Physiological effects of magnetite (Fe3O4) nanoparticles on perennial ryegrass (Lolium perenne L.) and pumpkin (Cucurbita mixta) plants

Abstract

To date, knowledge gaps and associated uncertainties remain unaddressed on the effects of nanoparticles (NPs) on plants. This study was focused on revealing some of the physiological effects of magnetite (Fe₃O₄) NPs on perennial ryegrass (Lolium perenne L.) and pumpkin (Cucurbita mixta cv. white cushaw) plants under hydroponic conditions. This study for the first time reports that Fe₃O₄ NPs often induced more oxidative stress than Fe₃O₄ bulk particles in the ryegrass and pumpkin roots and shoots as indicated by significantly increased: (i) superoxide dismutase and catalase enzyme activities, and (ii) lipid peroxidation. However, tested Fe₃O₄ NPs appear unable to be translocated in the ryegrass and pumpkin plants. This was supported by the following data: (i) No magnetization was detected in the shoots of either plant treated with 30, 100 and 500 mg l^?1 Fe₃O₄ NPs; (ii) Fe K-edge X-ray absorption spectroscopic study confirmed that the coordination environment of Fe in these plant shoots was similar to that of Fe-citrate complexes, but not to that of Fe₃O₄ NPs; and (iii) total Fe content in the ryegrass and pumpkin shoots treated with Fe₃O₄ NPs was not significantly increased compared to that in the control shoots.     

Suspension of Fe(3)O(4) nanoparticles stabilized by chitosan and o-carboxymethylchitosan

In this study, a well-dispersed suspension of superparamagnetic Fe₃O₄ nanoparticles was stabilized by chitosan (CS) and o-carboxymethylchitosan (OCMCS), respectively. The resulting magnetic Fe₃O₄ nanoparticles were characterized by dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM), zeta-potential measurement and vibrating sample magnetometry (VSM). TEM results demonstrated a spherical or ellipsoidal morphology with an average diameter of 14–20 nm. The adsorbed layer of CS and OCMCS on the magnetite surface was confirmed by FTIR. XRD illustrated that the resulting magnetic nanoparticles have a spinel structure and lastly VSM results showed the modified magnetic Fe₃O₄ nanoparticles were superparamagnetic. The adsorption mechanism of CS and OCMCS onto the surface of Fe₃O₄ nanoparticles is believed to be the electrostatic and coordination interactions, respectively. The mechanisms of both CS and OCMCS stabilizing the suspension of Fe₃O₄ nanoparticles were supposed electrostatic repulsion. These well-dispersed superparamagnetic Fe₃O₄ nanoparticles stabilized by the biocompatible CS or OCMCS dispersant should have potential applications in biotechnology fields.     

Siderite (FeCO3) and magnetite (Fe3O4) overload-dependent pulmonary toxicity is determined by the poorly soluble particle not the iron content

The two poorly soluble iron containing solid aerosols of siderite (FeCO₃) and magnetite (Fe₃O₄) were compared in a 4-week inhalation study on rats at similar particle mass concentrations of approximately 30 or 100?mg/m³. The particle size distributions were essentially identical (MMAD ≈1.4 μm). The iron-based concentrations were 12 or 38 and 22 or 66?mg Fe/m³ for FeCO₃ and Fe₃O₄, respectively. Modeled and empirically determined iron lung burdens were compared with endpoints suggestive of pulmonary inflammation by determinations in bronchoalveolar lavage (BAL) and oxidative stress in lung tissue during a postexposure period of 3 months. The objective of study was to identify the most germane exposure metrics, that are the concentration of elemental iron (mg Fe/m³), total particle mass (mg PM/m³) or particle volume (μl PM/m³) and their associations with the effects observed. From this analysis it was apparent that the intensity of pulmonary inflammation was clearly dependent on the concentration of particle-mass or -volume and not of iron. Despite its lower iron content, the exposure to FeCO₃ caused a more pronounced and sustained inflammation as compared to Fe₃O₄. Similarly, borderline evidence of increased oxidative stress and inflammation occurred especially following exposure to FeCO₃ at moderate lung overload levels. The in situ analysis of 8-oxoguanine in epithelial cells of alveolar and bronchiolar regions supports the conclusion that both FeCO₃ and Fe₃O₄ particles are effectively endocytosed by macrophages as opposed to epithelial cells. Evidence of intracellular or nuclear sources of redox-active iron did not exist. In summary, this mechanistic study supports previous conclusions, namely that the repeated inhalation exposure of rats to highly respirable pigment-type iron oxides cause nonspecific pulmonary inflammation which shows a clear dependence on the particle volume-dependent lung overload rather than any increased dissolution and/or bioavailability of redox-active iron.     

Evaluation of photosynthetic performance and carbon isotope discrimination in perennial ryegrass (<Emphasis Type="Italic">Lolium perenne</Emphasis> L.) under allelochemicals stress

Ferulic (FA) and p-hydroxybenzoic acid (pHBA) are commonly found as phenolic compounds (PHC) in many forage and cereal crops. Although the effects of these PHC on seedling growth are relatively explored, not many information is available regarding the phytotoxicity on ecophysiological processes of perennial ryegrass adult plants. The experiment was conducted with the aim to evaluate the phytotoxic potential of PHC on the seedling growth, leaf water relation, chlorophyll fluorescence attributes and carbon isotope discrimination adult plants of perennial ryegrass (Lolium perenne L.). The results clearly indicated that PHC behaved as potent inhibitors of chlorophyll fluorescence yield (F_v/F_m) in leaves of L. perenne and plants showed poor tolerance against allelochemicals stress. Quantum yield (ΦPSII), chlorophyll fluorescence quenching (qP) and non-photochemical quenching (NPQ) were decreased following exposure to FA and pHBA. The portion of absorbed photon energy that was thermally dissipated (D) in L. perenne was decreased. Exposure of the L. perenne seedlings to FA and pHBA stress led to a decrease in fresh/dry weight, relative water content and leaf osmotic potential. Carbon isotope composition ratio (δ¹³C) was significantly less negative than the control following treatment with FA or pHBA. The results suggested that PHC uptake was a key step for the effectiveness of these secondary metabolites and their phytotoxicity on L. perenne adult plants was mainly due to the alteration of leaf water status accompanied by photosystem II damage. Acquisition of such knowledge may ultimately provide a better understanding about the mode of action of the tested compounds.     

银铁纳米复合材料的脑胶质瘤放射增敏作用

目的 研究银/四氧化三铁纳米复合材料(Ag/Fe3O4)对人源性脑胶质瘤U251细胞的放射敏感性的影响.方法 人源性脑胶质瘤U251细胞分为对照组、Ag/Fe3O4组、放疗组、Ag/Fe3O4复合放疗组.用集落形成实验检测Ag/Fe3O4对U251细胞放疗效果;流式细胞术检测银纳米颗粒(AgNPs)对细胞周期和凋亡率的影响.结果 Ag/Fe3O4能够引起U251细胞G2/M期阻滞,并使细胞放疗后凋亡率显著提高(P＜0.05).结论 可利用Ag/Fe3O4纳米颗粒提高脑胶质瘤放射敏感性.     

磁性纳米四氧化三铁颗粒制备及其对ICR小鼠脏器的影响

目的 研究磁性纳米四氧化三铁颗粒(Fe O4-MNPs)的制备及比较不同浓度的Fe3O4-MNPs对ICR小鼠脏器的影响.方法 化学共沉淀法制备Fe3 O4-MNPs;透射电镜、扫描电镜观察Fe3O4-MNPs的形貌；不同剂量FeO4-MNPs(0、300、600、1200 mg/kg)给40只小鼠分4组(每组10只)一次性喂食,14d后处死小鼠收集标本,取小鼠皮肤、肝脏、脾脏、大肠,观察其组织病理学改变.结果 化学共沉淀法制备出黑色颗粒状晶体.透射电镜观察发现Fe3 O4-MNPs外形呈现大小不等的近似球形,扫描电镜观察发现Fe3O4-MNPs外形呈现大小不等的不规则状.不同剂量Fe O4-MNPs喂食的ICR小鼠皮肤、肝脏、大肠及脾脏组织病理学均无明显差异.结论 化学共沉淀法成功制备了Fe3 O4-MNPs.一定剂量范围的Fe3 O4-MNPs对正常小鼠脏器无明显的组织病理学损害.     

Synthesis,purification, and anticancer effect of magnetic Fe3O4-loaded poly (lactic-co-glycolic) nanoparticles of the natural drug tetrandrine

Abstract

Here, we have successfully synthesised and purified multifunctional PLGA-based nanoparticles by the co-encapsulation of an anticancer drug (tetrandrine) and a magnetic material (Fe₃O₄). The obtained Tet-Fe₃O₄-PLGA NPs had a uniform spherical shape with a particle size of approximately 199?nm and a negative surface charge of –18.0?mV, displaying a high encapsulation efficiency. Furthermore, TEM studies provided representative images of the purification process of the magnetic nanoparticles with MACS^® technology. The MFM and VSM results indicated that both the Fe₃O₄ NPs and Tet-Fe₃O₄-PLGA NPs were superparamagnetic. The DSC spectrum demonstrated that Tet was successfully encapsulated within the PLGA-based nanoparticles. Significantly, the release studies revealed NPs had a relatively slower release rate than free Tet after 8?h’s initial burst release, which had decreased from 98% to 65% after 24?h. In vitro cellular studies revealed that NPs could effectively penetrate into A549 cells and A549 multicellular spheroids to exert cytotoxicity, displaying a significantly high anti-proliferation effect. Moreover, western blot demonstrated that the co-loaded NPs had a higher anticancer activity by injuring lysosomes to activate the mitochondria pathway and induce A549 cell apoptosis. The magnetic characteristics and high anticancer activity support the use of Tet/Fe₃O₄ co-loaded PLGA-based nanoparticles as a promising strategy in the treatment of lung cancer.     

Subchronic inhalation toxicity of iron oxide (magnetite, Fe(3) O(4) ) in rats: pulmonary toxicity is determined by the particle kinetics typical of poorly soluble particles

Wistar rats were nose‐only exposed to pigment‐sized iron oxide dust (Fe₃O₄, magnetite) in a subchronic 13‐week inhalation study according to the OECD testing guidelines TG#413 and GD#39. A 4 week pilot study with a 6 month post exposure period served as basis for validating the kinetic modeling approaches utilized to design the subchronic study. Kinetic analyses made during this post exposure period demonstrated that a diminution in particle clearance and lung inflammation occurred at cumulative exposure levels exceeding the lung overload threshold. Animals were exposed 6 h per day, five days per week for 13 consecutive weeks at actual concentrations of 0, 4.7, 16.6 and 52.1 mg m^?3 (mass median aerodynamic diameter ≈1.3 μm, geometric standard deviation = 2). The exposure to iron oxide dust was tolerated without mortality, consistent changes in body weights, food and water consumption or systemic toxicity. While general clinical pathology and urinalysis were unobtrusive, hematology revealed changes of unclear toxicological significance (minimally increased differential neutrophil counts in peripheral blood). Elevations of neutrophils in bronchoalveolar lavage (BAL) appeared to be the most sensitive endpoint of study. Histopathology demonstrated responses to particle deposition in the upper respiratory tract (goblet cell hyper‐ and/or metaplasia, intraepithelial eosinophilic globules in the nasal passages) and the lower respiratory tract (inflammatory changes in the bronchiolo‐alveolar region). Consistent changes suggestive of pulmonary inflammation were evidenced by BAL, histopathology, increased lung and lung‐associated‐lymph node (LALN) weights at 16.6 and 52.1 mg m^?3. Increased septal collagenous fibers were observed at 52.1 mg m^?3. Particle translocation into LALN occurred at exposure levels causing pulmonary inflammation. In summary, the retention kinetics iron oxide reflected that of poorly soluble particles. The empirical no‐observed‐adverse‐effect level (NOAEL) and the lower bound 95% confidence limit on the benchmark concentration (BMCL) obtained by benchmark analysis was 4.7 and 4.4 mg m^?3, respectively, and supports an OEL (time‐adjusted chronic occupational exposure level) of 2 mg m^?3 (alveolar fraction). Copyright © 2011 John Wiley & Sons, Ltd.     

Magnetite (Fe 3 O 4) microcapsules prepared using a glass membrane and solvent removal

Fine magnetite powders dispersed in polymer solution were encapsulated from an oil-in-water emulsion prepared by an emulsification process employing a porous glass membrane and subsequent evaporation of the solvent. Styrenebased copolymers were dissolved in a magnetic fluid, and then continuously pushed through the pores of glass membrane into the aqueous phase, which had dissolved polyvinyl alcohol (PVA) and sodium dodecyl sulphate (SDS) as a mixed stabilizer. P(styrene-co-acrylic acid) (PS-AA), P(stryrene-co-butyl acrylate) (PS-BA) and styrene-butadiene rubber (SBR) were dissolved in the specially ordered magnetite fluid (25 wt% magnetite dispersed in toluene) separately or as a mixture, and uniform droplets suspending the magnetic particles were obtained. After the evaporation of toluene, PS-AA capsules retained a spherical shape and uniformity, whereas PS-AA/PS-BA capsules revealed a creased surface and broader size distribution. The microcapsules entrapped 30-40 wt% of magnetite, and the encapsulation yield of magnetite was 20-40%. Glass membranes with 9.5, 5.25 and 1.42 #119 m pore size were employed and 5-40 #119 m microcapsules were obtained depending on the pore size. When magnetite suspended in chloroform was used, magnetite capsules with broader size distributions were obtained because of the sticking of the droplets to the membrane wall. The advantage of the membrane emulsification which provides uniform sized droplets was lost.     

Serum proteins prevent aggregation of Fe2O3 and ZnO nanoparticles

Abstract

Aggregation of metal oxide nanoparticles in aqueous media complicates interpretation of in vitro studies of nanoparticle–cell interactions. We used dynamic light scattering to investigate the aggregation dynamics of iron oxide and zinc oxide nanoparticles. Our results show that iron oxide particles aggregate more readily than zinc oxide particles. Pretreatment with serum stabilises iron oxide and zinc oxide nanoparticles against aggregation. Serum-treated iron oxide is stable only in pure water, while zinc oxide is stable in water or cell culture media. These findings, combined with zeta potential measurements and quantification of proteins adsorbed on particle surface, suggest that serum stabilisation of iron oxide particles occurs primarily through protein adsorption and resulting net surface charge. Zinc oxide stabilisation, however, also involves steric hindrance of particle aggregation. Fluid shear at levels used in flow experiments breaks up iron oxide particle aggregates. These results enhance our understanding of nanoparticle aggregation and its consequences for research on the biological effects of nanomaterials.     

Phytotoxic and genotoxic effects of ZnO nanoparticles on garlic (Allium sativum L.): a morphological study

The effects of zinc oxide nanoparticles (ZnO NPs) on the root growth, root apical meristem mitosis and mitotic aberrations of garlic (Allium sativum L.) were investigated. ZnO NPs caused a concentration-dependent inhibition of root length. When treated with 50 mg/L ZnO NPs for 24 h, the root growth of garlic was completely blocked. The 50% inhibitory concentration (IC(50)) was estimated to be 15 mg/L. The mitosis index was also decreased in a concentration- and time-dependent manner. ZnO NPs also induced several kinds of mitotic aberrations, mainly consisted of chromosome stickiness, bridges, breakages and laggings. The total percentage of abnormal cells increased with the increase of ZnO NPs concentration and the prolongation of treatment time. The investigation provided new information for the possible genotoxic effects of ZnO NPs on plants.     

Magnetite (Fe3O4) microcapsules prepared using a glass membrane and solvent removal.

Fine magnetite powders dispersed in polymer solution were encapsulated from an oil-in-water emulsion prepared by an emulsification process employing a porous glass membrane and subsequent evaporation of the solvent. Styrene-based copolymers were dissolved in a magnetic fluid, and then continuously pushed through the pores of glass membrane into the aqueous phase, which had dissolved polyvinyl alcohol (PVA) and sodium dodecyl sulphate (SDS) as a mixed stabilizer. P(styrene-co-acrylic acid) (PS-AA), P(stryrene-co-butyl acrylate) (PS-BA) and styrene-butadiene rubber (SBR) were dissolved in the specially ordered magnetite fluid (25 wt% magnetite dispersed in toluene) separately or as a mixture, and uniform droplets suspending the magnetic particles were obtained. After the evaporation of toluene, PS-AA capsules retained a spherical shape and uniformity, whereas PS-AA/PS-BA capsules revealed a creased surface and broader size distribution. The microcapsules entrapped 30-40 wt% of magnetite, and the encapsulation yield of magnetite was 20-40%. Glass membranes with 9.5, 5.25 and 1.42 microm pore size were employed and 5-40 microm microcapsules were obtained depending on the pore size. When magnetite suspended in chloroform was used, magnetite capsules with broader size distributions were obtained because of the sticking of the droplets to the membrane wall. The advantage of the membrane emulsification which provides uniform sized droplets was lost.     

纳米级四氧化三铁的药物动力学和组织分布研究

目的研究纳米级四氧化三铁在家兔体内的药物动力学和在小鼠体内的分布与排泄.方法将纳米级四氧化三铁静脉注射到家兔体内,用原子吸收光谱法测量血药浓度,将血药浓度时间数据用3P87程序拟合,计算出药物动力学参数.另将纳米级四氧化三铁注入小鼠体内,测量小鼠不同脏器中的铁含量.收集给药后48 h内的尿液和粪便,测量其中的铁含量.结果家兔静脉注射四氧化三铁后呈双室模型代谢.四氧化三铁在小鼠体内主要分布在肝脏和脾脏等网状内皮细胞和吞噬细胞较多的脏器,并且在小鼠体内排泄缓慢.结论四氧化三铁在家兔体内呈双室模型代谢,在体内的分布依次为:肝脏、脾脏、心脏和肾脏.     

Encapsulation of Fe3O4 in gelatin nanoparticles: effect of different parameters on size and stability of the colloidal dispersion

Encapsulation of magnetite (IOPs) in gelatin nanoparticles has been carried out by in situ precipitation of the particles in presence of gelatin, followed by desolvation and cross-linking of the composite nanoparticles. The aim of the study was to investigate the effect of various formulation parameters (viz; desolvating agent, cross-linking agent and percentage of IOPs) on the hydrodynamic size of the gelatin-coated magnetic iron oxide composite nanoparticles (GIOPs) and stability of the colloidal dispersion. Extensive characterization by dynamic light scattering, thermogravimetric analysis, X-ray diffraction, infrared spectroscopy, transmission electron microscopy and atomic force microscopy shows complete encapsulation of IOPs of size below 8 nm into gelatin nanoparticles of varying size. Size as well as stability of the colloidal dispersion of the GIOPs was found to be dependent on the investigated parameters. Furthermore, the nanoparticle dispersion was found to be stable in pH ranges from 2-12. Thus, obtained composite nanoparticles could hold promise as a carrier system in biomedical applications.     

Encapsulation of Fe3O4 in gelatin nanoparticles: Effect of different parameters on size and stability of the colloidal dispersion

Encapsulation of magnetite (IOPs) in gelatin nanoparticles has been carried out by in situ precipitation of the particles in presence of gelatin, followed by desolvation and cross-linking of the composite nanoparticles. The aim of the study was to investigate the effect of various formulation parameters (viz; desolvating agent, cross-linking agent and percentage of IOPs) on the hydrodynamic size of the gelatin-coated magnetic iron oxide composite nanoparticles (GIOPs) and stability of the colloidal dispersion. Extensive characterization by dynamic light scattering, thermogravimetric analysis, X-ray diffraction, infrared spectroscopy, transmission electron microscopy and atomic force microscopy shows complete encapsulation of IOPs of size below 8 nm into gelatin nanoparticles of varying size. Size as well as stability of the colloidal dispersion of the GIOPs was found to be dependent on the investigated parameters. Furthermore, the nanoparticle dispersion was found to be stable in pH ranges from 2–12. Thus, obtained composite nanoparticles could hold promise as a carrier system in biomedical applications.     

Magnetic poly epsilon-caprolactone nanoparticles containing Fe3O4 and gemcitabine enhance anti-tumor effect in pancreatic cancer xenograft mouse model

We prepared magnetic (Fe(3)O(4)) poly epsilon-caprolactone (PCL) nanoparticles (mean diameter 164 +/- 3 nm) containing an anticancer drug (gemcitabine) using emulsion-diffusion method in order to develop more efficient drug delivery for cancer treatment. Nanoparticles were smooth, well individualized and homogeneous in size. The values of magnetizations for the magnetic PCL nanoparticles were observed around 10.2 emu/g at 2000 Oe magnetic field intensity and showed super-paramagnetic property. In case of the drug, the drug loading contents was 18.6% and entrapment efficiency was 52.2%. The anti-tumor effects caused by these particles were examined using nude mice bearing subcutaneous human pancreatic adenocarcinoma cells (HPAC) in vivo. We divided that these mice were randomly assigned to one of five treatment groups for experimental contrast. The antitumor effect was showed with 15-fold higher dose when compared to free gemcitabine. From the result, the magnetic PCL nanoparticles may provide a therapeutic benefit by delivering drugs efficiently to magnetically targeted tumor tissues, thus achieving safe and successful anti-tumor effects with low toxicity.     

沙蓬化学成分的分离与鉴定(Ⅱ)

目的对沙蓬地上部分体积分数70%乙醇提取物的水层和乙酸乙酯层萃取物的化学成分进行研究。方法采用反复硅胶柱色谱、ODS柱色谱、Sephadex LH-20柱色谱和半微量制备高效液相色谱分离纯化,根据ESI-MS、EI-MS、1H-NMR和13C-NMR谱学数据进行结构鉴定。结果从体积分数为70%乙醇提取物中分离得到9个单体化合物,分别鉴定为生物碱类化合物N-(4-(1H-pyrazol-1-yl)phenyl)acetamide(1)、N-(4-(1H-pyrazol-1-yl)-phenyl)formamide(2)、扑热息痛[p-(acetylamino)phenol,3]、N-(3-chloro-4-hydroxylphenyl)acetamide(4)、N-(2,5-dichloro-4-hydroxyphenyl)acetamide(5)和N-(2,3,5-trichloro-4-hydroxyphenyl)acetamide(6),2个异黄酮类化合物aya-menin A(7)和irisone B(8),1个酚苷类化合物水扬苷(salicin,9)。结论化合物2为新化合物,化合物1为新天然产物,化合物4～6为扑热息痛(3)的3种新光解产物,化合物7、8为首次从藜科植物中分离得到,化合物9为首次从沙蓬属植物中分离得到。