Abstract Title
AFM Study of Cholesterol Containing Lipid Bilayer
Additional Funding Sources
The project described was supported by the Pacific Northwest Louis Stokes Alliance for Minority Participation through the National Science Foundation under Award No. HRD-1410465 and the National Institutes of Health under Grant No. R01EY030067.
Abstract
Cholesterol is present in plasma membrane which not only strengthen it but also decrease the permeability and regulate the fluidity of the membrane phospholipid. The aim of this study is to investigate the change of membrane mechanical property induced by cholesterol on 1-palmitoyl 2-oleyl -sn-glycero-3-phosphocholine (POPC) lipid membrane using atomic force microscopy (AFM). Rapid Solvent Exchange (RSE) method was used to prepare the multilamellar vesicle. Sonication of these multilamellar vesicles produced small unilamellar vesicles which were employed to prepare the supported lipid bilayer (SLB). When the image roughness (Rq) of each type of bilayer were compared, POPC lipid bilayer with 50mol% cholesterol is obtained to be 0.15 nm whereas POPC alone bilayer is 0.13 nm. This indicates cholesterol increases the membrane smoothness. The stability of the bilayer is determined by the breakthrough force; this is the maximum force the bilayer can withstand. The average breakthrough force of the POPC alone bilayer was obtained as 5.26 ± 0.28 nN where as for the POPC bilayer containing 50mol% cholesterol the breakthrough force was obtained to be 9.25 ± 0.57nN. This indicates the stability of the POPC bilayer containing cholesterol is higher than without cholesterol.
AFM Study of Cholesterol Containing Lipid Bilayer
Cholesterol is present in plasma membrane which not only strengthen it but also decrease the permeability and regulate the fluidity of the membrane phospholipid. The aim of this study is to investigate the change of membrane mechanical property induced by cholesterol on 1-palmitoyl 2-oleyl -sn-glycero-3-phosphocholine (POPC) lipid membrane using atomic force microscopy (AFM). Rapid Solvent Exchange (RSE) method was used to prepare the multilamellar vesicle. Sonication of these multilamellar vesicles produced small unilamellar vesicles which were employed to prepare the supported lipid bilayer (SLB). When the image roughness (Rq) of each type of bilayer were compared, POPC lipid bilayer with 50mol% cholesterol is obtained to be 0.15 nm whereas POPC alone bilayer is 0.13 nm. This indicates cholesterol increases the membrane smoothness. The stability of the bilayer is determined by the breakthrough force; this is the maximum force the bilayer can withstand. The average breakthrough force of the POPC alone bilayer was obtained as 5.26 ± 0.28 nN where as for the POPC bilayer containing 50mol% cholesterol the breakthrough force was obtained to be 9.25 ± 0.57nN. This indicates the stability of the POPC bilayer containing cholesterol is higher than without cholesterol.