Self-assembly of nucleic acids and their biomedical applications

DNA has been extensively explored as a building block for nanostructures based on rational design and self-assembly. The potential applications of DNA nanostructures include nanoelectronics, nanofabrications, biological sensors, and bionanotechnology. My major research interest is to develop novel DNA/RNA nanostructures and to apply them in the bionanotechnology area. One of the advantages from DNA sequence symmetry strategy is reduction of the required number of different DNA strands. Recently our group has developed a DNA nanotube (DNA-NT) system with a single component, a 52-base-long DNA single strand, which consists of four palindromic segments. During my Ph.D. research, the DNA NT has been furthermore utilized as a carrier of drug delivery. DNA is potentially a good candidate because it is biodegradable and a natural component in human bodies. The DNA-NTs conjugated with folate, a cancer cell target agent, are effectively and selectively taken by cancer cells because folate receptors are over-expressed on the cell surfaces of various cancer cells. We have developed another strategy for biomedical application of DNA which can reversibly control RNA-based nanomotors. For reversible control of nanomotor, we used a single antisense DNA strand, which is introduced/removed from pRNA complexes using isothermal DNA strand displacement, driven by the maximization of DNA base pairing. This work provides a way to control biological nanomotor activities and the same strategy can be applied to control other RNA-containing biological complexes. Finally we have developed a new strategy to make DNA programmed RNA self-assembly. RNA strands are guided by DNA strands to self-assemble into RNA/DNA hybrid, branched motifs and they are further self-assemble into large, extended structures. We expect that this strategy will allow us to assemble into large nanostructures with multi-functional RNA modalities