Benzo(a)pyrene and Cerium Dioxide Nanoparticles in Co-Exposure Impair Human Trophoblast Cell Stress Signaling.

Human placenta is a multifunctional interface between maternal and fetal blood. Studying the impact of pollutants on this organ is crucial because many xenobiotics in maternal blood can accumulate in placental cells or pass into the fetal circulation. Benzo(a)pyrene (BaP) and cerium dioxide nanoparticles (CeO2 NP), which share the same emission sources, are found in ambient air pollution and also in maternal blood. The aim of the study was to depict the main signaling pathways modulated after exposure to BaP or CeO2 NP vs. co-exposure on both chorionic villi explants and villous cytotrophoblasts isolated from human term placenta. At nontoxic doses of pollutants, BaP is bioactivated by AhR xenobiotic metabolizing enzymes, leading to DNA damage with an increase in γ-H2AX, the stabilization of stress transcription factor p53, and the induction of its target p21. These effects are reproduced in co-exposure with CeO2 NP, except for the increase in γ-H2AX, which suggests a modulation of the genotoxic effect of BaP by CeO2 NP. Moreover, CeO2 NP in individual and co-exposure lead to a decrease in Prx-SO3, suggesting an antioxidant effect. This study is the first to identify the signaling pathways modulated after co-exposure to these two pollutants, which are common in the environment.

An integrated ICP-MS-based analytical approach to fractionate and characterize ionic and nanoparticulate Ce species.

Cerium dioxide nanoparticles (CeO2 NPs) are widely used in various fields, leading to concern about their effect on human health. When conducting in vivo investigations of CeO2 NPs, the challenge is to fractionate ionic Ce and CeO2 NPs and to characterize CeO2 NPs without changing their properties/state. To meet this challenge, we developed an integrated inductively coupled plasma-mass spectrometry (ICP-MS)-based analytical approach in which ultrafiltration is used to fractionate ionic and nanoparticulate Ce species while CeO2 NPs are characterized by single particle-ICP-MS (sp-ICP-MS). We used this technique to compare the effects of two sample pretreatment methods, alkaline and enzymatic pretreatments, on ionic Ce and CeO2 NPs. Results showed that enzymatic pretreatment was more efficient in extracting ionic Ce or CeO2 NPs from animal tissues. Moreover, results further showed that the properties/states of all ionic and nanoparticulate Ce species were well preserved. The rates of recovery of both species were over 85%; the size distribution of CeO2 NPs was comparable to that of original NPs. We then applied this analytical approach, including the enzymatic pretreatment and ICP-MS-based analytical techniques, to investigate the bioaccumulation and biotransformation of CeO2 NPs in mice. It was found that the thymus acts as a "holding station" in CeO2 NP translocation in vivo. CeO2 NP biotransformation was reported to be organ-specific. This is the first study to evaluate the impact of enzymatic and alkaline pretreatment on Ce species, namely ionic Ce and CeO2 NPs. This integrated ICP-MS-based analytical approach enables us to conduct in vivo biotransformation investigations of CeO2 NPs.

Structural and physical-chemical characterization of redox active CeO2nanoparticles synthesized by precipitation in water-alcohol solutions.

A set of cerium dioxide nanoparticles (CeO2NPs) was synthesized by precipitation in water-alcohol solutions under conditions when the physical-chemical parameters of synthesized NPs were controlled by changing the ratio of the reaction components. The size of CeO2NPs is controlled largely by the dielectric constant of the reaction solution. An increase of the percentage of Ce3+ions at the surface was observed with a concomitant reduction of the NP sizes. All synthesized CeO2NPs possess relatively high positive values of zeta-potential (ζ > 40 mV) suggesting good stability in aqueous suspensions. Analysis of the valence- and size-dependent rate of hydrogen peroxide decomposition revealed that catalase/peroxidase-like activity of CeO2NPs is higher at a low percentage of Ce3+at the NP surface. In contrast, smaller CeO2NPs with a higher percentage of Ce3+at the NP surface display a higher oxidase-like activity.

Interactions between cerium dioxide nanoparticles and humic acid: Influence of light intensities and molecular weight fractions.

Cerium dioxide nanoparticles (CeO2 NPs) are ubiquitous in the water environment due to the extensive commercial applications. The complexity of heterogeneous humic acid (HA) plays a significant role in affecting the physicochemical properties of CeO2 NPs in aqueous environments. However, the effects of light intensities and HA fractions on the interaction mechanism between CeO2 NPs and HA are poorly understood. Here, we provided the evidence that both light intensities (>3 E L-1 s-1) and molecular weights (>10 kDa) can effectively affect the interactions between CeO2 NPs and HA. The absolute content of reactive oxygen species (ROS) and quantum yield (Φ) of 3HA* were inhibited when HA (10 mg of C L-1) interacts with CeO2 NPs. However, they were positively correlated with the increasing irradiation time and simulated sunlight intensities. High molecular weights of HA fraction (>100 kDa) restrained the ROS generation and Φ of 3HA* due to surface adsorption between HA and CeO2 NPs blocking reactive sites, competitive absorption for simulated sunlight. Fourier transform infrared and three-dimensional excitation-emission matrix fluorescence spectroscopy confirmed that the carboxylic groups of HA have high complexation capacity with CeO2 NPs. These findings are essential for us to improve the understanding of the impacts of HA on CeO2 NPs under different conditions in natural waters.

Surface-modified cerium dioxide nanoparticles with improved anti-amyloid and preserved nanozymatic activity.

Cerium dioxide nanoparticles (CeO2 NPs) are used increasingly in nanotechnology and particularly in biotechnology and bioresearch. Thus, CeO2 NPs have been successfully tested in vitro as a potential therapeutic agent for various pathologies associated with oxidative stress, including the formation of protein amyloid aggregates. In this study, to increase the anti-amyloidogenic efficiency and preserve the antioxidant potential, the surface of the synthesized CeO2 NPs is modified with a nonionic, sugar-based surfactant, dodecyl maltoside (DDM), which is known for its high anti-amyloidogenic activity and biocompatibility. Dynamic light scattering and Fourier transform infrared spectroscopy demonstrated successful modification by DDM. The apparent hydrodynamic diameters of CeO2 NPs and DDM-modified NPs (CeO2@DDM NPs) are found to be ⁓180 nm and ⁓260 nm, respectively. A positive zeta potential value of + 30.5 mV for CeO2 NPs and + 22.5 mV for CeO2 @DDM NPs suggest sufficient stability and good dispersion of NPs in an aqueous solution. A combination of Thioflavin T fluorescence analysis and atomic force microscopy is used to assess the effect of nanoparticles on the formation of insulin amyloid fibrils. Results show that the fibrillization of insulin is inhibited by both, naked and modified NPs in a dose-dependent manner. However, while the IC50 of naked NPs is found to be ∼270 ± 13 µg/mL, the surface-modified NPs are 50% more efficient with IC50 equaled to 135 ± 7 µg/mL. In addition, both, the naked CeO2 NPs and DDM-modified NPs displayed an antioxidant activity expressed as oxidase-, catalase- and SOD-like activity. Therefore, the resulting nanosized material is very well suited to prove or disprove the hypothesis that oxidative stress plays a role in the formation of amyloid fibrils.

Functionalized Cerium Dioxide Nanoparticles with Antioxidative Neuroprotection for Alzheimer's Disease.

Background: Oxidative stress induced reactive oxygen species (ROS) and aggregation of amyloid ß (Aß) in the nervous system are significant contributors to Alzheimer's disease (AD). Cerium dioxide and manganese oxide are known as to be effective and recyclable ROS scavengers with high efficiency in neuroprotection. Methods: A hollow-structured manganese-doped cerium dioxide nanoparticle (LMC) was synthesized for loading Resveratrol (LMC-RES). The LMC-RES were characterized by TEM, DLS, Zeta potential, and X-ray energy spectrum analysis. We also tested the biocompatibility of LMC-RES and the ability of LMC-RES to cross the blood-brain barrier (BBB). The antioxidant effects of LMC-RES were detected by SH-SY5Y cells. Small animal live imaging was used to detect the distribution of LMC-RES in the brain tissue of AD mice. The cognitive abilities of mice were tested by water maze and nesting experiments. The effects of LMC-RES in reducing oxidative stress and protecting neurons was also explored by histological analysis. Results: The results showed that LMC-RES had good sustained release effect and biocompatibility. The drug release rate of LMC-RES at 24 hours was 80.9 ± 2.25%. Meanwhile, LMC-RES could cross the BBB and enrich in neurons to exert antioxidant effects. In Aß-induced SH-SY5Y cells, LMC-RES could inhibits oxidative stress through the Nrf-2/HO-1 signaling pathway. In AD model mice, LMC-RES was able to reduce ROS levels, inhibit Aß-induced neurotoxicity, and protect neurons and significantly improve cognitive deficits of AD mice after drug administration. Conclusion: LMC-RES can effectively across the BBB, reduce oxidative stress, inhibit Aß aggregation, and promote the recovery of neurological function.

Uptake and toxicity of cerium dioxide nanoparticles with different aspect ratio.

Cerium dioxide nanoparticles (CeONPs) have been extensively applied in research for future energy development due to two common oxidation states on their surface. Considering that shape (aspect ratio) is a key determinant of NPs-induced toxicity, we compared the toxicity of hexagonal (H)- and rod-shaped (R)-CeONPs in mice. At 24 h after pharyngeal aspiration, both types of CeONPs recruited surrounding immune cells (monocytes and neutrophils) into the lung, and R-CeONPs induced a more severe pulmonary inflammatory response compared with H-CeONPs. To identify an indicator to predict pulmonary inflammatory responses at the cellular level, we also investigated their responses in alveolar macrophage cells. At 24 h after treatment, both types of CeONPs were mainly located within the vacuoles (partially, in the lysosome) in the cytoplasm. Mitochondrial damage, intracellular calcium accumulation, and increased NO production were observed in cells exposed to both types of CeONPs, ultimately resulting in a decrease in cell viability. More interestingly, both types of CeONPs formed multinucleated giant cells. Meanwhile, contrary to when suspended in deionized water, R-CeONPs were strongly aggregated with a negative charge in cell culture media, whereas H-CeONPs were relatively well-dispersed with a positive charge. R-CeONPs-induced lysosomal extension was also recovered by premix with negatively charged DNA, and even NPs suspended in cell culture media without cells were detected under the FACS system, suggesting interference by protein corona. Therefore, we suggest that shape (aspect ratio) is an important factor determining inhaled NPs-induced pathology and that the effect of the surface charge and protein corona should be carefully considered in interpreting results derived from in vitro tests. Furthermore, we propose that the relationship between the formation of multinucleated giant cells and the inflammatory response of inhaled CeONPs should be further studied.

Germanium Dioxide Nanoparticles Mitigate Biochemical and Molecular Changes Characterizing Alzheimer's Disease in Rats.

Alzheimer's disease (AD) is a neurodegenerative disorder that jeopardizes the lives of diagnosed patients at late stages. This study aimed to assess, for the first time, the efficiency of germanium dioxide nanoparticles (GeO2NPs) in mitigating AD at the in vivo level compared to cerium dioxide nanoparticles (CeO2NPs). Nanoparticles were synthesized using the co-precipitation method. Their antioxidant activity was tested. For the bio-assessment, rats were randomly assigned into four groups: AD + GeO2NPs, AD + CeO2NPs, AD, and control. Serum and brain tau protein, phosphorylated tau, neurogranin, amyloid ß peptide 1-42, acetylcholinesterase, and monoamine oxidase levels were measured. Brain histopathological evaluation was conducted. Furthermore, nine AD-related microRNAs were quantified. Nanoparticles were spherical with diameters ranging from 12-27 nm. GeO2NPs exhibited a stronger antioxidant activity than CeO2NPs. Serum and tissue analyses revealed the regression of AD biomarkers to almost control values upon treatment using GeO2NPs. Histopathological observations strongly supported the biochemical outcomes. Then, miR-29a-3p was down-regulated in the GeO2NPs-treated group. This pre-clinical study substantiated the scientific evidence favoring the pharmacological application of GeO2NPs and CeO2NPs in AD treatment. Our study is the first report on the efficiency of GeO2NPs in managing AD. Further studies are needed to fully understand their mechanism of action.

Cerium dioxide nanoparticles synthesized via precipitation at constant pH: Synthesis, physical-chemical and antioxidant properties.

Cerium oxide nanoparticles (CeO2 NPs) are well known for their application in various fields of industry, as well as in biology and medicine. Knowledge of synthesis schemes, physicochemical and morphological features of nanoscale CeO2 is important for assessing their antioxidant behavior and understanding the mechanism of oxidative stress and its consequences. The choice of the method of synthesis should be based on the possibility to choose the conditions and parameters for obtaining CeO2 with controlled dimensions and a ratio of Се3+/Се4+ on their surface. In this study, CeO2 NPs are synthesized by precipitation in mixed water-alcohol solutions at constant pH = 9. The properties of obtained NPs are studied using various methods of physical-chemical characterization such as X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and dynamic light scattering. The size of CeO2 NPs varied from 14 to 4.2 nm with increasing alcohol concentration, while the effect of constant pH during synthesis on the morphology of the particles was insignificant. The synthesized nanoparticles form highly stable aqueous suspensions since their zeta-potential is higher than + 40 mV. It is found that the ability of CeO2 NPs to self-stabilize is associated with the presence of hydrated Ce4+ ions on their surface. In vitro biological studies have shown that, regardless of particle size, CeO2 NPs have antioxidant potential, but smaller NPs with a higher percentage of Ce3+ on the surface had a more effective antioxidant effect. In addition, the size-depended activity of CeO2 NPs to inhibit the amyloid formation of insulin is demonstrated.

miR-99 family is potential target to reverse cerium dioxide nanoparticle-induced placental cell dysfunction.

Background: Cerium dioxide nanoparticles (CeO2 NPs) are increasingly used as diesel additive, causing a lot of concern about their toxic effects when released into the atmosphere. To date, there is little knowledge about the toxic effects of CeO2 NPs on the female reproductive system. Methods: The morphology and size distribution of CeO2 NPs was observed by transmission electronic microscope (TEM) and Zetasizer Nano, respectively. The uptake of CeO2 NPs by cells was also observed by TEM after treatment. The cytotoxicity of CeO2 NPs was studied by Cell Counting Kit-8 (CCK-8), the cellular invasive and migratory ability was examined by transwell assay, the cell apoptosis and reactive oxygen species (ROS) were studied by flow cytometry (FCM), and the mRNAs and proteins expressions were revealed by quantitative real-time PCR (qRT-PCR) and western blotting. The cytoskeletons and autophagy levels were revealed by immunofluorescence. The target regulation of miR-99 to mammalian target of rapamycin (mTOR) was proved by dual luciferase reporter assay after transfection. Results: We studied the cytotoxic effects of CeO2 NPs on human trophoblastic cells (HTR-8/Svneo) and found that the invasive and migratory abilities of HTR-8/SVneo cells were decreased after CeO2 NPs exposure. Immunofluorescence assays showed that the cellular microtubule networks and microfilament arrangement were obviously altered, and although the expression of cytoskeleton proteins (α-tubulin, ß-tubulin, actin) did not change, the protein levels of invasion- and migration-related factors [matrix metalloproteinase 2 (MMP2), protein kinases B (AKT), mTOR] were decreased in exposed cells. Accordingly, the expression level of miR-99 family members (miR-99a, miR-99b, miR-100), which can regulate mTOR, was significantly increased after CeO2 NPs exposure. Dual luciferase reporter assay indicated that the miR-99 family members directly targeted mTOR. Conclusions: CeO2 NPs impaired the invasive and migratory abilities, which play an important role in embryo implantation, as well as determining placental function and embryonic development.

Foliar Application of CeO2 Nanoparticles Alters Generative Components Fitness and Seed Productivity in Bean Crop (Phaseolus vulgaris L.).

In the era of technology, nanotechnology has been introduced as a new window for agriculture. However, no attention has been paid to the effect of cerium dioxide nanoparticles (nCeO2) on the reproductive stage of plant development to evaluate their toxicity and safety. To address this important topic, bean plants (Phaseolus vulgaris L.) treated aerially with nCeO2 suspension at 250-2000 mg L-1 were cultivated until flowering and seed production in the greenhouse condition. Microscopy analysis was carried out on sectioned anthers and ovules at different developmental stages. The pollen's mother cell development in nCeO2 treatments was normal at early stages, the same as control plants. However, the results indicated that pollen grains underwent serious structural damages, including chromosome separation abnormality at anaphase I, pollen wall defect, and pollen grain malformations in nCeO2-treated plants at the highest concentration, which resulted in pollen abortion and yield losses. On the ovule side, the progression of development only at the highest concentration was modified in the two-nucleated embryo sac stage, probably due to apoptosis in nuclei. Nevertheless, the findings confirmed the more pronounced vulnerability of male reproductive development under nCeO2 exposure than female development. The higher concentration decreased seed productivity, including seed set in either pods or whole plant (13% and 18% compared to control, respectively). The data suggested the potential application of nCeO2 at optimal dosages as a plant productivity ameliorative. However, a higher dosage is considered as an eco-environmental hazard. To our best knowledge, this is the first study analyzing reproductive plant response upon exposure to nCeO2.

Relatively Low Dosages of CeO2 Nanoparticles in the Solid Medium Induce Adjustments in the Secondary Metabolism and Ionomic Balance of Bean (Phaseolus vulgaris L.) Roots and Leaves.

Nanoparticles (NPs) are known to significantly alter plant metabolism in a dose-dependent manner, with effects ranging from stimulation to toxicity. The metabolic adjustment and ionomic balance of bean (Phaseolus vulgaris L.) roots and leaves gained from plants grown in a solid medium added with relatively low dosages (0, 25, 50, and 100 mg/L) of CeO2 NPs were investigated. Ce accumulated in the roots (up to 287.91 mg/kg dry weight) and translocated to the aerial parts (up to 2.78% at the highest CeO2 dosage), and ionomic analysis showed that CeO2 NPs interfered with potassium, molybdenum, and zinc. Unsupervised hierarchical clustering analysis from metabolomic profiles suggested a dose-dependent and tissue-specific metabolic reprogramming induced by NPs. The majority of differential metabolites belonged to flavonoids and other phenolics, nitrogen-containing low molecules (such as alkaloids and glucosinolates), lipids, and amino acids.

Biological activity of cerium dioxide nanoparticles.

Cerium dioxide nanoparticles (CeO2 NPs) with a high value of ζ-potential (≥30 mV) have been synthesized in reverse microemulsions and they are able to form the high-stable aqueous suspension without any additional stabilizers. It has been shown that the interaction of such CeO2 NPs with transport proteins, such as BSA, affects their molecular conformation and biochemical activity. The observed changes in the UV-absorbance spectrum and intrinsic fluorescence quenching of BSA molecule are indicative of the occurrence of structural changes caused by binding with the surface of CeO2 NPs. Low affinity between BSA and CeO2 NPs has been confirmed by differential scanning calorimetry (DSC). Moreover, CeO2 NPs can act as regenerative free-radical scavengers, and their antioxidant activity depends on the concentration. The positive charge of CeO2 NPs can be attributed to their low toxicity toward human malignant lymphocytes MT-4 and breast cancer cells MCF-7 however, the morphofunctional features of MCF-7 cells interacting with CeO2 NPs are indicative of the decrease in oncogenicity.

Neuropathic diabetic foot ulcers treated with cerium dioxide nanoparticles: A case report.

Wound healing in diabetes is frequently impaired and its treatment remains a challenge. The ability of topical application of cerium (Ce) dioxide nanoparticles (CNPs) to accelerate wound healing in an animal model provides a rationale to develop this technology for use in humans affected by traumatic injury, diabetes and burns. We first described a case report of successful topical treatment of neuropathic diabetic foot ulcers with novel gel containing CNPs. The CNPs has bacteriostatic activity, anti-inflammatory properties and can penetrated into the wound tissue and reduced oxidative damage therefore protect regenerative tissue, suggesting a therapeutic potential for topical treatment of diabetic foot ulcers.

Calcium-activated chloride channel regulator 1 (CLCA1): More than a regulator of chloride transport and mucus production.

CLCA1 is a member of the CLCA (calcium-activated chloride channel regulator) family and plays an essential role in goblet cell mucus production from the respiratory tract epithelium. CLCA1 also regulates Ca2+-dependent Cl- transport that involves the channel protein transmembrane protein 16A (TMEM16A) and its accessary molecules. CLCA1 modulates epithelial cell chloride current and participates in the pathogenesis of mucus hypersecretory-associated respiratory and gastrointestinal diseases, including asthma, chronic obstructive pulmonary disease, cystic fibrosis, pneumonia, colon colitis, cystic fibrosis intestinal mucous disease, ulcerative colitis, and gastrointestinal parasitic infection. Most studies have been focused on the expression regulation of CLCA1 in human specimens. Limited studies used the CLCA1-deficient mice and CLCA1 blocking agents and yielded inconsistent conclusions regarding its role in these diseases. CLCA1 not only regulates mucin expression, but also participates in innate immune responses by binding to yet unidentified molecules on inflammatory cells for cytokine and chemokine production. CLCA1 also targets lymphatic endothelial cells and cancer cells by regulating lymphatic cell proliferation and lymphatic sinus growth in the lymphatic organs and controlling cancer cell differentiation, proliferation, and apoptosis, all which depend on the location of the lymphatic vessels, the type of cancers, the presence of Th2 cytokines, and possibly the availability and type of CLCA1-binding proteins. Here we summarize available studies related to these different activities of CLCA1 to assist our understanding of how this secreted modifier of calcium-activated chloride channels (CaCCs) affects mucus production and innate immunity during the pathogenesis of respiratory, gastrointestinal, and malignant diseases.

Very low concentration of cerium dioxide nanoparticles induce DNA damage, but no loss of vitality, in human spermatozoa.

Cerium dioxide nanoparticles (CeO2NP) are widely used for industrial purposes, as in diesel, paint, wood stain and as potential therapeutic applications. The Organization for Economic Cooperation and Development included CeO2NP in the priority list of nanomaterials requiring urgent evaluation. As metal nanoparticles can cross the blood-testis barrier, CeO2NP could interact with spermatozoa. The genotoxicity of CeO2NP was demonstrated in vitro on human cell lines and mouse gametes. However, the effects of CeO2NP on human spermatozoa DNA remain unknown. We showed significant DNA damage induced in vitro by CeO2NP on human spermatozoa using Comet assay. The genotoxicity was inversely proportional to the concentration (0.01 to 10 mg·L-1). TEM showed no internalization of CeO2NP into the spermatozoa. This study shows for the first time that in vitro exposure to very low concentrations of cerium dioxide nanoparticles can induce significant DNA damage in human spermatozoa. These results add new and important insights regarding the reproductive toxicity of priority nanomaterials, which require urgent evaluation.

Genotoxicity and physiological effects of CeO2 NPs on a freshwater bivalve (Corbicula fluminea).

The rapid development of nanotechnology and the increased use of nanomaterials in products used in everyday life have raised the question of the potential release of nanoparticles into the aquatic environment. Their fate and effects in natural ecosystems are not currently well understood but harmful effects of nanoparticles have been demonstrated at low concentrations on some freshwater and marine species. Cerium dioxide nanoparticles (CeO2 NPs) are produced in large quantities and used in products in many different fields, such as automotives or optics. Because of their widespread use in daily products, CeO2 NPs are included in the OECD priority list of manufactured nanomaterials for human and environmental assessment. Indeed some studies have been conducted to assay various enzymatic biomarkers, which showed the CeO2 NPs potential to modify anti-oxidative defenses and cellular membrane stability. Nevertheless, only a few studies were performed on their genotoxic potential. The aim of this work was to evaluate the genotoxic and physiological effects of CeO2 NPs on a widespread freshwater bivalve Corbicula fluminea by using comet assay and a multi-enzymatic biomarker approach. Exposure to two CeO2 NP concentrations during a short term experiment (6 days) was set up. The first one (10 µg/L) was chosen in order to work with low but measurable concentrations whereas the second one was ten times higher (100 µg CeO2 NPs/L). DNA damage was significantly more pronounced compared with control for both concentrations tested as early as two days of exposure and seemed to increase with time. Some enzymatic biomarkers of anti-oxidative defenses (total antioxidant capacity, catalase activity), anti-toxic mechanisms (glutathione-S-transferase activity, caspase-3 activity) or metabolism (lactate dehydrogenase activity) tended to increase after 6 days of exposure but only the induction of caspase pathway and DNA damages appeared significant for exposed organisms. In this study, time and concentration effects of CeO2 NPs were highlighted by coupling genotoxic and cellular biomarker assessments.

Cerium dioxide-doped carboxyl fullerene as novel nanoprobe and catalyst in electrochemical biosensor for amperometric detection of the CYP2C19*2 allele in human serum.

The disposition dose of clopidogrel is different in CYP2C19*2 gene carriers and non-carriers. High-dose clopidogrel has been recommended to overcome a low-responsiveness to clopidogrel in patients with the CYP2C19*2 gene. To guide the choice of clopidogrel dosage and catalyse a development in the field of personalized therapy, we developed an ultrasensitive electrochemical biosensor to detect CYP2C19*2 gene. We constructed a novel assay based on cerium dioxide (CeO2)-functionalized carboxyl fullerene (c-C60) supported by Pt nanoparticles (c-C60/CeO2/PtNPs) for signal amplification. Au nanoparticles @ Fe-MIL-88NH2 (AuNPs@Fe-MOFs) were synthesized by one-step method as the support platform to enhance the conductivity and immobilize more biotin-modified capture probe (bio-CP) through the superior affinity and specificity between streptavidin and biotin. c-C60/CeO2/PtNPs were labeled with signal probe to form the signal label. After the sandwich reaction of CYP2C19*2 gene between capture probe and the signal label, a distinguishing electrochemical signal from the catalysis of H2O2 by signal label would be observed. Amperometry was applied to record electrochemical signals. Under optimized conditions, the approach showed a good linear dependence between current and the logarithm of CYP2C19*2 gene concentrations in the range of 1 fM to 50nM with a low detection limit of 0.33fM (S/N = 3). The proposed method showed good specificity to target DNA compared with possible interfering substances. More importantly, the fabricated biosensor achieved accurate quantitative detection of CYP2C19*2 gene in human serum samples demonstrated by excellent correlations with standard DNA sequencing and provided a promising strategy for electrochemical biosensor detection of other gene mutations.

Responses of wastewater biofilms to chronic CeO2 nanoparticles exposure: Structural, physicochemical and microbial properties and potential mechanism.

With the accelerated application of CeO2 nanoparticles (NPs), wastewater treatment plants will increasingly receive CeO2 NPs, thus inevitably causing CeO2 NPs to encounter microaggregates. Here, we comprehensively elucidate the responses in the structural, physicochemical and microbial properties of wastewater biofilms to chronic exposure (75 days) to different CeO2 NPs concentrations, with a particular emphasis on the protective mechanisms of stratified extracellular polymeric substances (EPSs). Chronic exposure to 0.1 mg/L CeO2 NPs boosted the content and broadened the distribution of α-d-glucopyranose polysaccharides (PS), while the sharply increased production and breadth of ß-d-glucopyranose PS, forming a formidable shield, was a response to 10 mg/L CeO2 NPs. After the bacteria were exposed to CeO2 NPs, loosely bound EPSs (LB-EPSs) aggregated into macromolecules (increasing in apparent molecular weight (AMW)) but at a lower abundance, whereas the average AMW in tightly bound EPSs (TB-EPSs) decreased. The acetyl content and (α-helix+3-turn helix)/ß-sheet value of TB-EPSs increased to resist CeO2 NPs. Furthermore, long-term exposure to CeO2 NPs decreased cell viability, reduced microbial diversity and shifted the microbial composition. N-acylated-l-homoserine lactone concentrations increased with increased density of Pseudomonas, which was associated with PS-regulated control, thus promoting PS production in EPSs in response to CeO2 NPs. These results expand the understanding of how microaggregates resist environmental stress caused by NPs.

Anti-inflammatory and antioxidant effect of cerium dioxide nanoparticles immobilized on the surface of silica nanoparticles in rat experimental pneumonia.

A massage with the potent counter-inflammatory material, cerium dioxide nanoparticles, is promising and the antioxidant properties of CeO2 are considered the main, if not the only, mechanism of this action. Nevertheless, the elimination of ceria nano-particles from the organism is very slow and there is a strong concern for toxic effect of ceria due to its accumulation. To overcome this problem, we engineered a combined material in which cerium nanoparticles were immobilized on the surface of silica nanoparticles (CeO2 NP), which is shown to be easily removed from an organism and could be used as carriers for nano-ceria. In our study particle size was 220±5nm, Zeta-potential -4.5mV (in water), surface charge density -17.22µC/cm2 (at pH 7). Thirty-six male Wistar rats, 5 months old and 250-290g were divided into four groups: 1) control; 2) CeO2 NP treatment; 3) experimental pneumonia (i/p LPS injection, 1mg/kg); and 4) experimental pneumonia treated with CeO2 NP (4 times during the study in dosage of 0.6mg/kg with an orogastric catheter). Gas exchange and pulmonary ventilation were measured four times: 0, 1, 3 and 24h after LPS injection in both untreated and CeO2 NP-treated animals. The mRNA of TNF-α, Il-6, and CxCL2 were determined by RT-PCR. ROS-generation in blood plasma and lung tissue homogenates were measured by means of lucigenin- and luminol-enhanced chemiluminescence. Endotoxemia in the acute phase was associated with: (1) pathological changes in lung morphology; (2) increase of ROS generation; (3) enhanced expression of CxCL2; and (4) a gradual decrease of VO2 and VE. CeO2 NP treatment of intact animals did not make any changes in all studied parameters except for a significant augmentation of VO2 and VE. CeO2 NP treatment of rats with pneumonia created positive changes in diminishing lung tissue injury, decreasing ROS generation in blood and lung tissue and decreasing pro-inflammatory cytokine expression (TNF-α, Il-6 and CxCL2). Oxygen consumption in this group was increased compared to the LPS pneumonia group. In our study we have shown anti-inflammatory and antioxidant effects of CeO2 NP. In addition, this paper is the first to report that CeO2 NP stimulates oxygen consumption in both healthy rats, and rats with pneumonia. We propose the key in understanding the mechanisms behind the phenomena lies in the property of CeO2 NP to scavenge ROS and the influence of this potent antioxidant on mitochondrial function. The study of biodistribution and elimination of СеО2NP is the purpose of our ongoing study.