Dielectric breakdown set-up. A silicon membrane, either SiN or SiO2, was mounted into a holder (nanoporesolutions.com) and washed with 1 M KCl solution. Two electrodes were then inserted into each of the fluid cells, with one connected to a power source consisting of either a DC regulated power supply (obtained from Circuit Specialists) or a bank of 1.6 V batteries. The power supply was also connected to a multimeter (FLUKE 179), which was in turn connected to the remaining electrode in the pore holder.