(415c) Nanopore Sensing and Characterization of Hepatitis B Viral Capsids

Shrinking the lateral dimensions of micromachined channels to nanometer length scales provides unique opportunities for sensing and separation applications. Some aspects of microchannel transport transfer directly to operation of smaller nanoscale channels, but nanofluidic systems can be significantly influenced by phenomena such as double layer overlap, surface charge, ion current rectification, diffusion, and entropic forces, which are either insignificant or absent in larger microchannels. For example, funnel-shaped nanochannels rectify ion current, and nanofunnels with smaller taper angles exhibit higher current rectification. These devices are also used to sense transiting particles, e.g., viruses, and to characterize particle properties, e.g., surface charge and payload. We will present characterization of Hepatitis B Viral (HBV) capsids that translocate through a single conical nanopore, which is chemically etched in a poly(ethylene terephthalate) (PET) membrane after being tracked by a heavy ion. The nanopore is chemically modified to minimize the electroosmotic flow inside the pore as well as charge-charge interactions between the capsid and pore wall. The HBV capsids are electrophoretically driven through the nanopore, and their presence is sensed by a change in the ionic current as the capsids transit through the nanopore. We demonstrate that discrimination of HBV capsids with different sizes (a T=3 capsid is ~31 nm in diameter and a T=4 capsid is ~37 nm in diameter) is feasible based on the difference in the change in ionic current. These results illustrate the potential of these nanopore devices for sensitive size characterization of biomolecules or particles in real time.