G-quadruplex forming oligonucleotides with tailor-made modifications as effective aptamers for potential therapeutical applications

The unique properties of G4-based nucleic acids provide the base for a variety of applications. A whole set of biomedical as well as bioanalytical applications is based on the ability of G-quartets to stabilize defined three-dimensional nucleic acid structures that exhibit a high affinity to a target molecule. Such aptamers can therefore show similar binding properties as antibodies with comparable applications in diagnostics and therapy, but exhibit striking advantages like ex-vivo synthesis and increased physicochemical stability. Moreover, they can even show catalytic behavior that can be utilized for bioanalytical purposes. The chapter contains examples for applications in these fields. The structural properties described in previous chapters are the base for applications in molecular nanotechnology and ???electronics. Nucleic acids represent the most promising materials in these fields, and here G4 structures show even outstanding mechanical stability and length control from the nano- into the micrometer range. An important step on the way to respective applications is the integration of G4-based nanostructures into technical environments such as microelectrodes. Here electrical field-based approaches ??? e.g. dielectrophoresis DEP ??? represent the most promising technique, which has been demonstrated for the integration and subsequent characterization of even single G4 structures. These techniques have also been used to enable the characterization of electrical properties of G4 assemblies as described in this chapter. In conclusion, by presenting various biomedical as well as nanobiotechnological demonstrations this chapter demonstrates the great application potential of G4-based nanostructures.