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Thermal lens spectrometry is a high-sensitivity method for measuring the optical and thermal parameters of samples of different nature. To obtain both thermal diffusivity and absorbance-based signal measurements with high accuracy and precision, it is necessary to pay attention to the factors that influence the trueness of photothermal measurements. In this study, the features of liquid objects are studied, and the influence of optical and thermal effects accompanying photothermal phenomena are investigated. Thermal lens analysis of dispersed solutions and systems with photoinduced activity is associated with a large number of side effects, the impact of which on trueness is not always possible to determine. It is necessary to take into account the physicochemical properties and optical and morphological features of the nanophase and components exhibiting photoinduced activity. The results obtained make it possible to reduce systematic and random errors in determining the thermal-diffusivity-based and absorbance-based photothermal signals for liquid objects, and also contribute to a deeper understanding of the physicochemical processes in the sample. [ABSTRACT FROM AUTHOR]

Redox metabolism is an integral part of the glutathione system, encompassing reduced and oxidized glutathione, hydrogen peroxide, and associated enzymes. This core process orchestrates a network of thiol antioxidants like thioredoxins and peroxiredoxins, alongside critical thiol-containing proteins such as mercaptoalbumin. Modifications to thiol-containing proteins, including oxidation and glutathionylation, regulate cellular signaling influencing gene activities in inflammation and carcinogenesis. Analyzing thiol antioxidants, especially glutathione, in biological fluids offers insights into pathological conditions. This review discusses the analytical methods for biothiol determination, mainly in blood plasma. The study includes all key methodological aspects of spectroscopy, chromatography, electrochemistry, and mass spectrometry, highlighting their principles, benefits, limitations, and recent advancements that were not included in previously published reviews. Sample preparation and factors affecting thiol antioxidant measurements are discussed. The review reveals that the choice of analytical procedures should be based on the specific requirements of the research. Spectrophotometric methods are simple and cost-effective but may need more specificity. Chromatographic techniques have excellent separation capabilities but require longer analysis times. Electrochemical methods enable real-time monitoring but have disadvantages such as interference. Mass spectrometry-based approaches have high sensitivity and selectivity but require sophisticated instrumentation. Combining multiple techniques can provide comprehensive information on thiol antioxidant levels in biological fluids, enabling clearer insights into their roles in health and disease. This review covers the time span from 2010 to mid-2024, and the data were obtained from the SciFinder® (ACS), Google Scholar (Google), PubMed®, and ScienceDirect (Scopus) databases through a combination search approach using keywords. [ABSTRACT FROM AUTHOR]

Coatings with xenogenic materials, made of detonation nanodiamonds, provide additional strength and increase elasticity. A functionally developed surface of nanodiamonds makes it possible to apply antibiotics. Previous experiments show the stability of such coatings; however, studies on stability in the bloodstream and calcification of the material in natural conditions have yet to be conducted. Tritium-labeled nanodiamonds (negative and positive) were obtained by the tritium activation method and used to develop coatings for a pork aorta to analyze their stability in a pig’s bloodstream using a radiotracer technique. A chitosan layer was applied from a solution of carbonic acid under high-pressure conditions to prevent calcification. The obtained materials were used to prepare a porcine conduit, which was surgically stitched inside the pig’s aorta for four months. The aorta samples, including nanodiamond-coated and control samples, were analyzed for nanodiamond content and calcium, using the radiotracer and ICP-AES methods. A histological analysis of the materials was also performed. The obtained coatings illustrate a high in vivo stability and low levels of calcification for all types of nanodiamonds. Even though we did not use additional antibiotics in this case, the development of infection was not observed for negatively charged nanodiamonds, opening up prospects for their use in developing coatings [ABSTRACT FROM AUTHOR]

The diversity of catalytic activities and antioxidant properties of cerium oxide nanoparticles (CeO2 NPs) makes them promising materials for the theranostics of various diseases, especially those caused by disturbances in free radical homeostasis in living systems. Despite the fact that the functionalisation of nanoparticles' surface plays a critical role in nanomedicine applications, the effect of different coatings on their enzyme-like behaviour and antioxidant properties is still poorly understood, which limits the biomedical application of CeO2 NPs. This paper reports on the effect of low and high molecular weight biocompatible ligands on the SOD-like activity and radical scavenging properties of CeO2 NPs, which was analysed using a phosphate-rich medium resembling a natural environment. The results obtained show that these ligands modulate the SOD-like properties of CeO2 NPs as follows. Citrate and polysaccharide (maltodextrin and dextran) surface coatings increase the SOD-like activity of CeO2 NPs by an average of 2.2 times, and the protein corona (γ-globulin, γ-IgG) increases this activity by an average of 1.8 times. Citrate-coated CeO2 NPs and CeO2 nanoparticles modified with polysaccharide molecules are more effective SOD mimetics than CeO2@γ-IgG NPs. The SOD-like activity of phosphatidylcholine-coated CeO2 and CeO2@γ-IgG NPs is due to the combined action of nanoscale CeO2 and ligands. The antioxidant activity of CeO2 NPs after their modification with different ligands with respect to alkyl peroxyl radicals is multidirectional. Unexpectedly, citrate-, maltodextrin- and dextran-coated CeO2 NPs are more effective antioxidants than bare CeO2 NPs. CeO2 NPs modified with phosphatidylcholine or γ-IgG exhibited less radical-scavenging ability than bare CeO2 nanoparticles. Thus, common biocompatible ligands are able to regulate the biochemical activity of CeO2 NPs. [ABSTRACT FROM AUTHOR]

Modern heat-conducting materials require special attention to analyze their thermophysical properties. Compared to classical methods, thermal lens spectrometry (TLS) has advantages due to its high sensitivity to physical and chemical composition. To avoid a systematic error in the analysis of complex systems, it is necessary to realize the limits of the applicability of the method. This study considers the features of thermal-diffusivity measurements by TLS in the stationary state for dispersed systems with absorbances up to 0.05. The limits of applicability of the method in analyzing heterogeneous systems are shown, and a mathematical apparatus is proposed for indicating a systematic error in finding thermal diffusivity that does not exceed 1%. Graphene oxide (GO), which has attractive physicochemical properties, was used as the object of analysis. GO belongs to 2D objects, the study of which requires highly sensitive methods and special attention when discussing the results. The thermophysical properties of aqueous dispersions of graphene oxide in a wide range of concentrations (up to 2 g/L) and lateral sizes (up to 4 µm) were studied by TLS. It has been found that with increasing nanophase concentration, the thermal diffusivity of graphene oxide dispersions passes through a minimum, which can be used in solving thermal insulation problems. It has been established that prolonged laser irradiation of the dispersion leads to a change in thermal diffusivity, which indicates the photochemical reduction of graphene oxide. [ABSTRACT FROM AUTHOR]

The development of magnesium calcium phosphate bone cements (MCPCs) has garnered substantial attention. MCPCs are bioactive and biodegradable and have appropriate mechanical and antimicrobial properties for use in reconstructive surgery. In this study, the cement powders based on a (Ca + Mg)/P = 2 system doped with Zn2+ at 0.5 and 1.0 wt.% were obtained and investigated. After mixing with a cement liquid, the structural and phase composition, morphology, chemical structure, setting time, compressive strength, degradation behavior, solubility, antibacterial activities, and in vitro behavior of the cement materials were examined. A high compressive strength of 48 ± 5 MPa (mean ± SD) was achieved for the cement made from Zn2+ 1.0 wt.%-substituted powders. Zn2+ introduction led to antibacterial activity against Staphylococcus aureus and Escherichia coli strains, with an inhibition zone diameter of up to 8 mm. Biological assays confirmed that the developed cement is cytocompatible and promising as a potential bone substitute in reconstructive surgery. [ABSTRACT FROM AUTHOR]

Excitation–emission matrix (EEM) fluorescence spectroscopy of unmodified (pristine) fullerenes C60 and C70 in benzene, toluene, and n-hexane at room temperature was used for their quantification by their solvent-dependent EEM bands specific to each fullerene. The intensity and parameters of fluorescence depend on both the fullerene and solvent and provide the conditions for the quantification of both fullerenes in their mixtures without separation. The detection limits for C60 in n-hexane and C70 in benzene under the selected conditions are 7 and 2 nmol/L, respectively. The approach was tested for model and real mixtures of fullerenes C60 and C70. [ABSTRACT FROM AUTHOR]

A fast method for preparing aqueous graphene oxide (GO) dispersions by electrochemical oxidation of a graphite anode without preliminary intercalation with oxidizing agents is proposed. Ultrasonic probing was used in the modulation mode of ultrasonic waves (work/rest) for more efficient graphite oxidation–exfoliation. It is shown that the 4/2 s mode of ultrasonic modulation is the most effective due to the probe material's low corrosion while maintaining the optimum synthesis temperature not exceeding 30–35 °C and achieving the best characteristics of the resulting product. Three cases of anodic oxidation of graphite to obtain graphene oxide were considered: (1) a combined cathode–anode compartment, (2) a split cathode–anode salt-bridged compartment, and (3) separated anode compartment with a 3.5 kDa dialysis membrane. It was determined that the approach to synthesis with a divided cathode–anode compartment makes it possible to obtain GO sheets with fewer defects compared to chemical methods or methods with a combined cathode–anode compartment and makes it possible to control the oxidation degree of the material (C:O ratio) by varying the current density. The prepared samples showed good stability for more than six months. The spectral and morphological characteristics were studied. Using chemiluminometry in the luminol/Co(II)/H2O2 system, the antioxidant properties concerning three key reactive oxygen species (H2O2, superoxide anion radical, and hydroxyl radical) were demonstrated. It was also shown that the prepared GO dispersions do not induce lipid and phospholipid peroxidation. [ABSTRACT FROM AUTHOR]

Thermal lens spectrometry along with spectrophotometric titration were used to assess the composition of the complex of oxidized cytochrome c (ferricytochrome c) with 1,1′,2,2′-tetraoleyl cardiolipin, which plays a key role in the initiation of apoptosis. Spectrophotometric titration was carried out for micromolar concentrations at which the complex is mainly insoluble, to assess the residual concentration in the solution and to estimate the solubility of the complex. Thermal lens spectrometry was used as a method of molecular absorption spectroscopy, which has two advantages over conventional optical transmission spectroscopy: the higher sensitivity of absorbance measurements and the possibility of studying the light absorption by chromophores and heat transfer in complex systems, such as living cells or tissues. Thermal lens measurements were carried out at nanomolar concentrations, where the complex is mainly in solution, i.e., under the conditions of its direct measurements. From the thermal lens measurements, the ratios of cytochrome c and cardiolipin in the complex were 50 at pH 7.4; 30 at pH 6.8; and 10 at pH 5.5, which fit well to the spectrophotometric data. The molecular solubility of the complex at pH 6.8–7.4 was estimated as 30 µmol/L. [ABSTRACT FROM AUTHOR]

The growing interest in heat-conducting nanofluids requires highly sensitive methods for analyzing the thermal properties. Thermal lens spectrometry (TLS), despite its advantages over classical methods, does not have a general approach for measuring and interpreting results for dispersed systems. In this paper, for nanofluids of silicon oxide in water in a wide range of concentrations and sizes, the selection of measurement parameters for transient and steady-state thermal lensing is justified, and the interpretation of the results of thermal diffusivity measurements is substantiated. The features of the measurements of thermal diffusivity by TLS under stationary states for dispersed systems are considered. Using this approach, it is possible to detect and distinguish thermal effects with high accuracy. For dispersions of silicon oxide, with increasing concentrations, the thermal diffusivity passes through a minimum threshold. Silicon oxide dispersions can be used both as coolants or as heat-removing liquids by selecting the particle size and concentration. [ABSTRACT FROM AUTHOR]

A simultaneous steady-state and transient photothermal-lens modality was used for both the thermal and optical parameters of aqueous dispersed systems (carbon and silica nanoparticles, metal iodides, surfactants, heme proteins, albumin, and their complexes). Heat-transfer parameters (thermal diffusivity and thermal effusivity), the temperature gradient of the refractive index, light absorption, and concentration parameters were assessed. To simultaneously measure thermal and optical parameters, the time scale of thermal lensing (characteristic time, t c ) should correspond to an excitation beam size of 60–300 µm, and the relative time intervals 0.5 ÷ 5 t c and (5 ÷ 20) t c should be selected for transient and steady-state measurements, respectively. Dual-beam thermal-lens spectrometers in a mode-mismatched optical schematic at various excitation wavelengths were built. The spectrometers implement back-synchronized detection, providing different measurement conditions for the heating and cooling parts of the thermal-lens cycle. By varying the measurement parameters depending on the dispersed system, the conditions providing the suitable precision (replicability, repeatability, and reproducibility) of thermal-lens measurements were found; setups with a broad excitation beam (waist size, 150 and 300 μm) provide longer times to attain a thermal equilibrium and, thus, the better precision of measurements of thermal diffusivity. [ABSTRACT FROM AUTHOR]

Generalized anxiety disorder (GAD) is a prevalent disorder. The search for biomarkers may contribute to new knowledge about molecular pathogenesis and treatment. Since oxidative stress and micronutrient imbalance play a key role in the development of mental disorders, we aimed to study salivary antioxidant capacity and magnesium in patients with GAD in an anxiety model of solving problems with increasing complexity. The study subgroup consisted of 15 patients with GAD, and 17 healthy volunteers of the same age made up the control subgroup. Participants took a test with six levels of difficulty, which included false feedback. In this test, the participants were asked to remember the colors of balloons and react when the color changed. The reaction time, the number of correct answers, as well as biochemical parameters such as the antioxidant capacity of saliva and salivary magnesium, were assessed. There was no difference in the results of the quest between the subgroups; however, anxious participants spent more time at the moment of experimental frustration due to incorrect feedback and additional negative psycho-emotional load. Antioxidant capacity did not differ between the subgroups both before and after the experimental session. Average antioxidant capacity also did not change significantly at the endpoint of the experiment. However, the endpoint antioxidant capacity correlated negatively with the reaction time in anxious patients in the second block (where the false feedback as a frustrating factor appeared). Magnesium was initially significantly higher in the group of anxious participants and decreased at the experiment endpoint; in healthy patients, there were no changes in salivary magnesium at the endpoint. In conclusion, the compensatory potential of oxidative metabolism and magnesium in patients with GAD was spent with additional psycho-emotional stress, in contrast to healthy individuals, but it was sufficient to avoid exhaustion during experimental frustrating exposure. [ABSTRACT FROM AUTHOR]

A semi-automated diffusion-dialysis purification procedure is proposed for the preparation of uncontaminated graphene oxide (GO) aqueous dispersions. The purification process is integrated with analytical-signal processing to control the purification degree online by several channels: oxidation-reduction potential, conductivity, and absorbance. This approach reduces the amounts of reagents for chemical treatment during dialysis. The total transition metal (Mn and Ti) content was reduced to a sub-ppb level (assessed by slurry nebulization in inductively coupled plasma optical atomic emission spectroscopy). Purified aqueous GO samples possess good stability for about a year with a zeta-potential of ca. −40 mV and a lateral size of ca. sub-µm. Purified GO samples showed increased antioxidant properties (up to five times compared to initial samples according to chemiluminometry by superoxide-radical (O2−) generated in situ from xanthine and xanthine oxidase with the lucigenin probe) and significantly decreased peroxidase-like activity (assessed by the H2O2–L-012 system). [ABSTRACT FROM AUTHOR]

New sodium vanadium(III) hydrogenphosphate hydrate NaV(HPO4)2(H2O)0.5 and sodium vanadium(III) hydrogenphosphate β‐NaV(HPO4)2 were prepared in mild hydrothermal conditions. The crystal structures of NaV(HPO4)2(H2O)0.5 [space group Cc, Z = 4, a = 8.46174(19) Å, b = 9.52583(19) Å, c = 8.69376(15) Å, β = 110.9553(11) °, V = 654.41(2) Å3] and β‐NaV(HPO4)2 [space group C2/c, Z = 4, a = 7.8681(3) Å, b = 9.8451(3) Å, c = 8.5180(2) Å, β = 107.626(2) °, V = 628.85(3) Å3] were solved and refined from X‐ray powder diffraction data. Both compounds were used as precursors in a new route for the preparation of attractive cathode material β‐NaVP2O7. The formation of the structure motive providing fast sodium ion diffusion at the first synthesis stage and its further conservation upon stepwise dehydration was revealed. The oversized Na+‐embedding channels are stabilized by site‐coordinated water in NaV(HPO4)2(H2O)0.5 structure. The topology resemblance and difference in known sodium vanadium(III) complex phosphates are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Aqueous dispersions of an unmodified (pristine) (AFD) nY@C82 (symmetry C2v) endofullerene were produced with a nearly 100% yield relative to the initial toluene solution of the endofullerene. To the best of our knowledge, this is the first report of this kind of endofullerene aqueous dispersions. The solvent‐exchange ultrasound‐assisted procedure requires no modification of the endofullerene surface or addition of any stabilizing agents into the aqueous phase. The procedure is applicable to any endohedral metallofullerene aqueous dispersions suitable for biomedical applications. The resulting dispersions are stable for at least 6 months. For the produced aqueous dispersions of Y@C82, the zeta potential of ca. –42 mV shows good stability; the average diameter of clusters was as small as ca. 120 nm. Techniques for purification and purity control of nY@C82 and of the intermediate toluene solution of Y@C82 were developed. The residual quantity of organic compounds was less than 1 ppb after the purification. Based on ICP–AES, headspace GC–MS, and MALDI–TOF, a procedure to assess endofullerene concentrations in the aqueous phase was proposed. [ABSTRACT FROM AUTHOR]

Pyrochemistry is a promising technology that can provide benefits for the safe reprocessing of relatively fresh spent nuclear fuel with a short storage time (3–5 years). The radioactive waste emanating from this process is an electrolyte (LiCl–KCl) mixture with fission products included. Such wastes are rarely immobilized through common matrices such as cement and glass. In this study, samples of ceramic materials, based on natural bentonite clay, were studied as matrices for radioactive waste in the form of LiCl–KCl eutectic. The phase composition of the samples, and their mechanical, hydrolytic, and radiation resistance were characterized. The possibility of using bentonite clay as a material for immobilizing high-level waste arising from pyrochemical processing of spent nuclear fuel is further discussed in this paper. [ABSTRACT FROM AUTHOR]

Background: Fullerenes and metallofullerenes can be considered promising nanopharmaceuticals themselves and as a basis for chemical modification. As reactive oxygen species homeostasis plays a vital role in cells, the study of their effect on genes involved in oxidative stress and anti-inflammatory responses are of particular importance. Methods: Human fetal lung fibroblasts were incubated with aqueous dispersions of C60, C70, and Gd@C82 in concentrations of 5 nM and 1.5 µM for 1, 3, 24, and 72 h. Cell viability, intracellular ROS, NOX4, NFκB, PRAR-γ, NRF2, heme oxygenase 1, and NAD(P)H quinone dehydrogenase 1 expression have been studied. Results & conclusion: The aqueous dispersions of C60, C70, and Gd@C82 fullerenes are active participants in reactive oxygen species (ROS) homeostasis. Low and high concentrations of aqueous fullerene dispersions (AFD) have similar effects. C70 was the most inert substance, C60 was the most active substance. All AFDs have both "prooxidant" and "antioxidant" effects but with a different balance. Gd@C82 was a substance with more pronounced antioxidant and anti-inflammatory properties, while C70 had more pronounced "prooxidant" properties. [ABSTRACT FROM AUTHOR]

The antioxidant potential (capacity and activity) of aqueous fullerene dispersions (AFD) of non-functionalized C60, C70, and Gd@C82 endofullerene (in micromolar concentration range) was estimated based on chemiluminescence measurements of the model of luminol and generation of organic radicals by 2,2′-azobis(2-amidinopropane) dihydrochloride (ABAP). The antioxidant capacity was estimated by the TRAP method, from the concentration of half-suppression, and from the suppression area in the initial period. All three approaches agree and show that the antioxidant capacity of AFDs increased in the order Gd@C82 < C70 < C60. Mathematical modeling of the long-term kinetics data was used for antioxidant activity estimation. The effect of C60 and C70 is found to be quenching of the excited product of luminol with ABAP-generated radical and not an actual antioxidant effect; quenching constants differ insignificantly. Apart from quenching with a similar constant, the AFD of Gd@C82 exhibits actual antioxidant action. The antioxidant activity in Gd@C82 is 300-fold higher than quenching constants. [ABSTRACT FROM AUTHOR]

Procedures for the photothermal lens determination of metals and organic compounds, on the basis of solid-phase mesoporous optical-sensing materials (polymethacrylate [PMA]) matrices with immobilized reagents, were developed. These procedures combine (i) selective and efficient preconcentration of trace substances to be analyzed in specially designed and synthesized transparent mesoporous PMA plates; (ii) sensitive determination with the reliable and traceable photometric reactions previously developed for classical spectrophotometry; and (iii) the sensitivity enhancement of photothermal lens detection in polymers, which provides at least a ten-fold increase in sensitivity compared with solutions due to polymer thermo-optical properties (solid phase-enhanced thermal lensing). It is shown that the overall sensitivity of photothermal lens measurements in PMA matrices is two orders higher than photometric absorbance measurements for the same excitation source power, which is in good agreement with the expected theoretical sensitivity. Changes in the preparation of transparent PMA plates and analytical procedures for photothermal measurements compared with spectrophotometry are discussed. PMA matrices modified with various analytical reagents were applied to trace determination of Hg(II), Fe(II), Ag(I), Cu(II), and ascorbic acid, with subnanomolar to nanomolar limits of detection. [ABSTRACT FROM AUTHOR]

NASICON-structured cathode materials are considered as possible candidates for high-performance Na-ion batteries. Further increase of energy density of the Na 3 V 2 (PO 4) 3 may be achieved by substitution of the V cations by other transition metals. Here, we show that a family of Na 3+x Mn x V 2-x (PO 4) 3 (0≤x≤1, Δx=0.2) cathode materials demonstrates remarkable diversity of the electrochemical properties and phase transformations depending on degree of substitution and cut-off voltage. An intermediate "Na 2 M 2 (PO 4) 3 " phase was found for all compounds studied by means of operando powder X-ray diffraction. When Mn content is low (x~0–0.4), it coexists with Na 3+x Mn x V 2-x (PO 4) 3 or Na 1+x Mn x V 2-x (PO 4) 3. Increase in Mn content extends the length of the solid solution region corresponding to sodiated, intermediate and desodiated phases. All Mn-substituted samples are characterized by additional high-voltage plateau (~3.9 V) at charge-discharge curves. Na 3+x Mn x V 2-x (PO 4) 3 (x≥0.4) compositions exhibit 8–10% energy density gain in comparison to Na 3 V 2 (PO 4) 3 material, Na 3.2 Mn 0.2 V 1.8 (PO 4) 3 and Na 3.4 Mn 0.4 V 1.6 (PO 4) 3 are most preferable in terms of cycling stability. Image 1 • Na 3+x Mn x V 2-x (PO 4) 3 cathode materials demonstrate 5–10% energy gain over Na 3 V 2 (PO 4) 3. • Increase in Mn content extends the length of the solid solution regions. • An intermediate "Na 2 M 2 (PO 4) 3 " phase was found for Na 3+x Mn x V 2-x (PO 4) 3 compounds. • Similar structural transitions may result in different electrochemical signatures. [ABSTRACT FROM AUTHOR]

The interaction of inorganic nanomaterials with biological fluids containing proteins can lead not only to the formation of a protein corona and thereby to a change in the biological activity of nanoparticles but also to a significant effect on the structural and functional properties of the biomolecules themselves. This work studied the interaction of nanoscale CeO 2 , the most versatile nanozyme, with human serum albumin (HSA). Fourier transform infrared spectroscopy, MALDI-TOF mass spectrometry, UV-vis spectroscopy, and fluorescence spectroscopy confirmed the formation of HSA-CeO 2 nanoparticle conjugates. Changes in protein conformation, which depend on the concentration of both citrate-stabilized CeO 2 nanoparticles and pristine CeO 2 nanoparticles, did not affect albumin drug-binding sites and, accordingly, did not impair the HSA transport function. The results obtained shed light on the biological consequences of the CeO 2 nanoparticles' entrance into the body, which should be taken into account when engineering nanobiomaterials to increase their efficiency and reduce the side effects.

Fullerenes and metallofullerenes play an active role in homeostasis of reactive oxygen species and may cause oxidative damage to cells. As pristine fullerenes are a basis for derivatization, studying oxidative DNA damage/repair and apoptosis is important in terms of genotoxicity and cytotoxicity for their biomedical application. Aqueous dispersions of C 60 , C 70 , and Gd@C 82 (5 nM and 1.5 μM) were cultured with human fetal lung fibroblasts for 1, 3, 24, and 72 h. Oxidative DNA damage/repair was assessed through concentration of 8-oxodG, double-strand breaks, and activation of BRCA1. Activity of apoptosis was assessed through the BCL2/BAX ratio. All three fullerenes caused oxidative modification of DNA at the early stages; C 60 caused the most long-term damage, Gd@C 82 caused the most short-term damage, and C 70 caused "wave-like" dynamics. The dynamics of DNA repair correlated with the dynamics of oxidative damage, but Gd@C 82 caused more prolonged activation of the repair system than C 60 or C 70 . The oxidative toxicity of Gd@C 82 , is minor and the oxidative toxicity of C 60 is mild and short-term, in contrast to C 70 . In relation to the studied effects, the fullerenes can be arranged in a safety row of Gd@C 82 > C 60 > C 70 .

Endohedral metal fullerene are potential nanopharmaceuticals for MRI; thus, it is important to study their effect on reactive oxygen species (ROS) homeostasis. Superoxide anion radical is one of the key ROS. The reactivity of aqueous dispersions of pristine (non-functionalized) fullerenes and Gd@C 82 endofullerene have been studied with respect to superoxide in the xanthine/xanthine oxidase chemiluminescence system. It was found that C 60 and C 70 in aqueous dispersions react with superoxide as scavengers by a similar mechanism; differences in activity are determined by cluster parameters, primarily the concentration of available, acting molecules at the surface. Gd endofullerene is characterized by a significantly (one-and-a-half to two orders of magnitude) higher reactivity with respect to C 60 and C 70 and is likely to exhibit nanozyme (SOD-mimic) properties, which can be accounted for by the nonuniform distribution of electron density of the fullerene cage due to the presence of the endohedral atom; however, in the cell model, Gd@C 82 showed the lowest activity compared to C 60 and C 70 , which can be accounted for by its higher affinity for the lipid phase., Competing Interests: The authors declare no conflict of interest.