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

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 (Fe(3)O(4)) 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 Fe(3)O(4) NPs often induced more oxidative stress than Fe(3)O(4) 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 Fe(3)O(4) 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) Fe(3)O(4) 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 Fe(3)O(4) NPs; and (iii) total Fe content in the ryegrass and pumpkin shoots treated with Fe(3)O(4) NPs was not significantly increased compared to that in the control shoots.     

Phytotoxicity and biotransformation of La2O3 nanoparticles in a terrestrial plant cucumber (Cucumis sativus)

Abstract

With the increasing applications of metal-based nanoparticles in various commercial products, it is necessary to address their environmental fate and potential toxicity. In this work, we assessed the phytotoxicity of lanthanum oxide (La₂O₃) NPs to cucumber plants and determined its distribution and biotransformation in roots by TEM and EDS, as well as STXM and NEXAFS. LaCl₃ was also studied as a reference toxicant. La₂O₃ NPs and LaCl₃ were both transformed to needle-like LaPO₄ nanoclusters in the intercellular regions of the cucumber roots. In vitro experiments demonstrated that the dissolution of La₂O₃ NPs was significantly enhanced by acetic acid. Accordingly, we proposed that the dissolution of NPs at the root surface induced by the organic acids extruded from root cells played an important role in the phytotoxicity of La₂O₃ NPs. The reactions of active NPs at the nano-bio interface should be taken into account when studying the toxicity of dissolvable metal-based nanoparticles.     

Origin of the different phytotoxicity and biotransformation of cerium and lanthanum oxide nanoparticles in cucumber

Abstract

To investigate how the physicochemical properties of nanoparticles (NPs) affect their biological and toxicological effects, we evaluated the phytotoxicity of CeO₂ and La₂O₃ NPs to cucumber (Cucumis sativus) plants and tried to clarify the relation between physicochemical properties of NPs and their behaviors. CeO₂ NPs had no phytotoxicity to cucumber at all tested concentrations, while La₂O₃ NPs showed significant inhibition on root elongation (?≥?2?mg/L), shoot elongation (at 2000?mg/L), root biomass (?≥?2?mg/L), and shoot biomass (?≥?20?mg/L), as well as induced more reactive oxygen species and cell death in roots (2000?mg/L). The different distribution and speciation of Ce and La in plants were determined by synchrotron-based micro X-ray fluorescence microscopy and X-ray absorption spectroscopy. In the aerial parts, all of La was combined with phosphate or carboxylic group, while a fraction of Ce was changed to Ce(III)–carboxyl complexes, implying that La₂O₃ acted as its ionic form, while CeO₂ displayed the behavior of particles or particle–ion mixtures. The higher dissolution of La₂O₃ than CeO₂ NPs might be the reason for their significant difference in phytotoxicity and transporting behaviors in cucumbers. To our knowledge, this is the first detailed study of the relation between the level of dissolution of NPs and their behaviors in plant systems.     

Tumor-targeted Gd-doped mesoporous Fe3O4 nanoparticles for T1/T2 MR imaging guided synergistic cancer therapy

In this study, a novel intelligent nanoplatform to integrate multiple imaging and therapeutic functions for targeted cancer theranostics. The nanoplatform, DOX@Gd-MFe₃O₄ NPs, was constructed Gd-doped mesoporous Fe₃O₄ nanoparticles following with the doxorubicin (DOX) loading in the mesopores of the NPs. The DOX@Gd-MFe₃O₄ NPs exhibited good properties in colloidal dispersity, photothermal conversion, NIR triggered drug release, and high T₁/T₂ relaxicity rate (r₁=9.64 mM⁻¹s⁻¹, r₂= 177.71 mM⁻¹s⁻¹). Benefiting from the high MR contrast, DOX@Gd-MFe₃O₄ NPs enabled simultaneous T₁/T₂ dual-modal MR imagining on 4T1 bearing mice in vivo and the MR contrast effect was further strengthened by external magnetic field. In addition, the DOX@Gd-MFe₃O₄ NPs revealed the strongest inhibition to the growth of 4T1 in vitro and in vivo under NIR irradiation and guidance of external magnetic field. Moreover, biosafety was also validated by in vitro and in vivo tests. Thus, the prepared DOX@Gd-MFe₃O₄ NPs would provide a promising intelligent nanoplatform for dual-modal MR imagining guided synergistic therapy in cancer theranostics.     

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.     

Specific targeting of cancer cells by multifunctional mitoxantrone-conjugated magnetic nanoparticles

Abstract

We report on the synthesis of bifunctional mitoxantrone (MTX)-grafted magnetic nanoparticles (MNPs) modified by dopamine-polyethylene glycol-folic acid (DPA-PEG-FA) for targeted imaging and therapy of cancer. MNPs (～7–10?nm) were synthesized using the thermal decomposition reaction of Fe(acac)₃. Bromoacetyl (BrAc) terminal polyethylene glycol dopamine (DPA-PEG-BrAc) was synthesized and treated with ethylene diamine to form bifunctional PEG moiety containing dopamine at one end and amino group at the other end (i.e. DPA-PEG-NH₂). It was then reacted with Fe₃O₄ nanoparticles (NPs) to form Fe₃O₄-DPA-PEG-NH₂ NPs. The activated folic acid (FA) was chemically coupled to Fe₃O₄-DPA-PEG-NH₂, forming Fe₃O₄-DPA-PEG-FA. MTX was then conjugated to Fe₃O₄-DPA-PEG-FA, forming Fe₃O₄-DPA-PEG-FA-MTX. Physicochemical characteristics of the engineered MNPs were determined. The particle size analysis and electron microscopy showed an average size of ～35?nm for Fe₃O₄-DPA-PEG-FA-MTX NPs with superparamagnetic behavior. FT-IR spectrophotometry analysis confirmed the conjugation of FA and MTX onto the MNPs. Fluorescence microscopy, cytotoxicity assay and flow cytometry analysis revealed that the engineered Fe₃O₄-DPA-PEG-FA-MTX NPs were able to specifically bind to and significantly inhibit the folate receptor (FR)-positive MCF-7 cells, but not the FR-negative A549 cells. Based upon these findings, we suggest the Fe₃O₄-DPA-PEG-FA-MTX NPs as an effective multifunctional-targeted nanomedicine toward simultaneous imaging and therapy of FR-positive cancers.     

Biological evaluation of Fe3O4–poly(l-lactide)–poly(ethylene glycol)–poly(l-lactide) magnetic microspheres prepared in supercritical CO2

The biocompatibility of Fe₃O₄–poly(l-lactide)–poly(ethylene glycol)–poly(l-lactide) magnetic microspheres (Fe₃O₄–PLLA–PEG–PLLA MMPs) prepared in a process of suspension-enhanced dispersion by supercritical CO₂ (SpEDS) was evaluated at various levels: cellular, molecular, and integrated. At the cellular level, the investigations of cytotoxicity and intracellular reactive oxygen species (ROS) generation indicate that the polymer-coated MMPs (2.0 mg/mL) had a higher toxicity than uncoated Fe₃O₄ nanoparticles, which led to about 20% loss of cell viability and an increase (0.2 fold) in ROS generation; the differences were not statistically significant (p > 0.05). However, an opposite phenomenon was observed in tests of hemolysis, which showed that the MMPs displayed the weakest hemolytic activity, namely only about 6% at the highest concentration (20 mg/mL). This phenomenon reveals that polymer-coated MMPs created less toxicity in red blood cells than uncoated Fe₃O₄ nanoparticles. At the molecular level, the MMPs were shown to be less genotoxic than Fe₃O₄ nanoparticles by measuring the micronucleus (MN) frequency in CHO-K1 cells. Furthermore, the mRNA expression of pro-inflammatory cytokines demonstrates that polymer-coated MMPs elicited a less intense secretion of pro-inflammatory cytokines than uncoated Fe₃O₄ nanoparticles. Acute toxicity tests of MMPs show quite a low toxicity, with an LD₅₀ > 1575.00 mg/kg. The evidence of low toxicity presented in the results indicates that the Fe₃O₄–PLLA–PEG–PLLA MMPs from the SpEDS process have great potential for use in biomedical applications.     

In vitro evaluation of the toxicity and underlying molecular mechanisms of Janus Fe3O4‐TiO2 nanoparticles in human liver cells

Recent studies show that Janus Fe₃O₄‐TiO₂ nanoparticles (NPs) have potential applications as a multifunctional agent of magnetic resonance imaging (MRI) and photodynamic therapy (PDT) for the diagnosis and therapy of cancer. However, little work has been done on their biological effects. To evaluate the toxicity and underlying molecular mechanisms of Janus Fe₃O₄‐TiO₂ nanoparticles, an in vitro study using a human liver cell line HL‐7702 cells was conducted. For comparison, the Janus Fe₃O₄‐TiO₂ NPs parent material TiO₂ NPs was also evaluated. Results showed that both Fe₃O₄‐TiO₂ NPs and TiO₂ NPs decreased cell viability and ATP levels when applied in treatment, but increased malonaldehyde (MDA) and reactive oxygen species (ROS) generation. Mitochondria JC‐1 staining assay showed that mitochondrial membrane permeability injury occurred in both NPs treated cells. Cell viability analysis showed that TiO₂ NPs induced slightly higher cytotoxicity than Fe₃O₄‐TiO₂ NPs in HL7702 cells. Western blotting indicated that both TiO₂ NPs and Fe₃O₄‐TiO₂ NPs could induce apoptosis, inflammation, and carcinogenesis related signal protein alterations. Comparatively, Fe₃O₄‐TiO₂ NPs induced higher signal protein expressions than TiO₂ NPs under a high treatment dose. However, under a low dose (6.25 μg/cm²), neither NPs had any significant toxicity on HL7702 cells. In addition, our results suggest both Fe₃O₄‐TiO₂ NPs and TiO₂ NPs could induce oxidative stress and have a potential carcinogenetic effect in vitro. Further studies are needed to elaborate the detailed mechanisms of toxicity induced by a high dose of Fe₃O₄‐TiO₂ NPs.     

Assessment of impact of α‐Fe2O3 and γ‐Fe2O3 nanoparticles on phytoplankton species Selenastrum capricornutum and Nannochloropsis oculata

In this study, the impact of alpha‐iron oxide (α‐Fe₂O₃, 20‐40 nm) and gamma iron oxide (γ‐Fe₂O₃, 20‐40 nm) nanoparticles (NPs) on phytoplankton species Selenastrum capricornutum and Nannochloropsis oculata was investigated Characterizations of the NPs were systematically carried out by TEM, dynamic light scattering, zeta potential, X‐ray diffraction, SEM, and Fourier transformation infrared spectroscopy. Acute toxicity was tested between 0.2 and 50 mg/L for each NP for a period of 72 hours exposure. γ‐Fe₂O₃ NP inhibited development of N oculata at the rate of 54% in 0.2 mg/L group with a high mortality rate of up to 82%. α‐Fe₂O₃ NPs were less toxic that induced 97% mortality on N oculata at 10 mg/L suspensions. In contrast, α‐Fe₂O₃ NP inhibited growth of S capricornutum strongly (73%) in 0.2 mg/L group. γ‐Fe₂O₃ NPs showed similar growth inhibition (72%) on S capricornutum in 10 mg/L suspensions. Despite the differential effects, the results indicated acute toxicity of α‐Fe₂O₃ and γ‐Fe₂O₃ NPs on N oculata and S capricornutum.     

Close association of intestinal autofluorescence with the formation of severe oxidative damage in intestine of nematodes chronically exposed to Al(2)O(3)-nanoparticle

In nematodes, acute exposure (24-h) to 8.1–30.6 mg/L Al₂O₃-nanoparticles (NPs) or Al₂O₃ did not influence intestinal autofluorescence, whereas chronic exposure (10-d) to Al₂O₃-NPs at concentrations of 8.1–30.6 mg/L or Al₂O₃ at concentrations of 23.1–30.6 mg/L induced significant increases of intestinal lipofuscin accumulation, and formation of severe stress response and oxidative damage in intestines. Moreover, significant differences of intestinal autofluorescence, stress response and oxidative damage in intestines of Al₂O₃-NPs exposed nematodes from those in Al₂O₃ exposed nematodes were detected at examined concentrations. Oxidative damage in intestine was significantly correlated with intestinal autofluorescence in exposed nematodes, and oxidative damage in intestine was more closely associated with intestinal autofluorescence in nematodes exposed to Al₂O₃-NPs than exposed to Al₂O₃. Thus, chronic exposure to Al₂O₃-NPs may cause adverse effects on intestinal lipofuscin accumulation by inducing the formation of more severe oxidative stress in intestines than exposure to Al₂O₃ in nematodes.     

Fe3O4 nanoparticles with daunorubicin induce apoptosis through caspase 8-PARP pathway and inhibit K562 leukemia cell-induced tumor growth in vivo

Nanomaterials can enhance the delivery and treatment efficiency of anticancer drugs, but the mechanisms of the tumor-reducing activity of ferrous-ferric oxide (Fe₃O₄) nanoparticles (NPs) with daunorubicin (DNR) have not been established. Here we investigate the synergistic effects of Fe₃O₄ NPs with DNR on the induction of apoptosis using K562 leukemia cells. Fe₃O₄ NPs increased the ability of DNR to induce apoptosis in both adriamycin-sensitive and adriamycin-resistant K562 cells through the caspase 8-poly(ADP-ribose) polymerase pathway. Fe₃O₄ NPs combined with DNR also effectively inhibited the tumor growth induced by the inoculation of K562 cells into nude mice. The increased cell apoptotic rate was closely correlated with the enhanced inhibition of tumor growth. Biodistribution studies in xenograft tumors indicated that Fe₃O₄ NPs could be potentially excreted from the body via the gastrointestinal system. In conclusion, our study suggests that Fe₃O₄ NPs combined with anticancer drugs could serve as a better alternative for targeted therapeutic approaches to cancer treatments.

From the Clinical Editor

In this paper, the synergistic effects on tumor growth of ferrous-ferric oxide nanoparticles with daunorubicin are investigated. The combined treatment was demonstrated to be superior in a leukemia cell line murine model in vivo.     

Fe3O4 nanoparticle redox system modulation via cell‐cycle progression and gene expression in human mesenchymal stem cells

The use of engineered nanoparticles (NPs) across multiple fields and applications has rapidly increased over the last decade owing to their unusual properties. However, there is an increased need in understanding their toxicological effect on human health. Particularly, iron oxide (Fe₃O₄) have been used in various sectors, including biomedical, food, and agriculture, but the current understanding of their impact on human health is inadequate. In this investigation, we assessed the toxic effect of Fe₃O₄ NPs on human mesenchymal stem cells (hMSCs) adopting cell viability, cellular morphological changes, mitochondrial transmembrane potential, and cell‐cycle progression assessment methodologies. Furthermore, the expression of oxidative stress, cell death, and cell‐cycle regulatory genes was assessed using quantitative polymerase chain reaction. The Fe₃O₄ NPs induced cytotoxicity and nuclear morphological changes in hMSCs by dose and time exposure. Cell‐cycle analysis indicated that Fe₃O₄ NPs altered the cell‐cycle progression through a decrease in the proportion of cells in the G₀–G₁ phase. The hMSC mitochondrial membrane potential loss increased with an increase in the concentration of Fe₃O₄ NPs exposure. The observed expression levels of the CYP1A, TNF3, TNFSF10, E2F1, and CCNC genes were significantly upregulated in hMSCs in response to Fe₃O₄ NPs exposure. Our findings suggest that Fe₃O₄ NPs caused metabolic stress through altered cell cycle, oxidative stress, and cell death regulatory gene expression in hMSCs. The results of this investigation revealed that Fe₃O₄ NPs exhibited moderate toxicity on hMSCs and that Fe₃O₄ NPs may have biomedical applications at low concentrations. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 901–912, 2016.     

Glycine-functionalized Fe3O4@TiO2:Er3+,Yb3+ nanocarrier for microwave-triggered controllable drug release and study on mechanism of loading/release process using microcalorimetry

Objectives: The current study aimed at developing microwave-triggered controlled-release drug delivery systems using glycine-modified Fe₃O₄@TiO₂:Er³⁺,Yb³⁺ multifunctional core-shell nanoparticles. We also studied the drug loading and release mechanisms by means of microcalorimetry.

Methods: We used hydrothermal method to prepare glycine-functionalized Fe₃O₄@TiO₂:Er³⁺,Yb³⁺ multifunctional nanoparticles. The controlled release of the Fe₃O₄@TiO₂:Er³⁺,Yb³⁺–glycine–VP16 triggered by microwave was determined with ultraviolet-visible spectroscopic analysis. We studied the cytotoxicity of the nanocarrier by MTT assay.

Results: The thermodynamic parameter values (ΔH = -17.46 kJ mol^?1, ΔS = ?365.20 kJ mol^?1) showed that the main interaction between the carrier and drug molecules is hydrogen bonding. The molar enthalpy (ΔH) of the drug-release process was 72.01 kJ mol^?1, which indicates an endothermic process. This suggests that drug release can be controlled by microwave heating. The release profile can be controlled by the duration and number of cycles of microwave application. The particles also exhibit good magnetization and upconversion luminescence properties, which will allow simultaneous targeting and monitoring of the loaded drug.

Conclusion: The modification of glycine and the introduction of absorbing material not only increased the load properties of the composite materials but also realized the microwave-stimulated anticancer drug controlled release.     

Facile Synthesis of Core–shell Magnetic Mesoporous Silica Nanoparticles for pH‐sensitive Anticancer Drug Delivery

The facile synthesis of core–shell magnetic mesoporous silica nanoparticles (Fe₃O₄@mSiO₂ NPs) was reported in aqueous phase using cetyltrimethylammonium bromide as a template under alcohol‐free conditions. Compared to the conventional synthesis method for core–shell Fe₃O₄@mSiO₂ NPs, the approach in this study is rapid (only 5‐min reaction time), cheap (without using organic agents), and environmentally friendly (one‐step synthesis in alcohol‐free medium). Doxorubicin (DOX)‐loaded Fe₃O₄@mSiO₂ NPs exert extraordinarily high specificity for liver cancer cells, which was due to the pH‐sensitive doxorubicin release, as well as higher endocytosis capacity in liver cancer cells rather than normal liver cells. The potential advantages of using such Fe₃O₄@mSiO₂ NPs as the vehicle of anticancer drugs were that the Fe₃O₄@mSiO₂ NPs exhibit good biocompatibility, high loading and protection of the guest molecules, selective killing effect, and efficient cellular uptake. The exciting pH‐dependent release properties of doxorubicin‐loaded Fe₃O₄@mSiO₂ NPs make their use a promising strategy for enhancing efficient therapy toward tumors, while reducing the cytotoxicity of doxorubicin to human normal neutral tissue or cells.     

Repeated exposure to iron oxide nanoparticles causes testicular toxicity in mice

The aim of this study was to determine whether repeated exposure to iron oxide nanoparticles (Fe₂O₃‐NPs) could be toxic to mice testis. Fe₂O₃‐NPs (25 and 50 mg/kg) were intraperitoneally administered into mice once a week for 4 weeks. Our study showed that Fe₂O₃‐NPs have the ability to cross the blood‐testis barrier to get into the testis. The findings showed that exposure resulted in the accumulation of Fe₂O₃‐NPs which was evidenced from the iron content and accumulation in the testis. Furthermore, 25 and 50 mg/kg Fe₂O₃‐NPs administration increased the reactive oxygen species, lipid peroxidation, protein carbonyl content, glutathione peroxidase activity, and nitric oxide levels with a concomitant decrease in the levels of antioxidants—superoxide dismutase, catalase, glutathione, and vitamin C. Increased expression of Bax, cleaved‐caspase‐3, and cleaved‐PARP confirms apoptosis. Serum testosterone levels increased with increased concentration of Fe₂O₃‐NPs exposure. In addition, the histopathological lesions like vacuolization, detachment, and sloughing of germ cells were also observed in response to Fe₂O₃‐NPs treatment. The data from our study entailed that testicular toxicity caused by Fe₂O₃‐NPs exposure may be associated with Fe₂O₃‐NPs accumulation leading to oxidative stress and apoptosis. Therefore, precautions should be taken in the safe use of Fe₂O₃‐NPs to avoid complications in the fertility of males. Further research will unravel the possible molecular mechanisms on testicular toxicity of Fe₂O₃‐NPs. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 594–608, 2017.     

Iron oxide nanoparticles mediated cytotoxicity via PI3K/AKT pathway: Role of quercetin

Recently Fe₂O₃ NPs (iron oxide nanoparticles) have been extensively used in medical imaging and in industry also. As a result, people are increasingly exposed day by day to those nanoparticles. The adverse effect of Fe₂O₃ NPs is not so significant at lower doses but at higher doses Fe₂O₃ NPs causes significant damage to cells. The present study investigates the cell signaling mechanism of Fe₂O₃ NPs induced oxidative stress and cytotoxicity in vitro using murine hepatocytes as the working model. In addition, the cytoprotective action of quercetin in this pathophysiology has also been investigated. Dose-dependent studies suggest that incubation of hepatocytes with 250 μg/ml Fe₂O₃ NPs for 4 h significantly decreased the cell viability and intra-cellular antioxidant ability. This study also showed that exposure to Fe₂O₃ NPs caused hepatocytes death via apoptotic pathway. Incubation of hepatocytes with quercetin (50 μmol/L) prior to 1 h of Fe₂O₃ NPs exposure protects the cells from the altering activities of antioxidant indices, cytotoxicity and apoptotic death. Results suggest that Fe₂O₃ NPs induced cellular damage and quercetin plays a protective role in Fe₂O₃ NPs induced cytotoxicity and apoptotic death.     

Transmissions of serotonin,dopamine, and glutamate are required for the formation of neurotoxicity from Al2O3-NPs in nematode Caenorhabditis elegans

Abstract

In this study, we investigated genetic mechanisms of neurotransmitters in regulating the formation of adverse effects on locomotion behavior in Al₂O₃ nanoparticles (NPs)-exposed Caenorhabditis elegans. Al₂O₃-NPs exposure caused the decrease of locomotion behavior with head thrash and body bend as endpoints. Interestingly, the neurotransmitters of glutamate, serotonin, and dopamine were required for the adverse effects of Al₂O₃-NPs on locomotion behavior in nematodes. Glutamate transporter EAT-4, serotonin transporter MOD-5, and dopamine transporter DAT-1 might serve as the molecular targets of Al₂O₃-NPs for neurotoxicity formation. Moreover, the behavioral response of nematodes to Al₂O₃-NPs exposure was primarily mediated by non-NMDA glutamate receptors GLR-2 and GLR-6, ionotropic serotonin receptor MOD-1, and D1-like dopamine receptor DOP-1. Therefore, Al₂O₃-NPs exposure influences locomotion behavior of nematodes primarily by impinging on their glutamatergic, serotoninergic, and dopaminergic systems. Our data will shed light on questions surrounding the involvement of neurotransmitters in mediating the adverse behavioral effects from Al₂O₃-NPs.     

包含四氧化三铁纳米粒的聚电解质微囊的制备

本文以生物相容性四氧化三铁纳米粒 (ferrosoferric oxide nanoparticles, Fe₃O₄ NPs) 及聚烯丙基胺盐酸盐 (poly allyamine hydrochloride, PAH) 为囊材, 制备包含Fe₃O₄ NPs的聚电解质微囊。本文采用化学共沉淀法制备Fe₃O₄ NPs, 并对其表观形态、红外光谱、粒径及zeta电位、成膜性能及磁学性质进行考察; 以Fe₃O₄ NPs和PAH作为囊材, 碳酸钙粒子为模板, 通过迭层自组装技术制备聚电解质微囊。结果得到粒径为 (4.9 ± 1.2) μm、分布均匀、饱和磁化强度为8.94 emu·g⁻¹、具有超顺磁性的聚电解质微囊。以罗丹明B异硫氰酸酯标记的牛血清白蛋白 (Rhodamin B isothiocyanate labeled bovine serum albumin, RBITC-BSA) 作为模型药物, 利用囊膜的pH敏感特性将其载入囊内。荧光显微镜观察和包封率测定结果表明, 该聚电解质微囊可成功实现大分子药物的包载, 测得包封率和载药量分别达到 (86.08 ± 3.36) %和 (8.01 ± 0.30) mg·mL⁻¹。