Preparing giant unilamellar vesicles (GUVs) of complex lipid mixtures on demand: Mixing small unilamellar vesicles of compositionally heterogeneous mixtures

TY - JOUR

T1 - Preparing giant unilamellar vesicles (GUVs) of complex lipid mixtures on demand

T2 - Mixing small unilamellar vesicles of compositionally heterogeneous mixtures

AU - Bhatia, Tripta

AU - Husen, Peter

AU - Brewer, Jonathan

AU - Bagatolli, Luis A.

AU - Hansen, Per L.

AU - Ipsen, John H.

AU - Mouritsen, Ole G.

PY - 2015/12/1

Y1 - 2015/12/1

N2 - Giant unilamellar vesicles (GUVs) are simple model membrane systems of cell-size, which are instrumental to study the function of more complex biological membranes involving heterogeneities in lipid composition, shape, mechanical properties, and chemical properties. We have devised a method that makes it possible to prepare a uniform sample of ternary GUVs of a prescribed composition and heterogeneity by mixing different populations of small unilamellar vesicles (SUVs). The validity of the protocol has been demonstrated by applying it to ternary lipid mixture of DOPC, DPPC, and cholesterol by mixing small unilamellar vesicles (SUVs) of two different populations and with different lipid compositions. The compositional homogeneity among GUVs resulting from SUV mixing is quantified by measuring the area fraction of the liquid ordered-liquid disordered phases in giant vesicles and is found to be comparable to that in GUVs of the prescribed composition produced from hydration of dried lipids mixed in organic solvent. Our method opens up the possibility to quickly increase and manipulate the complexity of GUV membranes in a controlled manner at physiological buffer and temperature conditions. The new protocol will permit quantitative biophysical studies of a whole new class of well-defined model membrane systems of a complexity that resembles biological membranes with rafts.

AB - Giant unilamellar vesicles (GUVs) are simple model membrane systems of cell-size, which are instrumental to study the function of more complex biological membranes involving heterogeneities in lipid composition, shape, mechanical properties, and chemical properties. We have devised a method that makes it possible to prepare a uniform sample of ternary GUVs of a prescribed composition and heterogeneity by mixing different populations of small unilamellar vesicles (SUVs). The validity of the protocol has been demonstrated by applying it to ternary lipid mixture of DOPC, DPPC, and cholesterol by mixing small unilamellar vesicles (SUVs) of two different populations and with different lipid compositions. The compositional homogeneity among GUVs resulting from SUV mixing is quantified by measuring the area fraction of the liquid ordered-liquid disordered phases in giant vesicles and is found to be comparable to that in GUVs of the prescribed composition produced from hydration of dried lipids mixed in organic solvent. Our method opens up the possibility to quickly increase and manipulate the complexity of GUV membranes in a controlled manner at physiological buffer and temperature conditions. The new protocol will permit quantitative biophysical studies of a whole new class of well-defined model membrane systems of a complexity that resembles biological membranes with rafts.

KW - Confocal fluorescence microscopy

KW - Domains

KW - Giant unilamellar vesicles

KW - Lipid heterogeneity

KW - Membranes

KW - Rafts

UR - http://www.scopus.com/inward/record.url?scp=84944206072&partnerID=8YFLogxK

U2 - 10.1016/j.bbamem.2015.09.020

DO - 10.1016/j.bbamem.2015.09.020

M3 - Journal article

C2 - 26417657

AN - SCOPUS:84944206072

SN - 0005-2736

VL - 1848

SP - 3175

EP - 3180

JO - Biochimica et Biophysica Acta - Biomembranes

JF - Biochimica et Biophysica Acta - Biomembranes

IS - 12

ER -