半柔性管状聚合物的微结构化蠕虫链模型

摘要

A microstructure-based wormlike chain (WLC) model was proposed for semiflexible tubular polymers taking into account their hollow tube microstructure with locally orthotropic elastic properties.Closed-form analytical solutions were obtained for the stretching behaviors and undulation space of such polymers.The results show that,in its physiologically important range of contour length L from 1 to 20 μm,microtubule,a typical semiflexible tubular polymer,exhibits a stretching stiffness k that scales with L as k～L-1.3,compared with the classical WLC behavior of k～L-4,and that the average search space of a microtubule scales as V～L2.5,compared with the classical WLC behavior of V～L4.It was speculated that the unique properties of microtubules may have profound implications for their biological functions such as search and positioning of organelles.%考虑半柔性管状聚合物的结构特征和构成材料的各向异性特性,建立了描述其统计热力学行为的微结构化蠕虫链模型,给出了半柔性管状聚合物拉伸特性与排斥体积的解析解.分析了微管这一典型管状聚合物的统计力学性质.结果表明,在1～20 μm这一细胞生物学最重要的长度区间内,微管的抗拉刚度k和平均排斥体积V与其几何长度L之间的尺度关系分别为k～L-1.3和V～L2.5,明显区别于经典聚合物的k～L-4和V～L4.微管这些独特的力学性质在其捕获与定位细胞器时发挥着重要作用.