【作者】 陈李萍； 梁好均； 肖石燕；

【Author】 Liping Chen;Haojun Liang;Shiyan Xiao;Department of Polymer Science and technology,University of Science and Technology of China;CAS Key Laboratory of Soft Matter Chemistry;

【机构】 中国科学技术大学高分子科学与工程系； 软物质重点实验室；

【摘要】 内吞是细胞摄入外界物质的主要方式,动力学模拟能够让我们以更直观的方式观察其内吞过程。以往内吞的对象多限于刚性的纳米粒子,对于柔性粒子的内吞过程的研究多在理论方面[1]。因此我们在隐式溶剂体系中建立了柔性纳米粒子模型模拟柔性纳米粒子的内吞过程。纳米粒子是通过简化红细胞的dpd模型[2]得到,它是由三角网格构成的封闭壳层,通过键和二面角的作用维持纳米粒子的初始形状;同时为了维持纳米粒子的表面积和体积的相对稳定,我们对两者分别施加了弹簧势约束;四种势能共同作用维持了纳米粒子的形状的相对稳定,使纳米粒子能够承受一定的应力并产生形变。纳米粒子在内吞过程中产生形变,最大形变发生在内吞一开始的时候,而后会快速回复到接近初始的形状。而后形状会在垂于与膜的方向轻微拉伸,最后在完成内吞时回复到初始形状。我们可以通过改变体积和表面积的约束和二面角来改变粒子的柔性,柔性越强的粒子在内吞过程中具有越大的形变(Fig.2),并且内吞所需的时间也越长(Fig.1)。更多还原

【Abstract】 Endocytosis is the main way to uptake outside material for cell.We can investigate more details of endocytosis by simulation.We focused on the uptake of rigid nanoparticles before,and there was theoretical study about the uptake of soft nanoparticles[1].So we built the model of soft nanoparticles to simulate its endocytic process in implicit solvent.Our model is based on the dpd model of RBD[2].It’s a closed shell covered by triangle mesh,and the potential of bonds and dihedrals prevents its initial shape changing.To keep the surface area and volume of nanoparticle stable,we applied a harmonic potential on surface area and volume.By the constraints of bond,dihedral,volume and surface area,the nanoparticle has stable initial shape and will deform as there is force applied on it.Nanoparticles deform during the process of endocytosis,and the biggest deformation comes up in the beginning.Then its shape would revert to its initial state quickly.Before the nanoparticle is wholly wrapped,the nanoparticle would be "elongated" slightly vertical to the membrane surface.The flexibility of nanoparticle differs as we change the parameters of constraints of volume,surface area and dihedrals.Softer nanoparticle would deform more during endocytic process(Fig.2),and it would spend more time for membrane to wholly wrapping the softer nanoparticle(Fig.1).更多还原