Cholesterol protects phosphatidylcholine liposomes from N,N-dimethyldodekanamine N-oxide influence

Abstract

The interaction of N,N-dimethyldodekanamine N-oxide (C12(CH3)2NO) with egg yolk phosphatidylcholine (EYPC) liposomes containing cholesterol (CHOL) in molar ratios nCHOL:nEYPC = 0-0,8 was studied. The perturbation of CHOL-EYPC bilayers in unilamellar liposomes (ULL) was observed by the leakage of fluorescent probe calcein. The dependence of fluorescence intensity on the C12(CH3)2NO concentration is composed of three parts. DTPERT and DTREL were evaluated as the total C12(CH3)2NO concentrations, causing the onset of the intensive leakage of calcein and the total release of calcein, respectively. More detergent is needed to perturb the membrane when the amount of CHOL in bilayer increases. The process of CHOL-EYPC ULL solubilization induced by C12(CH3)2NO also consists of three stages. DTSAT and DTSOL were determined turbidimetrically as the total C12(CH3)2NO concentrations, causing the onset of bilayer – micellar phase transition and the completion of solubilization, respectively. Both DTSAT and DTSOL increase with the increasing nCHOL:nEYPC. The structure of liposomes is still preserved at total calcein release (DTREL) for all nCHOL:nEYPC.

Keywords

• unilamellar liposome
• solubilization
• cholesterol
• calcein
• leakage
• N,N-dimethyldodekanamine N-oxide