Multiscale tensegrity model for the tensile properties of DNA nanotubes

DNA nanotubes(DNTs) with user-defined shapes and functionalities have potential applications in many fields. So far, compared with numerous experimental studies, there have been only a handful of models on the mechanical properties of such DNTs. This paper aims at presenting a multiscale model to quantify the correlations among the pre-tension states, tensile properties, encapsulation structures of DNTs, and the surrounding factors. First, by combining a statistical worm-like-chain(WLC) model of single DNA deformation and Parsegian’s mesoscopic model of DNA liquid crystal free energy, a multiscale tensegrity model is established, and the pre-tension state of DNTs is characterized theoretically for the first time. Then, by using the minimum potential energy principle, the force-extension curve and tensile rigidity of pre-tension DNTs are predicted. Finally, the effects of the encapsulation structure and surrounding factors on the tensile properties of DNTs are studied. The predictions for the tensile behaviors of DNTs can not only reproduce the existing experimental results, but also reveal that the competition of DNA intrachain and interchain interactions in the encapsulation structures determines the pre-tension states of DNTs and their tensile properties. The changes in the pre-tension states and environmental factors make the monotonic or non-monotonic changes in the tensile properties of DNTs under longitudinal loads.