Stability, aggregation, and sedimentation behaviors of typical nano metal oxide particles in aqueous environment

Multi-level FeCo/N-doped carbon nanosheet for peroxymonosulfate oxidation and sterilization inactivation

Magnetic carbon-based catalysts with environmental friendliness have exhibited prominent effects on advanced oxidation processes. Herein, a multi-level FeCo/N-doped carbon nanosheet (FeCo/CNS) was synthesized by facile impregnation iron-cobalt salt onto cotton and followed by confined pyrolysis. We identified excellent advantages of the modified FeCo/CNS materials: (i) The convenience of the synthesis method and (ii) The dual effect of sterilization and contaminant degradation achieved through the FeCo/CNS-activated Peroxymonosulfate (PMS). The comparative experimental showed that FeCo/CNS could provide favorable catalytic performance, completely removing bisphenol A (BPA) and tetracycline (TC) within 5 min. Moreover, the potent sterilization properties against Staphylococcus aureus and Escherichia coli were also verified. Analysis of the degradation pathway confirmed the existence of intermediates, and toxicological research demonstrated that the toxicity of the degradation intermediates of BPA gradually decreased over time. Our research provided an excellent application of FeCo/CNS in PMS oxidation and sterilization inactivation.

A critical review on fate, behavior, and ecotoxicological impact of zinc oxide nanoparticles on algae

The rapid inclusion of zinc oxide nanoparticles (ZnO NPs) in nanotechnology-based products over the last decade has generated a new threat in the apprehension of the environment. The massive use of zinc nanosized products will certainly be disposed of and be released, eventually entering the aquatic ecosystem, posing severe environmental hazards. Moreover, nanosized ZnO particles owing the larger surface area per volume exhibit different chemical interactions within the aquatic ecosystem. They undergo diverse potential transformations because of their unique physiochemical properties and the feature of receiving medium. Therefore, assessment of their impact is critical not only for scavenging the present situation but also for preventing unintended environmental hazards. Algae being a primary producer of the aquatic ecosystem help assess the risk of massive NPs usage in environmental health. Because of their nutritional needs and position at the base of aquatic food webs, algal indicators exhibit relatively unique information concerning ecosystem conditions. Moreover, algae are presently the most vital part of the circular economy. Hence, it is imperative to understand the physiologic, metabolic, and morphologic changes brought by the ZnO NPs to the algal cells along with the development of the mechanism imparting toxicity mechanism. We also need to develop an appropriate scientific strategy in the innovation process to restrain the exposure of NPs at safer levels. This review provides the details of ZnO NP interaction with algae. Moreover, their impact, mechanism, and factors affecting toxicity to the algae are discussed.

Detection, distribution and environmental risk of metal-based nanoparticles in a coastal bay

Metal-based nanoparticles (NPs) attract increasing concerns because of their adverse effects on aquatic ecosystems. However, their environmental concentrations and size distributions are largely unknown, especially in marine environments. In this work, environmental concentrations and risks of metal-based NPs were examined in Laizhou Bay (China) using single-particle inductively coupled plasma-mass spectrometry (sp-ICP-MS). First, separation and detection approaches of metal-based NPs were optimized for seawater and sediment samples with high recoveries of 96.7% and 76.3%, respectively. Spatial distribution results showed that Ti-based NPs had the highest average concentrations for all the 24 stations (seawater, 1.78 × 108 particles/L; sediments, 7.75 × 1012 particles/kg), followed by Zn-, Ag-, Cu-, and Au-based NPs. For all the NPs in seawater, the highest abundance occurred around the Yellow River Estuary, resulting from a huge input from Yellow River. In addition, the sizes of metal-based NPs were generally smaller in sediments than those in seawater (22, 20, 17, and 16 of 22 stations for Ag-, Cu-, Ti-, and Zn-based NPs, respectively). Based on the toxicological data of engineered NPs, predicted no-effect concentrations (PNECs) to marine species were calculated as Ag at 72.8 ng/L < ZnO at 2.66 µg/L < CuO at 7.83 µg/L < TiO2 at 72.0 µg/L, and the actual PNECs of the detected metal-based NPs may be higher due to the possible presence of natural NPs. Station 2 (around the Yellow River Estuary) was assessed as "high risk" for Ag- and Ti-based NPs with risk characterization ratio (RCR) values of 1.73 and 1.66, respectively. In addition, RCRtotal values for all the four metal-based NPs were calculated to fully assess the co-exposure environmental risk, with 1, 20, and 1 of 22 stations as "high risk", "medium risk", and "low risk", respectively. This study helps to better understand the risks of metal-based NPs in marine environments.

Ocean acidification enhances the embryotoxicity of CuO nanoparticles to Oryzias melastigma

Concerns are raised towards individual effects of ocean acidification (OA) and engineered nanoparticles (NPs) on marine organisms. However, there are scarce studies regarding nanotoxicity under OA conditions. We investigated the combined effects of OA (pHs, 7.70 and 7.40) and CuO NPs on the embryotoxicity of marine medaka Oryzias melastigma and the bioavailability of CuO NPs in embryos. The results showed that OA alleviated the aggregation of CuO NPs and promoted the dissolution of CuO NPs in seawater (increased by 0.010 and 0.029 mg/L under pHs 7.70 and 7.40, respectively). Synergistic effects of OA with CuO NPs on medaka embryos were observed as indicated by much higher mortality and oxidative damage. Importantly, the enhanced toxicity of CuO NPs to medaka embryos under OA conditions mainly originated from the higher bioavailability of particulate CuO (e.g., 30.28 mg/kg at pH 7.40) rather than their released Cu²⁺ ions (e.g. 3.04 mg/kg at pH 7.40). The weaker aggregation of NPs under OA conditions resulted in higher penetration of individual particles (or small aggregates) into embryos through the micropyle and chorionic pores, causing enhanced bioavailability of NPs. The obtained results provided underlying insights into understanding the risk of NPs to marine ecosystem under OA conditions.

Effects of nano metal oxide particles on denitrifying phosphorus removal system: Potential stress mechanism and recovery strategy

The accumulation of nano metal oxide particles (NMOPs) in municipal sewage treatment systems harms the microbial community and its metabolism in activated sludge system, resulting in the degradation of its pollutants removal performance. In this work, the stress effect of NMOPs on the denitrifying phosphorus removal system was systematically investigated in terms of pollutants removal performance, key enzyme activities, microbial community diversity and abundances, and intracellular metabolites. Among the ZnO NPs, TiO₂ NPs, CeO₂ NPs, and CuO NPs, the ZnO NPs showed the most significant impacts with the chemical oxygen demand, total phosphorus, and nitrate nitrogen removal ratio decreased from above 90 % to 66.50 %, 49.13 %, and 57.11 %, respectively. The addition of surfactants and chelating agents could relieve the toxic effect of NMOPs on the denitrifying phosphorus removal system, and the chelating agents were more effective than surfactants in performance recovery. After adding ethylene diamine tetra acetic acid, the removal ratio of chemical oxygen demand, total phosphorus, and nitrate nitrogen under ZnO NPs stress was restored to 87.31 %, 88.79 %, and 90.35 %, respectively. The study provides valuable knowledge to better understand the impacts and stress mechanism of NMOPs on activated sludge systems and provides a solution to recover the nutrients removal performance of denitrifying phosphorus removal system under NMOPs stress.

Micelle encapsulation zinc-doped copper oxide nanocomposites reverse Olaparib resistance in ovarian cancer by disrupting homologous recombination repair

Micelle Encapsulation Zinc-doped copper oxide nanocomposites (MEnZn-CuO NPs) is a novel doped metal nanomaterial prepared by our group based on Zinc doped copper oxide nanocomposites (Zn-CuO NPs) using non-micellar beam. Compared with Zn-CuO NPs, MEnZn-CuO NPs have uniform nanoproperties and high stability. In this study, we explored the anticancer effects of MEnZn-CuO NPs on human ovarian cancer cells. In addition to affecting cell proliferation, migration, apoptosis and autophagy, MEnZn-CuO NPs have a greater potential for clinical application by inducing HR repair defects in ovarian cancer cells in combination with poly (ADP-ribose) polymerase inhibitors for lethal effects.

Combined exposure to titanium dioxide and tetracycline induces neurotoxicity in zebrafish

In aquatic environment, engineered materials may inevitably interact with the coexisted organic pollutants, which affect their bioavailability and toxicity. In this contribution, the combined impacts of tetracycline (TC) and titanium dioxide nanoparticles (TiO₂ NPs) on the neurodevelopment of zebrafish larvae were investigated, and the underlying mechanisms were further elucidated. Firstly, it was confirmed that the co-existence of TC would increase the size and decrease the zeta potential of TiO₂ NPs. Following, developmental indicators and motor behaviors were investigated. Our results indicated that co-exposure to TC and TiO₂ NPs exhibited enhanced embryonic malformation rates and abnormal nervous system development in zebrafish embryos. Meanwhile, the locomotor behavior was increased upon treatment of TC and TiO₂ NP. Further, pathway enrichment analyses of transcriptomic sequencing provided detailed information that either lipid metabolism or PPAR signaling pathway were significantly affected in the co-exposure group. Also, TC + TiO₂ NP exposure significantly changed the mRNA expression of neural development-related genes and up-regulated the expression levels of neurotransmitters like 5-hydroxytryptamine, dopamine, acetylcholinesterase, and γ-aminobutyric acid. Taken together, our results demonstrated that the co-exposure of TC and TiO₂ NPs had the potential to cause neurotoxicity in zebrafish embryos.