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Effect of Electrical Parameters and Cholesterol Concentration on Giant Unilamellar Vesicles Electroformation. Cell Biochem Biophys 2020 Jun;78(2):157-164

Date

04/23/2020

Pubmed ID

32319021

Pubmed Central ID

PMC7608754

DOI

10.1007/s12013-020-00910-9

Abstract

Giant unilamellar vesicles (GUVs) are used extensively as models that mimic cell membranes. The cholesterol (Chol) content in the fiber cell plasma membranes of the eye lens is extremely high, exceeding the solubility threshold in the lenses of old humans. Thus, a methodological paper pertaining to preparations of model lipid bilayer membranes with high Chol content would significantly help the study of properties of these membranes. Lipid solutions containing 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) and Chol were fluorescently labeled with phospholipid analog 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiIC18(3)) and spin-coated to produce thin lipid films. GUVs were formed from these films using the electroformation method and the results were obtained using fluorescent microscopy. Electroformation outcomes were examined for different electrical parameters and different Chol concentrations. A wide range of field frequency-field strength (ff-fs) combinations was explored: 10-10,000 Hz and 0.625-9.375 V/mm peak-to-peak. Optimal values for GUVs preparation were found to be 10-100 Hz and 1.25-6.25 V/mm, with largest vesicles occurring for 10 Hz and 3.75 V/mm. Chol:POPC mixing ratios (expressed as a molar ratio) ranged from 0 to 3.5. We show that increasing the Chol concentration decreases the GUVs size, but this effect can be reduced by choosing the appropriate ff-fs combination.

Author List

Boban Z, Puljas A, Kovač D, Subczynski WK, Raguz M

Author

Witold K. Subczynski PhD Professor in the Biophysics department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Cell Membrane
Cholesterol
Humans
Lens, Crystalline
Lipid Bilayers
Lipids
Microscopy, Fluorescence
Phosphatidylcholines
Phospholipids
Solubility
Solvents
Temperature
Unilamellar Liposomes