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.

In this work, copper substituted cobalt ferrite nanoparticles Co1-xCuxFe2O4 (×=0, 0.3, and 0.7), has been synthesized via laser assisted hydrothermal synthesis (LAHS) methods. The XRD patterns showed single phase spinel structure, comparative study between the two preparation methods, effect of laser irradiation on the structural properties, and average crystallite size that is evaluated from most intense peak (311) utilizing Scherrer formula. Further studies for laser assisted hydrothermal as-prepared ferrite samples using each of Field emission-scanning electron microscope (FE-SEM) which revealed the study of topography, shape, particle size, vibrating sample magnetometer (VSM) with in 15kOe as maximum field. That was used to study the magnetic properties and confirmed the super-paramagnetic property of the prepared ferrite nanoparticles. Coercivity (Hc), remanence (Mr), saturation magnetization (Ms) and sequarness ratio were directly extracted from hysteresis loops. Moreover, results showed that the magnetic characteristics are on the basis of each particle size as well as cation distribution. In addition, the antibacterial property of the prepared nanoparticles against S. aureus and E. coli found to be improved after substitution of Cu in Co ferrite matrix.