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Issue 1, 2011
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Effects of pipette modulation and imaging distances on ion currents measured with Scanning Ion Conductance Microscopy (SICM)

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Abstract

Local conductance variations can be estimated by measuring ion current magnitudes with scanning ion conductance microscopy (SICM). Factors which influence image quality and quantitation of ion currents measured with SICM have been evaluated. Specifically, effects of probe-sample separation and pipette modulation have been systematically studied for the case of imaging conductance variations at pores in a polymer membrane under transmembrane concentration gradients. The influence of probe-sample separation on ion current images was evaluated using distance-modulated (ac) feedback. Approach curves obtained using non-modulated (dc) feedback were also recorded to determine the relative influence of pipette-generated convection by comparison of ion currents measured with both ac and dc feedback modes. To better interpret results obtained, comparison to a model based on a disk-shaped geometry for nanopores in the membrane, as well as relevant position-dependent parameters of the experiment is described. These results advance our current understanding of conductance measurements with SICM.

Graphical abstract: Effects of pipette modulation and imaging distances on ion currents measured with Scanning Ion Conductance Microscopy (SICM)

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Publication details

The article was received on 03 Aug 2010, accepted on 29 Oct 2010 and first published on 23 Nov 2010


Article type: Paper
DOI: 10.1039/C0AN00604A
Citation: Analyst, 2011,136, 90-97
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    Effects of pipette modulation and imaging distances on ion currents measured with Scanning Ion Conductance Microscopy (SICM)

    C. Chen and L. A. Baker, Analyst, 2011, 136, 90
    DOI: 10.1039/C0AN00604A

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