论文部分内容阅读
脂筏是近年来在生物膜研究中发现的一种富含鞘脂、胆固醇和特殊蛋白质的动态微区结构,其结构和功能的改变,会引发多种疾病.本文利用LB膜技术模拟脂筏的动态微区结构,通过测量表面压力与平均分子面积(π-A)曲线数据,计算出鞘氨醇/胆固醇LB单层膜的过量分子面积(πA(ex))、表面过量吉布斯自由能(ΔG(ex))、活度系数(f1和f2)以及弹性模量(Cs-1),系统的研究了二元组份混合单层膜的热力学特性,并用原子力显微镜对鞘氨醇与胆固醇混合膜的形态进行观察.热力学分析表明过量分子面积和过量吉布斯自由能相对理想状态都具有负偏差作用,这说明分子间相互作用表现为吸引力,且单层膜的稳定性、弹性模量和活度系数的数值明显的依赖于胆固醇与鞘氨醇的比例.AFM观察结果表明,纯鞘氨醇单分子膜表现为小的颗粒体结构;当鞘氨醇与胆固醇按不同摩尔比混合时,随着胆固醇摩尔比例的增加,混合膜呈现出从链状结构向较大的片层与网状共存结构的转化.最终纯胆固醇形成高度紧密的膜结构.AFM实验有力的支持了理论分析的结果.
Lipid raft is a dynamic micro-structure rich in sphingolipids, cholesterol and special proteins found in biofilm research in recent years, and its structure and function will lead to many diseases.In this paper, LB membrane technology was used to simulate lipid rafts , The excess molecular area (πA (ex)) of the sphingosine / cholesterol LB monolayer was calculated by measuring the surface pressure and the average molecular area (π-A) curve data. The surface excess Gibbs free (ΔG (ex)), activity coefficients (f1 and f2) and elastic modulus (Cs-1) were investigated systematically. The thermodynamic properties of the binary mixed monolayers were investigated systematically. Cholesterol mixed membrane morphology was observed thermodynamic analysis showed that excess molecular area and excess Gibbs free energy relative to the ideal state has a negative bias, indicating that the interaction between molecules showed attractive, and monolayer stability, elasticity The values of modulus and activity coefficient obviously depend on the ratio of cholesterol to sphingosine.The results of AFM showed that sphinganine monolayer showed small granular structure.When sphingosine and cholesterol were mixed at different molar ratios When mixed, with gall The molar ratio of sterols increased, the hybrid membranes showed the transition from the chain-like structure to the larger lamellae and reticular coexistence structure.At last, pure cholesterol formed a highly compact membrane structure.The AFM experiment strongly supported the theoretical analysis.