Fabrication, modification and sensing behaviour of quartz micro/nanopipettes

Abstract

In this work we have used a laser-based micropipette puller system for the production of micro/nanopipettes from quartz ca pillaries. The pipettes were characterized via optical microscopy and SEM. We have studied the translocation events of polystyrene microparticles at different concentration and potential values to investigate the resistive-pulse sensing behaviour and performance of the obtained pipettes. We have also modified the pipette surface with (3-aminopropyl)triethoxysilane using silane chemistry in order to obtain a more neutral surface charge and promote the translocation of the particles. The modification of the pipette surface was verified using electrochemical measurements. With this purpose, current-potential (i-v) measurements were obtained and rectifications in the ionic current were investigated. The sensing of the particles was also carried out with modified pipettes which yielded longer pulse durations and higher amplitudes that improved signal to noise ratio. Furthermore, signals could be obtained at much lower potentials for modified pipettes than bare ones.