Design, Assembly and Triggering of Interlocked DNA Nanoarchitectures

Abstract

Interlocked molecular systems are well known in supramolecular chemistry and are widely used for various applications like sensors, molecular machines and logic gates. However, these systems present some drawbacks, as the synthesis is demanding and their handling in aqueous media and biocompatibility is rather problematic. <br /> Due to Watson Crick base pairing rules, DNA is an optimal material for the self-assembly of highly ordered and complex nanoarchitectures. Furthermore, it is synthetically accessible, relatively stable, water-soluble and shows good biocompatibility. <br /> Therefore, the study of novel DNA based interlocked systems is of interest for nanotechnology. Indeed, a DNA rotaxane reported by Famulok et al. gained great attention and the threading principle described in that work was used for the assembly of various interlocked DNA architectures. <br /> In the present study, DNA rotaxanes were modified in order to precisely control and switch on and off the molecular motion of its mechanically trapped components. Such switching was utilized to create a molecular shuttle in which a macrocycle is <br /> translocated along an axle from one station towards another in a controlled fashion. Another aim of this research was to design and assemble entirely new DNA based interlocked systems suitable for the introduction of diverse functions. In this context, a [3]pseudorotaxane was assembled and fully characterized by means of gel electrophoresis and Atomic Force Microscopy. Indeed, by introducing different triggers into this system, a logic AND gate could be created. Apart from the rotaxane structures, also novel catenane structures could be assembled and properly characterized, which were then used for several applications, such as the construction of complex logic gates or catalytic activity control in a DNAzyme based system. <br /> The presented DNA based systems proved to be optimal frameworks for the introduction of highly controllable functionality and pave the way in order to build dynamic nanostructures and complex nanomachinery.