Cytotoxicity, antibacterial and antifungal activities of ZnO nanoparticles prepared by the Artocarpus gomezianus fruit mediated facile green combustion method

Spherical nanoparticles of zinc oxide (ZnO NPs) were synthesized by an eco-friendly green combustion method using citrate containing Artocarpus gomezianus fruit extract as a fuel. The morphology, compositions and structure of the product were characterized by Powder X-ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infra-red (FTIR), UV–Visible (UV–Vis) and Raman Spectroscopy. Highly uniform spherical zinc oxide NPs were subjected to cytotoxicity, antifungal and antibacterial activities. PXRD patterns show that the product formed belongs to a hexagonal wurtzite system. SEM micrographs reveal that the particles are agglomerated. The TEM images demonstrate that the particles are highly uniform spherical in shape and loosely agglomerated. Scherrer's method and WH plots were used to calculate the average crystallite sizes, yielding 39, 35, 31 and 40, 37, 32 nm for ZnO NPs prepared with 5, 10 and 15 mL of 10% Artocarpus gomezianus fruit extract, respectively. These results were confirmed by the TEM observations. Breast cancer cell lines (MCF-7) were subjected to in vitro anticancer activity. MTT assay revealed a good anticancer activity of ZnO NPs against MCF-7. Zone of the inhibition method shows that the spherical ZnO NPs also exhibit significant antibacterial activity against staphylococcus aureus and antifungal activity against Aspergillus niger. The synthesized ZnO NPs can find plausible biological applications. Keywords: Green synthesis, ZnO nanoparticles, Anticancer activity, MCF-7, Antibacterial, Antifunga

Designing of Au doped TiO2 NPs as an electrocatalyst for nitrite sensor

In the present work, a simple ionothermal protocol for the synthesis of Au doped TiO2 and its subsequent application as an electrochemical interface for the trace level electroanalytical quantification of nitrite ion has been described. The surface morphology and the composition has been described with the help of Scanning electron microscope and Energy Dispersive X-Ray techniques. Further, it has been used in the fabrication of thin film electrodes by a simple physical drop casting method. Cyclic voltammetry has been used to decipher the electrocatalytic property of the modified interface towards nitrite ions and square wave voltammetry to work in the low concentration levels of nitrite ions. The developed sensor interface revealed superior nitrite sensing performance in the dynamic concentration range from 3.3 to 120 µM with a very low experimental detection limit of 0.095 µM with a sensitivity of 0.9973. The analytical applicability of the developed interference has been validated by determining the presence of nitrite from real samples with least interference from commonly encountered foreign ions. The stability and reproducibility of the proposed interface has been studied over a period of several months and the results were found to be highly reproducible with a relative standard deviation of ± 5 %. These results show that, the proposed interface electrode display better electrocatalytic activity compared to the previously reported sensors for the electro oxidation of nitrite ions