中文摘要：

目的 初步研究聚乙二醇（PEG）分子表面修饰密度对于纳米颗粒和磷脂膜作用的影响.方法 应用粗粒度分子动力学计算方法,研究表面PEG修饰的纳米颗粒与细胞膜作用的动态过程.结果 通过对作用过程中PEG结构和能量的变化以及细胞膜构象的变化等参数的分析发现,修饰的PEG分子增大了颗粒的尺寸,并改善了刚性颗粒的表面弹性;PEG表面修饰能够抑制刚性纳米颗粒吸附所造成的磷脂膜弯曲形变,这种抑制作用与颗粒表面修饰的PEG分子密度相关.结论 PEG表面修饰能够抑制刚性颗粒吸附时所造成的磷脂膜的弯曲形变,此关系依赖于PEG表面修饰密度的变化;其所抑制膜弯曲的作用机理有可能限制细胞对纳米颗粒的有效吞噬,从而延长纳米载体在体内的循环时间.

英文摘要：

Objective To investigate the influence of surface grafting density of polyethylene glycol （PEG） molecules on the interactions of nanoparticle with the biomembrane.Methods The dynamics of polymer as well as its shielding effect on the wrap of the membrane were investigated using coarse-grained （CG） molecular dynamics simulations.A coarse grained model force field,MARTINI,was employed for its ability to reproduce experimental properties of various lipid dynamics and some kinds of polymer as well.Results As a result,structural variations and energy changes of grafted PEG molecules on the nanoparticles,adsorbing dynamics of PEGs on the membrane as well as the wrap rates of the membrane were obtained to shed light on the PEGylation-mediated shielding mechanism in the adsorption of PEGylated nanoparticles on the membrane.Conclusions The surface grafting density of PEGylated nanoparicles has been found to play a crucial role in the stealth shielding behavior of PEGylated nanocarriers.These studies are consistent with experimental observations and to some extent give a molecular level interpretation of the macroscale observations of prolonged circulation half-life of stealth nanocarriers.