Synthesis and characterization of polypyrrole and its composites coatings on flexible surface and its antibacterial properties

The main motivation of this work was to develop a simple and efficient way to obtain polypyrrole-Ag, polypyrrole-Au, and unmodified polypyrrole layers on non-conducting, flexible surfaces as advanced antibacterial agents. We used filtering paper as a substrate for conducting polymer and its composite polymerization. The material was covered by polypyrrole, polypyrrole-Au, and polypyrrole-Ag composites during electroless (chemical) polymerization occurring at a boundary of two immiscible liquids. A presence of metals in deposited PPy films was confirmed by EDS analyses. It was proven that PPy-Ag nanocomposites deposited on the flexible substrate exhibit good antibacterial properties against both Gram-negative and Gram-positive bacteria. The antibacterial properties of PPy-Au, and non-modified PPy materials were not observed. Both, PPy and PPy-Au deposits revealed low cytotoxicity on THP-1 cells line used as reference human cells. PPy-Ag films exhibited higher toxicity on THP-1 cells line, but much weaker than toxicity toward pathogenic bacteria. SEM imagining showed changes in the morphology of the cells and their activation in contact with conducting materials. Cyclic voltammetry experiments showed that the proposed procedure leads to obtain solid materials in conducting state. It is also an easy way of fabrication of conducting polymers deposited on non-conducting surfaces. Obtained materials possess good antibacterial properties and low cytotoxicity, which opens the broad applicability of those materials. Composites placed on flexible substrates are suitable for modification of inert electrodes surfaces, e.g., for enhancement of their electro-catalytical properties.