| Since the 1950s, traditional scientific research in physics, chemistry and biology has turned towards artificial manipulation of biological activities and construction of molecular level objects. Among all the molecules scientists investigate, nucleic acids and their natural hybridization behavior have aroused tremendous attention. Scientists have explored the chemistry and composition of isolated nucleic acids and have extended the research to the critical and versatile functions of these molecules in biological systems.;The first goal of this research was development of a drug delivery system utilizing aptamers for targeted chemotherapy. The aptamers that have used were discovered recently through cell SELEX with high binding selectivity and specificity to target cancer cells. These aptamers were grafted to a liposome particle surface to form a targeting carrier, which selectively bound to targeted cancer cells and released loaded drug molecules.;Another area of investigation was the development of advanced biomaterials for tissue engineering and drug delivery. A DNA hybridization mechanism was used to build a DNA-polymer hybrid hydrogel for potential biomedical and bioengineering applications by combining the advantages of both the polymer and DNA. By introducing an extra photoresponsive element, this hybrid hydrogel is photocontrollable and able to encapsulate and release payloads via sol-gel conversion. This is a promising biomaterial for tissue engineering and drug carriers.;The third individual research project focused on developing DNA-based nanomotors with the goal of engineering a reversible photo-driven molecular motor. A photoresponsive single DNA hairpin structure was engineered by incorporating photoresponsive moieties, azobenzenes, in the DNA backbone. The azobenzene incorporated DNA nanostructures can absorb at two different wavelengths, and displays reversible motor movement with higher energy conversion efficiencies than linear DNAs. The future goal is to develop high efficiency photo-driven molecular nanomotors using artificial light sources or even solar energy.;Overall this research has applied the basic chemistry and physics of nucleic acids, as well as their functionalities in special situations. The ultimate goal of these projects was to use nucleic acids and nanotechnology to design, develop and investigate functional and smart materials, which we envision will be useful in biomedical and pharmaceutical applications. |
