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The antibacterial activity and possible toxicity of graphene oxide and laser-irradiated graphene oxide (iGO) were investigated. Antibacterial activity was tested on Escherichia coli and shown to be higher for GO irradiated for at least three hours, which seems to be correlated to the resulting morphology of laser-treated GO and independent of the kind and amount of oxygen functionalities. X-ray photoelectron spectroscopy, Raman spectroscopy, dynamic light scattering and scanning electron microscopy (SEM) show a reduction of the GO flakes size after visible laser irradiation, preserving considerable oxygen content and degree of hydrophilicity. SEM images of the bacteria after the exposure to the iGO flakes confirm membrane damage after interaction with the laser-modified morphology of GO. In addition, a fish embryo toxicity test on zebrafish displayed that neither mortality nor sublethal effects were caused by the different iGO solutions, even when the concentration was increased up to four times higher than the one effective in reducing the bacteria survival. The antibacterial properties and the absence of toxicity make the visible laser irradiation of GO a promising option for water purification applications.

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Graphene oxide (GO) is one of the most appealing bidimensional materials able to interact non-covalently with achiral molecules and to act as chiral inducers. Vortexes can tune chirality and, consequently transfer a specific handedness to non-covalent host molecules, either when dispersed in water or when deposited on a solid surface.

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A systematic study into the MOCVD of V-O films using the vanadyl-acetylacetonate [VO(acac) 2 ] precursor is carried out. The films are prepared via low pressure MOCVD on Si(001) substrates. The nature and quality of films are examined by varying operational parameters, e.g., deposition temperature, precursor vaporization rate, and flow of oxygen reacting gas. X-ray diffraction data point to the formation of crystalline films in the range 200À550 8C. Outside of this temperature ranges amorphous phases were obtained. Field-emission scanning electron microscope (FESEM) images indicate very homogeneous surfaces with grain shape and dimensions depending on operational conditions. Energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analyses point to the absence of any C contamination.