Shear Unzipping of DNA

TL;DR

This paper presents a theoretical study of the mechanical failure of double-stranded DNA under shear, introducing a nonlinear ladder model to analyze unzipping transition and effects of heterogeneity and temperature.

Contribution

It develops a nonlinear generalization of a DNA shear unzipping model, combining analytical and numerical methods to explore failure mechanisms.

Findings

Identifies a critical shear force for DNA unzipping at zero temperature.

Shows sequence heterogeneity affects unzipping behavior.

Analyzes temperature effects on DNA shear failure.

Abstract

We study theoretically the mechanical failure of a simple model of double stranded DNA under an applied shear. Starting from a more microscopic Hamiltonian that describes a sheared DNA, we arrive at a nonlinear generalization of a ladder model of shear unzipping proposed earlier by deGennes [deGennes P. G. C. R. Acad. Sci., Ser. IV; Phys., Astrophys. 2001, 1505]. Using this model and a combination of analytical and numerical methods, we study the DNA "unzipping" transition when the shearing force exceeds a critical threshold at zero temperature. We also explore the effects of sequence heterogeneity and finite temperature and discuss possible applications to determine the strength of colloidal nanoparticle assemblies functionalized by DNA.