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The raw-SWNTs and raw-MWNTs were chemically oxidized with a mixture of sulfuric acid and nitric acid under ultrasonic vibration. The functionalized-SWNTs (F-SWNTs) and functionalized-MWNTs (F-MWNTs) were characterized by using ultra violet-visible spectrophotometer, X-ray diffraction, and field emission scanning electron microscopy (FESEM). The antibacterial efficiency of SWNTs and MWNTs towards Escherichia coli (E. coli) as gram-negative bacteria was evaluated via viable count method and fluorescence microscopy. The results of viable count method showed that the SWNTs and MWNTs have higher inhibitory effect after being treated with H2SO4/HNO3.The E. coli images under fluorescence microscopy exhibited that almost red color for dead cells, which confirms the efficient lethal ability of F-SWNTs and F-MWNTs.

A facile method is proposed to use a computer controlled Arc discharge gap between graphite electrodes together with an yttrianickel catalyst to synthesize carbon nanotubes under an Ar-H 2 gases mixture atmosphere by applying different DC currents and pressure. This produces carbon nanotubes with decreased diameters and increased length. XRD evidence indicated a shift toward higher crystallinity nanotubes. Yields of the CNTs after purification were also enhanced.

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Graphene oxide (GO) nanosheets were prepared by a novel simplified Hummer's method. The morphological and cross section images of GO have been tested with field emission-scanning electron microscope (FE-SEM). The antibacterial activity of GO nansheets against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were investigated as a model for Gram-negative bacteria and Gram-positive bacteria respectively. Bacteriological tests were performed by agar well diffusion assay with different concentrations of GO nanosheets and the bacterial morphological change of two bacterial species has been studied by scanning electron microscope (SEM) before and after treated with GO nanosheets. These sheets have been approved to be an effective bactericide. The antibacterial activity of the nanosheets dispersion was measured by agar well diffusion method. Scanning electron microscopy (SEM) was used to investigate the biocidal action of this nanoscale material. The nanosheets of GO have shown a high antibacterial activity against Gram-positive bacteria. The results of the present work offer a novel assay to prepare GO nanosheets were it could be used as novel antibacterial agent in future for different areas of biomedical and pharmaceutical sciences, like biosensing, antibiotics, imaging, and drug delivery.