Investigation of antimicrobial activity and cytotoxicity of synthesized surfactant-modified carbon nanotubes/polyurethane electrospun nanofibers

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Carbon nanotubes (CNTs) are attractive materials because of their excellent physicochemical properties, electrical and thermal conductivity, mechanical strength, and chemical durability. Therefore, CNTs can be used in a wide range of various biological and pharmaceutical sectors. The impact of CNTs-fiber composites on the growth of microbial cells needs to be fully explored. In this work, we have investigated the antimicrobial role of thermoplastic polyurethane (TPU) nanofibers containing various concentrations of surfactant-modified CNTs, such as double-wall (DW) and multi-wall (MW) CNTs against different representative Gram-positive and Gram-negative bacterial and the fungal strains. Besides, the cytotoxic effects of synthesized nanofibers were also studied on the human adenocarcinomic lung epithelial cell line (A549). Various concentrations of surfactant-modified CNTs were prepared and then mixed with 10 % solution of polymer (TPU) in N, N-Dimethylformamide (DMF) solvent by using a magnetic stirrer. The prepared solution was passed through the electrospinning apparatus to obtain electrospun nanofibers using a highly stable dispersion. Fourier transform infrared spectroscopy (FTIR) results exhibited that polyurethane polymer was covalently attached to the sidewalls of functionalized CNTs. Further, the morphology of synthesized nanofibers and interaction between pathogens and TPU/f-CNTs fibers were studied by using a field-emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and fluorescence microscopy. In conclusion, the highest rate of microbial growth inhibition was recorded when using the surfactant-modified CNTs concentration of 100 μg/mL with 10 % TPU solution. The antimicrobial activity and cytotoxicity of TPU/f-CNTs nanofibers were both dependent on the treatment time and concentrations. The antimicrobial findings demonstrated the excellent microbicidal and prolonged microbial growth inhibition properties of electrospun nanofibers which propose their applicability as sustained antimicrobial biomaterials.