Ali Khodayari

Fe3O4–PVAc nanocomposites: surface modification of sonochemically prepared magnetite nanoparticles via chemical grafting of poly(vinyl acetate)

In the present study, magnetite nanoparticles (MNPs) were synthesized at room temperature under ultrasonic irradiation. The synthesized MNPs were then silylated with triethoxyvinylsilane to give a core–shell structure containing vinyl moieties on the surface. Encapsulation of the MNPs in a polysiloxane shell was clearly shown by transmission electron microscopy (TEM). The radical polymerization of the silylated product with vinyl acetate (VAc) leads to the formation of polymer nanocomposites (PN) in which some of the polymer chains are chemically grafted onto the MNPs. The homopolymer (PVAc) formed during polymerization was separated from the grafted MNPs using Soxhlet extraction. Chemical grafting of the polymer onto the MNPs was confirmed by Fourier transform infrared spectroscopy (FTIR). The amount of grafted polymer was calculated using thermogravimetric analysis (TGA). The thermal properties of the prepared MNPs, silylated MNPs, PVAc-grafted MNPs and PNs were studied using TGA. The MNPs and the nanocomposite containing 15 wt% of the PVAc-grafted MNPS (PN 15 wt%) were further investigated by scanning electron microscopy (SEM), TEM, XRD and energy dispersive X-ray analysis (EDAX). Vibrating sample magnetometry (VSM) showed the unique phenomenon of superparamagnetism for the prepared MNPs, silylated MNPs and PVAc-grafted MNPs.

Structural, Compositional, and Biological Characterization of Fe3O4 Nanoparticles Synthesized by Hydrothermal Method

In this research, magnetite nanoparticles (MNPs) have been prepared at 200°C for 2 h by hydrothermal method in presence of 3-mercaptopropionic acid (3-MPA) as a capping agent. Morphological and structural studies carried out by scanning electron microscope (SEM), that results show nanoparticles have been constructed in cubic shape with medium size about 20–30 nm, can produce clusters in 50–200 nm. X-ray diffraction results show that MNPs are in cubic crystal phase. Investigation of thermochemical properties and changing state of Fe2O3 in higher temperature, carried out with analysis of STA (DTA/TGA) that shows MNPs have changed the phase in 280°C and converted to hematite (α-Fe2O3) with rhombohedral crystal phase. Investigation of anticancer properties of nanoparticles show that after 72 h excellent anti-tumor activity against two kinds of cancer cells that are LNCAP (human prostate carcinoma) cells and HeLa (human cervix carcinoma) cells. The results are completely new and provide new views for using of the mentioned compounds in chemotherapy. Antibacterial properties of MNPs also have been studied and good results obtained.

Structural and Biological Properties of CuO Nanoparticles Prepared Under Ultrasonic Irradiation

In this research, the structural, optical, and biological characteristics of sonochemically prepared CuO nanoparticles have been investigated using scanning electron microscope (SEM), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), and antibacterial and anticancer test. The results show that nanoparticles have been formed in crystalline form with the average size of about 10–50 nm, which aggregated in the form of nanoclusters with average cluster size of about 50–200 nm. The copper oxide nanoparticles, after 48 h, show excellent antitumor activity against two kinds of cancer cells that are AGS (human gastric carcinoma) cells and HeLa (human cervix carcinoma) cells. The results are completely new and provide new views for using of the mentioned compound in chemotherapy. Antibacterial properties of nanoparticles also have been studied and were determined against the two gram-positive bacteria and also against the two gram-negative bacteria. Obtained results showed a strong antibacterial activity of CuO nanoparticles against gram-positive bacteria.