Hollow cerium nanoparticles synthesized by one-step method for multienzyme activity to reduce colitis in mice

BACKGROUND Inflammatory bowel disease(IBD)is a common chronic intestinal inflammatory disease.High oxidative stress is a treatment target for IBD.Cerium oxide(CeO2)nanomaterials as nanozymes with antioxidant activity are potential drugs for the treatment of colitis.AIM To synthesize hollow cerium(H-CeO2)nanoparticles by one-step method and to validate the therapeutic efficacy of H-CeO2 in IBD.METHODS H-CeO2 was synthesized by one-step method and examined its characterization and nanoenzymatic activity.Subsequently,we constructed dextran sulfate so-dium(DSS)-induced colitis in mice to observe the effects of H-CeO2 on colonic inflammation.The effects of H-CeO2 on colon inflammation and reactive oxygen species(ROS)levels in IBD mice were detected by hematoxylin and eosin staining and dichlorofluorescein diacetate staining,respectively.Finally,the biological sa-fety of H-CeO2 on mice was evaluated by hematoxylin and eosin staining,blood routine,and blood biochemistry.RESULTS H-CeO2 nanoparticles prepared by the one-step method were uniform,monodi-sperse and hollow.H-CeO2 had a good ability to scavenge ROS,∙OH and∙OOH.H-CeO2 reduced DSS-induced decreases in body weight and colon length,colonic epithelial damage,inflammatory infiltration,and ROS accumulation.H-CeO2 administration reduced the disease activity index of DSS-induced animals from about 8 to 5.H-CeO2 had no significant effect on body weight,total platelet count,hemoglobin,white blood cell,and red blood cell counts in healthy mice.No significant damage to major organs was observed in healthy mice following H-CeO2 administration.CONCLUSION The one-step synthesis of H-CeO2 nanomaterials had good antioxidant activity,biosafety,and inhibited deve-lopment of DSS-induced IBD in mice by scavenging ROS.

Neuroprotective Potential of Cerium Oxide Nanoparticles for Focal Cerebral Ischemic Stroke

During the previous years, with the emerging of nanotechnology, the enormous capabilities of nanoparticles have drawn great attention from researchers in terms of their potentials in various aspects of pharmacology. Cerium oxide nanoparticles（nanoceria）, considered as one of the most widely used nanomaterials, due to its tempting catalytic antioxidant properties, show a promising potential in diverse disorders, such as cerebral ischemic stroke（CIS）, cancer, neurodegenerative and inflammatory diseases. Overwhelming generation of reactive oxygen species（ROS） and reactive nitrogen species（RNS） during cerebral ischemia and reperfusion periods is known to aggravate brain damage via sophisticated cellular and molecular mechanisms, and therefore exploration of the antioxidant capacities of nanoceria becomes a new approach in reducing cerebral ischemic injury. Furthermore, utilizing nanoceria as a drug carrier might display the propensity to overcome limitations or inefficacy of other conceivable neuroprotectants and exhibit synergistic effects. In this review, we emphasize on the principle features of nanoceria and current researches concerning nanoceria as a potential therapeutic agent or carrier in improving the prognosis of CIS.

An overview on recent in vivo biological application of cerium oxide nanoparticles

Cerium oxide nanoparticles(CNPs)possess a great potential as therapeutic agents due to their ability to self-regenerate by reversibly switching between two valences+3 and+4.This article reviews recent articles dealing with in vivo studies of CNPs towards Alzheimer’s disease,obesity,liver inflammation,cancer,sepsis,amyotrophic lateral sclerosis,acute kidney injury,radiation-induced tissue damage,hepatic ischemia reperfusion injury,retinal diseases and constipation.In vivo anti-cancer studies revealed the effectiveness of CNPs to reduce tumor growth and angiogenesis in melanoma,ovarian,breast and retinoblastoma cancer cell-induced mice,with their conjugation with folic acid,doxorubicin,CPM,or CXC receptor-4 antagonist ligand eliciting higher efficiency.After conjugation with triphenylphosphonium or magnetite nanoparticles,CNPs were shown to combat Alzheimer’s disease by reducing amyloid-β,glial fibrillary acidic protein,inflammatory and oxidative stress markers in mice.By improving muscle function and longevity,the citrate/EDTA-stabilized CNPs could ameliorate amyotrophic lateral sclerosis.Also,they could effectively reduce obesity in mice by scavenging ROS and reducing adipogenesis,triglyceride synthesis,GAPDH enzyme activity,leptin and insulin levels.In CCl4-induced rats,stress signaling pathways due to inflammatory cytokines,liver enzymes,oxidative and endoplasmic reticulum messengers could be attenuated by CNPs.Commercial CNPs showed protective effects on rats with hepatic ischemia reperfusion and peritonitis-induced hepatic/cardiac injuries by decreasing oxidative stress and hepatic/cardiac inflammation.The same CNPs could improve kidney function by diminishing renal superoxide,hyperglycemia and tubular damage in peritonitis-induced acute kidney injury in rats.Radiation-induced lung and testicular tissue damage could be alleviated in mice,with the former showing improvement in pulmonary distress and bronchoconstriction and the latter exhibiting restoration in spermatogenesis rate and spermatid/spermatocyte number.Through enhancement of gastrointestinal motility,the CNPs could alleviate constipation in both young and old rats.They could also protect rat from light-induced retinal damage by slowing down neurodegenerative process and microglial activation.

Biochemical and cellular evidence of the benefit of a combination of cerium oxide nanoparticles and selenium to diabetic rats

AIM: To study the combinative effects of nanocerium and selenium in a murine model of diabetes. METHODS: Cerium oxide (CeO2) nanoparticles (60 mg/kg per day) and sodium selenite (5 μmol/kg per day) aloneor in combination, or the metal form of CeO2 (60 mg/kg) were administered for 2 wk by intraperitoneal injection to streptozotocin-induced diabetic rats. At the end of treatment blood was collected, liver tissue dissected and then oxidative stress markers, extent of energy depletion and lipid prof ile were evaluated.RESULTS: Antioxidant enzymes and high density lipoprotein decreased whereas oxidative stress, adenosine diphosphate/adenosine triphospahte levels, cholesterol, triglyceride and low density lipoprotein increased on induction of diabetes. All were improved by a combination of nanocerium and sodium selenite. There was a relative amelioration by CeO2 nanoparticles or sodium selenite alone, but the metal form of CeO2 showed no signif icant improvement. CONCLUSION: The combination of nanocerium and sodium selenite is more effective than either alone in improving diabetes-induced oxidative stress.

Nano transdermal system combining mitochondria-targeting cerium oxide nanoparticles with all-trans retinoic acid for psoriasis

Psoriasis is an inflammatory skin disease that is intricately linked to oxidative stress.Antioxidation and inhibition of abnormal proliferation of keratinocytes are pivotal strategies for psoriasis.Delivering drugs with these effects to the site of skin lesions is a challenge that needs to be solved.Herein,we reported a nanotransdermal delivery system composed of all-trans retinoic acid(TRA),triphenylphosphine(TPP)-modified cerium oxide(CeO2)nanoparticles,flexible nanoliposomes and gels(TCeO_(2)-TRA-FNL-Gel).The results revealed that TCeO_(2)synthesized by the anti-micelle method,with a size of approximately 5 nm,possessed excellent mitochondrial targeting ability and valence conversion capability related to scavenging reactive oxygen species(ROS).TCeO_(2)-TRA-FNL prepared by the film dispersion method,with a size of approximately 70 nm,showed high drug encapsulation efficiency(>96%).TCeO_(2)-TRA-FNL-Gel further showed sustained drug release behaviors,great transdermal permeation ability,and greater skin retention than the free TRA.The results of in vitro EGF-induced and H2O2-induced models suggested that TCeO_(2)-TRA-FNL effectively reduced the level of inflammation and alleviated oxidative stress in HaCat cells.The results of in vivo imiquimod(IMQ)-induced model indicated that TCeO_(2)-TRA-FNL-Gel could greatly alleviate the psoriasis symptoms.In summary,the transdermal drug delivery system designed in this study has shown excellent therapeutic effects on psoriasis and is prospective for the safe and accurate therapy of psoriasis.

Cerium Oxide Nanoparticles Protect against Oxaliplatin Induced Testicular Damage: Biochemical, Histological, Immunohistochemical, and Genotoxic Study

Oxaliplatin is a chemotherapeutic drug used for colorectal cancer treatment. The testicular toxic effect is one of its recorded toxicities which resulted in a few studies. Oxidative stress could be a direct cause of this testicular toxicity. Cerium oxide nanoparticles (CONPs) are optimistic antioxidants for applications in medicine. The aim of the work is to study the protective effect of CONPs on testicular toxicity induced by oxaliplatin in rats. Forty adult male albino rats were divided into 4 groups: Control group, CONPs group (60 mg/kg, 5 times/week), Oxaliplatin group (4 mg/kg, twice/week), and Oxaliplatin & CONPs group, for 4 weeks. Seventy-two hours after the last administration, blood samples were taken for hormonal levels and testes were used for both histopathology and immunohistochemical microscopic examination. Sperm smears were also performed and their results were statistically analyzed to detect any sperm abnormalities. Oxaliplatin increased MDA levels. SOD and GPx activity was decreased. GSH levels were decreased. Also, it decreased the sperm cell count and serum testosterone, and anti-Müllerian hormon. In the testicular sections, significant histopathology changes were seen and immunohistochemical examination confirmed these results. Upon supplementation of CONPs with oxaliplatin decreased MDA levels. SOD and GPx activity was increased, and GSH did not change. In testicular sections, normal morphology was seen. Also, there was an increase in the sperm cell count and serum testosterone anti-Müllerian with significant improvement of testicular architecture, and immunohistochemical examination confirmed these results. The utilization of CONPs produced significant protection against all of the above-mentioned changes.

Synthesis of Pd nanoparticles supported on CeO_2 nanotubes for CO oxidation at low temperatures

Developing efficient supported Pd catalysts and understanding their catalytic mechanism in CO oxidation are challenging research topics in recent years.This paper describes the synthesis of Pd nanoparticles supported on CeO2 nanotubes via an alcohol reduction method.The effect of the support morphology on the catalytic reaction was explored.Subsequently,the performance of the prepared catalysts was investigated toward CO oxidation reaction and characterized by Nitrogen sorption,X-ray diffraction,X-ray photoelectron spectroscopy,transmission electron microscopy,and CO-temperature-programmed desorption techniques.The results indicated that the catalyst of Pd on CeO2 nanotubes exhibits excellent activity in CO oxidation at low temperatures,due to its large surface area,the high dispersion of Pd species,the mesoporous and tubular structure of the CeO2-nanotube support,the abundant Ce3＋,formation of Pd–O–Ce bonding,and enhanced metal–support interaction on the catalyst surface.

The Oxidative Decarboxylation of Nitrilotriacetic Acid (NTA)——A Study of the Reaction of NTA with Cerium(Ⅳ) in HCIO_4

The reaction between Ce (IV ) and NTA was investigated titrimetrically and spectrophotometrically. Two equivalents of Ce( IV ) are reduced per mole of NTA almost instantaneously at room temperature. With increasing reaction time an ultimate of about 7 equivalents of Ce( IV) is consumed per mole of NTA at room temperature. Carbon dioxide, formaldehyde and dimethylamine are the major and readily detectable products of oxidation of NTA by Ce( IV ). The rates of the reaction in HClO4 were measured spectrophotometricaUy using the stopped flow technique. The effects of both acidity of the medium and added salts support and extend preliminary results.

Antibacterial properties of cerium oxide nanoparticles:Recent progresses and future challenges

Use of cerium oxide nanoparticles(CeO_(2) NPs)to optimize management of resistant microorganisms has received increasing attention due to non-specific activity of inorganic antibacterial agents.Understanding the mechanism of action is essential to elucidating the antibacterial activity of CeO_(2) NPs against bacteria.Therefore,this review aims to summarize the antibacterial mechanisms of CeO_(2) NPs and correlate the structural and physicochemical properties of CeO_(2) NPs to their antibacterial activity.We further summarize the strategies for the improvement of the antibacterial performance of CeO_(2) NPs and provide our opinions for future challenges as a conclusion.

Repeated release of cerium oxide nanoparticles altered algal responses:Growth,photosynthesis,and photosynthetic gene expression

The expanding production of engineered nanomaterials(ENMs)can eventually cause their increased release into and presence in aquatic ecosystems,potentially threatening the health of aquatic organisms and the stability of the ecological environment.Generally,ENMs are repeatedly released into real-world aquatic environments in relatively low concentrations,potentially affecting photosynthesis in primary producers such as algae.However,knowledge regarding the effects of repeated exposure to ENMs on algal photosynthesis is still lacking.Herein,the physiological responses of the freshwater algae Chlorella vulgaris following single and repeated exposures to cerium oxide nanoparticles(CeO2 NPs)were investigated at 10 mg/L,with a focus on photosynthesis.The results showed that repeated exposures triggered increased photosynthetic pigment contents,oxidative stress levels,decreased photosynthetic performance,and lower biomass in C.vulgaris compared to a single exposure.Photosynthesis-related genes(i.e.,petA,petB,psaA,atpB,and rbcL)were found to be upregulated following repeated exposures.Particularly for petB,repeated rather than single exposure treatment significantly upregulated its expression levels by 2.92–10.24-fold compared to unexposed controls.Furthermore,increased exposure times could aggravate the interaction between CeO2 NPs and algae,elevating 8.13%,12.13%,and 20.51%Ce distribution on the algal cell surface or intracellularly,compared to a single exposure.This study is the first to investigate the effects of ENM exposure times on algal photosynthesis,providing new insights into the assessment of the risks these materials pose to real-world aquatic environments.

Antibacterial mechanism and activity of cerium oxide nanoparticles

Nanomaterials have been applied as antibacterial agents by virtue of their unique functioning mechanism different from that of conventional antibiotics.Cerium oxide nanoparticles(CeO2 NPs)are important antibacterial agents due to their relatively low toxicity to normal cells and their distinct antibacterial mechanism based on the reversible conversion between two valence states of Ce(III)/Ce(IV).Some studies have been conducted to explore their antibacterial activities;however,systematic research reviews on the related mechanisms and influencing factors are still quite rare.In this review,we discuss the plausible mechanisms of the antibacterial activity of CeO2 NPs,analyze different influencing factors,and summarize various research reports on antibacterial effects on E.coli and S.aureus.We also propose the potential applications and prospects,and hope to provide an in-depth understanding on the antibacterial mechanism and a better guidance to the design and applications of this promising antibacterial material in the future.

In vitro and in vivo evaluation of cerium oxide nanoparticles in respiratory syncytial virus infection

Respiratory syncytial virus(RSV)is the most common cause of viral bronchiolitis among children worldwide,yet there is no vaccine for RSV disease.This study investigates the potential of cube and sphere-shaped cerium oxide nanoparticles(CNP)to modulate reactive oxygen(ROS)and nitrogen(RNS)species and immune cell phenotypes in the presence of RSV infection in vitro and in vivo.Cube and sphere-shaped CNP were synthesized by hydrothermal and ultrasonication methods,respectively.Physico-chemical characterization confirmed the shape of sphere and cube CNP and effect of various parameters on their particle size distribution and zeta potential.In vitro results revealed that sphere and cube CNP differentially modulated ROS and RNS levels in J774 macrophages.Specifically,cube CNP significantly reduced RSV-induced ROS levels without affecting RNS levels while sphere CNP increased RSV-induced RNS levels with minimal effect on ROS levels.Cube CNP drove an M1 phenotype in RSV-infected macrophages in vitro by increasing macrophage surface expression of CD80 and CD86 with a concomitant increase in TNFαand IL-12p70,while simultaneously decreasing M2 CD206 expression.Intranasal administration of sphere and cube-CNP were well-tolerated with no observed toxicity in BALB/c mice.Notably,cube CNP preferentially accumulated in murine alveolar macrophages and induced their activation,avoiding enhanced uptake and activation of other inflammatory cells such as neutrophils,which are associated with RSV-mediated inflammation.In conclusion,we report that sphere and cube CNP modulate macrophage polarization and innate cellular responses during RSV infection.

Coupling of on-Line Pre-Column Oxidative Cleavage and Solid-Phase Enrichment with Liquid Chromatography Using an Eco-Friendly Analytical Procedure to Determine Low Levels of Methotrexate

A simple, sensitive and precise green high-performance liquid chromatographic method including on-line pre-column oxidation combined by column switching with a short Hypersil ODS analytical column (100 mm × 4.0 mm i.d.) for enrichment and separation was developed and validated to determine low levels of methotrexate (MTX). The method was based on oxidative cleavage of MTX into highly fluorescence products, 2,4-diaminopteridine-6-carboxaldehyde and the corresponding 2,4-diaminopteridine-6-carboxylic acid, during the flow of phosphate buffer (0.04 M, pH 3.4) containing the analyte through the packed reactor of cerium (IV) trihydroxyhydroperoxide (CTH) at a flow-rate of 0.2 mL/min and 40℃. The fluorescent products were enriched on the head of ODS analytical column for the final separation. The separation was performed at room temperature using an environmentally friendly mobile phase consisting of ethanol and phosphate buffer (0.04 M, pH 3.4) in the ratio of 10:90 (v/v). The eluent was monitored at emission and excitation wavelengths of 463 and 367 nm, respectively. The method was successfully applied, without any interference from the excipients, for the determination of drug in tablets and vials with a detection limit of 0.06 ng/mL from 500 ?L of sample MTX.

Recent advances of cerium oxide nanoparticles in synthesis, luminescence and biomedical studies: a review

Nanostructured cerium oxide （CeO2） commonly known as nanoceria is a rare earth metal oxide, which plays a technologically important role due to its versatile applications as antomobile exhaust catalysts, oxide ion conductors in solid oxide fuel cells, electrode materials for gas sensors, ultraviolet absorbents and glass-polishing materials. However, nanoceria has little or weak luminescence, and therefore its uses in high-performance luminescent devices and biomedical areas are limited. In this review, we present the recent advances of nanoceria in the aspects of synthesis, luminescence and biomedical studies. The CeO2 nanoparticles can bc synthesized by solution-based methods including co-precipitation, hydrothemlal, microemulsion process, sol-gel techniques, combustion reaction and so on. Achieving controlled morphologies and enhanced luminescence efficiency of nanoceria particles arc quite essential for its potential energyand environment-related applications. Additionally, a new fiontier for nanoccria particles in biomedical research has also been opened, which involves low toxicity, retinopathy, biosensors and cancer therapy aspects. Finally, the summary and outlook on the challenges and perspectives of the nanoceria particles are proposed.

A review on biomedical and dental applications of cerium oxide nanoparticles——Unearthing the potential of this rare earth metal

Nanotechnology deals with particles ranging from 1 to 100 nm in size called as nanoparticles.These nano particles exhibit unique properties which find an application in many industries and medical fields.A growing body of evidence points out the newer developing technologies adopted in the field of medicine in terms of target therapies,imaging systems,drug deliveries,etc.is through the incorporation of nanoparticles.Cerium oxide nanoparticles have gained attention in the last decade due to exceptional properties such as redox activity,biofilm inhibition,antibacterial activity,anti-inflammatory activity,etc.The method of synthesis of cerium oxide nanoparticles plays a pivotal role in its application.It exhibits redox properties and catalytic activity and thus has found its use in biomedical applications.Nanoparticles are incorporated into dental materials such as restorative cements/sealants,adhesives,and denture systems to improve their properties.Among the various metal oxide nanoparticles,ce rium oxide nanoparticles(CeO_(2)NPs)are known to exhibit lower toxicity to mammalian cells and possess unique antibacterial mechanism.In addition,they exhibit potent properties such as antitumor,antiinflammatory,antibacterial activities,and functions as an immunosensor.CeO_(2)NPs have excellent scavenging properties for reactive oxygen species,which is why they are being considered for therapeutic purposes.In this review,various methods of synthesis of CeO_(2)NPs are discussed.Several factors that determine the particle size and morphology of these materials are important for biomedical and dental applications.Emphasis is given to preparation methods and variables such as calcination temperature,which have a profound effect on particle size and morphology.This article also presents various applications of CeO_(2)NPs in the biomedical and dental fields.

Tuning the intentional corona of cerium oxide nanoparticles to promote angiogenesis via fibroblast growth factor 2 signalling

Inadequate angiogenesis is a hallmark of conditions including cardiovascular diseases,stroke and chronic diabetic wounds,which exhibit tissue ischaemia ensuring that therapeutic strategies to promote angiogenesis are of great interest.However,many angiogenic treatments involve the delivery of growth factors which have limited clinical success due to poor stability,high manufacturing cost and poor efficacy.Cerium oxide nanoparticles(nanoceria)can either promote or inhibit angiogenesis depending on their surface corona chemistry.Here,nanoceria were functionalized with an intentional heparin corona,a polysaccharide which binds and signals growth factors,of different chain lengths and surface grafting density to establish their effect on angiogenesis.These nanoparticles promoted angiogenesis in vivo with the surface grafting density positively correlated with angiogenesis over the widest concentration range;however,chain length did not play a role.The heparin–nanoceria supported fibroblast growth factor 2(FGF2)signalling in vitro and promoted FGF2-mediated angiogenesis in vivo.The nanoparticles were internalized by endothelial cells in vitro where they trafficked to the lysosomes and reduced cell viability suggesting that the angiogenic activity of heparin–nanoceria is mediated in the extracellular environment.Together,this study adds to our knowledge of the angiogenic effects of heparin–nanoceria towards finding new angiogenic treatments.

化妆品中氧化铈纳米颗粒检测方法研究

初步建立了单颗粒电感耦合等离子体质谱(spICP-MS)测定化妆品中纳米氧化铈颗粒粒径大小及分布的方法。以0.1%Triton X-100为萃取剂超声辅助提取化妆品中的纳米氧化铈颗粒,在脉冲信号模式下采集数据并通过计算得到颗粒粒径大小及分布。探讨了spICP-MS用于检测化妆品中纳米颗粒时,不同计算方法对颗粒粒径检出限的影响。实验结果表明:粒径检出限不仅受到待测同位素背景信号的影响,也与化妆品基质相关。选择不同的计算方法时,粒径检出限及被识别为颗粒的个数均受到显著影响,直接关系到化妆品产品的合规性判定及安全性评价。阈值的准确选择是影响spICP-MS用于化妆品中纳米级颗粒存在与否判定的重要因素,应在现有化妆品基质分类的基础上,根据样品性质进行进一步评估。该方法可用于防晒类化妆品中纳米氧化铈颗粒的快速筛查,并可对其粒径大小及分布进行同时测定和表征,为含纳米颗粒化妆品的合规性和安全性考察提供了可供探讨的空间和途径。

纳米氧化铈在阿霉素诱导心脏毒性中的作用及其对P53基因表达的影响

目的研究纳米氧化铈在阿霉素心脏毒性损伤中的作用及其对P53基因表达的影响,探讨纳米氧化铈对阿霉素心脏毒性损伤的作用机制。方法培养H9C2心肌细胞,随机分为5组:对照组、模型组(1μmol/L阿霉素)、纳米氧化铈组(10μg/ml纳米氧化铈)、实验组(1μmol/L阿霉素+10μg/ml纳米氧化铈)、阳性对照组(1μmol/L阿霉素+10μmol/L右丙亚胺)。建立阿霉素心脏毒性损伤模型,CCK-8法检测心肌细胞的存活率;生化法检测心肌细胞内乳酸脱氢酶(lactic dehydrogenase,LDH)、丙二醛(malondialdehyde,MDA)的含量;流式细胞仪检测心肌细胞内活性氧(reactive oxygen,ROS)水平及细胞凋亡率;Western blot检测心肌细胞中Bax、Bcl-2及P53蛋白的表达。结果与对照组相比,模型组的细胞存活率下降,细胞LDH、MDA含量上升,细胞内ROS水平和凋亡率增加,Bax和P53蛋白表达量升高,Bcl-2蛋白表达量下降,且Bcl-2/Bax比值下降(均P<0.001);与模型组相比,实验组细胞存活率上升,细胞LDH、MDA含量下降,细胞ROS含量和凋亡率下降,Bax和P53蛋白表达量降低,Bcl-2蛋白表达量升高,且Bcl-2/Bax比值升高(均P<0.001)。结论纳米氧化铈能有效预防阿霉素诱导的心脏毒性损伤,其作用可能与下调P53基因的表达,抑制细胞凋亡相关。

纳米氧化铈对无脊椎动物的毒性效应

近年来,纳米氧化铈(CeO_(2)NPs)独特的理化性质使其生产规模和应用范围逐渐扩大,但CeO_(2)NPs在生产、运输和商品化过程中不可避免地被释放到环境中,具有环境污染的潜在风险,其生物安全性受到越来越多的关注.无脊椎动物是生物类群的重要组成,本文研究了国内外近十年的科学文献,综述了CeO_(2)NPs在生物累积、行为反应、组织损伤、生长发育毒性、免疫毒性、生殖毒性、遗传毒性等方面对无脊椎动物的影响以及CeO_(2)NPs毒性效应影响因素,总结了CeO_(2)NPs对无脊椎动物的毒性机制,最后对未来研究方向进行了展望,以期为CeO_(2)NPs的毒性评价、安全生产与应用提供参考.

基于金纳米粒子-纳米氧化铈-石墨烯复合物修饰电极对环境水体中As(Ⅲ)的检测

先通过滴涂法制备纳米氧化铈-石墨烯(CeO_(2)-Gr)复合物修饰玻碳电极(GCE),再在含氯金酸(HAuCl_(4))的缓冲溶液中,采用循环伏安法将Au(Ⅲ)还原到CeO_(2)-Gr表面,从而制得AuNPs/CeO_(2)/Gr/GCE。采用电化学阻抗谱法(EIS)对修饰电极进行电化学特性表征。研究了AuNPs/CeO_(2)/Gr/GCE快速、准确测定水环境中As(Ⅲ),采用差分脉冲溶出伏安法,探讨了氧化铈与石墨烯质量比、金纳米粒子沉积圈数、沉积时间和沉积电位及干扰离子等对测定结果的影响,并确定检测As(Ⅲ)的优化实验条件。在最优条件下,该电化学传感器对As(Ⅲ)具有良好的电流响应,其溶出伏安峰电流与As(Ⅲ)浓度的线性范围为13.35~387.15μmol/L,检出限为4.74μmol/L。在不同干扰离子存在的情况下,传感器对As(Ⅲ)的选择性较好。为了评估传感器的实际应用能力,以实验室自来水为样本进行As(Ⅲ)加标检测,加标回收率为90.5%~99.2%,表明该电化学传感器具有监测As(Ⅲ)的应用潜力。