arXivDaily arXiv每日学术速递 周一至周五更新
arXiv physics/0608171physics.bio-phphysics.comp-ph
收藏

病毒衣壳纳米压痕的非线性有限元分析

Nonlinear Finite Element Analysis of Nanoindentation of Viral Capsids

Melissa M. Gibbons, William S. Klug

摘要:

最近的原子力显微镜(AFM)纳米压痕实验测量的病毒的蛋白质外壳的机械响应提供了一个定量的描述,他们的强度和弹性。为了更好地理解和解释这些测量,并阐明潜在的机制,本文采用了三维非线性连续弹性的框架内的课程粒度建模方法。均匀,各向同性,弹性,厚壳模型提出了两个衣壳:球形豇豆褪绿斑驳病毒(CCMV),和椭圆柱噬菌体$ϕ29$。通过有限元方法分析,这些模型使参数表征的AFM针尖的几何形状,衣壳尺寸,和衣壳构成的描述的影响。壳体对压痕的非线性力响应对本构细节不敏感,受几何形状的影响很大。力响应的非线性硬化和软化取决于AFM针尖尺寸和壳体厚度。模型的拟合捕获了在实验测量中观察到的大致线性行为,并导致CCMV的杨氏模量估计值为$\approx$ 280- 360 MPa,$ϕ29$的杨氏模量估计值为$\approx$ 4.5 GPa。

英文摘要:

Recent Atomic Force Microscope (AFM) nanoindentation experiments measuring mechanical response of the protein shells of viruses have provided a quantitative description of their strength and elasticity. To better understand and interpret these measurements, and to elucidate the underlying mechanisms, this paper adopts a course-grained modeling approach within the framework of three-dimensional nonlinear continuum elasticity. Homogeneous, isotropic, elastic, thick shell models are proposed for two capsids: the spherical Cowpea Chlorotic Mottle Virus (CCMV), and the ellipsocylindrical bacteriophage $ϕ29$. As analyzed by the finite element method, these models enable parametric characterization of the effects of AFM tip geometry, capsid dimensions, and capsid constitutive descriptions. The generally nonlinear force response of capsids to indentation is shown to be insensitive to constitutive details, and greatly influenced by geometry. Nonlinear stiffening and softening of the force response is dependent on the AFM tip dimensions and shell thickness. Fits of the models capture the roughly linear behavior observed in experimental measurements and result in estimates of Young's moduli of $\approx$280--360 MPa for CCMV and $\approx$4.5 GPa for $ϕ29$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑