微观吸引作用对DNA膜弹性性质的影响

目的 研究高价盐下微观吸引作用对DNA膜弹性性质的影响。方法 采用Kornyshev静电拉链模型描述高价盐下DNA链间的相互作用势能；采用思想实验法和宏观连续介质弹性杆模型，预测单向应力状态下DNA膜的应力-应变关系、预应力和弹性模量。结果 在给定封装条件下，DNA膜具有拉伸预应力和负的弹性模量，预应力为-1.52～1.17 MPa，弹性模量为-4.2～64 MPa。结论 与单价盐下的情形不同，随着封装密度和盐浓度的变化，高价盐作用下微观吸引作用使得DNA膜弹性性能展现出非单调的变化，而且拉压弹性性能明显不同，拉伸预应力和压缩预应力以及正负弹性模量会出现转换。研究结果有助于进一步理解病毒复制的机制，并为基因检测和基因治疗提供参考。
Objective To investigate the influence of the microscale attractive interaction on the elastic properties of DNA film in multivalent ion solutions. Methods Kornyshev's electrostatic zipper model was employed to describe the interaction energy between the DNA strands. The thought experiment method and macroscopic continuum bar model were combined to predict the stress-strain relationship, prestress, and elastic modulus of the DNA biofilm.Results Given the packing conditions, the DNA film exhibited a tensile prestress and negative elastic modulus. The prestress of the DNA biofilm ranged from -1.52 MPa to 1.17 MPa, and its elastic modulus ranged from -4.2 MPa to 64 MPa. Conclusions In contrast with monovalent solutions, the microscopic attractive interactions in multivalent solutions caused the elastic properties of the DNA film to exhibit a non-monotonous relationship with the variation in the packing density and salt concentration. The tensile elastic properties were significantly different from the compressive ones, and the tensile/compressive prestress as well as the positive/negative elastic modulus transformed each other. These results can contribute to understanding the mechanism of viral replication and provide references for gene detection and gene therapy.