Simultaneous multipass resistive-pulse sensing and fluorescence imaging of DiO-labeled E. coli lipid liposomes. The driving force responsible for multipassing particles through the orifice of a nanopipette is the sum of the potential dependent electrokinetic forces acting upon the particle. An electroosmotic force arises from solution flow induced by the diffuse doublelayer formed on the negatively charged glass surface of the nanopipette, and an electrophoretic force arises from the negative charge of the E. coli lipid liposome surface. At positive potentials (external electrode vs. internal electrode) the electroosmotic force is directed into the pipette and the electrophoretic force is directed out of the pipette, while at negative potentials the directions of the two electrokinetic forces are reversed. Both the electroosmotic and electrophoretic forces increase with increasing applied potential, resulting in increased particle velocity during translocations. The primary force driving liposome multipassing in this study is electrophoresis, which determines the direction of the liposome transport.