(337e) Probing Complex DNA Topologies with Nanopores

Nanopores serve as an advanced tool for in situ characterization of various biological entities, including DNA, proteins and viruses. The device is essentially a nano-sized Coulter counter – a single nanopore divides the buffer into two reservoirs and ions and charged particles are driven through the pore by voltage. Passage of molecules will lead to partial current blockage. The magnitude, duration and shape of the resulting signal can be used to probe molecular attributes. In this talk I will describe how we are using these technologies to probe topologically complex DNA. First, I will describe how we can profile spontaneously occurring knots on linear DNA molecules and recent results for how solvent quality affects knot attributes. Next, I will present results for squeezing of DNA origami through small nanopores.