Exploring The Evolution Process And Requirements For Molecular Recognition Via Highly Functionalized Aptamers

Expanding the chemical diversity of oligonucleotide libraries has allowed the evolution of synthetic nucleic acid polymers with enhanced molecular recognition and catalytic abilities. Thus, synthetic methods that enable the sequence-defined incorporation of diverse chemical modifications in developing novel or improved nucleic acid polymers and selection methods that facilitate efficient enrichment of high-quality aptamers are of particular importance in identifying novel or improved nucleic acid polymers for diagnostics and therapeutics. In this thesis, the advancement of ligase-catalyzed oligonucleotide polymerization (LOOPER) is discussed as a method to increase the chemical diversity of oligonucleotide libraries and its application towards the evolution of modified aptamers. An evaluation of the use of different ligases, scope and number of modifications, sequence space, and evolutionary outcomes from in vitro selections is provided, along with a critical lens on challenges to be addressed for the method to mature into a more widely adapted technology. Further to this, a variety of selection methods are discussed striving towards efficient single-round aptamer selection. The successful single-round aptamer selection against Thrombin is an inspiring outcome for future selections.