ZnO, Ag and ZnO-Ag nanoparticles exhibit differential modes of toxic and oxidative action in hemocytes of mussel Mytilus galloprovincialis.

The present study investigates the cytotoxic and oxidative effects of custom-made nanoparticles (NPs) on hemocytes of Mytilus galloprovincialis, utilizing hemolymph serum (HS) as exposure medium. Specifically, hemocyte lysosomal membrane destabilization (in terms of neutral red retention time assay/NRRT), superoxide anion (O2-), nitric oxide (NO, in terms of nitrites) and lipid peroxidation content (in terms of malondialdehyde/MDA equivalents) were determined in cells treated for 1 h with different concentrations (0.1-50 µg mL-1) of ZnO NPs, Ag NPs and ZnO-Ag NPs, as well as AgNO3 and/or ZnCl2 (bulk ions, respectively). According to the results, Ag NPs were more cytotoxic than ZnO-Ag NPs and/or ZnO NPs, while NRRT values observed in AgNO3 treated cells were lower than those of ZnCl2. Furthermore, high levels of both O2- and MDA were detected in cells treated with Ag NPs, ZnO-Ag NPs, and AgNO3 at concentrations lower than 5 µg mL-1, while high NO generation was observed only in cells treated with 5-25 µg mL-1 of ZnO NPs or ZnCl2. Despite the absence of data, regarding the formation of NP-serum protein corona complexes that could mediate NP surface energy and uptake efficiency, the current study firstly revealed that ZnO NPs, probably via their surface charge, particle agglomeration, and NP Zn+ release could promote an immune-related generation of O2- and NO via the respiratory burst stimulation, a process that is questioned in the case of Ag NPs and/or ZnO-Ag NPs. Moreover, ZnO-Ag NP interaction with biological membranes and their oxidative mode of action seemed to be regulated by the release and the antagonistic/synergistic response of its ionic counterparts (ZnO+ and Ag+), but further studies are needed to elucidate the oxidative mode of action of NP metal ions in complex NP mixtures.

A Hybrid {Silk@Zirconium MOF} Material as Highly Efficient AsIII-sponge.

Exposure of humans to Arsenic from groundwater drinking sources is an acute global public health problem, entailing the urgent need for highly efficient/low-cost Arsenite (AsIII) up-taking materials. Herein we present an innovative hybrid-material, ZrMOF@SFd operating like an "AsIII-sponge" with unprecedented efficiency of 1800 mg AsIII gr-1. ZrMOF@SFd consists of a neutral Zirconium Metal-Organic Framework [ZrMOF] covalently grafted on a natural silk-fiber (SFd). ZrMOF itself exhibits AsIII adsorption of 2200 mg gr-1, which supersedes any -so far- known AsΙΙΙ-sorbent. Using XPS, FTIR, BET-porosimetry data, together with theoretical Surface-Complexation-Modeling (SCM), we show that the high-AsΙΙΙ-uptake is due to a sequence of two phenomena:[i] at low AsIII-concentrations, surface-complexation of H3AsO3 results in AsIII-coated voids of ZrMOF, [ii] at increased AsIII-concentrations, the AsIII-coated voids of ZrMOF are filled-up by H3AsO3 via a partitioning-like mechanism. In a more general context, the present research exemplifies a mind-changing concept, i.e. that a "partitioning-like" mechanism can be operating for adsorption of metalloids, such as H3AsO3, by metal oxide materials. So far, such a mechanism has been conceptualized only for the uptake of non-polar organics by natural organic matter or synthetic polymers.

Assessing the cyto-genotoxic potential of model zinc oxide nanoparticles in the presence of humic-acid-like-polycondensate (HALP) and the leonardite HA (LHA).

The present study investigates the potential cyto-genotoxic effects of model zinc oxide nanoparticles (ZnO NPs) on human lymphocytes, with and/or without humic acids (HAs). Two types of HAs were studied, a natural well-characterized leonardite HA (LHA) and its synthetic-model, a humic-acid-like-polycondensate (HALP). The Cytokinesis Block Micronucleus (CBMN) assay was applied in cell cultures treated with different concentrations of ZnO NPs (0.5, 5, 10, 20 µg mL-1) and under different concentrations of either HALP or LHA (ZnO NPs-HALP and ZnO NPs-LHA, at concentrations of 0.5-0.8, 5-8, 10-16, 20-32 and 0.5-2, 5-20, 10-40, 20-80 µg mL-1, respectively). According to the results, ZnO NPs lacked genotoxicity but demonstrated cytotoxic potential. Binary mixtures of ZnO NPs-HAs (ZnO NPs-HALP or ZnO NPs-LHA) showed negligible alterations of micronuclei (MN) formation in challenged cells, with cytotoxic effects revealed only in case of cells treated with ZnO NPs-LHA at the concentration 5-20 µg mL-1. Furthermore, no genotoxic phenomena were exerted neither by the ZnO NPs nor from their mixtures with HAs. These findings indicate [i] the cytotoxic activity of used ZnO NPs on human lymphocytes, and [ii] reveal the protective role of HAs against ZnO NPs mediated cytotoxicity.

A functionalized phosphonate-rich organosilica layered hybrid material (PSLM) fabricated through a mild process for heavy metal uptake.

A phosphonate-rich organosilica layered hybrid material (PSLM) made of 3-(trihydroxysilyl)propyl methylphosphonate, monosodium salt, as the single silica source, has been obtained from its aqueous solution through a xerogel process and mild thermal aging. The method is simple, affording bulk quantities of powdered PSLM in a single-step. The hybrid is stable in water and possesses a high content of phosphonate groups fixed on the solid matrix. In addition, PSLM shows good thermal stability, which exceeds 300°C in air. The material was characterized using SEM, TEM, XRD, FT-IR and TGA techniques. Potentiometric titrations show that PSLM bears high-surface density of phosphonate groups (3 mmol g(-1)). As a result, the material displays high metal uptake capacity for heavy metal ions such as Cu(2+) (2.72mmolg(-1)), Pb(2+) (1.67 mmol g(-1)) and Cd(2+) (1.00 mmol g(-1)) at neutral pH values e.g. the pH of natural waters. Detailed theoretical modeling using a Surface Complexation Model combined with Electron Paramagnetic Resonance (EPR) spectroscopy shows that the surface distribution of surface bound Cu(2+) ions is rather homogeneous e.g. copper-binding phosphonate sites are arranged in average distances 5-8Å.