Mechanism of Vesicle Structure Transform with Gemini Surfactants

囊泡是由两亲分子定向单层尾对尾地结合成封闭单分子双层所构成的外壳，和壳内包藏的微水相构成，它可分为两种类型：由天然的或合成的磷脂所组成的囊泡（脂质体）和由双亲分子自组装形成的囊泡。细胞膜一般是由40-50%的类脂和50-60%的蛋白质组成。按照流体镶嵌模型,由磷脂和糖脂等类脂构成的双分子层是生物膜的基本骨架，而蛋白质则包埋于磷脂基质中，可以从两侧表面嵌入或穿透整个双层分子，起着渗透屏障的作用。双分子层的每个磷脂分子都可以自由横向移动，其结果使双分子层具有流动性、柔韧性、高电阻性及对高极性分子的不通透性。因此，生物膜结构不是僵硬、静止的，而是动态、流动的结构。 Gemini表面活性剂是由联接基...Vesicle is composed of crust which forms from closed unimolecule-bilayer that combined with monolayers of two amphiphilic molecules in tail-to-tail orientationally, and micro-hydrofacies that is contained within the crust. It can be sort into two types: vesicle made up of natural or complex lecithin and vesicle made by self assembly of amphiphilic molecules. Cell membrane is made up of 40-50% lipo...学位：理学硕士院系专业：化学化工学院化学系_物理化学(含化学物理)学号：1912005130190

Effect of Cholesterol on the Stability of Lecithin Vesicle

采用透射电子显微镜研究了gEMInI表面活性剂诱导卵磷脂囊泡结构改变的机理,用lAngMuIr膜天平研究卵磷脂和胆固醇的不溶单分子混合膜在气-液界面的行为和混合膜分子间的相互作用,并结合动态光散射技术和停留法探讨胆固醇对gEMInI表面活性剂诱导卵磷脂囊泡结构改变的影响.从电镜结果可以推测带正电荷的gEMInI表面活性剂分子会嵌入到带负电荷的卵磷脂囊泡双分子层的外层,囊泡的双分子层之间的相互吸引力使双分子层的厚度减少,由于嵌入的表面活性剂分子在囊泡的双分子层中分布是不均匀的,这种分布的不均匀性必然会导致双分子层厚度的不均匀,从而使囊泡破裂.混合膜的过剩面积和动力学结果表明,胆固醇和卵磷脂是相互吸引的,即胆固醇的加入使卵磷脂囊泡更不容易被表面活性剂破坏.The mechanism of structure transformation of vesicle was explored through TEM.The mixed monolayer at the air/water interface of lecithin and cholesterol was investigated using Langmuir balance technique.We also studied the effect of cholesterol on the structure transformation of lecithin vesicle by the method of kinetic and dynamic light-scattering.The results show that positively charged Gemini surfactant intercalates into the bilayer of negatively charged lecithin vesicle and reduces the thickness of bilayer of lecithin vesicle.The asymmetric distributing of the surfactant molecular in the vesicle led to the asymmetric thickness of the bilayer,thus resulted in the vesicle breakdown.The excess area of the mixed monolayer and kinetic results show that the mutual attraction between lecithin and cholesterol made it hard to break the lecithin vesicle by adding cholesterol.厦门大学科技创新重点项目(批准号:XMKJCX20052001);厦门市科技计划项目(批准号:3502Z20055021)资

Studies on Mechanism of Vesicle Structure Transform Induced with Quaternary Ammonium Gemini Surfactants

用动态光散射技术以及荧光探针方法,研究了不同连接基长度的季铵盐型Gemini表面活性剂对卵磷脂囊泡结构改变的影响,并借助理论模型和临界堆积参数理论探索了Gemini表面活性剂诱导囊泡结构改变的机理.实验结果表明,表面活性剂诱导囊泡结构改变的主要原因是表面活性剂嵌入到囊泡的双分子层中,从而改变了囊泡的表面电荷强度以及嵌入后的表面活性剂在囊泡双分子层中分布的不均匀性.此外,表面活性剂分子的结构也会对其产生影响,不同连接基长度的季铵盐型Gemini表面活性剂对囊泡结构改变的影响不完全相同,但会呈现出一定的规律性.A combination of dynamic light-scattering and fluorescence probe techniques was used to study the structure transform of lecithin vesicle with surfactants with different spacer chain lengths.The mechanism of structure transform of vesicle is explored by model and effective packing parameter theory.The results show that the main reason which leads to the structure transform is the change of superficial electric charge and the asymmetric distribution of the surfactant molecular.Furthermore,the structure of surfactant is also one of the reasons.Surfactants with different spacer chain lengths have different effects on the changs of the structure of the vesicle,which turn out to have some rules.厦门大学科技创新重点基金项目(批准号:xmkjcx20052001)资

Effect of Cholesterol on the Stability of Lecithin Vesicle

The mechanism of structure transformation of vesicle was explored through TEM. The mixed monolayer at the air/water interface of lecithin and cholesterol was investigated using Langmuir balance technique. We also Studied the effect of cholesterol on the structure transformation of lecithin vesicle by the method of kinetic and dynamic light-scattering. The results show that positively charged Gemini surfactant intercalates into the bilayer of negatively charged lecithin vesicle and reduces the thickness of bilayer of lecithin vesicle. The asymmetric distributing of the surfactant Molecular in the vesicle led to the asymmetric thickness of the bilayer, thus resulted in the vesicle breakdown. The excess area of the mixed monolayer and kinetic results show that the Mutual attraction between lecithin and cholesterol made It hard to break the lecithin vesicle by adding cholesterol

大气颗粒物及多环芳烃暴露与慢性阻塞性肺疾病患者全身性氧化应激水平

目的:研究环境大气颗粒物及多环芳烃(polycyclic aromatic hydrocarbons, PAHs)暴露对慢性阻塞性肺疾病(chronic obstructive pulmonary disease, COPD)患者全身性氧化应激水平的影响。方法:招募45名居住在北京大学医学部半径5 km范围内的COPD患者作为研究对象,采用定组研究方法,于2014年11月至2015年5月对研究对象进行两次临床随访。通过肺功能检查测定第1秒用力呼气容积占预计值百分比(即FEV_1%预计值),用于评估COPD患者病情的严重程度。收集患者尿样,分别采用高效液相色谱(high performance liquid chromatography, HPLC)法和酶联免疫吸附测定(enzyme-linked immunosorbent assay, ELISA)法测定尿样中的全身性氧化应激指标丙二醛(malondialdehyde, MDA)和8-羟基脱氧鸟苷(8-hydroxy-2&#39;-deoxyguanosine, 8-OHdG)水平,同时,通过本课题组于校园内自行建立的空气污染监测站点连续收集研究期间该区域的环境大气污染物浓度以获得人群污染物暴露水平。利用线性混合效应模型,分别通过单污染物模型、双污染物模型和分层分析来研究大气污染物对COPD患者尿样中MDA和8-OHdG水平的影响。结果:滞后2 d(lag2)的超细颗粒物(ultrafine particles, UFP)和PAHs浓度与尿样中MDA水平呈显著正相关(P&lt;0.05),UFP和PAHs每升高四分位间距(interquartile range, IQR)浓度,MDA浓度分别升高28%(95%CI: 4%~57%)和36%(95%CI: 4%~77%),控制黑碳(black carbon, BC)的影响后,UFP和PAHs与MDA的关联强度略有升高。以COPD的严重程度进行分层分析后发现,多数污染物在疾病程度较轻的COPD患者中具有更强的氧化应激效应。在FEV_1%预计值&ge;50%的COPD患者中发现,UFP每升高IQR浓度,尿样中MDA浓度升高98%(95%CI: 38%~186%),BC、UFP和PAHs每升高IQR浓度,尿样中8-OHdG浓度分别升高87%(95%CI: 32%~166%)、69%(95%CI: 24%~130%)和156%(95%CI: 66%~294%)。本研究未观察到细颗粒物(fine particulate matter, PM_(2.5))与尿样中氧化应激指标的显著关联。结论:大气污染物暴露可加重COPD患者全身性氧化应激水平,其中UFP和PAHs的效应更为显著,并且污染物对于疾病程度较轻的COPD患者氧化应激效应更强。</p

Studies on Mechanism of Vesicle Structure Transform Induced with Quaternary Ammonium Gemini Surfactants

A combination of dynamic light-scattering and fluorescence probe techniques was used to study the structure transform of lecithin vesicle with surfactants with different spacer chain lengths. The mechanism of structure transform of vesicle is explored by model and effective packing parameter theory. The results show that the main reason which leads to the structure transform is the change of superficial electric charge and the asymmetric distribution of the surfactant molecular. Furthermore, the structure of surfactant is also one of the reasons. Surfactants with different spacer chain lengths have different effects on the changs of the structure of the vesicle, which turn out to have some rules