Scanning ion conductance microscopy measurement of paracellular channel conductance in tight junctions.

Analytical chemistry (2013-02-21)
Chiao-Chen Chen, Yi Zhou, Celeste A Morris, Jianghui Hou, Lane A Baker
RESUMEN

Elucidation of epithelial transport across transcellular or paracellular pathways promises to advance the present understanding of ion transport and enables regulation of cell junctions critical to the cell and molecular biology of the epithelium. Here, we demonstrate a new instrumental technique, potentiometric scanning ion conductance microscopy (P-SICM), that utilizes a nanoscale pipet to differentiate paracellular and transcellular transport processes at high spatial resolution. The technique is validated for well-defined polymer membranes and then employed to study wild type and claudin-deficient mutants of Madin-Darby Canine Kidney strain II (MDCKII) cells. Paracellular permeabilities conferred by claudin-2 are captured by P-SICM which demonstrates the utility to monitor apparent conductance at subcellular levels.

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Sigma-Aldrich
Dulbecco′s Modified Eagle′s Medium - high glucose, With 4500 mg/L glucose, L-glutamine, sodium pyruvate, and sodium bicarbonate, liquid, sterile-filtered, suitable for cell culture
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HEPES solution, 1 M, pH 7.0-7.6, sterile-filtered, BioReagent, suitable for cell culture
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Trypsin-EDTA solution, 10 ×, sterile-filtered, BioReagent, suitable for cell culture, 5.0 g porcine trypsin and 2 g EDTA • 4Na per liter of 0.9% sodium chloride