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We believe that unmodified hydrated C60 fullerene (C60FWS) and nanocrystalline cerium dioxide (NCD) are promising for biological research. It is knowns that these nanoparticles protect living cells from damaging environmental factors such as radioactive and ultraviolet radiation, temperature, hypoxia, toxic substances, etc. However, little attention has been paid in scientific reports to the use and study of these nanoparticles as possible adaptogens. In our studies, we tried to protect the culture of cyanobacteria Spirulina platensis with C60 and NCD from adverse conditions. The choice of Spirulina platensis is due to its sensitivity to adverse environmental factors. The results obtained show that the absence of toxic effects of C60 and NCD of selected concentrations on the Spirulina platensis culture has been found. Nanoparticles C60 and NCD maintained the culture of Spirulina platensis for at least 4 weeks in the absence of nutrients, light, low pH storage conditions and low temperature. Cyanobacteria stored for 1–4 weeks in distilled water with nanoparticles showed increased proliferative activity compared to samples stored at the same time in the standard Zarrouk’s nutrient medium. Keywords: fullerene C60, nanocrystalline cerium dioxide, Spirulina platensis, adaptogens.

Gadolinium orthovanadate GdVO4:Eu3+ nanoparticles (VNPs) have been shown to scavenge reactive oxygen species (ROS), making them a promising therapeutic agent in inflammation. This study aims to assess the effects of VNPs administered orally on E407a-induced inflammation. Materials and Methods: Fragments of the small intestine of 8 rats treated orally with a carrageenan-containing food additive E407a at a dose of 140 mg / kg of weight during 2 weeks, 8 animals orally exposed to both E407a and VNPs at a dose of 20 μg / kg of weight during the same period of time, and 8 control rats were stained routinely and immunostained for CD3 and CD68 with the subsequent immunohistochemical scoring. Moreover, analysis of viability and cell death modes of granulocytes was performed by flow cytometry using Annexin V and 7-aminoactinomycin D (7-AAD). Results: Oral exposure to the food additive E407a resulted in the development of enteritis associated with altered small intestinal morphology, infiltration of the lamina propria with macrophages and T-lymphocytes, and activation of peripheral blood granulocyte apoptosis. VNPs administered against the background of E407a-induced slight intestinal inflammation improved small intestinal morphology, decreased infiltration rate of the immune cells mentioned above without affecting the intensity of granulocyte apoptosis. Conclusion: Oral administration of VNPs ameliorates E407a-induced enteritis.

Effect of prolong use of orthovanadate nanoparticles (GdVO4/Eu3+ NPs (8 × 25 nm)) on life quality and survival of male Wistar rats on the late stage of ontogenesis (from 23 months to the end of life) has been investigated. Multi-parametric assessment of orthovanadate NPs influences against metformin (Met) which is a well-known calorie restriction mimetic (CR-mimetic) has been completed. The quality of life was assessed by taking into account age-related hallmarks-phenotype and some physiological parameters (condition of the coat, body weight, concentration of thyroxine, rectal temperature) as well as indicators of the pro-oxidant/antioxidant balance of blood and liver (the content of lipid hydroperoxides; aconitase, glutathione peroxidase, glutathione reductase, glutaredoxin activity, and activity of NADP+-dehydrogenases (DG) (glucose-6-phosphate DG, malate DG, and isocitrate DG)) in aging animals. Kaplan-Meier curve and Gehan tests with Yates' correction were performed for the survival analysis. It has been found that long-term use of GdVO4/Eu3+ NPs (0.25-0.30 mg/kg/day), as well as Met (100-110 mg/kg/day) with drinking water led to reliable improvement of physiological parameters and normalization of the pro-oxidant/antioxidant balance in the liver and blood of experimental animals. A significant increase in the survival rate of aging rats was observed; the apparent median survival for control rats was 900 days, while for experimental rats, 1010 and 990 days for GdVO4/Eu3+ NPs and Met, respectively. In general, the data obtained demonstrate the ability of GdVO4/Eu3+ NPs and CR-mimetic-Met to improve the quality of life and increase the survival of an elderly organism.

In the present paper, we analyze the impact of doping of GdYVO4 and LaVO4 nanoparticles (NPs) with Eu3+ ions on their redox properties, in particular, dark reactive oxygen species (ROS) generation ...

Both cerium oxide (CeOx) nanoparticles and mefenamic acid (MFA) are known anti-inflammatory agents with hepatoprotective properties and are therefore prescribed for one of the major diseases in the world, nonalcoholic fatty liver disease (NAFLD). To study the potential cytotoxicity and anti-inflammatory effects as well as drug retention of a potential therapeutic CeOx/MFA supramolecular complex, a well-standardized hepatic (HepG2) spheroid model was used. Results showed that the highest cytotoxicity for the CeOx/MFA supramolecular complex was found at 50 μg/mL, while effective doses of 0.1 and 1 μg/mL yielded a significant decrease of TNF-α and IL-8 secretion. Time-resolved analysis of HepG2 spheroids revealed a spatiotemporal distribution of the supramolecular complex and limited clearance from the internal microtissue over a period of 8 days in cultivation. In summary, our results point at rapid uptake, distribution, and biostability of the supramolecular complex within the HepG2 liver spheroid model as well as a significant anti-inflammatory response at noncytotoxic levels.

In comparison with the action of metformin — mimetic of the calorie restricted diet, which prolong the animals lifespan, it has been studied the effect of nanoparticles of cerium dioxide (CeO₂ NPs (1-2 nm)) on survival, physiological indices (the concentration of thyroxine, rectal temperature), as well as biochemical indices (content of lipid hydroperoxides, aconitase, glutathione peroxidase, glutaredoxin, glutathione reductase, NADP⁺ -dehydrogenase activities (glucose-6-phosphate-, malate- and isocitrate dehydrogenase)) in serum, liver mitochondrial and postmitochondrial fraction of ageing rats. It has been found that the prolonged use of CeO₂ NPs with drinking water (0.25-0.30 mg/kg of body weight per day) and metformin (100-110 mg/kg of body weight per day) from 670 days after the birth lead to a significant increase in survival (the median survival of control rats was 900, in animals treated with CeO₂ NPs — 960, and metformin — 990 days), a decrease in rectal temperature, a slowdown in the decrease in the level of thyroxine in blood, and normalization of the prooxidant/antioxidant balance in liver and blood tissues. Calculated integral index of reliability of prooxidant-antioxidant balance (reliability coefficient) in the studied tissues of rats in response to the application of the CeO₂ NPs increased 4.99 times, and metformin — 4.94 times compared to intact animals. The data obtained allow us concluding about the prospects of the CeO₂ NPs, as well as metformin for the development of geroprotector drugs, increasing the healthspan and survival of an ageing organism. У порівнянні з дією метформіну — міметика низькокалорійної дієти, що продовжує життя тварин, вивчається вплив наночастинок діоксиду церію (CeO₂ НЧ (1—2 нм)) на виживання, фізіологічні показники (концентрація тироксину, ректальна температура) та біохімічні показники (вміст ліпідних гідроперок сидів, активність ферментів аконітази, глутатіонпероксидази, глутаредоксину, глутатіонредуктази, НАДФ⁺-дегідрогеназ (глюкозо-6-фосфат дегідрогеназа, малат дегідрогеназа та ізоцитрат дегідрогеназа) у сироватці крові, мітохондріальної та постмітохондріальної фракцій печінки. Було встановлено, що тривале використання CeO₂ НЧ з питною водою (0,25—0,30 мг / кг маси тіла на добу) або метформіну (100—110 мг / кг маси тіла на добу) з 670 днів після народження призводило до значного збільшення виживання (медіана виживаності контрольних щурів становила 900 днів, у тварин, які отримували CeO₂ НЧ — 960 днів, і метформіну — 990 днів), зниження ректальної температури, уповільнення зниження тироксину в крові та нормалізації прооксидантно/антиоксидантного балансу в тканинах печінки та крові. Розрахований інтегральний показник надійності прооксидантно/антиоксидантного балансу (коефіцієнт надійності) у досліджуваних тканинах щурів у відповідь на використання CeO₂ НЧ зріс в 4,99 раза, а метформіну — у 4,94 раза порівняно з інтактними тваринами. Отримані дані дозволяють зробити висновки щодо перспектив наночастинок CeO₂, а також метформіну для розробки геропротекторних препаратів, що сприяють поліпшенню здоров’я та збільшують виживаність організму при старінні.

Objectives To assess the state of phospholipid bilayer of red blood cells (RBCs) in rats orally exposed to gadolinium orthovanadate GdVO4:Eu3+ nanoparticles (VNPs) during two weeks using fluorescent probes − ortho-hydroxy derivatives of 2,5-diaryl-1,3-oxazole. Methods Steady-state fluorescence spectroscopy: a study by the environment-sensitive fluorescent probes − 2-(2′-OH-phenyl)-5-phenyl-1,3-oxazole (probe O1O) and 2-(2′-OH-phenyl)-phenanthro[9,10]-1,3-oxazole (probe PH7). Results No significant changes are detected in the spectra of the fluorescent probes bound to the RBCs from the rats orally exposed to nanoparticles in comparison with the corresponding spectra of the probes bound to the cells from the control group of animals. This indicates that, in case of the rats orally exposed to nanoparticles, no noticeable changes in physico-chemical properties (i.e., in the polarity and the proton-donor ability) are observed in the lipid membranes of RBCs in the region, where the probes locate. Conclusions No changes in the physical and chemical properties of the erythrocyte membranes are detected in the region from glycerol backbones of phospholipids to the center of the phospholipid bilayer in the rats orally exposed to VNPs during 2 weeks.

Goltsev, A.M., Malyukin, Y.V., Babenko, N.M. et al. Antitumor activity of spherical nanoparticles GdYVO4:Eu3+ depends on pre-incubation time. Appl Nanosci 10, 2749–2758 (2020). https://doi.org/10.1007/s13204-020-01284-3 The significance of tumor cells incubation with spherical nanoparticles based on orthovanadates of rare-earth elements activated by europium GdYVO4:Eu3+ in the effectiveness of Ehrlich carcinoma growth inhibition was shown. Ehrlich carcinoma cells were incubated with nanoparticles for 1, 2, 3, and 4 h; afterwards, their accumulation in cells using a LSM 510 META confocal laser microscope (Carl Zeiss, Germany), changes in mitochondrial function and apoptotic/necrotic cells were assessed. Even from the 1st hour of incubation, there was observed an increase in mean fluorescence intensity, indicating the beginning of nanoparticles accumulation inside the cells. By the third hour of incubation, the fluorescence values of total Ehrlich carcinoma population reached the maximum values. At the same time, the appearance of single cells with ultra-high level of fluorescence was established; the number of those did not exceed 5%. By the third hour of incubation with nanoparticles, there was a significant mitochondrial dysfunction of Ehrlich carcinoma cells and a convincing increase in the proportion of cells in the late apoptosis (An+/PI+) and necrosis (An-/PI+) compared to the control. The aforesaid changes in the Ehrlich carcinoma cells after 3-h pretreatment with nanoparticles contributed to the highest decrease in intensity of tumor growth in vivo down to 41.80%. Thus, the successful implementation of an antitumor effect of nanoparticles based on orthovanadates of rare earth elements activated by europium GdYVO4:Eu3+ implies their penetration and accumulation inside the cells as well as associated with impaired mitochondrial function and induction of apoptotic and necrotic changes in tumor cells.

To assess the phospholipid bilayer of white blood cells (WBCs) and the ability of leukocytes to generate reactive oxygen species (ROS) in rats orally exposed to GdVO4:Eu3+ nanoparticle (VNP) solution for 2 weeks by fluorescent probes—ortho-hydroxy derivatives of 2,5-diaryl‑1,3‑oxazole. Steady-state fluorescence spectroscopy, i.e., a study by the environment-sensitive fluorescent probes 2‑(2′-OH-phenyl)-5-(4′-phenyl-phenyl)-1,3-oxazole (probe O6O) and 2‑(2′-OH-phenyl)-phenanthro[9,10]-1,3-oxazole (probe PH7), and flow cytometry, i.e., analysis of 2′,7′-dichlorofluorescein (DCF), a product of a dye 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA), fluorescence in CD45+/7-aminoactinomycin D (7-AAD)− cells, were used to evaluate the state of cell membranes and reactive oxygen species (ROS) generation in leukocytes of rats orally exposed to gadolinium orthovanadate nanoparticles(VNPs). No significant changes were detected in the spectra of the fluorescent probes bound to the WBCs from the rats orally exposed to nanoparticles in comparison with the corresponding spectra of the probes bound to the cells from the control group of animals. This indicates that in the case of the rats orally exposed to nanoparticles, no noticeable changes in physicochemical properties (i.e., in the polarity and the proton-donor ability) are observed in the lipid membranes of WBCs in the region where the probes locate. There was no statistically significant difference in the amount of ROShigh viable leukocytes in rats treated with VNPs and control samples. Neither changes in the physical and chemical properties of the leukocyte membranes nor in ROS generation by WBCs are detected in the rats orally exposed to VNP solution for 2 weeks.

Nanomaterials, which promote the generation of reactive oxygen species (ROS) and precipitate the onset of oxidative stress responsible for the development of a variety of adverse conditions, have a...

Aim. To evaluate the effects of GdYVO 4 :Eu3+ nanoparticles on the state of leukocyte cell membranes upon direct exposure.Materials and methods. The membranotropic fluorescent probe 2-(2’-OH-phenyl)-5-(4’-biphenyl)-1,3-oxazole was incubated directly with leukocyte suspensions obtained from blood treated directly with different concentrations of GdYVO 4 :Eu3+ nanoparticles (0 μg/ml, 20 μg/ml, 40 μg/ml, 80 μg/ml) during 24 h. The fluorescence of normal and tautomeric forms of the probe was registered using a FL8500 Fluorescence Spectrophotometer (Perkin Elmer, USA).Results. Our findings indicate that the statistically significant elevation in values of the tautomeric form fluorescence intensity-to-normal form fluorescence intensity ratio (I T* /I N* ) was observed only for suspensions with the highest concentration of nanoparticles used, while at low concentrations nanoparticles did not alter the state of phospholipid bilayer in the region of membranes where the probe locates.Conclusions. Low concentrations of GdYVO 4 :Eu3+ nanoparticles don’t alter the lipid order of leukocyte cell membranes, while their high concentrations promote an increase in lipid order suggesting a decrease in fluidity and an increase in microviscosity of the area of phospholipid bilayer where the probe locates.

Aim. To assess the viability and functional activity of cultured rat skin fibroblasts directly exposed to various concentrations of GdYVO 4 :Eu3+ nanoparticles.Materials and methods. Cultured rat dermal fibroblasts (n=8) were incubated with GdYVO 4 :Eu3+ nanoparticles at different concentrations (0 - 320 μg/ml) for 24 h. The cytotoxicity was evaluated in a complex manner. In particular, the MTT assay was used to assess cellular metabolic activity. The viability of cells was quantitatively estimated using the neutral red uptake assay. To evaluate the effects of nanoparticles on the mobility of dermal fibroblasts, the scratch assay was used. Results. Our experimental data demonstrated that the GdYVO 4 :Eu3+ nanoparticles had no effect on fibroblast viability at any concentration used, evidenced by the results of neutral red uptake assay. However, incubation of cultured fibroblasts starting from the concentration of 80 μg/ml and above increased the metabolic activity of cells, based on the outcome of MTT assay, and promoted the loss of adhesion. Similarly, scratch assay revealed the reduction of fibroblast migration capacity in cells exposed to 80 μg/ml and higher concentrations of nanoparticles. Conclusions. Low concentrations of GdYVO4:Eu3+ (below 40 μg/ml) show no cytotoxic properties towards fibroblasts, while their higher concentrations affect the metabolic activity and functional properties of cells.

Nanoparticles (NPs) have been reported to be promising enhancement agents for radiation therapy. The aim of the study was to assess the cytotoxicity of UV non-treated and UV pretreated GdYVO4:Eu3+ nanoparticles against erythrocytes and leukocytes by detecting eryptosis and reactive oxygen species (ROS) generation. Levels of intracellular ROS in erythrocytes and leukocytes using a ROS-sensitive dye 2ʹ,7ʹ-dichlorodihydrofuorescein diacetate (H2DCFDA), as well as eryptosis rate utilizing annexin V staining, following direct exposure to UV-activated and nonactivated NPs were detected by fow cytometry. Blood cells were collected from 9 intact WAG rats. Neither the UV light-untreated GdYVO4:Eu3+ NPs nor the treated ones promoted eryptosis and ROS generation in erythrocytes. Low concentrations of UV light-untreated NPs did not induce oxidative stress in leukocytes, evidenced by unafected intracellular ROS levels. UV light treatment grants prooxidant properties to NPs, confrmed by NP-induced ROS overproduction in leukocytes. High concentrations of both UV light-treated and untreated NPs altered the redox state of leukocytes. UV light treatment imparts prooxidant properties to GdYVO4:Eu3+ NPs, making them promising radiosensitizing agents in cancer radiation therapy. Ukrayna Sağlık Bakanlığı 0121U110920

This work reports abnormal dynamics of hydroxyl radicals generation under UV irradiation of water solution containing small (d = 2 nm) GdYVO4:Eu3+ nanoparticles (NPs). An analysis of the increase in OH concentration in time allows two parts in the OH generation curve to be revealed. The first slower part is shown to be associated with a predominate radical scavenging mechanism and explained by the presence of ions with a changeable valence state (V4+/V5+) and oxygen vacancies in the structure of GdYVO4:Eu3+ NPs. The second faster part is associated with photo-induced holes interaction with water molecules adsorbed at the surface of NPs followed by the hydroxyl radical production. The mutual contributions of the two mechanisms are changed in time and the depletion of the scavenging mechanism is observed in about 90 min after UV irradiation start. Our finding is a next step to understand the mechanism of NPs redox-activity for taking greater advantage of such nanomaterials in biomedical applications.

Hypochlorous acid (HOCl) and hypochlorite anions (−OCl) are nonselective oxidants produced by activated neutrophils and monocytes and play an important role in the formation of immune response of a living organism. At the same time, because of the strong oxidative properties of hypochlorites, their concentrations in cells need to be under strict control. In this paper, cerium oxide nanoparticles (nanoceria) were used for spectroscopically controlled catalytic decomposition of hypochlorite anions. The processes of scavenging of hypochlorite anions by ceria nanoparticles and regeneration of nanoceria were monitored using the changes in hypochlorite absorption and 5d → 4f luminescence of Ce3+ ions during oxidation–reduction cycles. The high oxygen deficiency of ceria nanoparticles provides sufficient mobility of oxygen ions, leading to the involvement of both surface and bulk Ce3+ ions into oxidation, whereas the recovery of initial Ce3+/Ce4+ ratio is terminated by the slow diffusion of oxygen out of ceria n...

We report Janus-faced redox activity (pro- and anti-oxidant action) of LnVO4:Eu3+ (GdYVO4:Eu3+, GdVO4:Eu3+, and LaVO4:Eu3+) nanoparticles (NPs), which was revealed at different external conditions....

Effect of prolong use of orthovanadate nanoparticles (GdVO

Goltsev, A. et al. (2020). Mechanisms of Antitumor Effect of Nanomaterials Based on Rare Earth Orthovanadates. In: Fesenko, O., Yatsenko, L. (eds) Nanooptics and Photonics, Nanochemistry and Nanobiotechnology, and Their Applications . Springer Proceedings in Physics, vol 247. Springer, Cham. https://doi.org/10.1007/978-3-030-52268-1_1 In experimental conditions in vivo the possibility of using GdYEuVO4 nanoparticles and hybrid nanocomplexes synthesized on their basis for the identification of cancer cells and inhibition of tumor growth is substantiated that allows to attribute these nanomaterials to promising drugs for the diagnosis and treatment of malignancies. The dependence of an antitumor effect of nanomaterials on the time of their pre-incubation with tumor cells was established. Treatment of EC cells in vitro with hybrid nanocomplexes within 3 hours resulted in a minimal EC intensity growth in vivo (33.16 ± 4.67%). Implementation of an antitumor effect of nanomaterials involves their penetration, accumulation inside tumor cells, damage to mitochondrial function with subsequent induction of apoptotic and necrotic changes. The established fact of the death of EC cells mainly by necrosis under the action of hybrid NCs is one of the conditions for further inactivation of a tumor. Double staining of EC cells with monoclonal antibodies to CD44, together with hybrid NCs, allowed them to establish their selective accumulation capacity in CD44+ EC cells with ultra-high fluorescence intensity of this marker (CD44 cells). This confirms that a successful implementation of anti-proliferative properties of hybrid NCs is accomplished by inhibiting the function of tumor cells with a stem potential.

Both cerium oxide (CeOx) nanoparticles and mefenamic acid (MFA) are known anti-inflammatory agents with hepatoprotective properties and are therefore prescribed for one of the major diseases in the world, nonalcoholic fatty liver disease (NAFLD). To study the potential cytotoxicity and anti-inflammatory effects as well as drug retention of a potential therapeutic CeOx/MFA supramolecular complex, a well-standardized hepatic (HepG2) spheroid model was used. Results showed that the highest cytotoxicity for the CeOx/MFA supramolecular complex was found at 50 μg/mL, while effective doses of 0.1 and 1 μg/mL yielded a significant decrease of TNF-α and IL-8 secretion. Time-resolved analysis of HepG2 spheroids revealed a spatiotemporal distribution of the supramolecular complex and limited clearance from the internal microtissue over a period of 8 days in cultivation. In summary, our results point at rapid uptake, distribution, and biostability of the supramolecular complex within the HepG2 liver spheroid model as well as a significant anti-inflammatory response at noncytotoxic levels.

Biomedical application of rare-earth-based nanoparticles attracts much attention due to their unique optical and redox properties and quite low toxicity. Earlier, we found age-related beneficial effects of rare-earth-based orthovanadate nanoparticles (OV NPs) on the prooxidant/antioxidant balance in liver and blood of Wistar rats, as reported by Nikitchenko et al. (Biol Trace Elem Res (2020). https://doi.org/10.1007/s12011-020-02196-7 ). However, the question remained unclear whether OV NPs' redox activity directly defines the protection ability. In the present work, antiradical, antioxidant, and membrane-protective properties of GdYVO

Aim: To evaluate the effects of orally administered gadolinium orthovanadate GdVO4:Eu3+ nanoparticles (VNPs) on the course of chronic carrageenan-induced intestinal inflammation. Methods: Samples of small intestinal tissue were collected from four groups of rats (intact, after administration of VNPs, with carrageenaninduced intestinal inflammation, with carrageenan-induced intestinal inflammation orally exposed to VNPs) to assess the intestinal morphology and HSP90α expression. Levels of seromucoid, C-reactive protein, TNF-α, IL-1β and IL-10 were determined in blood serum. Results: Oral exposure to VNPs was associated with neither elevation of inflammation markers in blood serum nor HSP90α overexpression in the small intestine, i.e. no toxic effects of VNPs were observed. Carrageenan-induced intestinal inflammation was accompanied by higher levels of TNF-α and IL-1β, as well as HSP90α upregulation in the intestinal mucosa, compared with controls. Administration of VNPs to rats with enteritis did not lead to statistically significant changes in concentrations of circulating pro-inflammatory cytokines with the trend towards their increase. Conclusion: No adverse effects were observed in rats orally exposed to VNPs at a dose of 20 μg/kg during two weeks. Using the experimental model of carrageenan-induced enteritis, it was demonstrated that VNPs at the dose used in our study did not affect the course of intestinal inflammation.

We report on strong X-ray-induced hydroxyl radical (. O H ) generation in an aqueous solution containing UV light pre-treated GdYVO4:Eu3+ nanoparticles (L-GdYVO). The methods of optical spectroscopy were used to detect . O H in the solutions. The complex nature of the mechanism of . O H generation has been revealed and discussed. The experimental data obtained indicate that the mechanism of . O H generation is associated with two main processes: (i) direct . O H generation with the participation of thermalized h+ formed at X-ray irradiation, and (ii) X-ray-facilitated jumps of h+ formed in the nanoparticles&rsquo, (NPs&rsquo, ) valence band at UV light pre-treatment and trapped in local levels formed by random scattering potential. At the same time, for GdYVO4:Eu3+ nanoparticles, which were not exposed to UV light before the X-ray irradiation (D-GdYVO), a strong radioprotective effect ascribed to the electron-donation properties of V4+ ions was observed. Thus, depending on the pre-treatment condition, we can change the redox properties of GdYVO4:Eu3+ NPs in an opposite direction, which makes this nanomaterial a unique theranostic agent for radiation therapy (RT) enhancement, allowing the problem of radiation therapy (RT)-resistant hypoxic tumours to be overcome.

Vanadium is an important ultra-trace element nowadays attracting attention with particular emphasis on medical application. But the therapeutic application of vanadium-based drugs is still questionable and restricted due to some toxic side effects. It was found that unique redox properties of vanadium in nanoform provided antioxidant activity and prevented oxidative disturbance in cells in vitro. Though, on the organism level, ambiguous effects of vanadium-based nanoparticles were observed. In this study, the age-related features of prooxidant/antioxidant balance in blood serum and liver mitochondrial and postmitochondrial fractions of 3 and 18-month-old Wistar male rats treated with orthovanadate nanoparticles (GdVO

High anionic conductivity in cerium oxide bulk materials and nanocrystals makes these materials perspective for development of solid oxide fuel cells. At the same time, the cation mobility in ceria is considered to be sufficiently less compared to anionic one. In spite of this, using the methods of luminescence spectroscopy we have observed an effective cation exchange between Ce3+ ions in ceria nanoparticles and RE3+ (RE = Eu, Tb) ions in colloidal solutions. This cation exchange leads to formation of RE3+-doped nanoceria with red (Eu3+) and green (Tb3+) luminescence, which intensity gradually increases during the cation exchange process. The dynamics of increase of RE3+ luminescence intensity at different conditions (UV irradiation, H2O2 addition) reveals a key role of Ce3+-Vo-Ce3+ complexes in the processes of incorporation of RE3+ ions into ceria nanoparticles.

The aggregation behavior of 1-methyl-1′-octadecyl-2,2′-cyanine perchlorate (amphi-PIC) and 3,3′-dimethyl-9-(2-thienyl)-thiacarbocyanine iodide (L-21) dyes in binary dimethylformamide (dimethylsulfo...

Europium-doped gadolinium orthovanadate nanoparticles (GdVO 4 :Eu 3+ ) were used as a donor in fluorescence resonance energy transfer (FRET) experiments in water solutions. Using Methylene Blue as an excitation energy acceptor, we have observed highly efficient FRET between GdVO 4 :Eu 3+ nanoparticles and MB. Despite the strong decrease of both the donor GdVO 4 :Eu 3+ luminescence and lifetime, the FRET-induced emission of the acceptor MB has not been observed. This feature has been explained by small fluorescence quantum yield of MB, high efficiency of the intersystem crossing and triplet state formation for MB and small amount of MB molecules bonded to the GdVO 4 :Eu 3+ nanoparticles. The long lifetime, large Stokes shift, narrow emission, X-ray excited luminescence and high FRET efficiency (∼ 90%) make GdVO 4 :Eu 3+ nanoparticles prospective as an excitation source for the photosensitizer MB activation in such applications as photodynamic therapy.

The stabilization of particles against aggregation in high-ionic-strength solutions such as biological media is one of the most important purposes in area of biomedical application of nanomaterials. Participation of protein-nanoparticle interaction mechanisms in stabilization processes is still poorly understood at the microscopic level. Considering fundamental scientific interest and potential applications, rare-earths based nanoparticles (NPs) were studied in this regard in model systems comprising serum and main serum proteins. The results demonstrated that size and composition of the particles as well as protein nature play important roles in the protein adsorption on NPs. It was found that stabilization layer formed by serum proteins prevented aggregation of NPs at threshold concentration of divalent ions in model system. A model for the formation of a multilayer protein corona around negatively charged nanoparticles is proposed.

To assess the phospholipid bilayer of white blood cells (WBCs) and the ability of leukocytes to generate reactive oxygen species (ROS) in rats orally exposed to GdVOSteady-state fluorescence spectroscopy, i.e., a study by the environment-sensitive fluorescent probes 2‑(2'-OH-phenyl)-5-(4'-phenyl-phenyl)-1,3-oxazole (probe O6O) and 2‑(2'-OH-phenyl)-phenanthro[9,10]-1,3-oxazole (probe PH7), and flow cytometry, i.e., analysis of 2',7'-dichlorofluorescein (DCF), a product of a dye 2',7'-dichlorodihydrofluorescein diacetate (HNo significant changes were detected in the spectra of the fluorescent probes bound to the WBCs from the rats orally exposed to nanoparticles in comparison with the corresponding spectra of the probes bound to the cells from the control group of animals. This indicates that in the case of the rats orally exposed to nanoparticles, no noticeable changes in physicochemical properties (i.e., in the polarity and the proton-donor ability) are observed in the lipid membranes of WBCs in the region where the probes locate. There was no statistically significant difference in the amount of ROSNeither changes in the physical and chemical properties of the leukocyte membranes nor in ROS generation by WBCs are detected in the rats orally exposed to VNP solution for 2 weeks.

Light-triggered redox activity of small (d = 2 nm) GdYVO4:Eu3+ nanoparticles (NPs) in aqueous solutions and lipid suspensions is reported. It has been revealed that depending on pre-treatment conditions (exposure to UV light or storage in the dark) the same NPs exhibit pro- or anti-oxidant properties. Pro-/anti-oxidant activity in aqueous solutions was evaluated by UV–vis spectroscopy using probe molecules for hydroxyl radicals (·OH) and superoxide anions (O2•−). Lipid oxidation under the effect of NPs has been also analyzed. Multi-functional GdYVO4:Eu3+ NPs are assumed to be a new theranostic agent in cancer therapy, which exhibit fluorescent properties, triggered redox activity and drug-carrier ability.

Contrary to numerous studies on the stability of fullerene aqueous colloidal solutions in the presence of electrolytes, the corresponding issue for the organosols was until recently almost unexplored. In this article, the state of C60 in methyl alcohol and the regularities of the coagulation of colloidal solution in this solvent were examined in the presence of electrolytes. Alcosols with a fullerene concentration of 4 × 10–6 M were prepared by the dilution of the C60 saturated solution in toluene by methanol. The ca. 300 nm-sized aggregates possess a negative electrokinetic potential value, ζ = −37 ± 8 mV. To determine the critical coagulation concentrations, CCC, the size increase of the species was followed up using the dynamic light scattering method. The analysis of the coagulation in terms of the Fuchs function, W, was accompanied by zeta potential monitoring. The consideration of the data for 1:1 electrolytes NaClO4 and N(n-C4H9)4ClO4 allows a rough estimate of the Hamaker constant of fullerene–ful...

It this letter, we report the study of free radicals and reactive oxygen species (ROS) generation in water solutions containing gadolinium orthovanadate GdVO4:Eu3+ nanoparticles (VNPs) and their complexes with methylene blue (MB) photosensitizer. The catalytic activity was studied under UV-Vis and X-ray irradiation by three methods (conjugated dienes test, OH· radical, and singlet oxygen detection). It has been shown that the VNPs–MB complexes reveal high efficiency of ROS generation under UV-Vis irradiation associated with both high efficiency of OH· radicals generation by VNPs and singlet oxygen generation by MB due to nonradiative excitation energy transfer from VNPs to MB molecules. Contrary to that under X-ray irradiation, the strong OH . radicals scavenging by VNPs has been observed.

Tumor development is the consequence of expanding the population of low differentiated cells with unlimited self-maintenance potential, i.e. cancer stem cells (CSCs). Application of new forms of nanocomposites capable of binding to CSCs and inducing the tumor destruction is perspective direction for treating this pathology. There have been developed the methods of obtaining hybrid nanocomplexes containing rare-earth orthovanadates GdYVO4:Eu³⁺, cholesterol and luminescent dye Dil. By immune fluorescence method using monoclonal antibodies to CD44, CD24, CD117 and Sca-1 markers there has been established the change in the ratio of tumor progenitors of various differentiation levels in a general pool of Ehrlich carcinoma (EC) after treatment with hybrid nanocomplexes. Essential reduction in the concentration of the most tumorogenic CD44high cells with simultaneous rise in the number of CD117⁺-cells resulted in an increased index of CD44high/CD117⁺ ratio. It has been demonstrated that application of hybrid nanocomplexes suppressed the tumor growth almost by 80%. The value of cooperative interactions of the cells with different phenotype signs in tumor sites has been proved. The index of CD44high/CD117⁺ ratio can be used as one of diagnostic and prognostic parameters of development and inactivation rate of tumor process when using different types of anti-tumor therapy.

The kinetic and thermodynamic stability of organic (sodium dodecylsulfate micelles and egg-yolk phosphatidylcholine zwitterionic liposomes) and inorganic (based on GdYVO0034:Eu3+ nanoparticles) nanocarriers (NCs) was studied by the λ-ratiometric method (analysis of fluorescence intensity at two wavelengths) using non-radiative transfer of electronic excitation energy. The kinetic and thermodynamic parameters of the redistribution of dyes DiO and DiI between NCs that was associated with the destruction of NC/DiO and NC/DiI complexes and the formation of new NC/(DiO + DiI) complexes were evaluated. Rate constants for the destruction of the complexes (K), lifetimes of the complexes (τ1/2), the activation energy for the destruction (E a), the equilibrium constant (K eq), and the change of free energy (ΔG 0), enthalpy (ΔH 0), and entropy (ΔS 0) of the process were calculated. The obtained kinetic parameters pointed to high kinetic stability for all investigated complexes whereas the thermodynamic ones indicated that dye redistribution required high temperatures.

Optical absorption spectroscopy and dynamic light scattering have been used to study the aggregation behavior of 1,1-diethyl-2,2-carbocyanine (PIN) and 3,3-dimethyl-9-(2-thienyl)-thiacarbocyanine (L-21) dyes in aqueous solutions containing orthovanadate-based ReEuVO 4 (Re = Gd, Y, La) nanoparticles (NPs) of various form-factor. It has been shown that the interaction of cationic dye molecules with the negatively charged surface of NPs leads to the dye aggregation and formation of large dye aggregates/NPs complexes. The coagulation process is found to be governed by the NPs surface area, rather than its form factor. The dye aggregate structure is analyzed within the Kasha and McRae exciton model framework.

One of the tasks of current oncology is identification of cancer stem cells and search of therapeutic means capable of their specific inhibition. The paper presents the data on phenotype characteristics of Ehrlich carcinoma cells as convenient and easy-to-follow model of tumor growth. The evidence of cancer stem cells as a part of Ehrlich carcinoma and significance of CD44+ and CD44– subpopulations in maintaining the growth of this type of tumor were demonstrated. A high (tenfold) tumorigenic activity of the Ehrlich carcinoma CD44+ cells if compared to CD44– cells was proven. In this pair of comparison, the CD44+ cells had a higher potential of generating in peritoneal cavity of CD44high, CD44+CD24–, CD44+CD24+ cell subpopulations, highlighting the presence of cancer stem cells in a pool of CD44+ cells. In this study, the ability of synthesized hybrid nanocomplexes, comprising the nanoparticles of rare earth orthovanadates GdYVO4:Eu3+ and cholesterol to inhibit the tumor growth and to increase the survival of the animals with tumors was established. A special contribution into tumor-inhibiting effect is made by each of its components. Treatment of Ehrlich carcinoma cells with two-component hybrid complex resulted in maximum reduction in the concentration of the most tumorigenic CD44high cells with simultaneous rise in the number of CD117+ cells that decreased an intensity of tumor growth by 74.70 ± 4.38% if compared with the control.

For the first time we report on ordered nano-sized hybrid complexes formation between fluorescent aggregates of potential-sensitive mitochondria probe 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolocarbocyanine iodide (JC-1) and ReVO4:Eu3 + nanoparticles (NPs) in aqueous solutions. To study the efficiency and driving forces of the dye aggregates/NPs complex formation, we analyzed the effects of the dye molecular structure on its aggregation behavior using JC-1 derivatives with different alkyl chain lengths and functional groups (JC-1/C4, JC-1/C3S). The aggregation behavior of the dyes in the solutions either with or without NPs has been analyzed within the Kasha exciton model framework. It was found that depending on the dye structure herringbone-type aggregation (for JC-1) and J-type aggregation (for JC-1/C4 dye) can be observed. The interactions with ReVO4:Eu3 + NPs take place due to Coulomb forces and provoke changes of the aggregate parameters such as the angle between polarization axes of the unit molecules and the line of molecular centers (θ), angle between transition dipole moments of the individual dye molecules (α) and center-to-center distance between molecules (R). The effect of NP shapes (spherical, spindle-like and rod-like) on the structure of hybrid complexes is studied. For the first time, using a microspectroscopic technique we demonstrate the JC-1 aggregates/NPs complex accumulation within the hepatocyte nucleus region in vitro experiment rather than a typical JC-1 specific accumulation in cell mitochondria.

Aggregation behavior of 2 nm, 10 nm × 50 nm, and 8 nm × 80 nm lanthanide orthovanadate nanoparticles under some electrolytes and physiological media influence was investigated. The results have shown that at the same CaCl2 concentration, particles of different sizes show different tendency to aggregate. At the same CaCl2 concentration in solution aggregation rates are higher for smaller particles. The critical coagulation concentration depends on particle size, and decreases as particle size decreases. The coagulation by inorganic electrolytes occurs in accordance with the Schulze-Hardy rule. In the case of organic electrolytes, including colloidal cationic surfactants, their coagulation points decrease with increasing hydrophobicity and surface activity of the cations. We have demonstrated significant effect of media composition (monovalent ions, serum) and thus the importance of NPs characterization under conditions that are representative of cell culture media or physiological conditions for understanding of NPs interaction with biological systems and for assessments of nanoparticle cytotoxicity. Solutions of nanoparticles in an isotonic medium (5% glucose) can be used for parenteral injection in experiments in vivo.

In this paper the process of nonfunctionalized negatively charged orthovanadate nanoparticle accumulation and redistribution in cells dependent on their shape and size was investigated. Aqueous colloidal solutions of nReVO 4 :Eu 3 + (Re = Gd, Y, La) luminescent nanocrystals of different sizes and shapes have been synthesized. The average sizes of spherical particles were 2, 20, and 300 nm, of spindle-like particles – 22 × 6.3 nm, and of rod-like particles – 57 × 4.4 nm. Luminescence of nReVO 4 :Eu 3 + nanocrystals was effectively excited by UV and visible irradiation. By means of luminescence microscopy and luminescence microspectroscopy, it has been revealed that spherical nanocrystals with an average diameter of 2 nm tend to accumulate mainly in the rat hepatocyte nuclei in situ and also in the isolated nuclei of these cells. An additional experiment has shown that nanoparticles reveal tropism to nuclear structural components. The penetration into nuclei does not require any modifications of the surface of nanoparticle and is governed by the shape and size of nanoparticle and also is determined by the cellular type.

Two distinct luminescence centers were revealed in ceria nanocrystals: first one – Ce3+ ions with 5d-4f luminescence at 390 nm, and second one – Ce4+–O2− complexes showing charge transfer (CT) luminescence at 630 nm. Intensity of Ce3+ luminescence depends directly on the concentration of oxygen vacancies in nanoceria and can be varied by means of change of both heat treatment atmosphere from oxidizing to reducing and the size of nanocrystal. Ce3+ luminescence can be used for visualization of the processes of interaction between ceria nanoparticles and reactive oxygen species using relative intensity of Ce3+ band as a measure of Ce4+/Ce3+ ratio during oxidation reaction.