Microfluidic Fabrication of Asymmetric Giant Lipid Vesicles

Hu, Peichi C.; Li, Su; Malmstadt, Noah

doi:10.1021/am101191d

Cited by 123 publications

(114 citation statements)

References 72 publications

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“…Upon removal of the organic phase, this method generates monodisperse bilayers with controllable bilayer composition. Using these microfluidic approaches, several recent studies have generated asymmetric vesicles starting from two different lipids or lipid mixtures [87][88][89][90][91] .…”

Section: Supported Lipid Bilayersmentioning

confidence: 99%

Lateral organization, bilayer asymmetry, and inter-leaflet coupling of biological membranes

Nickels

Smith

Cheng

2015

Chemistry and Physics of Lipids

108

115

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Understanding of cell membrane organization has evolved significantly from the classic fluid mosaic model. It is now recognized that biological membranes are highly organized structures, with differences in lipid compositions between inner and outer leaflets and in lateral structures within the bilayer plane, known as lipid rafts. These organizing principles are important for protein localization and function as well as cellular signaling. However, the mechanisms and biophysical basis of lipid raft formation, structure, dynamics and function are not clearly understood. One key question, which we focus on in this review, is how lateral organization and leaflet compositional asymmetry are coupled. Detailed information elucidating this question has been sparse because of the small size and transient nature of rafts and the experimental challenges in constructing asymmetric bilayers. Resolving this mystery will require advances in both experimentation and modeling. We discuss here the preparation of model systems along with experimental and computational approaches that have been applied in efforts to address this key question in membrane biology. We seek to place recent and future advances in experimental and computational techniques in context, providing insight into in-plane and transverse organization of biological membranes.

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Section: Supported Lipid Bilayersmentioning

confidence: 99%

Lateral organization, bilayer asymmetry, and inter-leaflet coupling of biological membranes

Nickels

Smith

Cheng

2015

Chemistry and Physics of Lipids

108

115

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“…32,33 Microfluidics offers a route to create uniform liposomes templated from either water-in-oil (W/O) single emulsion drops [34][35][36][37] or water-in-oil-in-water (W/O/W) double emulsion drops. 22,[38][39][40][41][42] In the single emulsion method, lipid-stabilized W/O emulsion drops are prepared and subsequently transferred to a water phase via centrifugation or specially designed microchannels, 34,35,37 to obtain lipid bilayers. However, this route is typically very low-yielding, with 95-99% of liposomes bursting as they cross into the aqueous phase.…”

mentioning

confidence: 99%

Monodisperse Uni- and Multicompartment Liposomes

Deng¹,

Yelleswarapu²,

Huck³

2016

J. Am. Chem. Soc.

232

228

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Liposomes are self-assembled phospholipid vesicles with great potential in fields ranging from targeted drug delivery to artificial cells. The formation of liposomes using microfluidic techniques has seen considerable progress, but the liposomes formation process itself has not been studied in great detail. As a result, high throughput, high-yielding routes to monodisperse liposomes with multiple compartments have not been demonstrated. Here, we report on a surfactant-assisted microfluidic route to uniform, single bilayer liposomes, ranging from 25 µm to 190 µm, and with or without multiple inner compartments. The key of our method is the precise control over the developing interfacial energies of complex W/O/W emulsion systems during liposome formation, which is achieved via an additional surfactant in the phase. The liposomes consist of single bilayers, as demonstrated by nanopore formation experiments and confocal fluoresce microscopy, and they can act as compartments for cell-free gene expression. The microfluidic technique can be expanded to create liposomes with a multitude of coupled compartments, opening routes to networks of multistep microreactors.There has been a significant interest in the use of liposomes, self-assembled phospholipid vesicles composed of bilayer membranes, in fields as diverse as targeted drug delivery, 1,2 membrane protein science, 3-5 bioreactors 6-8 and biosensors. 9,10 Cell-sized liposomes that encapsulate biomolecules and incorporate biological functions provide a versatile mimic of certain aspects of living cells, as exemplified by work showing RNA replication, [11][12][13] in vitro transcription and translation of gene networks, 6,14-16 and organization of cell division machinery in liposomes. [17][18][19][20][21][22][23][24]

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“…Examples of hybrid asymmetric vesicles are scarce and most reported systems consist of a bilayer formed from two different lipid types42, 43, 44, 45 or two different polymers 51, 52. To our knowledge there is only one reported example of such a system, but no clear evidence was provided to fully support the membrane asymmetry because of the impossibility to perform a fluorescence quenching assay 45.…”

Section: Resultsmentioning

confidence: 99%

Asymmetric Hybrid Polymer–Lipid Giant Vesicles as Cell Membrane Mimics

et al. 2017

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Lipid membrane asymmetry plays an important role in cell function and activity, being for instance a relevant signal of its integrity. The development of artificial asymmetric membranes thus represents a key challenge. In this context, an emulsion‐centrifugation method is developed to prepare giant vesicles with an asymmetric membrane composed of an inner monolayer of poly(butadiene)‐b‐poly(ethylene oxide) (PBut‐b‐PEO) and outer monolayer of 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (POPC). The formation of a complete membrane asymmetry is demonstrated and its stability with time is followed by measuring lipid transverse diffusion. From fluorescence spectroscopy measurements, the lipid half‐life is estimated to be 7.5 h. Using fluorescence recovery after photobleaching technique, the diffusion coefficient of 1,2‐dioleoyl‐sn‐glycero‐3‐phosphoethanolamine‐N‐(lissamine rhodamine B sulfonyl) (DOPE‐rhod, inserted into the POPC leaflet) is determined to be about D = 1.8 ± 0.50 μm2 s−1 at 25 °C and D = 2.3 ± 0.7 μm2 s−1 at 37 °C, between the characteristic values of pure POPC and pure polymer giant vesicles and in good agreement with the diffusion of lipids in a variety of biological membranes. These results demonstrate the ability to prepare a cell‐like model system that displays an asymmetric membrane with transverse and translational diffusion properties similar to that of biological cells.

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Microfluidic Fabrication of Asymmetric Giant Lipid Vesicles

Cited by 123 publications

References 72 publications

Lateral organization, bilayer asymmetry, and inter-leaflet coupling of biological membranes

Lateral organization, bilayer asymmetry, and inter-leaflet coupling of biological membranes

Monodisperse Uni- and Multicompartment Liposomes

Asymmetric Hybrid Polymer–Lipid Giant Vesicles as Cell Membrane Mimics

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