Characterisation of nanopipettes for nanoparticles experiments

Abstract

The purpose of this work has been to produce quartz nanopipettes with a diameter at the tip of about 200 − 300 nm using a Laser-Based Micropipette Puller. The nanopipettes have been characterized using optical and electronic imaging, and by measuring their conductance in a salt solution. We have come up with a formula relating the conductance and geometry of the nanopipettes. This formula can be used to estimate the size of the nanopipette aperture at the tip from its conductance. This is helpful for aproximating the aperture without having to use a scanning electron microscope (SEM). Finally we have tested the nanopipettes by performing translocations of mesoporous silica nanoparticles (NPs) using the resistive pulse sensing technique