Structure, surface analysis and bioactivity of Mn doped zinc oxide nanoparticles

Ecotoxicity of doped zinc oxide nanoparticles: Perspectives on environmental safety

Studies on the ecotoxicity of doped zinc oxide nanoparticles (ZnO NPs) are recent, with the first publications starting in 2010. In this sense, this is the first study that comprehensively reviews the ecotoxicological effects of ZnO NPs doped with lanthanide elements to fill this literature gap. This research explores a multifaceted question at the intersection of nanotechnology, toxicology, and environmental science. Different types of dopants commonly used for ZnO doping were investigated in this review, focusing on the ecotoxicological effects of lanthanides as dopants. Bacteria were the main class of organisms used in ecotoxicological studies, since antimicrobial activity of these nanomaterials is extensively explored to combat the imminent problem of resistant bacteria, in addition to enabling the safe use of these nanomaterials for biomedical applications. Doping appears to exhibit greater efficacy when compared to undoped ZnO NPs in terms of antimicrobial effects; however, it cannot be said that it has no impact on non-target organisms. An extensive examination of the literature also establishes the importance and need to evaluate the effects of doped ZnO NPs on organisms from different environmental compartments in order to identify their potential impacts. We underscore the dearth of research information regarding the environmental toxicity/ecotoxicity of doped ZnO nanoparticles across various ecological levels, thereby limiting the extrapolation of findings to humans or other complex models. Therefore, we emphasize the urgency of a multi-parameter assessment for the development of sanitary and environmentally safe nanotechnologies.

New synthetic silver-doped ZnO nanorods trigger cytotoxicity in MCF-7 through apoptosis and antimicrobial activity

The structural, composition, and molecular interaction of silver integrated zinc oxide (20 wt.% Ag/ZnO) were investigated by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), and Fourier transforms infrared (FTIR) spectrum. The XRD analysis showed the polycrystalline of small crystallite size, whereas the EDX spectrum confirmed the purity of the nanocomposite. The FTIR spectrum indicated the presence of Ag-Zn-O stretching vibration at 1034 cm-1. SEM and TEM images identified the surface morphology and particle size, indicating that Ag/ZnO of nanorods linked with spherical-like shapes. The nanorods of an average length of ∼ 110 nm and an average diameter of ∼ 10 nm. The optical characteristics showed a direct transition of electrons through an energy gap in the 3.30 eV-3.60 eV. The tested nanocomposite exhibited potent cytotoxicity against MCF-7 cells with an IC50 value of 0.26 µg/ml with cell growth inhibition by 97.3% at the highest concentration compared to Doxorubicin (IC50=6.72 µg/ml). It significantly stimulated total apoptotic breast cancer cell death by 51-fold (32.16% compared to 0.63 for the control), arresting the cell progression at the G1 phase. For further validation of apoptotic activity, the tested Ag/ZnO-NP upregulated the proapoptotic genes and down-regulated the anti-apoptotic gene. Moreover, a molecular docking study highlighted the binding disposition of the nanocomposite as Bcl-2 inhibitors. Additionally, Ag/ZnO-NP exhibited potent antimicrobial activity. Hence, the synthesized nanocomposite can serve as an antimicrobial and cytotoxic agent through apoptosis-induction and could be developed as a biologically active nanocomposite.Communicated by Ramaswamy H. Sarma.