Extension of a wormlike chain with variable persistence length in cylindrical tube confinement

Mechanical behavior of a wormlike chain with variable bending rigidity along the chain contour in free space

In this paper, we present a theory to efficiently deal with mechanical properties of heterogeneous polymer chain in free space and the central problem is to evaluate the diffusion equation and orientation-orientation correlation function, under the condition of varying persistence length (a measure of bending rigidity) along the chain contour. Additionally, we give the specifically experimental method to measure the variable persistence length to examine our theory. In order to verify the theoretical predictions, we also performed large numbers of Brownian dynamics simulations based on the Gen…

静电屏蔽对纳米通道中DNA单分子构象的影响

Effects of electrostatic screening on the conformation of single DNA molecules confined in a nanochannel

单个T4-DNA分子被限制在矩形通道中，所述矩形通道具有300 nm的深度和150-300 nm范围内的宽度，所述矩形通道浇铸在聚（二甲基硅氧烷）纳米流体芯片中。用荧光显微镜测量DNA分子的延伸，作为缓冲液的离子强度和组成以及YOYO-1染料的DNA嵌入水平的函数。数据进行了解释与缩放理论的蠕虫状聚合物在良好的溶剂中，包括约束，电荷，和自我回避的影响。结果发现，随着离子强度的降低，DNA分子的伸长可以解释为持续长度的增加。自我回避效应的延伸是温和的，由于通道横截面直径施加的小的相关长度。嵌入的染料的结果中的DNA轮廓长度的增加和DNA电荷的部分中和，但除了静电起源的影响，它没有显着的影响上的裸弯曲刚度。在二价阳离子的存在下，观察到DNA分子收缩，但它们不会塌陷成缩合结构。有人提出，这种收缩的结果，从二价counterweight介导的DNA分子的片段之间的吸引力。