel. The difference in flow resistance between the culture chamber and the by-pass channel causes the cells to flow into the capture position and fill the entrance of the small path. After ...

Watch this Scientific Journal Video about Establishing Single-Cell Based Co-Cultures in a Deterministic Manner with a Microfluidic Chip at JoVE.com

Establishing Single-Cell Based Co-Cultures in a Deterministic Manner with a Microfluidic Chip

This report describes a microfluidic chip-based method to set up a single cell culture experiment in which high-efficiency pairing and microscopic analysis of multiple single cells can be achieved.

Cell co-culture assays have been widely used for studying cell-cell interactions between different cell types to better understand the biology of diseases ...

It is critical to effectively combine capture efficiency with dynamic live cell image observation to understand the effect of cell-cell interaction on cell behaviors. This tube can highly efficiently capture multiple single cells in a larger chamber, and provide a sufficient cultures base, for dynamic tracking of multiple single-cell interaction behaviors. Start by preparing the PDMS device.Place a wafer mold in the weighing dish with 100 microliters of trichlorosilane in a desiccator and apply a vacuum for 15 minutes. Stop the vacuum and salinize the wafer mold in the desiccator at 37 degrees Celsius for at least one hour. Mix the PDMS base and PDMS curing agent at a ratio of ten to one, then pour a total of 20 grams of the mixture onto the wafer mold in a 15-centimeter dish.Place the 15-centimeter dish into a desiccator and apply a vacuum for one and a half minutes. Then remove the dish from the desiccator and eliminate residual air bubbles in the PDMS with nitrogen gas. Cure the PDMS by placing the dish in an oven at 65 degrees celsius for two to four hours.When finished, remove the PDMS replica from the wafer mold, and punch a 1.5-millimeter inlet and 0.5-millimeter outlet on the PDMS. Clean the PDMS replica and the slide surface with removable tape. Treat the surface with oxygen plasma.Then, manually align the PDMS replica with the slide and bring them into contact with each other. Leave the PDMS slide in the 65 degree Celsius oven for one day. The next day, immerse the PDMS device in a container filled with PBS.Place it into the desiccator, and apply vacuum for 15 minutes. Move the device to a cell culture hood and sterilize it with UV light for 30 minutes. Replace the PDMS device buffer with medium and incubate it at four degrees Celsius for one day.When the cells achieve 70 to 80%confluency, remove the culture medium and gently wash them three times with five milliliters of PBS. Add one milliliter of DMEM/F-12 medium containing one micromolar fluorescent dye to the WNT5B sh4 and pLKO-GFP cells, and incubate them for 30 minutes at room temperature. After the incubation, gently wash the cells three times with five milliliters of sterile PBS, remove the PBS, and add two milliliters of 0.25%Trypsin-EDTA.Incubate the cells for four minutes at room temperature, then gently tap the culture dish to promote cell detachment. Add four milliliters of DMEM/F-12 medium to disperse WNT5B sh4 and pLKO-GFP cells, transfer the cells into a 15-milliliter tube and centrifuge them at 300 xg for three minutes. Remove the supernatant and gently re-suspend the cell pellet in one milliliter of DMEM/F-12 medium.Prepare one milliliter of cell suspension at a concentration of three times ten to fifth cells per milliliter and keep it on ice to prevent cell aggregation. Connect the polytetrafluoroethylene tube between the outlet of the device and the syringe pump. Remove the medium, and add one microliter of the prepared cell suspension into the inlet of the PDMS device.Next, load the cell suspension into the device using a syringe pump at a flow rate of 0.3 microliters per minute. Add one microliter of DMEM/F-12 medium into the inlet of the device, then load the medium into the device using a syringe pump. Load 0.3 microliters of DMEM/F12 medium into the device with the syringe pump at a flow rate of 10 microliters per minute.After the cells are loaded, remove the tube, and seal the inlet and outlet with polyolefin tape to create a closed culture system. Move the PDMS device to a 10-centimeter culture dish and add 10 milliliters of sterile PBS around the device to avoid evaporation of medium. Transfer the culture dish to an incubator for triple single-cell culture.The PDMS device has a three-layer structure with a capture site that connects to the culture chamber and the bypass channel. The difference in flow resistance between the culture chamber and the bypass channel allows the cell to flow into the capture position, which causes the following cell to go through the bypass channel to the next capture site. The reflux step is used to release the cell from the capture site and send it into the culture chamber.Cell capture efficiency of this protocol was evaluated on three different cell types. Human lymphatic endothelial cells, or LECs, human oral squamous cell carcinoma T2.6 cells expressing WNT5B-specific short hairpin RNA, and pLKO-GFP vector control cells. The single-cell capture efficiencies of the three demonstrated cells were approximately 71%for the LECs, 74%for WNT5B sh4 cells, and 78%for the pLKO-GFP cells.The triple single-cell capture efficiency was 48%This method can be used for multiple single-cell co-cultures of lymphatic endothelial cells and squamous cancer cells, and the cell's proliferation and morphology can be observed under a microscope. It is important to make sure the prepared cell suspensions have minimal cell aggregates, because cell aggregates not only reduce single pairing efficiency, but can also clog the micro channels. Cell-cell interaction between individual cells plays an important role in controlling cell behaviors.Our method can provide an efficient tool to help researchers study cell-cell interaction at a single cell level, which may lead to the discovery of new mechanisms which cannot be easily obtained from population-based studies.

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A Microfluidic Platform for High-throughput Single-cell Isolation and Culture

Studying the heterogeneity of single cells is crucial for many biological questions, but is technically difficult. Thus, there is a need for a simple, yet ...

Co-culture of Living Microbiome with Microengineered Human Intestinal Villi in a Gut-on-a-Chip Microfluidic Device

Here, we describe a protocol to perform long-term co-culture of multi-species human gut microbiome with microengineered intestinal villi in a human ...

Image-guided, Laser-based Fabrication of Vascular-derived Microfluidic Networks

This detailed protocol outlines the implementation of image-guided, laser-based hydrogel degradation for the fabrication of vascular-derived microfluidic ...

Dry Film Photoresist-based Electrochemical Microfluidic Biosensor Platform: Device Fabrication, On-chip Assay Preparation, and System Operation

In recent years, biomarker diagnostics became an indispensable tool for the diagnosis of human disease, especially for the point-of-care diagnostics. An ...