Uncovering the Fate and Risks of Intravenously Injected Prussian Blue Nanoparticles in mice by an Integrated Methodology of Toxicology, Pharmacokinetics, Proteomics, and Metabolomics.

BACKGROUND: Prussian blue (PB) nanoparticles (NPs) have been intensively investigated for medical applications, but an in-depth toxicological investigation of PB NPs has not been implemented. In the present study, a comprehensive investigation of the fate and risks of PB NPs after intravenous administration was carried out by using a mouse model and an integrated methodology of pharmacokinetics, toxicology, proteomics, and metabolomics. RESULTS: General toxicological studies demonstrated that intravenous administration of PB NPs at 5 or 10 mg/kg could not induce obvious toxicity in mice, while mice treated with a relatively high dose of PB NPs at 20 mg/kg exhibited loss of appetite and weight decrease in the first two days postinjection. Pharmacokinetic studies revealed that intravenously administered PB NPs (20 mg/kg) underwent fast clearance from blood, highly accumulated in the liver and lungs of mice, and finally cleared from tissues. By further integrated proteomics and metabolomics analysis, we found that protein expression and metabolite levels changed significantly in the liver and lungs of mice due to the high accumulation of PB NPs, leading to slight inflammatory responses and intracellular oxidative stress. CONCLUSIONS: Collectively, our integrated experimental data imply that the high accumulation of PB NPs may cause potential risks to the liver and lungs of mice, which will provide detailed references and guidance for further clinical application of PB NPs in the future.

Polycyclodextrin as a linker for nanomedicine fabrication and synergistic anticancer application.

Polycyclodextrin (denoted PCD) composed of cyclodextrin monomer units and 1,3-diethoxypropan-2-ol containing many hydroxyl groups with lone pairs of electrons, easily coordinated with transition metals with empty orbitals. The CD unit can also provide host-guest binding sites for functional molecules. This article utilizes this feature of PCD for the first time as a "linker" to combine transition metal nanomaterials with synergistic functional molecules. We synthesized PCD with 50% CD monomer by epichlorohydrin cross-linking method. Utilizing the coordination effect of the hydroxyl group in PCD and the iron ion in photothermal nanoparticles (PB-Yb), the PCD is coated on its surface; simultaneously, CD in PCD can form a host-guest complex with adamantane-modified zinc phthalocyanine (Pc) photosensitizer. Using PCD as a "linker", PB-Yb and Pc (denoted PYPP) were combined to improve the solubility of PB-Yb, reduce the aggregation degree of Pc to increase their activity, and achieve photothermal and photodynamic synergistic tumor therapy.

Prussian Blue Nanozymes Prevent Anthracycline-Induced Liver Injury by Attenuating Oxidative Stress and Regulating Inflammation.

Anthracycline-induced liver injury (AILI) is becoming an increasingly serious and potential clinical complication and is linked to reactive oxygen species (ROS) production and subsequent inflammatory response. Herein, we demonstrated that artificial Prussian blue nanozymes (PBZs) prevented daunorubicin-induced liver injury, a prototype of AILI, by attenuating ROS production and regulating inflammation. PBZs exhibited multienzyme activity and could scavenge ROS and free radicals. At the cellular level, PBZs could effectively eliminate ROS, suppress hepatocyte apoptosis, reduce deoxyribonucleic acid damage, and decrease the levels of inflammatory cytokines and chemokines. According to the results of the in vivo study, pretreatment with PBZs also resulted in a desirable protective effect against AILI, as indicated by both a decrease in biochemical indicator levels and hepatocyte necrosis. PBZs upregulated antioxidative genes by activating the Nrf2 pathway to reduce oxidative stress. Meanwhile, PBZs counteracted the inflammatory response based on the decreased expression levels of myeloperoxidase and F4/80 in the liver. Collectively, our findings indicate that PBZ-based nanotherapy is a novel strategy for protecting against AILI.

Cancer Cytomembrane-Cloaked Prussian Blue Nanoparticles Enhance the Efficacy of Mild-Temperature Photothermal Therapy by Disrupting Mitochondrial Functions of Cancer Cells.

Despite its success against cancer, photothermal therapy (PTT) (>50 °C) suffers from several limitations such as triggering inflammation and facilitating immune escape and metastasis and also damage to the surrounding normal cells. Mild-temperature PTT has been proposed to override these shortcomings. We developed a nanosystem using HepG2 cancer cell membrane-cloaked zinc glutamate-modified Prussian blue nanoparticles with triphenylphosphine-conjugated lonidamine (HmPGTL NPs). This innovative approach achieved an efficient mild-temperature PTT effect by downregulating the production of intracellular ATP. This disrupts a section of heat shock proteins that cushion cancer cells against heat. The physicochemical properties, anti-tumor efficacy, and mechanisms of HmPGTL NPs both in vitro and in vivo were investigated. Moreover, the nanoparticles cloaked with the HepG2 cell membrane substantially prolonged the circulation time in vivo. Overall, the designed nanocomposites enhance the efficacy of mild-temperature PTT by disrupting the production of ATP in cancer cells. Thus, we anticipate that the mild-temperature PTT nanosystem will certainly present its enormous potential in various biomedical applications.

Near-Infrared Radiation-Assisted Drug Delivery Nanoplatform to Realize Blood-Brain Barrier Crossing and Protection for Parkinsonian Therapy.

Mitochondrial dysfunction, which is directly involved in Parkinson's disease (PD), is characterized by the production of reactive oxygen species (ROS) and aberrant energy metabolism. Thus, regulating mitochondrial function might be an effective strategy to treat PD. However, the blood-brain barrier (BBB) presents a significant challenge for the intracerebral delivery of drugs. Here, we synthesized a zeolitic imidazolate framework 8-coated Prussian blue nanocomposite (ZIF-8@PB), which was encapsulated with quercetin (QCT), a natural antioxidant, to treat PD. ZIF-8@PB-QCT exhibited superior near-infrared radiation (NIR) response and penetrated through the BBB to the site of mitochondrial damage guided by the photothermal effect. In the mice model of PD, the QCT released from ZIF-8@PB-QCT significantly increased the adenosine triphosphate levels, reduced the oxidative stress levels, and reversed dopaminergic neuronal damage as well as PD-related behavioral deficits without any damage to the normal tissues. Furthermore, we explored the underlying neuroprotective mechanism of ZIF-8@PB-QCT that was mediated by activating the PI3K/Akt signaling pathway. Thus, combined with noninvasive NIR radiation, the biocompatible ZIF-8@PB-QCT nanocomposite could be used to treat neurodegenerative diseases.

In vitro and in vivo genotoxicity assessment of ferric ferrocyanide and potassium-cobalt ferrocyanide.

Ferric hexacyanoferrate(II) (Fe4[Fe(CN)6]3), i.e. Prussian blue (PB) has been used for many years to remove from the body the two toxic isotopes of cesium and thallium following irradiation. Recently, potassium cobalt hexacyanoferrate(II) (K2COFe(CN)6), which has shown a better efficacy for decontamination, is also being considered for use to enhance the elimination of cesium isotopes. In view to its preclinical and clinical development, in vitro and in vivo GLP-compliant genotoxicity studies were carried out on this product as well as on PB for comparison. Several tests dissecting the main events leading to genotoxicity, i.e. mutagenicity and chromosomal aberrations, both structural and quantitative were implemented. In vitro, no mutagenic effect was observed in the Ames test but both compounds were positive in the mouse lymphoma assay on TK locus and induced clastogenic effects in the in vitro chromosomal aberrations test on human lymphocytes, either in absence or in presence of metabolic activation. K-Co-ferrocyanide was also assayed in vivo in the mouse bone marrow micronucleus assay and PB was assessed for DNA fragmentation in the rodent Comet assay in both glandular stomach and colon. In the in vivo micronucleus mouse bone marrow, K-Co-ferrocyanide did not display any genotoxic activity up to 2000 mg/kg/d (x2) by oral route. In opposite, PB induced a significant increase in DNA fragmentation both in the glandular stomach and in the colon of rat treated 3 times with intake ranging from 2000 to 500 mg/kg. PB should be considered as an in vivo mutagen as well as Potassium cobalt hexacyanoferrate(II) since the in vitro genotoxicity profiles of both ferrocyanides are quite similar. Their use as cesium/ thallium decontamination agents in human should be assessed following a benefit/risk approach to enable a robust decision-making.

Prussian blue nanoparticles: synthesis, surface modification, and biomedical applications.

Prussian blue nanoparticles (PBNPs) are a nanomaterial that presents unique properties and an excellent biocompatibility. They can be synthesized in mild conditions and can be derivatized with polymers and/or biomolecules. PBNPs are used in biomedicine as therapy and diagnostic agents. In biomedical imaging, PBNPs constitute contrast agents in photoacoustic and magnetic resonance imaging (MRI). They are a good adsorbent to be used as antidotes for poisoning with cesium and/or thallium ions. Moreover, the ability to convert energy into heat makes them useful photothermal agents (PAs) in photothermal therapy (PTT) or as nonantibiotic substances with antibacterial properties. Finally, PBNPs can be both reduced to Prussian white and oxidized to Prussian green. A large window of redox potential exists between reduction and oxidation, which result in the enzyme-like characteristics of these NPs.

Toxicological evaluation of Prussian blue nanoparticles after short exposure of mice.

Prussian blue nanoparticle (PBNP), a new type of theranostic nanomaterial, had been used for cancer magnetic resonance imaging and photothermal therapy. However, their long-term toxicity after short exposure in vivo was still unclear. In this study, we investigated the dynamic changes of the biochemical and immunity indicators of mice after PBNPs injection through tail vein. Histological results showed that the PBNPs were mainly accumulated in liver and spleen. In the spleen, we found the frequency of T cells was starting to decrease after 1 day of PBNPs injection, but then slowly recovered to normal level after 60 days of injection. Meanwhile, the frequency of T cells in the blood was firstly decreased after the PBNPs injection, and then the T cell frequency kept increasing and recovered back to normal levels after 7 days of injection. The serum indexes of liver functions (alanine transaminase, aspartate transaminase, total bilirubin, and alkaline phosphatase) increased rapidly to a relatively high level only after 1 h of injection, which meant certain acute liver damage, but these indexes were gradually decreased to normal levels after 60 days of injection. These results indicate that PBNPs have acute toxicity in vivo, however, their long-term toxicity after short-time exposure is low, which might provide guidance for further applications of PBNPs in future.

Uptake of ferrocyanide in willow and poplar trees in a long term greenhouse experiment.

Phytoremediation of sites contaminated with iron cyanides can be performed using poplar and willow trees. Poplar and willow trees were grown in potting substrate spiked with ferrocyanide concentrations of up to 2,000 mg kg(-1) for 4 and 8 weeks respectively. Soil solution and leaf tissue of different age were sampled for total cyanide analysis every week. Chlorophyll content in the leaves was determined to quantify cyanide toxicity. Results showed that cyanide in the soil solution of spiked soils differed between treatments and on weekly basis and ranged from 0.5 to 1,200 mg l(-1). The maximum cyanide content in willow and poplar leaves was 518 mg kg(-1) fresh weight (FW) and 148 mg kg(-1) FW respectively. Cyanide accumulated in the leaves increased linearly with increasing cyanide concentration in the soil solution. On the long term, significantly more cyanide was accumulated in old leaf tissue than in young tissue. Chlorophyll content in poplar decreased linearly with increasing cyanide in the soil solution and in leaf tissue, and over time. The inhibitory concentration (IC50) value for poplars after 4 weeks of exposure was 173 mg l(-1) and for willow after 8 weeks of exposure-768 mg l(-1). Results show that willows tolerate much more cyanide and over a longer period than poplars, making them very appropriate for remediating sites highly contaminated with iron cyanides.

2,4-dinitrophenol partially alleviates ferrocyanide-induced toxicity in Drosophila melanogaster.

The toxicity of potassium ferrocyanide (PFC) and protective effects of 2,4-dinitrophenol (DNP) under PFC treatment were tested on the Drosophila melanogaster model system. Fly larvae were raised on food supplemented with PFC at concentrations of 1.0 mM and mixtures with DNP in concentrations of 0.50 and 1.25 mM, either alone or in combination with 1.0 mM PFC. Food supplementation with PFC decreased larvae viability or pupation height, whereas when larvae were fed by PFC and DNP combination the decrease was less pronounced. Larval exposure to PFC and mixtures of DNP and PFC lowered activities of aconitase. Larval treatment with PFC resulted in higher carbonyl protein, uric acid, and low molecular mass thiols content and higher activity of thioredoxin reductase in adult flies, while DNP in mixtures with PFC relieved these effects. Furthermore, treatment with PFC/DNP mixtures resulted in higher activities of superoxide dismutase and glutathione-S-transferase. It is proposed that PFC toxicity is mainly related to the cyanide and iron ions, released during its decomposition. The potential mechanisms of protective DNP effects against PFC toxicity are discussed.

Interactions of free copper (II) ions alone or in complex with iron (III) ions with erythrocytes of marine fish Dicentrarchus labrax.

As a consequence of human activity, various toxicants - especially metal ions - enter aquatic ecosystems and many fish are exposed to considerable levels. As the free ion and in some complexes, there is no doubt that copper promotes damage to cellular molecules and structures through radical formation. Therefore, we have investigated the influence of copper uptake by the red blood of the sea bass (Dicentrarchus labrax), and its oxidative action and effects on cells in the presence of complexed and uncomplexed Fe3+ ions. Erythrocytes were exposed to various concentrations of CuSO4, Fe(NO3)3, and K3Fe(CN)6 for up to 5h, and the effects of copper ions alone and in the combination with iron determined. The results show that inside the cells cupric ion interacts with hemoglobin, causing methemoglobin formation by direct electron transfer from heme Fe2+ to Cu2+. Potassium ferricyanide as a source of complexed iron decreases Met-Hb formation induced by copper ions unlike Fe(NO3)3. We also found that incubation of fish erythrocytes with copper increased hemolysis of cells. But complexed and uncomplexed iron protected the effect of copper. CuSO4 increased the level of lipid peroxidation and a protective effect on complexed iron was observed. Incubation of erythrocytes with copper ions resulted in the loss of a considerable part of thiol content at 10 and 20 microM. This effect was decreased by potassium ferricyanide and Fe(NO3)3 only after 1 and 3h of incubation. The level of nuclear DNA damage assayed by comet assay showed that 20 microM CuSO4 as well as 20 microM Fe(NO3)3 and 10 mM K3Fe(CN)6 induce single- and double-strand breaks. The lower changes were observed after the exposure of cells to K3Fe(CN)6. The data suggest that complexed iron can act protectively against copper ions in contrast to Fe(NO3)3.

Assimilation and physiological effects of ferrocyanide on weeping willows.

Uptake, assimilation, and toxicity of exogenous iron cyanide complexes in plants were investigated. Pre-rooted young weeping willows (Salix babylonica L.) were exposed to hydroponic solutions spiked with potassium ferrocyanide at 24.0 ± 1°C for 192 h. Transpiration rates, chlorophyll contents, soluble protein, and activities of superoxide dismutases (SOD), catalase (CAT), and peroxidase (POD) of the plants were monitored to determine toxicity to the cuttings. Of all selected parameters, POD activity in leaves was the most sensitive bioindicator to the increase of ferrocyanide concentrations. Between 11% and 19% of applied ferrocyanide in the solutions was removed by willows at the end of the incubation period. Only small amounts of ferrocyanide were recovered in different parts of the plant materials. Mass balance analysis showed that more than 90% of the ferrocyanide taken up from the hydroponic solutions was assimilated by plants. The assimilation of ferrocyanide by plants showed a dose-dependent manner. These findings suggest that phytoremediation of ferrocyanide-contaminating wastewater and soils can be possible for the environmental cleaning up.

Uptake of iron cyanide complexes into willow trees.

The uptake of iron cyanide into willows was studied. Trees were grown in solutions with Prussian blue, ferricyanide, or ferrocyanide. Iron cyanide speciation in solution was determined by HPLC during the experiment. Total cyanide and total iron in solution and trees were measured at the end of the experiments. Ferrocyanide wasthe dominating species in most solutions at the end. Ferricyanide was preferably taken up from solutions. Between 20 and 83% of the cyanide was lost from the solutions, and up to 28% could be recovered from the plants, mainly from roots. Cyanide could also be detected in stems and leaves of most exposed trees. Uptake was increased when no other nitrogen source but cyanide was present in solutions. Iron contents in exposed trees, compared to controls, increased significantly. The ratio of iron to cyanide remained rather stable in solution, but changed to higher values inside the plants. This indicates that iron and cyanide were taken up together as a complex, which was dissolved inside plants, and then cyanide was metabolized. No toxic effects could be seen. The study shows that trees can take up and metabolize iron cyanide complexes, making phytoremediation of iron cyanide waste a feasible option.

Effects of a fire-retardant chemical to fathead minnows in experimental streams.

BACKGROUND: Each year millions of liters of fire-retardant chemicals are applied to wildfires across the nation. Recent laboratory studies with long-term fire-retardant chemicals indicate a significant photoenhanced toxicity of products containing sodium ferrocyanide corrosion inhibitors. Our objective of this study was to determine the toxicity of fire-retardant chemicals to fathead minnows during exposure in experimental outdoor streams. METHODS: Stream tests were conducted to determine the potential toxicity of a pulse of exposure as might occur when fire retardant chemical is rinsed from the watershed by rainfall. Two artificial 55-meter experimental streams were dosed with different concentrations of Fire-Trol GTS-R, or uncontaminated for a control. Replicate groups of fathead minnows were added to screened containers (10 fish per container) and exposed to retardant chemicals in the recirculating flow of the stream for up to 6 hours. RESULTS AND DISCUSSION: Under field conditions toxicity of GTS-R only occurred in the presence of sunlight. When GTS-R was tested on sunny days, 100% mortality occurred. However, when tested during heavily overcast conditions, no mortality occurred. CONCLUSIONS: Lethal concentrations of cyanide were measured when GTS-R with YPS exposures were conducted under sunny conditions, but not under cloudy conditions, indicating that a minimum UV level is necessary to induce toxicity as well as the release of cyanide from YPS. The toxicity observed with GTS-R was likely associated with lethal concentrations of cyanide. Rainwater runoff following applications of this fire-retardant at the recommended rate could result in lethal concentrations in small ponds and streams receiving limited water flow under sunny conditions. RECOMMENDATIONS AND OUTLOOK: In addition to avoiding application to aquatic habitats, it is important to consider characteristics of the treated site including soil binding affinity and erosive properties.

The effects of ultraviolet-B radiation on the toxicity of fire-fighting chemicals.

The interactive effects of ultraviolet (UV) and fire-retardant chemicals were evaluated by exposing rainbow trout (Oncorhyncus mykiss) juveniles and tadpoles of southern leopard frogs (Rana sphenocephala) to six fire-retardant formulations with and without sodium ferrocyanide (yellow prussiate of soda [YPS]) and to YPS alone under three simulated UV light treatments. Yellow prussiate of soda is used as a corrosion inhibitor in some of the fire-retardant chemical formulations. The underwater UV intensities measured were about 2 to 10% of surface irradiance measured in various aquatic habitats and were within tolerance limits for the species tested. Mortality of trout and tadpoles exposed to Fire-Trol GTS-R, Fire-Trol 300-F, Fire-Trol LCA-R, and Fire-Trol LCA-F was significantly increased in the presence of UV radiation when YPS was present in the formulation. The boreal toad (Bufo boreas), listed as endangered by the state of Colorado (USA), and southern leopard frog were similar in their sensitivity to these chemicals. Photoenhancement of fire-retardant chemicals can occur in a range of aquatic habitats and may be of concern even when optical clarity of water is low; however, other habitat characteristics can also reduce fire retardant toxicity.

Studies of any toxicological effects of Prussian blue compounds in mammals--a review.

The Chernobyl nuclear reactor accident, which resulted in widespread contamination with radiocaesium, led to studies of the use of Prussian Blue (PB) compounds as a countermeasure to reduce the caesium-137 and caesium-134 content of animal products. An important consideration in the practical use of PB compounds in agriculture is their possible toxicity. Hence it is pertinent to assess the work undertaken with laboratory rodents, domesticated animals and humans that has included studies of any toxic effects. Such studies showed that PB compounds had no adverse effects on animal health and production and, in addition, no toxic effects were noted in humans when PB was used experimentally or therapeutically.