The nanopipette was submerged in the external electrolyte solution at a 45 o angle with the nanopipette tip in focus of the optical objective (Figure ). A second Ag/AgCl electrode was placed in the external electrolyte solution. Fluorescent liposomes or fluorescent PS nanoparticles were added to the external electrolyte solution at a concentration of ~5 × 10 9 particles per mL.