Redox Cycling for Passive Modification of Polypyrrole Surface Properties: Effects on Cell Adhesion and Proliferation

Authors

  • Kartik M. Sivaraman,

    1. Institute of Robotics and Intelligent Systems (IRIS), ETH Zurich, Tannenstrasse 3, Zurich, CH 8092, Switzerland
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  • Berna Özkale,

    1. Institute of Robotics and Intelligent Systems (IRIS), ETH Zurich, Tannenstrasse 3, Zurich, CH 8092, Switzerland
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  • Olgaç Ergeneman,

    1. Institute of Robotics and Intelligent Systems (IRIS), ETH Zurich, Tannenstrasse 3, Zurich, CH 8092, Switzerland
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  • Tessa Lühmann,

    1. Institute of Pharmacy and Food Chemistry, Chair for Pharmaceutics and Biopharmacy, University of Würzburg, Am Hubland, Würzburg, 97074, Germany
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  • Giuseppino Fortunato,

    1. EMPA (Swiss Federal Laboratories for Materials Science and Technology), Laboratory of Advanced Fibers, Lerchenfeldstrasse 5, St. Gallen, CH 9014, Switzerland
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  • Muhammad Arif Zeeshan,

    1. Institute of Robotics and Intelligent Systems (IRIS), ETH Zurich, Tannenstrasse 3, Zurich, CH 8092, Switzerland
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  • Bradley J. Nelson,

    1. Institute of Robotics and Intelligent Systems (IRIS), ETH Zurich, Tannenstrasse 3, Zurich, CH 8092, Switzerland
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  • Salvador Pané

    Corresponding author
    1. Institute of Robotics and Intelligent Systems (IRIS), ETH Zurich, Tannenstrasse 3, Zurich, CH 8092, Switzerland
    • Institute of Robotics and Intelligent Systems (IRIS), ETH Zurich, Tannenstrasse 3, Zurich, CH 8092, Switzerland.
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Abstract

The surface properties of electrodeposited poly(pyrrole) (Ppy) doped with sodium dodecylbenzenesulphonate (NaDBS) are modified by two methods: addition of poly(ethylene glycol) (PEG) during the electrodeposition and through redox cycling post electrodeposition. X-ray photoelectron spectroscopy (XPS) was used to ascertain PEG incorporation and to analyze the change in the oxidation state of the polymer. Anodic cycling resulted in the formation of micrometer-sized surface cracks which increased the amount of Rhodamine-B dye adsorbed onto the surface, and played a role in decreasing the wettability of the surface. The change in surface wettability caused by these cracks was mitigated by the presence of PEG in the Ppy matrix. Compared to the incorporation of PEG, redox cycling was more effective in passively modulating the adhesion of NIH 3T3 fibroblast cells on the Ppy surface. Based on the attenuation of surface polarity of the Ppy surfaces by the incorporated PEG, a mechanism is proposed to explain the observed cell adhesion behavior.

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