Engineering and applications of molecular recognition: Bioanalysis and responsive systems

Selective molecular recognition through noncovalent interactions between specific molecules forms the basis of biological systems. Among all biomolecules, nucleic acids have drawn special attention due to the highly specific base-pairing. By molecular engineering, scientists have explored the potential of nucleic acids in functional materials and systems. Moreover, by mimicking naturally occurring systems, different types of artificial molecular recognition systems have also been developed, thus extending the variability and versatility of molecular recognition.;The first goal of this dissertation is the development of a novel method for bioanalysis with high sensitivity and selectivity based on enzymatic amplification. In this project, exonuclease III is used as a signal amplifier and graphene oxide as a fluorescence quencher. Exonuclease III can recognize and digest specific DNA hybridization structures to yield an amplified signal in the presence of targets. A similar strategy is also applied for the signal amplified analysis of telomerase activity, knowledge of which is essential not only for cancer diagnosis but also for the development of novel anti-cancer therapeutic agents.;The second part of this research focuses on the engineering of DNA-polymer hybrid hydrogels for the development of dynamic materials based on reversible DNA hybridization. The dynamic hydrogel takes advantage of the scaffold of the polymer network to enable molecular level changes to be collected and visualized through macroscopic volume change measurements. Therefore, the photoreversible DNA hydrogel can be used as a photon harvesting and conversion unit for a variety of applications, including actuators, solar absorbing units and sensors.;The last individual research project is the development of a reversible phase transfer system for nanoparticles and their catalytic applications. Using light as the stimulus, phase-transfer of nanoparticles is realized based on the photo-switchable molecular recognition between azobenzene ligands and alpha-cyclodextrin coated on nanoparticles. The photo-responsive phase transfer system is applied for the regulation of the AuNP-catalyzed reaction and catalyst recycling.;In summary, this research focuses on the engineering and applications of molecular recognition systems. Functional and smart materials and systems are constructed through rational molecular design and engineering. We envision that molecular recognition will be useful in various applications, including bioanalysis, dynamic materials development, and nanoparticle sciences.