An important research axis of the laboratory is to modify nucleic acids with chemical groups in order to improve their therapeutic usefulness. Particularly, modified aptamers (i.e. oligonucleotides capable of binding to targets with high selectivity and affinity) are developed by application of a Darwinian in vitro evolution method coined SELEX to develop therapeutic agents for the treatment and detection of various diseases including cancer, pneumonia, and malaria. Moreover, catalytic nucleic acids are developed to act as efficient gene silencing agents for the treatment of genetic diseases. Lastly, DNA-based materials are generated by using modified nucleoside triphosphates to create drug delivery systems.