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.

How Small DNA Minicircles Can Be Applied to Construct DNA Nanotubes？

DNA as a life＇s information carrier can be modified into geometrically fine nanostructures via self-assembly of designed nucleotides with specified length. In this work, three DNA minicircles with designed lengths of 48-nt, 50-nt, and 52-nt, are directed to self-assemble into nanotubes after hybridization with staple strands, following the folding strategy with each double crossover （DX） at 2.5 turns. Much smaller DNA minicircles such as the 32-nt ring are highly rigid once they form double helices, therefore they lack the flexibility to form finely ordered nanotubes. In the case of nanotubes comprising of 52-nt minicircles, most nanotubes were 800 nm long and 20% were up to 2 p.m, whereas the nanotubes composed of 50 base pair subunits and 48 base pair subunits with the DX at frustrated 2.5 turns showed relatively shorter nanotubes at 700 and 600 （or 500） nm, respectively.

Glass capillary nanopore for single molecule detection

Single molecule detection based on nanopore technology is a very promising approach for medical diagnostics, drug therapy and even DNA sequencing. Compared with other biological nanopores and solid-state nanopores, the glass capillary nanopore has low cost, easy availability and stable mechanical characteristics, thus it has been widely used in the nanopore technology for single molecule detection. In this review, we will focus on the studies of the glass nanopore sensors. The popular glass nanopore fabrication methods would be introduced, and the applications of glass nanopores in the detection of nanoparticles, proteins and DNA molecules would be presented. We hope this review will help widen field of vision and promote the development of the nanopore technology based on the glass capillary nanopores.