Development of DNA-based nanomachines foranalytical applications

DNA nanotechnology uses nucleic acids to manipulate the spatial and temporal distribution of matter. The exceptionally specifity and predictability of the Watson-Crick base pairing makes DNA a useful nanoscale building-block for the creation of self-assembled nanostructures. For example, DNA has been used to build increasingly complex and higher order 2-d and 3-d nanostructures with extraordinary nanometer precision. The majority of these nanostructures are static constructions without an apparent function. An obvious extension for this field is to convert static DNA structures into dynamic machines or functional devices, that are able to perform a specific task. To btain nanodevices with dynamic behavior is necessary to integrate a DNA functional unit into the static nanostructure. Such DNA functional unit can be a nanomachine or a conformational switch that is able to respond to a specific molecular input and trigger a nanomechanical motion. Therefore, in order to scale-up from static structure to smart nanodevices or DNA "biocomputer" the development of DNA nanomachines and nanoswitches represenents a major goal in the field of DNA nanotechnology. My PhD thesis regards the development of DNA nanomachines based on novel structure-switching mechanisms based on the formation of a DNA secondary structure. More specifically, I used the formation of triple helices structure to design different DNA-based nanoswitches that can be triggered by a specific DNA strand or by pH change. Besides the obvious applications in the field of DNA nanotechnology, the results of my thesis could open the door for important applications across synthetic bioly, drug release, smart-nanomaterials and cancer-targeting drugs.