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Soil salinization is a common environmental problem that seriously threatens crop yield and food security, especially through its impact on seed germination. Nanoparticle priming, an emerging seed treatment method, is receiving increasing attention in improving crop yield and stress resistance. This study used alfalfa seeds as materials to explore the potential benefits of cerium oxide nanoparticle (CeO2NP) priming to promote seed germination and improve salt tolerance. CeO2NPs at concentrations up to 500 mg/L were able to significantly alleviate salt stress in alfalfa seeds (200 mM), with 50 mg/L of CeO2NP having the best effect, significantly (P< 0.05) increasing germination potential (from 4.0% to 51.3%), germination rate (from 10.0% to 62.7%), root length (from 8.3 cm to 23.1 cm), and seedling length (from 9.8 cm to 13.7 cm). Priming treatment significantly (P< 0.05) increased seed water absorption by removing seed hardness and also reducing abscisic acid and jasmonic acid contents to relieve seed dormancy. CeO2NP priming increased α-amylase activity and osmoregulatory substance level, decreased reactive oxygen species and malonaldehyde contents and relative conductivity, and increased catalase enzyme activity. Seed priming regulated carotenoid, zeatin, and plant hormone signal transduction pathways, among other metabolic pathways, while CeO2NP priming additionally promoted the enrichment of α-linolenic acid and diterpenoid hormone metabolic pathways under salt stress. In addition, CeO2NPs enhanced α-amylase activity (by 6.55%) in vitro. The optimal tested concentration (50 mg/L) of CeO2NPs was able to improve the seed vigor, enhance the activity of α-amylase, regulate the osmotic level and endogenous hormone levels, and improve the salt tolerance of alfalfa seeds. This study demonstrates the efficacy of a simple seed treatment strategy that can improve crop stress resistance, which is of great importance for reducing agricultural costs and promoting sustainable agricultural development. [ABSTRACT FROM AUTHOR]

Soil salinization is a common environmental problem that seriously threatens crop yield and food security, especially through its impact on seed germination. Nanoparticle priming, an emerging seed treatment method, is receiving increasing attention in improving crop yield and stress resistance. This study used alfalfa seeds as materials to explore the potential benefits of cerium oxide nanoparticle (CeO2NP) priming to promote seed germination and improve salt tolerance. CeO2NPs at concentrations up to 500 mg/L were able to significantly alleviate salt stress in alfalfa seeds (200 mM), with 50 mg/L of CeO2NP having the best effect, significantly (P< 0.05) increasing germination potential (from 4.0% to 51.3%), germination rate (from 10.0% to 62.7%), root length (from 8.3 cm to 23.1 cm), and seedling length (from 9.8 cm to 13.7 cm). Priming treatment significantly (P< 0.05) increased seed water absorption by removing seed hardness and also reducing abscisic acid and jasmonic acid contents to relieve seed dormancy. CeO2NP priming increased α-amylase activity and osmoregulatory substance level, decreased reactive oxygen species and malonaldehyde contents and relative conductivity, and increased catalase enzyme activity. Seed priming regulated carotenoid, zeatin, and plant hormone signal transduction pathways, among other metabolic pathways, while CeO2NP priming additionally promoted the enrichment of α-linolenic acid and diterpenoid hormone metabolic pathways under salt stress. In addition, CeO2NPs enhanced α-amylase activity (by 6.55%) in vitro. The optimal tested concentration (50 mg/L) of CeO2NPs was able to improve the seed vigor, enhance the activity of α-amylase, regulate the osmotic level and endogenous hormone levels, and improve the salt tolerance of alfalfa seeds. This study demonstrates the efficacy of a simple seed treatment strategy that can improve crop stress resistance, which is of great importance for reducing agricultural costs and promoting sustainable agricultural development.

Abstract Background The biological effects of cerium dioxide nanoparticles (CeO2NPs), a novel material in the biomedical field, have attracted widespread attention. Our previous study confirmed that exposure to CeO2NPs during pregnancy led to abnormal trophoblast invasion during early placental development, thereby impairing placental development. The potential mechanisms may be related to low-quality decidualization triggered by CeO2NPs exposure, such as an imbalance in trophoblast invasion regulators secreted by decidual cells. However, the intermediate link mediating the “dialogue” between decidual cells and trophoblasts during this process remains unclear. As an important connection between cells, exosomes participate in the “dialogue” between endometrial cells and trophoblasts. Exosomes transfer bioactive microRNA into target cells, which can target and regulate the level of mRNA in target cells. Results Here, we constructed a mice primary uterine stromal cell-induced decidualization model in vitro, and detected the effect of CeO2NPs exposure on the expression of decidual-derived exosomal miRNAs by high-throughput sequencing. Bioinformatics analysis and dual-luciferase reporter assays were performed to identify target genes of the screened key miRNAs in regulating trophoblast invasion. Finally, the role of the screened miRNAs and their target genes in regulating trophoblast (HTR-8/SVneo cells) invasion was confirmed. The results showed that CeO2NPs exposure inhibited trophoblast invasion by promoting miR-99a-5p expression in decidual-derived exosomes, and Ppp2r5a is a potential target gene for miR-99a-5p to inhibit trophoblast invasion. Conclusions This study revealed the molecular mechanism by which CeO2NPs exposure inhibits trophoblast invasion from the perspective of decidual derived exosomal miRNAs. These results will provide an experimental basis for screening potential therapeutic targets for the negative biological effects of CeO2NPs exposure and new ideas for studying the mechanism of damage to trophoblast cells at the decidual-foetal interface by harmful environmental or occupational factors.

Background: The biological effects of cerium dioxide nanoparticles (CeO2NPs), a novel material in the biomedical field, have attracted widespread attention. Our previous study confirmed that exposure to CeO2NPs during pregnancy led to abnormal trophoblast invasion during early placental development, thereby impairing placental development. The potential mechanisms may be related to low-quality decidualization triggered by CeO2NPs exposure, such as an imbalance in trophoblast invasion regulators secreted by decidual cells. However, the intermediate link mediating the "dialogue" between decidual cells and trophoblasts during this process remains unclear. As an important connection between cells, exosomes participate in the "dialogue" between endometrial cells and trophoblasts. Exosomes transfer bioactive microRNA into target cells, which can target and regulate the level of mRNA in target cells. Results: Here, we constructed a mice primary uterine stromal cell-induced decidualization model in vitro, and detected the effect of CeO2NPs exposure on the expression of decidual-derived exosomal miRNAs by high-throughput sequencing. Bioinformatics analysis and dual-luciferase reporter assays were performed to identify target genes of the screened key miRNAs in regulating trophoblast invasion. Finally, the role of the screened miRNAs and their target genes in regulating trophoblast (HTR-8/SVneo cells) invasion was confirmed. The results showed that CeO2NPs exposure inhibited trophoblast invasion by promoting miR-99a-5p expression in decidual-derived exosomes, and Ppp2r5a is a potential target gene for miR-99a-5p to inhibit trophoblast invasion. Conclusions: This study revealed the molecular mechanism by which CeO2NPs exposure inhibits trophoblast invasion from the perspective of decidual derived exosomal miRNAs. These results will provide an experimental basis for screening potential therapeutic targets for the negative biological effects of CeO2NPs exposure and new ideas for studying the mechanism of damage to trophoblast cells at the decidual-foetal interface by harmful environmental or occupational factors. [ABSTRACT FROM AUTHOR]

Abstract Background The increasing use of cerium dioxide nanoparticles (CeO2NPs) in biomedical field has attracted substantial attention about their potential risks to human health. Recent studies have shown that nanoparticles can induce placental dysfunction and even fetal abortion, but a more detailed mechanism of nanoparticles affecting placental development remains elusive. Results Here, we constructed a mouse exposure model with different doses of CeO2NPs (2.5, 4, 5, 7.5, and 10 mg kg−1 day−1, average particle size 3–5 nm), finding that intravenous exposure to pregnant mice with CeO2NPs could cause abnormal placental development. Deposited nanoparticles were able to be observed in the placental trophoblast at doses of 5 and 7.5 mg kg−1 day−1. Diving into molecular mechanisms indicated that CeO2NPs exposure could lead to autophagy activation in placental trophoblast. At the cellular level, exposure to CeO2NPs inhibited the migration and invasion of HTR-8/SVneo and activated the autophagy through mammalian target of rapamycin complex1 (mTORC1) signaling pathway. Furthermore, inhibition of autophagy initiation by 3-Methyladenine (3-MA) partially restored the function of HTR-8/SVneo, while blocking autophagic flow by Chloroquine (CQ) aggravated the functional damage. Conclusions Maternal exposure to CeO2NPs impairs placental development through trophoblast dysfunction mediated by excessive autophagy activation. These results suggested that autophagy dysfunction may be a potential mechanism for the impairment of trophoblast by CeO2NPs exposure. As above, our findings provide insights into the toxicity mechanism to the reproductive system induced by rare-earth nanoparticles exposure. Graphical Abstract

Nanoparticles have a promising future in biomedical applications and knowing whether they affect ex vivo vascular reactivity is a necessary step before their use in patients. In this study, we have evaluated the vascular effect of cerium dioxide nanoparticles (CeO 2 NPs) on the human saphenous vein in response to relaxing and contractile agonists. In addition, we have measured the protein expression of key enzymes related to vascular homeostasis and oxidative stress. We found that CeO 2 NPs increased expression of both SOD isoforms, and the consequent reduction of superoxide anion would enhance the bioavailability of NO explaining the increased vascular sensitivity to sodium nitroprusside in the presence of CeO 2 NPs. The NOX4 reduction induced by CeO 2 NPs may lead to lower H 2 O 2 synthesis associated with vasodilation through potassium channels explaining the lower vasodilation to bradykinin. In addition, we showed for the first time, that CeO 2 NPs increase the expression of ACE2 in human saphenous vein, and it may be the cause of the reduced contraction to angiotensin II. Moreover, we ruled out that CeO 2 NPs have effect on the protein expression of eNOS, sGC, BKca channels and angiotensin II receptors or modify the vascular response to noradrenaline, endothelin-1 and TXA 2 analogue. In conclusion, CeO 2 NPs show antioxidant properties, and together with their vascular effect, they could be postulated as adjuvants for the treatment of cardiovascular diseases. HSV: human saphenous vein; Bk: bradykinin, SNP: sodium nitroprusside; Ang II: angiotensin II; SOD: superoxide dismutase; NOX4: NAPH oxidase 4; ACE2: angiotensin-converting enzyme 2; eNOS: endothelial nitric oxide synthase; EC: endothelial cell; BKca: large conductance calcium activated potassium channel. [Display omitted] • CeO 2 NPs increase SOD1 and SOD2 and decrease NOX4 protein expression. • CeO 2 NPs increase NO mediated vasodilation. • CeO 2 NPs decrease bradykinin-induced vasodilation. • CeO 2 NPs increase the ACE2 protein expression in human saphenous vein. • CeO 2 NPs decrease vasoconstrictor effect to angiotensin II. [ABSTRACT FROM AUTHOR]

Abstract The green synthesis (GS) of metallic nanoparticles has been reassessed by plant extracts for their natural potential to reduce metallic ions into neutral atoms at no expense of toxic and hazardous chemicals. Biomolecules found in plant extracts can be used to reduce metal ions to nanoparticles in a single step process. Cerium oxide nanoparticles (CeO2 NPs) have a wide variety of applications in different areas, especially in the biomedical fields including treatment of cancer. This study was focused on the biosynthesis of CeO2 NPs using Averrhoa carambola leaf extract acts as green reducing agents which are quite impressive to explore pharmaceutical and medical applications. The CeO2 NPs were characterized. The biomedical activities of CeO2 NPs were tested against prostate, colon and breast cancer cell lines by employing MTT assay. The overall studies highlight the antibacterial, antioxidant, anticancer, and anti-ROS potential of CeO2 NPs. HIGHLIGHTS Green chemistry for the synthesis of nanoparticles has increased its advantage in the field of biomedical and therapeutic applications. Single step synthesis. CeO2 NPs are good antibacterial agent because it inactivates the protein and lowers membrane permeability which results in cell death. CeO2 NPs are excellent therapeutic agents to detoxify the reactive oxygen species (ROS). CeO2 NPs are having invading property toward cancer cells. Green chemistry for the synthesis of nanoparticles has increased its advantage in the field of biomedical and therapeutic applications.Single step synthesis.CeO2 NPs are good antibacterial agent because it inactivates the protein and lowers membrane permeability which results in cell death.CeO2 NPs are excellent therapeutic agents to detoxify the reactive oxygen species (ROS).CeO2 NPs are having invading property toward cancer cells. [ABSTRACT FROM AUTHOR]

Background: The increasing use of cerium dioxide nanoparticles (CeO2NPs) in biomedical field has attracted substantial attention about their potential risks to human health. Recent studies have shown that nanoparticles can induce placental dysfunction and even fetal abortion, but a more detailed mechanism of nanoparticles affecting placental development remains elusive. Results: Here, we constructed a mouse exposure model with different doses of CeO2NPs (2.5, 4, 5, 7.5, and 10 mg kg−1 day−1, average particle size 3–5 nm), finding that intravenous exposure to pregnant mice with CeO2NPs could cause abnormal placental development. Deposited nanoparticles were able to be observed in the placental trophoblast at doses of 5 and 7.5 mg kg−1 day−1. Diving into molecular mechanisms indicated that CeO2NPs exposure could lead to autophagy activation in placental trophoblast. At the cellular level, exposure to CeO2NPs inhibited the migration and invasion of HTR-8/SVneo and activated the autophagy through mammalian target of rapamycin complex1 (mTORC1) signaling pathway. Furthermore, inhibition of autophagy initiation by 3-Methyladenine (3-MA) partially restored the function of HTR-8/SVneo, while blocking autophagic flow by Chloroquine (CQ) aggravated the functional damage. Conclusions: Maternal exposure to CeO2NPs impairs placental development through trophoblast dysfunction mediated by excessive autophagy activation. These results suggested that autophagy dysfunction may be a potential mechanism for the impairment of trophoblast by CeO2NPs exposure. As above, our findings provide insights into the toxicity mechanism to the reproductive system induced by rare-earth nanoparticles exposure. [ABSTRACT FROM AUTHOR]

Chlorpyrifos (CPF) is a widely used insecticide that causes toxicity to living organisms through the production of free radicals. Cerium oxide nanoparticles (CeO 2 NPs) are a new antioxidant agent that has proved therapeutic effects. We evaluated the effect of CeO 2 NPs on CPF hepatotoxicity. Forty rats were randomized into four groups. Group I: rats received 1 ml corn oil by gastric tube once daily and 0.5 ml PBS by intra-peritoneal injection twice a week for 4 weeks. Group II: received CeO 2 NPs 0.5 mg/kg in PBS by i.p. injection, twice weekly for four weeks. Group III: were treated with oral administration of CPF 13.5 mg/kg in corn oil daily for 4 weeks. Group IV: received CPF as in group III, then each animal received CeO 2 NPs twice weekly for four weeks as in group II. Twenty-four hours after the last dose, rats were anesthetized and sera were collected for liver enzymes assessment. Afterwards, rats were sacrificed, livers were excised, the right lobe of each liver was fixed for immunohistochemical studies, and the left lobe was homogenized for oxidative profile assessment and molecular analysis. CPF group showed significant increase in liver transaminases, disturbance of the oxidative profile with up-regulation of BAX expression and down-regulation in the Bcl-2, Gadd45 and NFE2L2. CPF caused severe histopathological liver damage as well as significant increase in anti-Caspase 3 and TNF immunostaining. The CeO 2 NPs treated group revealed significant improvement of all previous parameters. CeO 2 NPs could alleviate CPF hepatoxicity through decreasing expression of the inflammatory and apoptotic proteins and increasing the activity of antioxidant enzymes. [Display omitted] • Chronic exposure to Chlorpyrifos (CPF) induced hepatotoxicity in rats. • CPF induced up-regulation of inflammatory markers and apoptotic markers. • Cerium oxide nanoparticles (CeO 2 NPs) could alleviate CPF- induced hepatoxicity. • CeO 2 NPs cause down-regulation of anti-oxidative (SOD, CAT and NFE2L2) markers. • CeO 2 NPs cause down-regulation of anti-apoptotic (Bcl 2 & Gadd45) markers. [ABSTRACT FROM AUTHOR]

Cerium oxide nanoparticles (CeO2NPs) is an efficient neuroprotective agent and showed promising effects in some neurodegenerative diseases such as Alzheimer’s disease and multiple sclerosis. However, the implication of CeO2NPs in Parkinsonism remains to be investigated. The aim of this study was to assess the possible role of CeO2NPs as a neuroprotective agent against the development of behavioral and biochemical changes in rat model of Parkinson’s disease. Thirty rats were included and received left intrastriatal injection of either saline (controls, n = 10) or 6-hydroxy dopamine (6-OHDA) in untreated group (n = 10) and 10 rats were received intraperitoneal injection of low dose CeO2NPs two hours before surgery, and continued once daily for 6 weeks (preventive group). At the end of experimental period, rats were subjected to behavioral assessment and then killed for biochemical analysis of striatal dopamine levels, oxidative stress markers and caspase-3 activity. Results showed that CeO2NPs resulted in partial neuroprotection against disturbances in motor performance. It also partially decreased apoptosis and oxidative stress in preventive group, while it failed to increase striatal dopamine level as compared to untreated rats. The present study verified some neuroprotective effects of CeO2NPs in 6-OHDA-induced Parkinsonian rats through their antioxidant and anti apoptotic effects. Some of these effects persisted till the end of six weeks whereas others declined after three weeks. A larger dose may be needed to produce more valuable effects and to maintain protection for a longer period.

Soil salinization is a common environmental problem that seriously threatens crop yield and food security, especially through its impact on seed germination. Nanoparticle priming, an emerging seed treatment method, is receiving increasing attention in improving crop yield and stress resistance. This study used alfalfa seeds as materials to explore the potential benefits of cerium oxide nanoparticle (CeO 2 NP) priming to promote seed germination and improve salt tolerance. CeO 2 NPs at concentrations up to 500 mg/L were able to significantly alleviate salt stress in alfalfa seeds (200 mM), with 50 mg/L of CeO 2 NP having the best effect, significantly ( P< 0.05) increasing germination potential (from 4.0% to 51.3%), germination rate (from 10.0% to 62.7%), root length (from 8.3 cm to 23.1 cm), and seedling length (from 9.8 cm to 13.7 cm). Priming treatment significantly ( P< 0.05) increased seed water absorption by removing seed hardness and also reducing abscisic acid and jasmonic acid contents to relieve seed dormancy. CeO 2 NP priming increased α-amylase activity and osmoregulatory substance level, decreased reactive oxygen species and malonaldehyde contents and relative conductivity, and increased catalase enzyme activity. Seed priming regulated carotenoid, zeatin, and plant hormone signal transduction pathways, among other metabolic pathways, while CeO 2 NP priming additionally promoted the enrichment of α-linolenic acid and diterpenoid hormone metabolic pathways under salt stress. In addition, CeO 2 NPs enhanced α-amylase activity (by 6.55%) in vitro . The optimal tested concentration (50 mg/L) of CeO 2 NPs was able to improve the seed vigor, enhance the activity of α-amylase, regulate the osmotic level and endogenous hormone levels, and improve the salt tolerance of alfalfa seeds. This study demonstrates the efficacy of a simple seed treatment strategy that can improve crop stress resistance, which is of great importance for reducing agricultural costs and promoting sustainable agricultural development., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Gao, Liu, Zhao, Ding, Gao, Su, Song and He.)

Introduction: Green synthesis offers a fast, simple, and economical method for producing metallic nanoparticles.The basis of this method is to obtain nanoparticles using natural materials, such as plants, fungi, and bacteria, instead of harmful and expensive chemical-reducing agents. In this study, CeO2NPs were produced using Alhagi maurorum extract, and their anticancer and antibacterial activities were evaluated., Methods: Alhagi maurorum extract was prepared according to a previously described protocol, and CeO2NPs were synthesized from the salt of this extract. The resulting nanoparticles were characterized using Transmission electron microscopy (TEM), scanning electron microscope (SEM), and X-ray diffraction (XRD) techniques. The antibacterial and cytotoxic effects of the nanoparticles were measured by MIC, MBC, and MTT assays, respectively. The results were analyzed using one-way analysis of variance (ANOVA) using Prism software., Results: The MTT assay on breast cancer cell lines showed that the cytotoxic effect of CeO 2 NPs on cell lines was concentration-dependent. In addition, this nanoparticle was more effective against Gram-positive bacteria., Conclusion: These nanoparticles can be used as cancer drug delivery systems with specific targeting at low concentrations in addition to anticancer treatments. It can also have biological and medicinal applications, such as natural food preservation and wound dressing., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Sodium alginate based (SA) hydrogel supplemented Cerium Oxide nanoparticles (CeO 2 NPs) was produced to fabricate an antimicrobial thin film using an aqueous extract of G. salicornia (Gs). The Gs-CeO 2 NPs were characterized via SEM, FT-IR, EDX, XRD and DLS, the particle size was 200 nm, agreed with XRD. Gs - SA powder was extracted and incorporated with CeO 2 NPs. The Gs-SA and its composite thin film (Gs-CeO 2 NPs-SATF) were characterized including viscosity, FT-IR, TGA, and SEM. The adhesion of Gs-SA coating around Gs-CeO 2 NPs confirmed via FTIR. The antimicrobial properties of Gs-CeO 2 NPs and CeO 2 NPs-SATF were proved in MICs for E. coli and Candida albicans at 62.5 and 250.0 μg/mL. The biofilm inhibition efficiency of CeO 2 NPs-SATF was 74.67 ± 0.98% and 65.45 ± 0.40% for E. coli and Candida albicans. The CeO 2 NPs-SATF was polydisperse in nature and film structure gets fluctuated with NPs concentration. Increased NPs into SATF enhances pore size of gel and corroborated with viscous behaviour. The cytotoxicity of Gs-CeO 2 NP-SA in Artemia salina at higher concentration 100 μg/mL provides less lethal effect into the adult. The antioxidant activity of Gs-CeO 2 NP-SA in DPPH assay was noticed at 0.6 mg ml−1 with radical scavenging activity at 65.85 ± 0.81%. Thus the Gs-CeO 2 NP-SATF would be suitable in antimicrobial applications. • Maiden successful attempt of Cerium Oxide Nanoparticles (CeO 2 NPs) fabrication from Gracilaria salicornia aqueous extracts. • CeO 2 NPs impregnated/loaded Alginate thin films were developed. • CeO 2 NPs exhibits excellent antioxidant and antimicrobial action. [ABSTRACT FROM AUTHOR]

• The impact of exposure to CeO 2 NPs during early pregnancy is firstly confirmed. • CeO 2 NPs leads to poor pregnancy outcomes resulted by abnormal placental development. • Imbalanced trophoblast invasion and abnormal differentiation of uNK were the potential causes. • uNK could be one of the therapeutic targets to the negative effects of CeO 2 NPs. Cerium dioxide nanoparticles (CeO 2 NPs) has been widely used in many fields, and also recommended as a promising carrier for cancer targeted drugs in human medicine for its excellent properties. However, its biological safety to human health remains controversial. In this study, we propose a mouse model exposed to CeO 2 NPs during early pregnancy, to clarify the effect of maternal CeO 2 NPs exposure and related molecular mechanism. Pregnant mice are injected intravenously with CeO 2 NPs by once a day on D5, D6, and D7. The effects of CeO 2 NPs exposure on pregnancy outcomes are observed on D8, D9, D10 and D12. The results show that CeO 2 NPs exposure during early pregnancy would lead to poor pregnancy outcomes. Further study find that low-quality decidualization, including the imbalance of trophoblast invasion regulators secreted by decidual cells and abnormal recruitment and differentiation of uNK cells, leads to subsequent biological negative "ripple effects", including placental dysfunction, fetal loss or growth restriction. This study broadens the understanding of the biological safety of CeO 2 NPs, and provide clues for the prevention of its negative biological effects. Improving the function of uNK cells can be used as one of the therapeutic targets to prevent negative effects of CeO 2 NPs on pregnancy. [ABSTRACT FROM AUTHOR]

• Surface charge of inorganic colloids affected CeO 2 NPs-kaolin/goethite interaction. • Ca2+ ions were more efficient in destabilizing CeO 2 NP than Na+ ions. • The aggregation of CeO 2 NPs significantly varies with HA concentrations. • Ca2+ increased HA adsorption on CeO 2 NPs via complexation and bridging mechanism. The aggregation kinetics and colloidal stability of CeO 2 -NPs in the presence of monovalent or divalent electrolytes, as well as inorganic (kaolin and goethite) and organic (humic acid, HA) colloids were evaluated using time-resolved dynamic light scattering, advanced spectroscopic tools, and theoretical calculations. Critical coagulation concentrations for CeO 2 -NPs were generally lower in CaCl 2 than that in NaCl electrolyte. The negatively charged kaolin accelerated CeO 2 -NPs aggregation due to electrostatic attraction, whilst opposite phenomenon was observed for the positively charged goethite in NaCl solution. In CaCl 2 solution, goethite destabilized CeO 2 -NPs because of its well-crystal structure and specific adsorption of Ca2+. The presence of 0.1 mg C/L HA decreased the surface charge of CeO 2 -NPs, resulting in lower critical coagulation concentrations. Increasing the HA concentration from 0.1 to 1 mg C/L improved CeO 2 -NPs stability, mainly via electrostatic and steric repulsion. The Ca2+-bridging and complexation contributed significantly to CeO 2 -NPs aggregation. Additional aggregation experiments in seven natural waters revealed that CeO 2 -NPs remained stable in water types with high contents of organic colloids and low levels of salts, thus having higher transport potential. These findings provided new insights into the interactive influence of naturally occurring colloids and ions on the heteroaggregation behavior and fate of CeO 2 -NPs. [ABSTRACT FROM AUTHOR]

The extensive use of nano-fabricated products in daily life is releasing a large volume of engineered nanoparticles (ENPs) in the environment having unknown consequences. Meanwhile, little efforts have been paid to immobilize and prevent the entry of these emerging contaminants in the food chain through plant uptake. Herein, we investigated the biochar role in cerium oxide nanoparticles (CeO 2 NPs) bioaccumulation and subsequent translocation in wheat (Triticum aestivum L.) as well as impact on growth, photosynthesis and gas-exchange related physiological parameters. Results indicated that CeO 2 NPs up to 500 mg L−1 level promoted the plant growth by triggering photosynthesis, transpiration and stomatal conductance. Higher NPs concentration (2000 mg CeO 2 NPs L−1) has negatively affected the plant growth and photosynthesis related processes. Conversely, biochar amendment with CeO 2 NPs considerably reduced (~9 folds) the plants accumulated contents of Ce even at 2000 mg L−1 exposure level of CeO 2 NPs through surface complexation process and alleviated the phyto-toxic effects of NPs on plant growth. XPS and FTIR analysis confirmed the role of biochar-mediated carboxylate and hydroxyl groups bonding with CeO 2 NPs. These findings provides an inside mechanistic understanding about biochar interaction with nano-pollutants to inhibit their bioavailability to plant body. • Uptake and translocation of CeO 2 NPs in wheat under biochar amendment were investigated. • Biochar considerably reduced (~9 folds) the plants accumulated Ce contents. • Biochar alleviated the CeO 2 NPs impact on growth and photosynthesis in wheat. • Biochar space shield effect and complexation were main mechanism of CeO 2 NPs transformation. [ABSTRACT FROM AUTHOR]

Thousands of nanomaterials (NMs)-containing products are currently under development or incorporated in the consumer market, despite our very limited understanding of their genotoxic potential. Taking into account that the toxicity and genotoxicity of NMs strongly depend on their physicochemical characteristics, many variables must be considered in the safety evaluation of each given NM. In this scenario, the challenge is to establish high-throughput methodologies able to generate rapid and robust genotoxicity data that can be used to critically assess and/or predict the biological effects associated with those NMs being under development or already present in the market. In this study, we have evaluated the advantages of using a flow cytometry-based approach testing micronucleus (MNs) induction (FCMN assay). In the frame of the EU NANoREG project, we have tested six different NMs—namely NM100 and NM101 (TiO2NPs), NM110 (ZnONPs), NM212 (CeO2NPs), NM300K (AgNPs) and NM401 (multi-walled carbon nanotubes (MWCNTs)). The obtained results confirm the ability of AgNPs and MWCNTs to induce MN in the human bronchial epithelial BEAS-2B cell line, whereas the other tested NMs retrieved non-significant increases in the MN frequency. Based on the alignment of the results with the data reported in the literature and the performance of the FCMN assay, we strongly recommend this assay as a reference method to systematically evaluate the potential genotoxicity of NMs. [ABSTRACT FROM AUTHOR]