We thank Mike Vahey from the Fletcher Lab at the University of California, Berkeley for advice on the microjetting parameters. This work was sponsored by NIH grant DP2 HL117748-01.

1. Infinity Chamber Fabrication
<ol>
	<li>Design the infinity chamber (named for its shape) using a computer assisted design (CAD) software, and save the file such that it is compatible with a laser cutter. To create this shape, separate two circles of diameter 0.183 in&#160;by a center-to-center distance of 0.15 in. Cut the chamber from 1/8- 3/16 in&#160;clear acrylic with the laser cutter. The infinity shape facilitates droplet interface bilayer formation and stability.</li>
	<li>Drill a 1/16 in&#160;hole through the...

<ol>
	<li>Liu, A. P., Fletcher, 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=Biology+under+construction:+in+vitro+reconstitution+of+cellular+function.">Biology under construction: in vitro reconstitution of cellular function.</a> Nature reviews. Mol. Cell Biol. 10, 644-650 (2009).</li><li>Yeh, B. J., Lim, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthetic+biology:+lessons+from+the+history+of+synthetic+organic+chemistry.">Synthetic biology: lessons from the history of synthetic organic chemistry.</a> Nat. Chem. Biol. 3, 521-525 (2007).</li><li>Richmond, 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=Forming+giant+vesicles+with+controlled+membrane+composition,+asymmetry,+and+contents.">Forming giant vesicles with controlled membrane composition, asymmetry, and contents.</a> Proc. Natl. Acad. Soc. U.S.A. 108, 9431-9436 (2011).</li><li>Liu, A. 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=Membrane-induced+bundling+of+actin+filaments.">Membrane-induced bundling of actin filaments.</a> Nat. Phys. 4, 789-793 (2008).</li><li>Brown, K. 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=Xenopus+tropicalis+egg+extracts+provide+insight+into+scaling+of+the+mitotic+spindle.">Xenopus tropicalis egg extracts provide insight into scaling of the mitotic spindle.</a> J. Cell Biol. 176, 765-770 (2007).</li><li>Loose, M., Fischer-Friedrich, E., Ries, J., Kruse, K., Schwille, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatial+regulators+for+bacterial+cell+division+self-organize+into+surface+waves+in+vitro.">Spatial regulators for bacterial cell division self-organize into surface waves in vitro.</a> Science. 320, 789-792 (2008).</li><li>Angelova, M. I., Dimitrov, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liposome+electroformation.">Liposome electroformation.</a> Faraday Disc. Chem. Soc. 81, 301-311 (1986).</li><li>Bucher, P., Fischer, A., Luisi, L. P., Oberholzer, T., Walde, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Giant+Vesicles+as+Biochemical+Compartments:+The+Use+of+Microinjection+Techniques.">Giant Vesicles as Biochemical Compartments: The Use of Microinjection Techniques.</a> Langmuir. 14, 2712-2721 (1998).</li><li>Shum, H. C., Lee, D., Yoon, I., Kodger, T., Weitz, 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=Double+emulsion+templated+monodisperse+phospholipid+vesicles.">Double emulsion templated monodisperse phospholipid vesicles.</a> Langmuir. 24, 7651-7653 (2008).</li><li>Matosevic, S., Paegel, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stepwise+Synthesis+of+Giant+Unilamellar+Vesicles+on+a+Microfluidic+Assembly+Line.">Stepwise Synthesis of Giant Unilamellar Vesicles on a Microfluidic Assembly Line.</a> J. Am. Chem. Soc. 133, 2798-2800 (2011).</li><li>Hu, P. C. C., Li, S., Malmstadt, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+Fabrication+of+Asymmetric+Giant+Lipid+Vesicles.">Microfluidic Fabrication of Asymmetric Giant Lipid Vesicles.</a> ACS Appl. Mater. Inter. 3, 1434-1440 (1021).</li><li>Hwang, W. L., Chen, M., Cronin, B., Holden, M. A., Bayley, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Asymmetric+droplet+interface+bilayers.">Asymmetric droplet interface bilayers.</a> J. Am. Chem. Soc. 130, 5878-5879 (2008).</li><li>Stachowiak, J. C., Richmond, D. L., Li, T. H., Brochard-Wyart, F., Fletcher, 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=Inkjet+formation+of+unilamellar+lipid+vesicles+for+cell-like+encapsulation.">Inkjet formation of unilamellar lipid vesicles for cell-like encapsulation.</a> Lab Chip. 9, 2003-2009 (2009).</li><li>Meleard, P., Bagatolli, L. A., Pott, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Giant+unilamellar+vesicle+electroformation+from+lipid+mixtures+to+native+membranes+under+physiological+conditions.">Giant unilamellar vesicle electroformation from lipid mixtures to native membranes under physiological conditions.</a> Methods Enzymol. 465, 161-176 (2009).</li><li>Nishimura, K., Suzuki, H., Toyota, T., Yomo, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Size+control+of+giant+unilamellar+vesicles+prepared+from+inverted+emulsion+droplets.">Size control of giant unilamellar vesicles prepared from inverted emulsion droplets.</a> J. Colloid Interface Sci. 376, 119-125 (2012).</li><li>Teh, S. Y., Lin, R., Hung, L. H., Lee, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Droplet+Microfluidics.">Droplet Microfluidics.</a> Lab Chip. 8, 198-220 (2008).</li><li>Stachowiak, J. 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=Unilamellar+vesicle+formation+and+encapsulation+by+microfluidic+jetting.">Unilamellar vesicle formation and encapsulation by microfluidic jetting.</a> Proc. Natl. Acad. Sci. U.S.A. 105, 4697-4702 (2008).</li><li>Osaki, T., Yoshizawa, S., Kawano, R., Sasaki, H., Takeuchi, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid-coated+microdroplet+array+for+in+vitro+protein+synthesis.">Lipid-coated microdroplet array for in vitro protein synthesis.</a> Anal. Chem. 83, 3186-3191 (2011).</li><li>Liu, A. P., Fletcher, 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=Actin+polymerization+serves+as+a+membrane+domain+switch+in+model+lipid+bilayers.">Actin polymerization serves as a membrane domain switch in model lipid bilayers.</a> Biophys. J. 91, 4064-4070 (2006).</li></ol>

Many techniques have been developed for vesicle generation, including electroformation, emulsion, and droplet generation14-16. However, new experimental techniques are necessary to allow for the design of biological systems with growing similarity to living systems. Microfluidic methods in particular have offered an increased level of control governing membrane unilamellarity, monodispersity of size, and internal contents17,18, bringing vesicle models closer to biology. Furthermore, characterization...

It has become increasingly clear that cell biology is a multi-scale problem that involves integrating our understanding from molecules to cells. Consequently, knowing precisely how molecules work individually is not sufficient to understand complex cellular behaviors. This is partly due to the existence of emergent behaviors of multi-component systems, as exemplified by the reconstitution of actin network interaction with lipid bilayer vesicles4, mitotic spindle assembly in Xenopus extract5, and spatial dynamics of bacterial cell division machineries6. One way to complement the reductionist&#39;s approach of dissecting the molecular processes of living systems is to take the opposite approach of reconstituting cellular behaviors using a minimal set of biological components. A critical part of this approach involves the reliable encapsulation of biomolecules in a confined volume, a key feature of a cell.
Several strategies exist for encapsulating biomolecules for studying biomimetic systems. The most biologically relevant system is lipid bilayer membranes, which mimic the biochemical and physical constraints imposed by the cell&#39;s plasma membrane. Formation of giant unilamellar vesicles (GUVs) by electroformation7, one of the most widely used techniques for GUV generation14,&#160;typically has a poor encapsulation yield due to its incompatibility with high salt buffer8. Electroformation also requires large sample volumes (&#62;100 &#956;l), which could be a problem for working with purified proteins, and inefficiently incorporates large molecules due to difficulty of diffusion between closely spaced lipid layers. Several microfluidic approaches for generating lipid vesicles have been developed. The double emulsion methods, which pass components through two interfaces between layers water-oil-water (W/O/W), relies on the evaporation of a volatile solvent to drive lipid bilayer formation9. Others have used a microfluidic assembly line that produces a continuous stream of lipid bilayer vesicles10 or in two independent steps11. We have developed an alternate technique based on rapidly applying fluid pulses against a droplet interface bilayer12 to produce GUVs of controlled size, composition, and encapsulation. Our approach, known as microfluidic jetting, offers the combined advantages from several existing vesicle generation techniques, providing an approach for creating functional biomolecular systems for investigating a variety of biological problems.

<table border="0" cellpadding="0" cellspacing="0" style="width:633px;" width="633">
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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:153px;">Name</td>
			<td style="width:163px;">Company</td>
			<td style="width:157px;">Catalog Number</td>
			<td style="width:160px;">Comments</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:153px;">Piezoelectric Inkjet</td>
			<td style="width:163px;">MicroFab Technologies</td>
			<td style="width:157px;">MJ-AL-01-xxx</td>
			<td style="width:160px;">xxx denotes orifice diameter in microns</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:153px;">Jet Drive III Controller</td>
			<td style="width:163px;">MicroFab Technologies</td>
			<td style="width:157px;">CT-M3-02</td>
			<td style="width:160px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:153px;">High-speed camera</td>
			<td style="width:163px;">Vision Research</td>
			<td style="width:157px;">MiroEX2</td>
			<td style="width:160px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:153px;">DPhPC lipid in chloroform</td>
			<td style="width:163px;">Avanti</td>
			<td style="width:157px;">850356C</td>
			<td style="width:160px;">Ordered in small aliquots in vials</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:153px;">33mm PVDF filters, 0.2 &#181;m</td>
			<td style="width:163px;">Fisher Scientific</td>
			<td style="width:157px;">SLGV033RS</td>
			<td style="width:160px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:153px;">1ml syringes</td>
			<td style="width:163px;">Fisher Scientific</td>
			<td style="width:157px;">14823434</td>
			<td style="width:160px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:153px;">n-Decane</td>
			<td style="width:163px;">Acros Organics</td>
			<td style="width:157px;">111871000</td>
			<td style="width:160px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:153px;">Glucose</td>
			<td style="width:163px;">Acros Organics</td>
			<td style="width:157px;">410950010</td>
			<td style="width:160px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:153px;">Sucrose</td>
			<td style="width:163px;">Sigma-Aldrich</td>
			<td style="width:157px;">S7903-1KG</td>
			<td style="width:160px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:153px;">Methylcellulose</td>
			<td style="width:163px;">Fisher Scientific</td>
			<td style="width:157px;">NC9084958</td>
			<td style="width:160px;"></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:153px;">1/8&#34; Acrylic</td>
			<td style="width:163px;">McMaster Carr</td>
			<td style="width:157px;">8560K239</td>
			<td style="width:160px;">CAD designs for the infinity-shaped chamber are available upon request</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:153px;">0.2 mm Acrylic</td>
			<td style="width:163px;">Astra Products</td>
			<td style="width:157px;">Clarex clear 001</td>
			<td style="width:160px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:153px;">Acrylic Cement</td>
			<td style="width:163px;">TAP Plastics</td>
			<td style="width:157px;">10693</td>
			<td style="width:160px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:153px;">Loctite 495 Superglue</td>
			<td style="width:163px;">Fisher Scientific</td>
			<td style="width:157px;">NC9011323</td>
			<td style="width:160px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:153px;">Loctite 3494 UV Strengthening Adhesive</td>
			<td style="width:163px;">Strobels Supply</td>
			<td style="width:157px;">30765</td>
			<td style="width:160px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:153px;">Natural rubber</td>
			<td style="width:163px;">McMaster Carr</td>
			<td style="width:157px;">85995K14</td>
			<td style="width:160px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:153px;">Custom stage</td>
			<td style="width:163px;">Home made</td>
			<td style="width:157px;">N/A</td>
			<td style="width:160px;">CAD designs are available upon request</td>
		</tr>
	</tbody>
</table>

lipid bilayer vesicle generation using microfluidic jetting

Bottom-up synthetic biology presents a novel approach for investigating and reconstituting biochemical systems and, potentially, minimal organisms. This emerging field engages engineers, chemists, biologists, and physicists to design and assemble basic biological components into complex, functioning systems from the bottom up. Such bottom-up systems could lead to the development of artificial cells for fundamental biological inquiries and innovative therapies1,2. Giant unilamellar vesicles (GUVs) can serve as a model platform for synthetic biology due to their cell-like membrane structure and size. Microfluidic jetting, or microjetting, is a technique that allows for the generation of GUVs with controlled size, membrane composition, transmembrane protein incorporation, and encapsulation3. The basic principle of this method is the use of multiple, high-frequency fluid pulses generated by a piezo-actuated inkjet device to deform a suspended lipid bilayer into a GUV. The process is akin to blowing soap bubbles from a soap film. By varying the composition of the jetted solution, the composition of the encompassing solution, and/or the components included in the bilayer, researchers can apply this technique to create customized vesicles. This paper describes the procedure to generate simple vesicles from a droplet interface bilayer by microjetting.

We have assembled a microfluidic jetting setup on a conventional inverted fluorescence microscope with a custom stage assembled from machined parts and manual micrometers (Figure 1). Characterization of the inkjet provides insight into the vesicle generation process. Varying the distance between the inkjet nozzle and lipid bilayer affects the force applied to cause deformation of the membrane. Close proximity to the bilayer focuses the jet stream and prevents the membrane from dispersing energy away from...

Watch this Scientific Journal Video about Lipid Bilayer Vesicle Generation Using Microfluidic Jetting at JoVE.com

Lipid Bilayer Vesicle Generation Using Microfluidic Jetting

Microfluidic jetting against a droplet interface lipid bilayer provides a reliable way to generate vesicles with control over membrane asymmetry, incorporation of transmembrane proteins, and encapsulation of material. This technique can be applied to study a variety of biological systems where compartmentalized biomolecules are desired.

Bottom-up synthetic biology presents a novel approach for investigating and reconstituting biochemical systems and, potentially, minimal organisms. This ...

lipid-bilayer-vesicle-generation-using-microfluidic-jetting

Research

JoVE Journal

Bioengineering

14.7K visualizações.  University of Michigan.  Jorrando Microfluidic contra uma bicamada lipídica interface de gota fornece uma maneira confiável para gerar vesículas com controle sobre a assimetria da membrana, a incorporação de proteínas transmembrana, e encapsulamento do material. Esta técnica pode ser aplicada ao estudo de uma grande variedade de sistemas biológicos, onde são desejados biomoléculas compartimentadas. 