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New Giant Unilamellar Vesicles

Thursday 31 January 2013, by mcube

Giant Unilamellar Vesicles are a choice system for studying and micro-manipulating lipid bilayers under an optical microscope, providing information on structure or mechanical properties.

Inverse phase method

We have discovered that a simple modification of the well-known method of giant vesicle electroformation allows for a direct addition of water-soluble species to the phospholipid bilayers, and consequently into the vesicles being formed, bringing thus an alternate method for solving the recurrent problem in vesicle formation by electroformation (Fig. 1) [1].

Figure 1: Electroformation of giant unilamellar vesicles from an inverse phase precursor, allowing the direct incorporation of water- soluble species inside and outside the vesicle.

PVA gel method

We have shown that a wide variety of lipids or lipid mixtures can grow into GUVs in absence of electric field, by swelling lipid precursor films on top of a dried polyvinyl alcohol (PVA) gel surface in a swelling buffer (Fig. 2) [2].
Not only charged lipids, but also salted buffers can be used without restriction.

GUVs-on-PVA.jpg
Figure 2: Giant unilamellar vesicles growing on a PVA gel, confocal image. In green the PVA gel, in red the bilayer.

Footnotes

[1Mertins O.; Silveira, N. P.; Pohlmann, A. R.; Schröder A. P.; Marques, C. M. Electroformation of giant vesicles from an inverse phase precursor, Biophys. J., 96, 2719 (2009)

[2Weinberger A.; Tsai F.-C.; Koenderink G.H.; Schmidt T. F.; Itri R.; Meier W.; Schmatko T.; Schröder A. P.; Marques C. M. Gel-Assisted Formation of Giant Unilamellar Vesicles, Biophys. J., 105, 154 (2013)