Mycosynthesis of ZnO Nanoparticles UsingTrichodermaspp. Isolated from Rhizosphere Soils and Its Synergistic Antibacterial Effect againstXanthomonas oryzaepv.oryzae

The Plant Growth Promoting Fungi (PGPF) is used as a source of biofertilizers due to their production of secondary metabolites and beneficial effects on plants. The present work is focused on the co-cultivation ofTrichodermaspp. (T. harzianum(PGT4),T. reesei(PGT5) andT. reesei(PGT13)) and the production of secondary metabolites from mono and co-culture and mycosynthesis of zinc oxide nanoparticles (ZnO NPs), which were characterized by a UV visible spectrophotometer, Powder X-ray Diffraction (PXRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDAX) and Transmission Electron Microscope (TEM) and Selected Area (Electron) Diffraction (SAED) patterns. The fungal secondary metabolite crude was extracted from the mono and co-culture ofTrichodermaspp. And were analyzed by GC-MS, which was further subjected for antibacterial activity againstXanthomonas oryzaepv.Oryzae, the causative organism for Bacterial Leaf Blight (BLB) in rice. Our results showed that the maximum zone of inhibition was recorded from the co-culture ofTrichodermaspp. rather than mono cultures, which indicates that co-cultivation of beneficial fungi can stimulate the synthesis of novel secondary metabolites better than in monocultures. ZnO NPs were synthesized from fungal secondary metabolites of mono cultures of Trichoderma harzianum (PGT4), Trichoderma reesei (PGT5), Trichoderma reesei (PGT13) and co-culture (PGT4 + PGT5 + PGT13). These ZnO NPs were checked for antibacterial activity against Xoo, which was found to be of a dose-dependent manner. In summary, the biosynthesized ZnO NPs and secondary metabolites from co-culture ofTrichodermaspp. are ecofriendly and can be used as an alternative for chemical fertilizers in agriculture

CaFe2O4 sensitized hierarchical TiO2 photo composite for hydrogen production under solar light irradiation

Hierarchical spheres of self organized nanosheets of TiO2 are prepared by solvothermal method. The spheres comprising nanosheets are expected to exhibit high conducting properties. The present work is an attempt to explore the conducting properties of these spheres of TiO2 nanosheets that facilitate charge transfer and charge mobility. And at the same time to extend the absorption of TiO2 to visible light, it is combined with a low bandgap semiconductor CaFe2O4. In this perspective, CaFe2O4/TiO2 composite photocatalyst consisting of CaFe2O4 and TiO2 hierarchical spheres of nanosheets is prepared by solid state dispersion (SSD) method. The photocatalysts are characterized by thermo gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption desorption, photoluminescence (PL) and UV-Vis diffuse reflectance spectra (DRS). SEM and TEM images show TiO2 spheres and the mesoporous structure is substantiated by the N2 adsorption desorption studies. UV-Vis DRS of the composites show visible light absorption confirming the sensitization of TiO2 by CaFe2O4. XRD shows the crystallinity of the prepared composites is anatase and SEM confirms that the TiO2 spheres are intact at 400??C calcination temperature. However, deformation of spheres is seen at higher temperatures. Photocatalytic activity of the composites is studied using methanol water mixtures and optimum conditions for hydrogen production are established. By comparing the activity of CaFe2O4/TiO2 composite under visible and solar light irradiation, the possible charge transfer processes that are responsible for the synergistic activity are visualized. Based on the results, a mechanism highlighting the structure activity correlation has been proposed.close0

Mycogenic Synthesis of Extracellular Zinc Oxide Nanoparticles from Xylaria acuta and Its Nanoantibiotic Potential

Purpose: The study aimed to find an effective method for fungal-mediated synthesis of zinc oxide nanoparticles using endophytic fungal extracts and to evaluate the efficiency of synthesized ZnO NPs as antimicrobial and anticancerous agents. Methods: Zinc oxide nanoparticles (ZnO NPs) were produced from zinc nitrate hexahydrate with fungal filtrate by the combustion method. The spectroscopy and microscopy techniques, such as ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), and transmission electron microscopy (TEM) with selected area electron diffraction (SAED), were used to characterize the obtained product. Antibacterial activity on Gram-positive (Staphylococcus aureus and Bacillus cereus) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) samples was tested by broth microplate dilution technique. ZnO NPs antifungal activity was determined against plant pathogenic and regular contaminating fungi using the food-poison method. The anticancerous assay of the synthesized ZnO NPs was also investigated by cell uptake, MTT assay, and apoptosis assay. Results: The fungal synthesized ZnO NPs were pure, mainly hexagonal in shape and size range of 34-55 nm. The biosynthesized ZnO NPs could proficiently inhibit both Gram-positive and Gram-negative bacteria. ZnO NPs synthesized from fungal extract exhibited antifungal activity in a dose-dependent manner with a high percentage of mycelial inhibition. The cell uptake analysis of ZnO NPs suggests that a significant amount of ZnO NPs (1 mu g/mL) was internalized without disturbing cancer cells' morphology. As a result, the synthesized ZnO NPs showed significant anticancer activity against cancer cells at 1 mu g/mL concentration. Conclusion: This fungus-mediated synthesis of ZnO NPs is a simple, eco-friendly, and non-toxic method. Our results show that the synthesized ZnO NPs are an excellent novel antimicrobial and anticancer agent. Further studies are required to understand the mechanism of the antimicrobial, anticancerous action of ZnO NPs and their possible genotoxicity

1.3 μm emitting SrF2:Nd3+ nanoparticles for high contrast in vivo imaging in the second biological window

Novel approaches for high contrast, deep tissue, in vivo fluorescence biomedical imaging are based on infrared-emitting nanoparticles working in the so-called second biological window (1,000–1,400 nm). This allows for the acquisition of high resolution, deep tissue images due to the partial transparency of tissues in this particular spectral range. In addition, the optical excitation with low energy (infrared) photons also leads to a drastic reduction in the contribution of autofluorescence to the in vivo image. Nevertheless, as is demonstrated here, working solely in this biological window does not ensure a complete removal of autofluorescence as the specimen’s diet shows a remarkable infrared fluorescence that extends up to 1,100 nm. In this work, we show how the 1,340 nm emission band of Nd3+ ions embedded in SrF2 nanoparticles can be used to produce autofluorescence free, high contrast in vivo fluorescence images. It is also demonstrated that the complete removal of the food-related infrared autofluorescence is imperative for the development of reliable biodistribution studie