Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.515
Filtrar
1.
Environ Pollut ; 292(Pt A): 118308, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34626705

RESUMO

Aggravating the pollution of microcystins (MCs) in freshwater environments is detrimental to aquatic living organisms and humans, and thus threatens the stability of ecosystems. Some environmental factors have been verified to promote the production of MCs in Microcystis aeruginosa, thereby aggravating the pollution of MCs. However, the effects of cerium (Ce), the most abundant rare earth element in global water environments, on the production of MCs in M. aeruginosa are unknown. Here, Lake Taihu water was selected as a representative of freshwater environments. By using interdisciplinary methods, it was found that: (1) the exposure level of Ce [Ce(III) and Ce(IV)] in Lake Taihu water is in the range of 0.271-0.282 µg/L; (2) Ce exposure in Lake Taihu water promoted the contents of three main MCs (MC-LR, MC-LW and MC-YR) in M. aeruginosa and water; (3) a cellular mechanism of Ce promoting the production of MCs in M. aeruginosa in Lake Taihu water was suggested: Ce enhanced endocytosis in cells of M. aeruginosa to promote the essential element uptake by M. aeruginosa for MC synthesis. Thus, Ce exposure in Lake Taihu water aggravates the pollution of MCs via enhancing endocytosis in cells of M. aeruginosa. The results provide reference for assessing the environmental risk of Ce in water environments, investigating the mechanism of the pollution of MCs induced by environmental factors, and developing strategies aimed at preventing and controlling the pollution of MCs.


Assuntos
Cério , Microcystis , Cério/toxicidade , China , Ecossistema , Endocitose , Humanos , Lagos , Microcistinas , Água
2.
Chemosphere ; 287(Pt 1): 131932, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34455122

RESUMO

Efficient elimination of fluoride from wastewater is an urgent need for ensuring water safety. In the present study, a stable and reusable nanocomposite (NCO@PAE) was synthesized by impregnating nanosized cerium oxides (NCO) inside a porous polystyrene anion exchanger (PAE) host for efficient fluoride removal from wastewater. The newly fabricated NCO@PAE exhibited excellent resistance to acid and alkali environment, allowing it to be utilized in a wide pH range (2-12). Fluoride uptake onto NCO@PAE was a pH-dependent process, which could reach the maximum capacity at pH 3.0. Compared with its host PAE, NCO@PAE showed conspicuous adsorption affinity towards fluoride in the coexistence of other competing anions at high concentrations. Adsorption kinetics confirmed its high efficiency for achieving equilibrium within 120 min. Fixed-bed adsorption runs demonstrated that the effective processing capacity of NCO@PAE for synthetic fluoride-containing wastewater (initial fluoride 2.5 mg/L) was about ~330 BV (bed volume), while only 22 BV for the host PAE. The exhausted NCO@PAE could be effectively revived by a simple in-situ desorption method for long-term cycle operation without conspicuous capacity loss. All the results indicated that NCO@PAE is a reliable and promising adsorbent for water defluoridation.


Assuntos
Cério , Poluentes Químicos da Água , Purificação da Água , Adsorção , Ânions , Fluoretos , Concentração de Íons de Hidrogênio , Cinética , Poliestirenos , Porosidade , Água , Poluentes Químicos da Água/análise
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120295, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34450572

RESUMO

Cerium, an abundant lanthanide element, is widely used in human industry. The accumulation of Ce4+ ion, however, will damage the environment and biological organism. Therefore, its facile detection is highly needed. Herein, we design a hybrid sensing platform consisting of carbon dots (C-dots) and bathophenanthroline-disulfonate-Fe2+ complex (Bphen-Fe2+) for trace-level determination of Ce4+. Based on inner filter effect (IFE), the red-colored Bphen-Fe2+ complex severely quenches the fluorescence of C-dots. After addition of Ce4+, Fe2+ is oxidized to Fe3+, and the colorless Bphen-Fe3+ complex generates, which weakens the IFE efficiency and leads to the fluorescence recovery of C-dots. Meanwhile, due to the decreasing amount of Bphen-Fe2+ upon Ce4+ addition, the red color of the solution gradually fades, which enables visual detection of Ce4+ by the naked eyes. Under the optimized conditions, the C-dots/Bphen-Fe2+ system realizes the fluorometric and colorimetric sensing of Ce4+ in the range of 0.5-100 and 1.9-80 µM, with the limits of detection as low as 0.5 and 1.9 µM, respectively. This method also shows high selectivity over other common ions, and has an excellent applicability for monitoring of Ce4+ in real water samples.


Assuntos
Cério , Pontos Quânticos , Carbono , Colorimetria , Humanos , Íons , Fenantrolinas
4.
Saudi Med J ; 42(11): 1247-1251, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34732559

RESUMO

OBJECTIVES: To examine the effects of desflurane and cerium oxide (CO) on lung tissue following ischemia-reperfusion injury (IRI). METHODS: Experiments were conducted in Gazi University Animal Laboratory, Ankara, Turkey. Thirty rats were divided into 5 groups: control (C), IRI, IRI-CO, IRI-desflurane (IRID), IRI-CO-desflurane (IRICOD). Cerium oxide was given intraperitoneally. Lower extremity IRI was induced. Desflurane was applied during IRI. Lung histopathological examinations and serum biochemical analyses were performed. RESULTS: Serum nitric oxide (NO) and malondialdehyde (MDA) levels were higher in group IRI (p=0.006) than in group C (p=0.001). Serum MDA and NO levels were significantly lower in groups IRICO and IRICOD than in group IRI. Significantly greater alveolar wall thickening and neutrophil infiltration were recorded in group IRI than in group C. Co-administration of desflurane and CO significantly decreased alveolar wall thickening and neutrophil infiltration compared to group IRI. Total lung injury scores were significantly lower in groups IRID, IRICO, and IRICOD than in group IRI. CONCLUSION: Intraperitoneal CO with desflurane, reduced oxidative stress and corrected the damage in lung. Cerium oxide given before and desflurane given during IRI have been shown to have protective effects on lung damage in rats.


Assuntos
Anestesia , Lesão Pulmonar , Traumatismo por Reperfusão , Animais , Cério , Desflurano , Extremidade Inferior , Ratos , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/prevenção & controle
5.
Environ Sci Technol ; 55(21): 14649-14657, 2021 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-34652129

RESUMO

The time-course association of soil physicochemical properties and fate of CeO2 nanoparticles (NPs) is not well understood. This study for the first time investigated the dissolution and retention of CeO2 NPs (<25 nm) during soil short-term (6 h) and long-term (30 d) aging processes with dynamic redox conditions. Under the additional reductant-induced initial reductive condition, theoretically, up to 220‰ of Ce(IV) was temporarily reductively dissolved within 10 min, accompanied by a slow retention process (180 min) of Ce species in soil solutions. Conversely, the dissolution and slow retention of Ce species were not significant in soil solutions without added reductant. X-ray absorption near edge spectroscopy (XANES) shows that most of Ce species were present as Ce(IV) (94.0%-97.8%) in all soils after a long-term aging process. These results indicate that the soil dynamic redox conditions induced by oxidant/reductant intrinsically determined the different time-course dissolution and retention of CeO2 NPs, highlighting the occasional reductive condition in soil solution that may contribute to the migration and diffusion of Ce species. The time-course study should be also adopted to develop a comprehensive understanding of the nano-soil interactions.


Assuntos
Cério , Nanopartículas Metálicas , Nanopartículas , Oxirredução , Solo , Solubilidade
6.
Ecotoxicol Environ Saf ; 226: 112852, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34601268

RESUMO

New cerium-doped carbon quantum dots (CDs:Ce) were developed in this study using hydrothermal synthesis method. The small and uniform sizes and nearly spherical lattice of CDs:Ce indicate its high stability, satisfactory water solubility, and biocompatibility. Wheat was treated with Ce, CDs, and different concentrations (0.01, 0.025, 0.05, 0.1, 0.2, and 0.4 mg/mL) of CDs:Ce. The results showed that, compared with the control group, Ce, CDs, and CDs:Ce could promote the growth and development of wheat in a certain concentration range. Wheat demonstrated the optimal morphological index (compared with the control, the root number, root length, leaf length, and plant height were increased by 45%, 57%, 28%, and 46%, respectively), maximum chlorophyll content (increased by 51%) and peroxidase activity (increased by 76%), and minimum malondialdehyde content (reduced by 68%) after treatment of 0.025 mg/mL of CDs:Ce. Hence, wheat plants can adsorb and transport CDs:Ce from roots to stems and leaves through fibrovascular tissues. The majority of CDs:Ce are concentrated in roots while some accumulate in leaves. A considerable amount of CDs:Ce gather in cell walls, fibrovascular tissues, leaf veins, and stomata. CDs:Ce can be applied to agricultural production activities as a new agricultural nanofertilizer and technology of plant in vivo imaging.


Assuntos
Cério , Pontos Quânticos , Carbono , Cério/toxicidade , Crescimento e Desenvolvimento , Triticum
7.
Nanotoxicology ; 15(8): 1035-1058, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34468264

RESUMO

Metal oxide nanoparticles are widely used in both consumer products and medical applications, but the knowledge regarding exposure-related health effects is limited. However, it is challenging to investigate nanoparticle interaction processes with biological systems. The overall aim of this project was to improve the possibility to predict exposure-related health effects of metal oxide nanoparticles through interdisciplinary collaboration by combining workflows from the pharmaceutical industry, nanomaterial sciences, and occupational medicine. Specific aims were to investigate nanoparticle-protein interactions and possible adverse immune reactions. Four different metal oxide nanoparticles; CeOx nanocrystals with 5% or 14% Gd, Co3O4, and Fe2O3, were characterized by dynamic light scattering and high-resolution transmission electron microscopy. Nanoparticle-binding proteins were identified and screened for HLA-binding peptides in silico. Monocyte interaction with nanoparticle-protein complexes was assessed in vitro. Herein, for the first time, immunogenic properties of nanoparticle-binding proteins have been characterized. The present study indicates that especially Co3O4-protein complexes can induce both 'danger signals', verified by the production of inflammatory cytokines and simultaneously bind autologous proteins, which can be presented as immunogenic epitopes by MHC class II. The clinical relevance of these findings should be further evaluated to investigate the role of metal oxide nanoparticles in the development of autoimmune disease. The general workflow identified experimental difficulties, such as nanoparticle aggregate formation and a lack of protein-free buffers suitable for particle characterization, protein analyses, as well as for cell studies. This confirms the importance of future interdisciplinary collaborations.


Assuntos
Cério , Nanopartículas Metálicas , Nanopartículas , Cério/toxicidade , Cobalto , Gadolínio , Nanopartículas Magnéticas de Óxido de Ferro , Nanopartículas Metálicas/toxicidade , Monócitos , Nanopartículas/toxicidade , Óxidos/toxicidade
8.
Huan Jing Ke Xue ; 42(10): 4815-4825, 2021 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-34581124

RESUMO

A cerium-modified water hyacinth biochar adsorbent(Ce-BC) was developed through co-precipitation-pyrolysis to remove phosphate from wastewater. The study investigated the effects of Ce-BC dosing, wastewater pH, reaction time, and coexisting competing ions on the adsorption process. The results showed that the best adsorption performance was achieved with a maximum adsorption capacity of 35.00 mg·g-1 at a Ce-BC dosage of 0.4 g·L-1 and an initial pH range of 3-10 in the phosphate solution. The adsorption process of phosphate by the Ce-BC followed the quasi-second-order kinetic model, and a phosphate removal efficiency of 98% within 1 h was achieved. In addition, Ce-BC had a strong anti-competitive anion interference and a good regeneration ability; after four cycles of regeneration, the adsorption efficiency remained above 90%. Characterization using field emission scanning electron microscopy-energy dispersive spectrometry(FESEM-EDS), Fourier-transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), and X-ray photoelectron spectroscopy(XPS) showed that the adsorption mechanism of Ce-BC with respect to phosphate mainly involved ligand exchange and inner sphere complexation. The Ce-BC adsorbent prepared in this study effectively removed and recovered phosphates found in domestic sewage, thereby avoiding the eutrophication of water bodies as well as enabling the recovery and utilization of phosphorus resources.


Assuntos
Cério , Eichhornia , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Cinética , Fosfatos , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
9.
Molecules ; 26(17)2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-34500851

RESUMO

The mechanism behind the cytoprotective potential of cerium oxide nanoparticles (CeO2 NPs) against cytotoxic nitric oxide (NO) donors and H2O2 is still not clear. Synthesized and characterized CeO2 NPs significantly ameliorated the lipopolysaccharide (LPS)-induced cytokines IL-1ß and TNF-α. The main goal of this study was to determine the capacities of NPs regarding signaling effects that could have occurred due to reactive oxygen species (ROS) and/or NO, since NP-induced ROS/NO did not lead to toxicity in HUVE cells. Concentrations that induced 50% cell death (i.e., IC50s) of two NO donors (DETA-NO; 1250 ± 110 µM and sodium nitroprusside (SNP); 950 ± 89 µM) along with the IC50 of H2O2 (120 ± 7 µM) were utilized to evaluate cytoprotective potential and its underlying mechanism. We determined total ROS (as a collective marker of hydrogen peroxide, superoxide radical (O2•-), hydroxyl radical, etc.) by DCFH-DA and used a O2•- specific probe DHE to decipher prominent ROS. The findings revealed that signaling effects mediated mainly by O2•- and/or NO are responsible for the amelioration of toxicity by CeO2 NPs at 100 µg/mL. The unaltered effect on mitochondrial membrane potential (MMP) due to NP exposure and, again, CeO2 NPs-mediated recovery in the loss of MMP due to exogenous NO donors and H2O2 suggested that NP-mediated O2•- production might be extra-mitochondrial. Data on activated glutathione reductase (GR) and unaffected glutathione peroxidase (GPx) activities partially explain the mechanism behind the NP-induced gain in GSH and persistent cytoplasmic ROS. The promoted antioxidant capacity due to non-cytotoxic ROS and/or NO production, rather than inhibition, by CeO2 NP treatment may allow cells to develop the capacity to tolerate exogenously induced toxicity.


Assuntos
Anti-Inflamatórios/química , Cério/química , Nanopartículas Metálicas/química , Doadores de Óxido Nítrico/metabolismo , Óxido Nítrico/metabolismo , Superóxidos/metabolismo , Anti-Inflamatórios/farmacologia , Sobrevivência Celular , Cério/farmacologia , Citocinas/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Células Endoteliais da Veia Umbilical Humana , Humanos , Peróxido de Hidrogênio/metabolismo , Lipopolissacarídeos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo
10.
Small ; 17(40): e2102413, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34494360

RESUMO

Molybdenum phosphide (MoP) is regarded as one of the most promising alternatives to noble-metal based electrocatalysts for efficient hydrogen evolution reaction (HER) due to its similar d-band electronic structure to noble metals and tunable features associated with phase and composition. However, it still remains a great challenge to construct MoP electrocatalysts with abundant active sites that possess ideal H binding strength to promote catalytic performance. In this work, it is found that by anchoring a rare earth compound, cerium phosphate (CePO4 ) on MoP (CePO4 /MoP), the stabilized Ce3+ in CePO4 can significantly boost the formation of oxygen vacancies in ceria (CeO2 ) in situ formed on CePO4 surface during HER, which effectively regulates the d-band electronic density-of-states of MoP, increases the numbers of active sites, and promotes the vectorial electron transfer, therefore greatly enhancing the HER performance of MoP. The optimized CePO4 /MoP/carbon cloth (CC) electrocatalyst exhibits a significantly improved HER performance with an overpotential of 48 mV at 10 mA cm-2 and a Tafel slope of 38 mV dec-1 , about two times better than the HER performance of MoP catalyst without CePO4 (with an overpotential >80 mV dec-1 at 10 mA cm-2 ), very close to commercial Pt/C catalyst.


Assuntos
Hidrogênio , Molibdênio , Cério , Eletrônica , Fosfatos
11.
Anal Methods ; 13(40): 4747-4755, 2021 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-34559169

RESUMO

Eu3+-Doped nanoceria (Eu:CeO2) with self-integrated catalytic and luminescence sensing functions was synthesized by a simple and gentle one-pot method to build a dual-readout nanozyme platform for organophosphate compound (OPC) sensing in this work. The catalytic degradation of the model substrate of OPC, p-nitrophenyl phosphate (p-NPP), by as-prepared Eu:CeO2 can be completed in 2 min with little influence of temperature and pH values, highlighting the advantages of Eu:CeO2 as an artificial enzyme for dephosphorylation. Most importantly, the characteristic red emission of Eu3+ (592 nm) from Eu:CeO2 can be quenched by p-NPP, accompanied by a color change from colorless to yellow. Based on this, linear ranges of 4-50 µM with a detection limit of 3.3 µM and 1-20 µM with a detection limit of 0.6 µM for p-NPP were obtained by colorimetric and fluorescence methods, respectively. Furthermore, the fluorescence strategy was effectively applied to the determination of ethyl para-nitrophenyl (EPN), one of the most commonly used pesticides, with a detection limit of 5.86 µM. The proposed strategy was also successfully applied to the assay of p-NPP and EPN in real water samples, showing great application prospects in detecting OPC in the environment.


Assuntos
Cério , Monoéster Fosfórico Hidrolases , Colorimetria , Organofosfatos
12.
J Org Chem ; 86(19): 13371-13380, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34533324

RESUMO

Herein we described an access to biaryl lactones from ortho-aryl benzoic acids via intramolecular O-H/C-H oxidative coupling with the commonly used cerium ammonium nitrate (CAN) as the one-electron oxidant under a thermal condition. The radical interrupting experiment suggested a radical process, while the kinetic isotope effect (KIE) showed that the C-H cleavage likely was not involved in the rate-determining step. Competitive reactions, especially the strikingly different ρ values of Hammett equations, indicated that the reaction rate was more sensitive to the electronic properties on the aryl moiety rather than the carboxylic moiety, which corresponded to the first single electron transfer (SET) step. In addition, the quite negative ρ values (-4.7) of the aryl moiety unveiled the remarkable electrophilic nature of the second intramolecular radical addition process, which was also consistent with product yields and regioselectivity. Moreover, control experiments disclosed that the single electron in the third step was also transferred to CeIV instead of molecular oxygen. Besides, the possible role of co-solvents trifluoroethanol (TFE) and its influences on the CeIV species were discussed. This work elucidated the possible mechanism by proposing the step that had more effects on the total reaction rate and the species that was responsible for the last single electron transfer.


Assuntos
Compostos de Amônio , Cério , Lactonas , Nitratos , Oxirredução
13.
Int J Mol Sci ; 22(18)2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34576334

RESUMO

Cancers are a major challenge to health worldwide. Spinel ferrites have attracted attention due to their broad theranostic applications. This study aimed at investigating the antimicrobial, antibiofilm, and anticancer activities of ebselen (Eb) and cerium-nanoparticles (Ce-NPs) in the form of ZnCexFe2-XO4 on human breast and colon cancer cell lines. Bioassays of the cytotoxic concentrations of Eb and ZnCexFe2-XO4, oxidative stress and inflammatory milieu, autophagy, apoptosis, related signalling effectors, the distribution of cells through the cell-cycle phases, and the percentage of cells with apoptosis were evaluated in cancer cell lines. Additionally, the antimicrobial and antibiofilm potential have been investigated against different pathogenic microbes. The ZOI, and MIC results indicated that ZnCexFe2-XO4; X = 0.06 specimen reduced the activity of a wide range of bacteria and unicellular fungi at low concentration including P. aeruginosa (9.5 mm; 6.250 µg/mL), S. aureus (13.2 mm; 0.390 µg/mL), and Candida albicans (13.5 mm; 0.195 µg/mL). Reaction mechanism determination indicated that after ZnCexFe2-xO4; X = 0.06 treatment, morphological differences in S.aureus were apparent with complete lysis of bacterial cells, a concomitant decrease in the viable number, and the growth of biofilm was inhibited. The combination of Eb with ZFO or ZnCexFe2-XO4 with γ-radiation exposure showed marked anti-proliferative efficacy in both cell lines, through modulating the oxidant/antioxidant machinery imbalance, restoring the fine-tuning of redox status, and promoting an anti-inflammatory milieu to prevent cancer progression, which may be a valuable therapeutic approach to cancer therapy and as a promising antimicrobial agent to reduce the pathogenic potential of the invading microbes.


Assuntos
Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Cério/farmacologia , Raios gama , Células HT29 , Humanos , Isoindóis/farmacologia , Compostos Organosselênicos/farmacologia
14.
Molecules ; 26(18)2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34577094

RESUMO

Among rare earth elements, cerium has the unique ability of regulating the growth of plant cells and the biosynthesis of metabolites at different stages of plant development. The signal pathways of Ce3+-mediated ginsenosides biosynthesis in ginseng hairy roots were investigated. At a low concentration, Ce3+ improved the elongation and biomass of hairy roots. The Ce3+-induced accumulation of ginsenosides showed a high correlation with the reactive oxygen species (ROS), as well as the biosynthesis of endogenous methyl jasmonate (MeJA) and ginsenoside key enzyme genes (PgSS, PgSE and PgDDS). At a Ce3+ concentration of 20 mg L-1, the total ginsenoside content was 1.7-fold, and the total ginsenosides yield was 2.7-fold that of the control. Malondialdehyde (MDA) content and the ROS production rate were significantly higher than those of the control. The activity of superoxide dismutase (SOD) was significantly activated within the Ce3+ concentration range of 10 to 30 mg L-1. The activity of catalase (CAT) and peroxidase (POD) strengthened with the increasing concentration of Ce3+ in the range of 20-40 mg L-1. The Ce3+ exposure induced transient production of superoxide anion (O2•-) and hydrogen peroxide (H2O2). Together with the increase in the intracellular MeJA level and enzyme activity for lipoxygenase (LOX), there was an increase in the gene expression level of MeJA biosynthesis including PgLOX, PgAOS and PgJMT. Our results also revealed that Ce3+ did not directly influence PgSS, PgSE and PgDDS activity. We speculated that Ce3+-induced ROS production could enhance the accumulation of ginsenosides in ginseng hairy roots via the direct stimulation of enzyme genes for MeJA biosynthesis. This study demonstrates a potential approach for understanding and improving ginsenoside biosynthesis that is regulated by Ce3+-mediated signal transduction.


Assuntos
Acetatos/metabolismo , Cério/farmacologia , Ciclopentanos/metabolismo , Ginsenosídeos/biossíntese , Oxilipinas/metabolismo , Panax/química , Panax/metabolismo , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Ginsenosídeos/análise , Panax/efeitos dos fármacos , Panax/crescimento & desenvolvimento , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos
15.
ACS Biomater Sci Eng ; 7(9): 4388-4401, 2021 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-34468119

RESUMO

Bioactive glasses (BGs) for biomedical applications are doped with therapeutic inorganic ions (TIIs) in order to improve their performance and reduce the side effects related to the surgical implant. Recent literature in the field shows a rekindled interest toward rare earth elements, in particular cerium, and their catalytic properties. Cerium-doped bioactive glasses (Ce-BGs) differ in compositions, synthetic methods, features, and in vitro assessment. This review provides an overview on the recent development of Ce-BGs for biomedical applications and on the evaluation of their bioactivity, cytocompatibility, antibacterial, antioxidant, and osteogenic and angiogenic properties as a function of their composition and physicochemical parameters.


Assuntos
Cério , Antibacterianos/farmacologia , Catálise , Vidro , Osteogênese
16.
J Hazard Mater ; 416: 125941, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492868

RESUMO

Herein, we demonstrate the use of cerium (Ce)-UiO-66 metal organic framework (MOF) for the removal of a variety of potentially toxic pollutants. The Ce-UiO-66 MOF, with similar framework topologies to Zr-UiO-66, has not been explored for its adsorptive properties in water remediation. The replacement of Zr metal center with Ce yields a MOF that can be synthesized in shorter durations with lesser energy consumptions and with excellent multipollutant adsorption properties. Further, the Ce-UiO-66 MOF was also studied for its adsorption abilities in the binary component system. Interestingly, the adsorbent showed higher adsorption capacities in the presence of other pollutants. Removal studies for other potentially toxic anionic and cationic dyes showed that the Ce-UiO-66 MOF has a wide range of contaminant removal abilities. Investigations of individual adsorption capacities revealed that the Ce-UiO-66 MOF has a maximum adsorption capacity of 793.7 mg/g for congo red (CR), 110 mg/g for methylene blue (MB), 66.1 mg/g for fluoride (F-), 30 mg/g for Cr6+ and 485.4 mg/g for the pharmaceutical waste diclofenac sodium (DCF). To imply the practical applications of the Ce-UiO-66 MOF we have also demonstrated an adaptable filter that could separate all the potentially toxic pollutants.


Assuntos
Cério , Estruturas Metalorgânicas , Poluentes Químicos da Água , Purificação da Água , Adsorção , Cério/toxicidade , Poluentes Químicos da Água/análise
17.
Sci Total Environ ; 790: 148229, 2021 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-34380244

RESUMO

Significant release of rare earth elements (REEs) into the environment is mainly due to active or abandoned mining sites, but their presence is globally increasing due to their use in several industrial sectors. The effects on primary producers as Raphidocelis subcapitata are still limited. This research focused on La and Ce as the two most widespread REEs that can be currently found up to hundreds of µg/L in water and wastewater. Microalgae were exposed to La and Ce for 3 days (pH = 7.8) (short-term exposure) to derive the effective concentrations inhibiting the growth on 10% (EC10) of the exposed population. EC10 values (0.5 mg/L of La and 0.4 mg/L of Ce) were used for the 28 days long-term exposure (renewal test) to observe after 7, 14, 21, and 28 days on a multi-endpoint basis microalgae growth inhibition (GI), biomarkers of stress (reactive oxygen species (ROS), superoxide dismutase (SOD), and catalase (CAT)), and bioconcentration. Results evidenced that La and Ce EC10 increased GI (day 28) up to 38% and 28%, respectively. ROS, CAT, and SOD activities showed differential responses from day 7 to day 14, 21, and 28, suggesting, in most of the cases, that La and Ce effects were counteracted (i.e., being the values at day 28 not significantly different, p > 0.05, from the relative negative controls), except for La-related ROS activities. La and Ce significantly bioconcentrated in microalgae populations up to 2- and 5-fold (i.e., at day 28 compared to day 7), in that order. Bioconcentrated La and Ce were up to 3157 and 1232 µg/g dry weight (day 28), respectively. These results suggested that low La and Ce concentrations can be slightly toxic to R. subcapitata having the potential to be bioaccumulated and potentially transferred along the food web.


Assuntos
Cério , Metais Terras Raras , Microalgas , Catalase , Cério/toxicidade , Lantânio/toxicidade
18.
Molecules ; 26(15)2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34361812

RESUMO

Metal oxide nanoparticles synthesized by the biological method represent the most recent research in nanotechnology. This study reports the rapid and ecofriendly approach for the synthesis of CeO2 nanoparticles mediated using the Abelmoschus esculentus extract. The medicinal plant extract acts as both a reducing and stabilizing agent. The characterization of CeO2 NPs was performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), and Fourier transform infrared spectroscopy (FTIR). The in vitro cytotoxicity of green synthesized CeO2 was assessed against cervical cancerous cells (HeLa). The exposure of CeO2 to HeLa cells at 10-125 µg/mL caused a loss in cellular viability against cervical cancerous cells in a dose-dependent manner. The antibacterial activity of the CeO2 was assessed against S. aureus and K. pneumonia. A significant improvement in wound-healing progression was observed when cerium oxide nanoparticles were incorporated into the chitosan hydrogel membrane as a wound dressing.


Assuntos
Abelmoschus/química , Antioxidantes/síntese química , Extratos Vegetais/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Proliferação de Células/efeitos dos fármacos , Cério/química , Química Verde/tendências , Células HeLa , Humanos , Nanopartículas Metálicas/química , Microscopia Eletrônica de Varredura , Extratos Vegetais/química , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/patogenicidade , Cicatrização/efeitos dos fármacos
19.
Int J Nanomedicine ; 16: 5333-5341, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34408413

RESUMO

Purpose: The use of cerium oxide nanoparticles (CeO2 NPs), a lanthanide element oxide and bivalent compound, has been growing continuously in industry and biomedicine. Due to their wide application, the potential human health problems of CeO2 NPs have attracted attention, but studies on the toxicity of this compound to human eyes are lacking. This study investigated the cytotoxicity and reactive oxygen species (ROS) of CeO2 NPs in human retinal pigment epithelial cells (ARPE-19 cells). Methods: Using the transmission electron microscope (TEM), the size distribution and shape of CeO2 NPs were characterized. To explore the effect of CeO2 NP size on ophthalmic toxicity in vitro, three sizes (15, 30 and 45 nm) of CeO2 NPs were investigated using ATP content measurement, LDH release measurement and cell proliferation assay in ARPE-19 cells. ROS values and mitochondrial membrane potential depolarization were evaluated by H2DCF-DA staining and JC-1 staining. Morphology changes were detected using a phase-contrast microscope. Results: The cytotoxicity of 15 nm CeO2 NPs was found to be the highest and hence was further explored. Treatment with 15 nm CeO2 NPs caused the morphology of ARPE-19 cells to change in a dose- and time-dependent manner. Moreover, the treatment induced excessive ROS generation and mitochondrial membrane potential depolarization. In addition, cytotoxicity was attenuated by the application of a ROS scavenger N-acetyl-L- cysteine (NAC). Conclusion: CeO2 NPs induced cytotoxicity in ARPE-19 cells and excessive production of ROS and decreasing mitochondrial membrane potential. The Overproduction of ROS partially contributes to CeO2 NP-induced cytotoxicity.


Assuntos
Nanopartículas Metálicas , Cério/toxicidade , Humanos , Nanopartículas Metálicas/toxicidade , Espécies Reativas de Oxigênio , Pigmentos da Retina
20.
ACS Nano ; 15(9): 14544-14556, 2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34436866

RESUMO

The COVID19 pandemic has brought global attention to the threat of emerging viruses and to antiviral therapies, in general. In particular, the high transmissibility and infectivity of respiratory viruses have been brought to the general public's attention, along with the need for highly effective antiviral and disinfectant materials/products. This study has developed two distinct silver-modified formulations of redox-active nanoscale cerium oxide (AgCNP1 and AgCNP2). The formulations show specific antiviral activities toward tested OC43 coronavirus and RV14 rhinovirus pathogens, with materials characterization demonstrating a chemically stable character for silver nanophases on ceria particles and significant differences in Ce3+/Ce4+ redox state ratio (25.8 and 53.7% Ce3+ for AgCNP1 & 2, respectively). In situ electrochemical studies further highlight differences in formulation-specific viral inactivation and suggest specific modes of action. Altogether, the results from this study support the utility of AgCNP formulations as high stability, high efficacy materials for use against clinically relevant virus species.


Assuntos
COVID-19 , Cério , Humanos , Rhinovirus , SARS-CoV-2
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...