脂质体-纳米粒与单个巨型囊泡相互作用的理论模拟  

Simulation on the Interaction of Lipoparticle with Single Giant Vesicle

作　　者：苏群[1] 孙敏娜[2,3] 张进军[2] 潘俊星 郭宇琦[2] 张慧慧[2] 王宝凤[2] 

机构地区：[1]山西师范大学物理与信息工程学院,临汾041004 [2]山西师范大学化学与材料科学学院,临汾041004 [3]山西师范大学现代文理学院,临汾041004

出　　处：《高分子学报》2016年第10期1455-1464,共10页Acta Polymerica Sinica

基　　金：高等学校博士学科点专项科研基金(基金号20121404110004);山西省基础研究项目(项目号2015011004);山西省高等学校科技创新项目资助

摘　　要：采用自洽平均场方法模拟了脂质体-纳米粒与巨型囊泡的相互作用.在初始状态,脂质体-纳米粒与巨型囊泡之间有一定距离,随着距离的变化,脂质体-纳米粒与囊泡发生相互作用,最终脂质体小囊泡和巨型囊泡会融合并使粒子释放.随着囊泡的磷脂分子组分的变化,体系呈现出丰富的结构变化.磷脂头体积分数较大时体系形成融合通道(stalk相)或半融合隔膜(HD相)以及融合小孔;磷脂头体积分数较小时体系出现囊泡的渗漏形成亲水聚集体(棒状HII相或IMI相)和融合小孔.改变了所包裹的纳米粒半径,发现对体系的结构影响不大.我们定量的计算了各个体系的自由能,从自由能分析可知,随着距离的减小,脂质体-纳米粒与巨型囊泡相互作用的过程是一个自发过程.在相互作用过程中,新结构的形成需要克服能量壁垒,且能量壁垒随着磷脂头体积分数和纳米粒半径的增大都会有一定程度的增加.We mainly investigate the interaction of a lipoparticle with a giant vesicle in solvent by using the self-consistent field theory method. A certain distance of the lipoparticle and the giant vesicle is set as the initial state. As the lipoparticle is close to the giant vesicle,the lipoparticle will interact with the giant vesicle. With decreasing the distance between the lipoparticle and giant vesicle, the interaction with each other increases gradually. We discuss the influence of hydrophilic and radius of the lipoparticle on the membrane structure of the giant vesicle, respectively. When the hydrophilic of lipoparticle is changed, a lot of interesting structural transformation can be obtained during the transmembrane process. It is mainly stalk phase and hemifusion diaphgram （ HD phase） when the hydrophilic fraction （f） is 0.35 ; and it is inverted mieellar intermediates （ IMI phase） whenf = 0. 3. Whenf = 0.25 ,it can form hydrophilic aggregates of rod,which is called rod HII phase. It occurs multiple scattered IMI phase whenf =0.2. However,there is a little effect on the membrane structure of giant vesicle when the radius of inclusion particle of lipoparticle is changed. In addition, we calculate the free energy of the system quantitatively. The system free energy decreases with the decrease of the distance between the lipopartiele and the giant vesicle. It is shown that the interaction between the lipoparticle and giant vesicle is a spontaneous process with the decrease of the distance. It is important to overcome an energy barrier for the new morphology in the interaction. The energy barrier will increase if the hydrophilic fraction of the lipoparticle increases. When the phospholipid head volume fraction increases, it reduces the spontaneous curvature of membrane. The system free energy also increases with the increase of the radius of the inclusion particle.

关 键 词：脂质体-纳米粒 囊泡 自洽场理论 自组装 

分 类 号：O641[理学—物理化学] TQ460.1[理学—化学]