ALINA ASANDEI, F. PINTILIE, T. LUCHIAN
Laboratory of Biophysics and Medical Physics, Faculty of Physics, “Alexandru I. Cuza” University, 11, Carol I Blvd., Iaşi, ROMANIA
Abstract. The use of cysteine-functionalized membranes with known porosity may allow a better understanding of separation and transport characteristic through biomembranes. In this work, polycarbonate membrane was gold-coated via electroless deposition onto the pore walls, followed by L-cysteine chemisorption on the modified surface. By measuring the electrical current flow through these membranes and analyzing the current-potential difference diagrams, we showed that such membranes display variable conductivities, depending on the pH value of the contacting solution. Interestingly, the spectral behavior of such functionalized membranes quantified by their electrical impedance shows a strong dependence upon the pH value of the contacting solution, departing visibly at high pH values from the theoretical predictions of a simple parallel-RC model. A possible extension of the present work may be the exploration of the so-called artificial ion channels, which would resemble their biological counterparts from the viewpoint of ion selectivity and gating properties.
Key words: track-etched membranes, cysteine, nanopores, voltage-clamp, impedance.
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