Microbial biofilms on biomaterial implants or devices are hard to eliminate by antibiotics due to their protection by exopolymeric substances that embed the organisms in a matrix, impenetrable for most antibiotics and immune-cells. Application of metals in their nanoparticulated form is currently considered to resolve bacterial infections. Gold and iron-oxide nanoparticles are widely used in different medical applications, but their utilisation to eradicate biofilms on biomaterials implants is novel. Here, we studied the effect of gold and iron oxide nanoparticles on Staphylococcus aureus and Pseudomonas aeruginosa biofilms. We report that biofilm growth was reduced at higher concentrations of gold and iron-oxide nanoparticles compared to absence of nanoparticles. Thus nanoparticles with appropriate concentration could show significant reduction in biofilm formation.

ZnSe nano and microstructures were grown on Si substrates in high vacuum by thermal evaporation at different source temperatures ranging from 850 to 950°C. Morphology, chemical composition and structural properties of these grown ZnSe nano and microstructures were studied using scanning electron microscope (SEM) and transmission electron microscope (TEM). SEM studies revealed that the morphology of grown structures contains nanowires, nanobelts and microcrystals. TEM studies showed that the grown nanowires and nanobelts are single crystalline in nature with growth direction along [110] of zinc blende structure. The room temperature photoluminescence (PL) spectra of these nanostructures grown at different temperatures exhibited a strong broad defect level (DL) emission peak and a weak narrow near band edge (NBE) emission peak. Further, the intensity of DL emission peak was found to increase with increase in source temperature.

ZnS nanostructures were grown on Si substrates in high vacuum by modified thermal evaporation technique. Morphology, chemical composition and structural properties of grown ZnS nanostructures were studied using scanning electron microscope (SEM), X-ray diffractometer and transmission electron microscope (TEM). SEM studies showed that morphology of the grown structures varies with incident flux and source temperature. TEM studies showed that grown nanostructures are single crystalline in nature without structural defects such as stacking faults and twins. No catalytic particle was included in this growth process, and hence these micro and nanostructures were assumed to grow by VS mechanism.

ZnO nanostructured films were deposited on glass substrates at room temperature by activated reactive evaporation technique. Thermal evaporation of zinc at high deposition rate in presence of oxygen plasma resulted in deposition of ZnO nanostructured film with different flower-like morphologies on glass substrates. The structural and morphological properties of these nanostructured films were studied by XRD, SEM and TEM. A gas phase growth mechanism has been proposed for the formation of nanostructures. The room temperature photoluminescence spectra of these films exhibited weak ultraviolet (UV) and strong broad visible emission peaks. Further, the position of visible emission peak is found to vary with morphology of the grown nanostructured films. Photocurrent measurements indicated that these ZnO nanostructured films show high sensitivity to UV light, and hence can be used as efficient UV photodetectors.