(27bm) Dynamic DNA Nanoaggregation Driven By Ionic Self-Association

Exploring ways to harness the power of DNA as a basis for future technologies is of peak interest. The remarkable molecular interactions of DNA have facilitated the development of diverse DNA nanostructures. In our study, we have synthesized stable, well-defined DNA nanoparticles by controlling the relatively high ionic strength. When exposing DNA suspensions to increasing salt environments, we observe the onset of aggregation. This eventually leads to the formation of stable, reproducible and well-defined aggregates at high salt concentrations. They are within the ~200-400 nm size range and were found to remain stable for days and even weeks without any precipitation or degradation. We used dynamic light scattering (DLS) to investigate changes in size and charge of these salt-actuated nanoparticles based on the DNA structure (i.e., minor, and major groove, base stacking, and charged phosphate backbone) and its flexibility and stickiness. This study explains the fundamentals behind the formation of these DNA nanoparticles and focuses on how size, hybridization and sequences can affect the binding. While the size of the nanoparticles varies depending on whether the DNA is single or double stranded, as well as on the length of the DNA strands, our observation shows that altering the DNA sequence does not have an impact on the size of the aggregates. These fundamentals of colloidal and surface science allow to explore the capabilities of DNA based nanostructures towards some applications such as high-density and high-capacity information storage, drug-delivery and self-healing materials.