Pressure-Modulated, Electroosmotic Flow-Driven DNA Translocations Determine DNA Super-Structure

Electroosmotic flow (EOF) has been increasingly studied and utilized to improve single molecule sensing of DNA and protein. Here we confirm, via PCR, that EOF is sufficiently strong enough to transit DNA through the pore despite electrophoretic force (EPF) opposing the DNA's net motion. In this study, we explore how pressure-induced fluid flow modulates the intrinsic flow profiles generated by EOF and therefore DNA capture and superstructure. Despite both modes of fluid flow having parabolic or plug-shaped flow profiles inside the pore, the fluid flow profiles exterior to the pore are quite unique and offers a methodology to alter how the DNA ultimately enter the pore. Herein, we demonstrate that pressure induced, hydrodynamic fluid flow opposing the direction of transport not only slows down but also linearizes DNA molecules during translocation. Furthermore, we show that DNA gating (i.e., turning on/off DNA passage through the pore) is possible using lower pressure biases and smaller pores than previous studies.