Study Of Paranemic Crossover (PX) Motif In The Content Of Design And Self-assembly Behavior

DNA is a superb molecule for nanoconstruction and a wide range of nanostrucutures have been assembled from DNA.The potential applications have been demonstrated in nanoelectronic,biosensing,and computational applications.A key to the success is the development of geometrically well-defined,stiff building blocks,or nanomotifs,or tiles.Another factor is the predictable cohesion between the tiles.To further develop structural DNA nanotechnology to achieve ever more complex structures via robust and cost-effective approaches for new applications,it requires novel motifs and cohesion methods.My major research topics focus on developing new PX?Paranemic Crossover?DNA motifs and studying on their self-assembly behavior.The main contents are as follows:Firstly,we have systematically examined the structural variables of PX motifs including PX55,PX65,PX75,PX85,PX95,PX64 and PX74,and found the optimal parameters for PX motifs to assemble into 2D arrays.This is a stringent test on DNA nanomotifs for structural DNA nanotechnology as the successful motif must be stiff,flat or near flat,and having predictable helical twist.Among all versions of PX motifs,PX65 has been identified as the optimal motif for 2D assembly.Besides,we identified the lattices with JX₂ are better than JX₄ owing to electrostatic repulsion.Secondly,we developed a strategy of“loose-tight balance”to construct 2D arrays for unstable PX55,PX64 and PX95 structure by adjusting the number of nucleotides in JX region.Thirdly,we have attempted to design PX nanotubes using PX65 motif to obtain different diameter nanotubes.The nanotubes have larger diameter,in which,3PX,4PX,5PX or 6PX were enclosed with T-linkage as bridge,which potentially applied to nanoelectronic and biomedicine.These results lead to the possibility of building complex DNA structures from PX motifs only:PX structures to be the building tiles and the inter-tile interaction mechanism.