Functional nucleic acids (aptamers, DNAzymes, ribozymes, and aptazymes) are generated by in vitro Darwinian evolution methods (SELEX and related methods of in vitro selection). We are interested to expand the capacity of these functional nucleic acids in terms of nuclease resistance, binding capacity, catalytic activity, and scope. An interesting method to improve the capacity of functional nucleic acids is to include modified nucleoside triphosphates (dN*TPs) into the selection experiments. Thus, an important project of the laboratory consists in the chemical synthesis and biochemical characterization of dN*TPs with modifications of the nucleobase and the sugar unit. This will allow for the exploration of larger chemical spaces in selection experiments.