Oxidative stress and genotoxic effects of diamond nanoparticles

A novel treatment approach using vitamin B12-conjugated sericin for mitigating nanodiamond-induced toxicity in darkling beetles

The escalating use of nanodiamonds (NDs) has raised concerns about their ecotoxicological impact, prompting exploration of therapeutic interventions. This paper pioneers the examination of Vitamin B12-conjugated sericin (VB12-SER) as a potential therapeutic approach against ND-induced toxicity in darkling beetles (Blaps polychresta). The study analyzes mortality rates and organ-specific effects, covering the testis, ovary, and midgut, before and after treatments. Following exposure to 10 mg NDs/g body weight, within a subgroup of individuals termed ND2 with a mortality rate below 50%, two therapeutic treatments were administered, including pure sericin (SER) at 10 mg/mL and VB12-SER at 10.12 mg/mL. Consequently, five experimental groups (control, SER, ND2, ND2+SER, ND2+SER+VB12) were considered. Kaplan-Meier survival analysis was performed to assess the lifespan distribution of the insects in these groups over a 30-d period. Analyses revealed increased mortality and significant abnormalities induced by NDs within the examined organs, including cell death, DNA damage, enzyme dysregulation, antioxidant imbalances, protein depletion, lipid peroxidation, and morphological deformities. In contrast, the proposed treatments, especially (ND2+SER+VB12), demonstrated remarkable recovery, highlighting VB12-conjugated SER's potential in mitigating ND-triggered adverse effects. Molecular docking simulations affirmed binding stability and favorable interactions of the VB12-SER complex with target proteins. This research enhances understanding of NDs' effects on B. polychresta, proposing it as an effective bioindicator, and introduces VB12-conjugated SER as a promising therapeutic strategy in nanotoxicological studies.

Investigation of potential cytotoxicity of a water-soluble, red-fluorescent [70]fullerene nanomaterial in Drosophila melanogaster

Fullerenes (C60, C70) as carbon nanomaterials can enter the environment through natural processes and anthropogenic activities, while synthetic fullerenes are commonly used in medicine in targeted therapies in association with antibodies, or anticancer and antimicrobial drugs. As the nanoparticles, they can pass through cell membranes and organelles and accumulate in the entire cytoplasm. The red-fluorescent, water-soluble [70]fullerene derivative C70-OMe-ser, which produces reactive oxygen species upon illumination with an appropriate wavelength, passed into the cytoplasm of the middle region in the Drosophila melanogaster digestive system. To determine whether [70]fullerene nanomaterials that produce fluorescence after entering the cell cytoplasm will hurt its homeostasis, it is necessary to investigate the activation of degenerative and possibly regenerative processes. In vivo, studies on the model species D. melanogaster may help to elucidate whether the water-soluble [70]fullerene derivative that produces fluorescence can still be considered among the most promising nanomaterials. The experiment involved feeding insects ad libitum with yeast paste supplemented with 40 µg of fullerenes/mL for 1 week and 1 month. Thus, adult females and males of D. melanogaster were divided into control (CWM, CWF, CMM, and CMF) and experimental groups (FWM, FWF, FMM, and FMF). The quantitative and qualitative analysis enabled the presentation of the effects of the water-soluble [70]fullerene derivatives on cell proliferation and degeneration. Our study presented that [70]fullerene derivative showed a cytoprotective effect and activated cell proliferation. Therefore, we could conclude that analyzed carbon nanomaterials seemed to be safe for the cells into which they have penetrated.

Comprehensive toxicity assessment of nanodiamond on Blaps polychresta: implications and novel findings

With the increasing development of nanomaterials, the use of nanodiamonds (NDs) has been broadly manifested in many applications. However, their high penetration into the ecosystem indubitably poses remarkable toxicological risks. This paper investigates the toxic effects of NDs on the darkling beetle, Blaps polychresta Forskal, 1775 (Coleoptera: Tenebrionidae). Survival analysis was carried out by monitoring the beetles for 30 d after the injection of four different doses of NDs. A dose of 10.0 mg NDs/g body weight, causing less than 50% mortality effect, was assigned in the analysis of the different organs of studied beetles, including testis, ovary, and midgut. Structural and ultrastructural analyses were followed using light, TEM, and SEM microscopes. In addition, a variety of stress markers and enzyme activities were assessed using spectrophotometric methods. Furthermore, cell viability and DNA damage were evaluated using cytometry and comet assay, respectively. Compared to the control group, the NDs-treated group was exposed to various abnormalities within all the studied organs as follows. Significant disturbances in enzyme activities were accompanied by an apparent dysregulation in the antioxidant system. The flow cytometry results indicated a substantial decrease of viable cells along with a rise of apoptotic and necrotic cells. The comet assay demonstrated a highly increased level of DNA damage. Likewise, histological analyses accentuated the same findings showing remarkable deformities in the studied organs. Prominently, the research findings substantially contribute for the first time to evaluating the critical effects of NDs on B. polychresta, adopted as the bioindicator in this paper.

Survival, growth and digestive functions after exposure to nanodiamonds - Transgenerational effects beyond contact time in house cricket strains

The long-term exposure effects of nanodiamonds (NDs), spanning an organism's entire lifespan and continuing for subsequent generation, remain understudied. Most research has focused on evaluating their biological impacts on cell lines and selected organisms, typically over short exposure durations lasting hours or days. The study aimed to assess growth, mortality, and digestive functions in wild (H) and long-lived (D) strains of Acheta domesticus (Insecta: Orthoptera) after two-generational exposure to NDs in concentrations of 0.2 or 2 mg kg-1 of food, followed by their elimination in the third generation. NDs induced subtle stimulating effect that depended on the strain and generation. In the first generation, more such responses occurred in the H than in the D strain. In the first generation of H strain insects, contact with NDs increased survival, stimulated the growth of young larvae, and the activity of most digestive enzymes in mature adults. The same doses and exposure time did not cause similar effects in the D strain. In the first generation of D strain insects, survival and growth were unaffected by NDs, whereas, in the second generation, significant stimulation of those parameters was visible. Selection towards longevity appears to support higher resistance of the insects to exposure to additional stressor, at least in the first generation. The cessation of ND exposure in the third generation caused potentially harmful changes, which included, e.g., decreased survival probability in H strain insects, slowed growth of both strains, as well as changes in heterochromatin density and distribution in nuclei of the gut cells in both strains. Such a reaction may suggest the involvement of epigenetic inheritance mechanisms, which may become inadequate after the stress factor is removed.

Does Selection for Longevity in Acheta domesticus Involve Sirtuin Activity Modulation and Differential Response to Activators (Resveratrol and Nanodiamonds)?

Sirtuins, often called "longevity enzymes", are pivotal in genome protection and DNA repair processes, offering insights into aging and longevity. This study delves into the potential impact of resveratrol (RV) and nanodiamonds (NDs) on sirtuin activity, focusing on two strains of house crickets (Acheta domesticus): the wild-type and long-lived strains. The general sirtuin activity was measured using colorimetric assays, while fluorescence assays assessed SIRT1 activity. Additionally, a DNA damage test and a Kaplan-Meier survival analysis were carried out. Experimental groups were fed diets containing either NDs or RV. Notably, the long-lived strain exhibited significantly higher sirtuin activity compared to the wild-type strain. Interestingly, this heightened sirtuin activity persisted even after exposure to RVs and NDs. These findings indicate that RV and NDs can potentially enhance sirtuin activity in house crickets, with a notable impact on the long-lived strain. This research sheds light on the intriguing potential of RV and NDs as sirtuin activators in house crickets. It might be a milestone for future investigations into sirtuin activity and its potential implications for longevity within the same species, laying the groundwork for broader applications in aging and lifespan extension research.

Age- and Lifespan-Dependent Differences in GO Caused DNA Damage in Acheta domesticus

The rising applicability of graphene oxide (GO) should be preceded by detailed tests confirming its safety and lack of toxicity. Sensitivity to GO of immature, or with different survival strategy, individuals has not been studied so far. Therefore, in the present research, we focused on the GO genotoxic effects, examining selected parameters of DNA damage (total DNA damage, double-strand breaks-DSB, 8-hydroxy-2'-deoxyguanosine-8-OHdG, abasic site-AP sites), DNA damage response parameters, and global methylation in the model organism Acheta domesticus. Special attention was paid to various life stages and lifespans, using wild (H), and selected for longevity (D) strains. DNA damage was significantly affected by stage and/or strain and GO exposure. Larvae and young imago were generally more sensitive than adults, revealing more severe DNA damage. Especially in the earlier life stages, the D strain reacted more intensely/inversely than the H strain. In contrast, DNA damage response parameters were not significantly related to stage and/or strain and GO exposure. Stage-dependent DNA damage, especially DSB and 8-OHdG, with the simultaneous lack or subtle activation of DNA damage response parameters, may result from the general life strategy of insects. Predominantly fast-living and fast-breeding organisms can minimize energy-demanding repair mechanisms.

Does age pay off? Effects of three-generational experiments of nanodiamond exposure and withdrawal in wild and longevity-selected model animals

Nanodiamonds (NDs) are considered a material with low toxicity. However, no studies describe the effects of ND withdrawal after multigenerational exposure. The aim was to evaluate ND exposure (in the 1st and 2nd generations) effects at low concentrations (0.2 or 2 mg kg^-1) and withdrawal (in the 3rd generation) in the wild (H) and longevity-selected (D) model insect Acheta domesticus. We measured selected oxidative stress parameters, immunity, types of cell death, and DNA damage. Most of the results obtained in the 1st generation, e.g., catalase (CAT), total antioxidant capacity (TAC), heat shock proteins (HSP70), defensins, or apoptosis level, confirmed no significant toxicity of low doses of NDs. Interestingly, strain-specific differences were observed. D-strain crickets reduced autophagy, the number of ROS+ cells, and DNA damage. The effect can be a symptom of mobilization of the organism and stimulation of physiological defense mechanisms in long-living organisms. The 2nd-generation D-strain insects fed ND-spiked food at higher concentrations manifested a reduction in CAT, TAC, early apoptosis, and DNA damage, together with an increase in HSP70 and defensins. ROS+ cells and cells with reduced membrane potential and autophagy did not differ significantly from the control. H-strain insects revealed a higher number of ROS+ cells and cells with reduced membrane potential, decreased CAT activity, and early apoptosis. Elimination of NDs from the diet in the 3rd generation did not cause full recovery of the measured parameters. We noticed an increase in the concentration of HSP70 and defensins (H-strain) and a decrease in apoptosis (D-strain). However, the most visible increase was a significant increase in DNA damage, especially in H-strain individuals. The results suggest prolonged adverse effects of NDs on cellular functions, reaching beyond "contact time" with these particles. Unintentional and/or uncontrolled ND pollution of the environment poses a new challenge for all organisms inhabiting it, particularly during multigenerational exposure.

Recent Synergy of Nanodiamonds: Role in Brain-Targeted Drug Delivery for the Management of Neurological Disorders

The aim of the present review article is to summarize the role of nanodiamonds in various neurological diseases. We have taken related literature of making this review article from ScienceDirect, springer, Research gate, PubMed, Sci-finder, etc. The current approaches for treating neurological conditions such as glioblastoma includes chemotherapy or combination anti-retro viral therapy for HIV (human immunodeficiency virus) or use of anti-Alzheimer drugs during cognitive impairment. These approaches can provide only symptomatic relief as they do not target the cause of the disease due to their inability to penetrate the blood brain barrier. On long-term use, they may cause CNS toxicity due to accumulation in the brain. So nanodiamonds could prove as a promising approach in the brain targeting of the bioactive and to treat many neurological disorders such as Alzheimer's disease, Parkinson's disease, brain tumor (glioblastoma), HIV, amyotrophic multiple sclerosis, Huntington disease, stroke (cerebrovascular attack), batten disease, schizophrenia, epilepsy, and bacterial infections (encephalitis, sepsis, and meningitis) due to their ability to penetrate the blood-brain barrier and owing to their excellent surface properties, i.e., nano size and high surface area, ease of functionalization, multiple drug binding, and biocompatibility; they can be useful for brain targeted drug delivery with minimal side effects.

Time-delayed effects of a single application of AgNPs on structure of testes and functions in Blaps polychresta Forskal, 1775 (Coleoptera: Tenebrionidae)

Silver nanoparticles (AgNPs) are currently the most frequently used engineered nanoparticles. The penetration of AgNPs into ecosystems is undeniable, and their adverse effects on organism reproduction are of fundamental importance for ecosystem stability. In this study, the survival time of the Egyptian beetle Blaps polychresta Forskal, 1775 (Coleoptera: Tenebrionidae), after a single application of 7 different doses, was calculated for 30 days. Then, for the group for which the effect on mortality was calculated as LOAEL - the Lowest Observed Adverse Effect Level, namely, 0.03 mg AgNPs/g body weight (b.w.t.), the following were assessed: structure and ultrastructure of gonads by TEM and SEM, cell viability by cytometry, DNA damage by the comet assay, and a variety of stress markers by spectrophotometric methods. A dose-dependent reduction in the survival time of the insects was revealed. Detailed analysis of the testes of beetles treated with 0.03 mg AgNPs/g b.w.t. revealed numerous adverse effects of nanoparticles in structure and ultrastructure, accompanied by increased apoptosis (but not necrosis), increased DNA damage, increased lipid peroxidation, and decreased levels of antioxidant enzymes. Most likely, the observed results are connected with the gradual release of Ag⁺ from the surface of the nanoparticles, which, once applied, are internalized in cells and become a long-lasting, stable source of Ag⁺ ions. Thus, a single exposure to AgNPs may have the effects of chronic exposure and lead to structural damage and dysfunction of the gonads of B. polychresta.

Multigenerational selection towards longevity changes the protective role of vitamin C against graphene oxide-induced oxidative stress in house crickets

This research was designed to investigate changes that can arise in an invertebrate organism due to stress caused by a strong prooxidant, graphene oxide (GO), and a potent antioxidant, vitamin C. The study aimed to investigate if vitamin C may support convalescence after chronic GO intoxication. We investigated the toxicity of chronic dietary graphene oxide administration in house cricket (Acheta domesticus) types: wild and selected for longevity (with a better developed antioxidant system, conducive to long life). Vitamin C was applied immediately after cessation of graphene oxide intoxication to check if it can support the remedial effect. The condition of cells, DNA stability, catalase activity, and the reproduction potential, measured as the Vitellogenin (Vg) protein expression level, were investigated in control and GO treated groups, recovery groups (-GO), and recovery groups with Vit. C (-GO + Vit.C). In this study vitamin C had no evident remedial effect on the house crickets exposed to graphene oxide. Most probably, the mechanism of vitamin C action, in case of intoxication with nanoparticles, is much more complicated. In the context of the results obtained, it is worth considering whether Vit. C, applied after GO intoxication, causes further disturbance of homeostasis in terms of the cells' redox potential.

Do nanoparticles cause hormesis? Early physiological compensatory response in house crickets to a dietary admixture of GO, Ag, and GOAg composite

This study aimed to identify the physiological responses of house cricket females following short-term exposure to relatively low dietary doses of graphene oxide (GO, 20 μg · g^-1 food), silver (Ag, 400 μg · g^-1 food) nanoparticles (NPs), or graphene oxide‑silver nanoparticle composite (GO-AgNPs, 20: 400 μg · g^-1 food). Energy intake and distribution were measured on the third, sixth, and tenth day. A semi-quantitative API®ZYM assay of digestive enzyme fingerprints was performed on the third and tenth day of continuous treatment. Physicochemical properties of the NPs were obtained by combining SEM, EDX spectrometry, AFM, and DLS techniques. The obtained results showed decreased energy consumption, particularly assimilation as an early response to dietary NPs followed by compensatory changes in feeding activity leading to the same consumption and assimilation throughout the experimental period (10 days). The increased activities of digestive enzymes in NP-treated females compared to the control on the third day of the experiment suggest the onset of compensatory reactions of the day. Moreover, the insects treated with GO-AgNP composite retained more body water, suggesting increased uptake. The observed changes in the measured physiological parameters after exposure to NPs are discussed in light of hormesis.

Application of Carbon Nanoparticles in Oncology and Regenerative Medicine

Currently, carbon nanoparticles play a large role as carriers of various types of drugs, and also have applications in other fields of medicine, e.g., in tissue engineering, where they are used to reconstruct bone tissue. They also contribute to the early detection of cancer cells, and can act as markers in imaging diagnostics. Their antibacterial and anti-inflammatory properties are also known. This feature is particularly important in dental implantology, where various types of bacterial infections and implant rejection often occur. The search for newer and more effective treatments may lead to future use of nanoparticles on a large scale. In this work, the current state of knowledge on the possible use of nanotubes, nanodiamonds, and fullerenes in therapy is reviewed. Both advantages and disadvantages of the use of carbon nanoparticles in therapy and diagnostics have been indicated.

The Structure-Properties-Cytotoxicity Interplay: A Crucial Pathway to Determining Graphene Oxide Biocompatibility

Interest in graphene oxide nature and potential applications (especially nanocarriers) has resulted in numerous studies, but the results do not lead to clear conclusions. In this paper, graphene oxide is obtained by multiple synthesis methods and generally characterized. The mechanism of GO interaction with the organism is hard to summarize due to its high chemical activity and variability during the synthesis process and in biological buffers' environments. When assessing the biocompatibility of GO, it is necessary to take into account many factors derived from nanoparticles (structure, morphology, chemical composition) and the organism (species, defense mechanisms, adaptation). This research aims to determine and compare the in vivo toxicity potential of GO samples from various manufacturers. Each GO sample is analyzed in two concentrations and applied with food. The physiological reactions of an easy model Acheta domesticus (cell viability, apoptosis, oxidative defense, DNA damage) during ten-day lasting exposure were observed. This study emphasizes the variability of the GO nature and complements the biocompatibility aspect, especially in the context of various GO-based experimental models. Changes in the cell biomarkers are discussed in light of detailed physicochemical analysis.

Phytotoxic effect and molecular mechanism induced by nanodiamonds towards aquatic Chlorella pyrenoidosa by integrating regular and transcriptomic analyses

The growing diverse applications of nanodiamonds (NDs), especially as adsorbents and catalysts for wastewater treatment, have significantly increased their discharge and potential risk towards aquatic ecosystems. Although NDs have been certified for superior biocompatibility and lower toxicity towards numerous human cell lines, the characteristic response and underlying mechanism of aquatic microalgal response remains unclear. Here, the response of Chlorella pyrenoidosa to five concentrations of NDs was thoroughly investigated by comprehensive phenotypic and transcriptional examinations. Results indicated that higher concentration of NDs (50 mg/L) induced 75.4% growth inhibition, exacerbated oxidative stress and malformed morphology of microalgae after 48 h exposure. Meanwhile, the aggregated microalgae formed several flocs, apparently under 50 mg/L NDs. Noticeably, photosynthesis was susceptible to the NDs exposure. Although, the chlorophyll content and genes involved in photosynthesis were significantly improved by NDs, the results obtained from the photochemical parameters indicated that the excessive electrons during photosynthesis might be a pivotal reason for oxidative stress generation. Additionally, the genes included in amino acids metabolism and protein synthesis were up-regulated to alleviate the oxidative stress. Collectively, this work discloses the explicit molecular mechanisms of aquatic microalgae and provides comprehensive insights of potential aqueous environmental risk of gradually emergent NDs.

Vitellogenin expression, DNA damage, health status of cells and catalase activity in Acheta domesticus selected according to their longevity after graphene oxide treatment

The increased use of graphene oxide (GO) raises worrisome questions regarding its possible threat to various ecosystems. Invertebrates represent valuable organisms for environmental studies. The lifespan can influence the ability to cope with toxins, especially those that act via oxidative stress. Two strains of Acheta domesticus, which are selected for longevity, were tested. The main aim was to investigate how GO, when administrated in food, affects: the condition of cells, DNA stability, ROS generation and the reproduction potential (the Vitellogenin (Vg) protein expression). The "recovery effect" - after removing GO from the diet for 15 days - was also measured. The results revealed different responses to GO in the wild (H) and long-living (D) strains. The D strain had a higher catalase activity compared to the H strain on the 25th day of the imago stage. Removing GO from the food resulted in a decrease in the catalase activity to the level of the control. On the 5th day of the imago stage, the H strain had a higher cell mortality than the D strain in the GO-intoxicated groups. There was more DNA damage in the H strain compared to the long-living strain. A remedial effect was seen after the GO was removed from the diet. The total Vg protein expression was higher in the H strain and lower in the D strain. The results indicated a GO concentration-dependent outcome. In both strains, removing the GO from the food led to a high Vg expression. The Vg expression after GO treatment, particularly translation and post-translational processing, should be studied in detail in the future. The D strain of crickets had more specialized mechanisms for maintaining homeostasis than the H strain. Organisms can fight off negative effects of GO, especially when they have systems that are well developed against oxidative stress.

The sp3/sp2 carbon ratio as a modulator of in vivo and in vitro toxicity of the chemically purified detonation-synthesized nanodiamond via the reactive oxygen species generation

Nanodiamonds have been suggested as biocompatible materials and are suitable for various biomedical applications, but little is known about how to synthesize safer nanodiamonds. Herein, seven different detonation-synthesized nanodiamonds (DNDs) with sequential sp³/sp² carbon ratios were assembled by controlling the chemical purification parameters and the role of sp³/sp² carbon ratio on the toxicity of DNDs was investigated. Carbon black and nickel oxide nanoparticles were used as reference particles. The intrinsic reactive oxygen species (ROS) generation potential of DNDs was estimated by a 2'7'-dichlorofluorescein diacetate (DCFH-DA) assay, and these values showed a good negative correlation with the sp³/sp² carbon ratios, which implies that ROS generation increased as the sp³/sp² carbon ratio decreased. As a model to investigate inflammogenic potential of DND samples, a rat intratracheal instillation model was used as the lung is very sensitive to nanoparticle exposures. The sp³/sp² carbon ratios or the estimated values of ROS generation potential showed excellent linear correlations with the number of neutrophils and pro-inflammatory cytokines in bronchoalveolar lavage fluid at 24 h after instillation. Treatment of DND samples to THP-1 derived macrophages also showed that the sp³/sp² carbon ratios or the estimated values of ROS generation potential were closely related with the toxicity endpoints such as cell viability and pro-inflammatory cytokines. Taken together, these data demonstrate that the sp³/sp² carbon ratio is the key determinant for the toxicity of DNDs, which can be a useful tool for the safer-by-design approach of DNDs and the safety assessment of carbon nanoparticles.

Graphene oxide as a new anthropogenic stress factor - multigenerational study at the molecular, cellular, individual and population level of Acheta domesticus

Although interest in transgenerational phenomena is constantly growing, little is known about the long-term toxicity of nanoparticles. In this study we investigate the multigenerational effects of graphene oxide (GO) which was given to Acheta domesticus in low doses (0.2, 2 and 20 μg·g^-1 of food) for three subsequent generations. We assessed the influence of GO nanoparticles in many contexts, basing on parameters which represented different levels of biological organization: activity of antioxidant enzymes, level of apoptosis, DNA damage, histological analysis, hatching abilities, body mass and body length of insects, as well as their survival rate. The results have shown that exposing insects to nanoparticles over an extended period of time causes surprising intergenerational effects, based on significant differences in the life cycle and reproductive processes, which are not always dose-dependent. The second generation of insects appeared as the most unstable among the parameters that were studied, and did not match trends and patterns in the first and third generation categories. An increase of DNA damage was observed, but only in the third generation. This reduction of genome stability can be perceived as an essential element of adaptation, leading to an increase of genotype variants, which then undergo selection.

Developmental toxicity of carbon nanoparticles during embryogenesis in chicken

Nanoparticles (NPs) are very small particles present in a wide range of materials. There is a dearth of knowledge regarding their potential secondary effects on the health of living organisms and the environment. Increasing research attention, however, has been directed toward determining the effects on humans exposed to NPs in the environment. Although the majority of studies focus on adult animals or populations, embryos of various species are considered more susceptible to environmental effects and pollutants. Hence, research studies dealing mainly with the impacts of NPs on embryogenesis have emerged recently, as this has become a major concern. Chicken embryos occupy a special place among animal models used in toxicity and developmental investigations and have also contributed significantly to the fields of genetics, virology, immunology, cell biology, and cancer. Their rapid development and easy accessibility for experimental observance and manipulation are just a few of the advantages that have made them the vertebrate model of choice for more than two millennia. The early stages of chicken embryogenesis, which are characterized by rapid embryonic growth, provide a sensitive model for studying the possible toxic effects on organ development, body weight, and oxidative stress. The objective of this review was to evaluate the toxicity of various types of carbon black nanomaterials administered at the beginning of embryogenesis in a chicken embryo model. In addition, the effects of diamond and graphene NPs and carbon nanotubes are reviewed.

Toxicity of multi-wall carbon nanotubes inhalation on the brain of rats

This study was designed to investigate the brain toxicity following the respiratory contact with multi-wall carbon nanotubes (MWCNTs) in male Wistar rats. Rats were exposed to 5 mg/m3 MWCNT aerosol in different sizes and purities for 5 h/day, 5 days/week for 2 weeks in a whole-body exposure chamber. After 2-week exposure, mitochondrial isolation was performed from different parts of rat brain (hippocampus, frontal cortex, and cerebellum) and parameters of mitochondrial toxicity including mitochondrial succinate dehydrogenase (SDH) activity, generation of reactive oxygen species (ROS), mitochondrial membrane potential (MMP) collapse, mitochondrial swelling, and cytochrome c release, ATP level, mitochondrial GSH, and lipid peroxidation were evaluated. Our results demonstrated that MWCNTs with different characteristics, in size and purity, significantly (P < 0.05) decreased SDH activity, GSH, and ATP level, and increased mitochondrial ROS production, lipid peroxidation, mitochondrial swelling, MMP collapse, and cytochrome c release in the brain mitochondria. In conclusion, we suggested that MWCNTs with different characteristics, in size and purity, induce damage in varying degrees on the mitochondrial respiratory chain and increase mitochondrial ROS formation in different parts of rat brain (hippocampus, frontal cortex, and cerebellum).

Relationship between ROS production, MnSOD activation and periods of fasting and re-feeding in freshwater shrimp Neocaridina davidi (Crustacea, Malacostraca)

The middle region of the digestive system, the midgut of freshwater shrimp Neocaridina davidi is composed of a tube-shaped intestine and the hepatopancreas formed by numerous caeca. Two types of cells have been distinguished in the intestine, the digestive cells (D-cells) and regenerative cells (R-cells). The hepatopancreatic tubules have three distinct zones distinguished along the length of each tubule—the distal zone with R-cells, the medial zone with differentiating cells, and the proximal zone with F-cells (fibrillar cells) and B-cells (storage cells). Fasting causes activation of cell death, a reduction in the amount of reserve material, and changes in the mitochondrial membrane potential. However, here we present how the concentration of ROS changes according to different periods of fasting and whether re-feeding causes their decrease. In addition, the activation/deactivation of mitochondrial superoxide dismutase (MnSOD) was analyzed. The freshwater shrimps Neocaridina davidi (Crustacea, Malacostraca, Decapoda) were divided into experimental groups: animals starved for 14 days, animals re-fed for 4, 7, and 14 days. The material was examined using the confocal microscope and the flow cytometry. Our studies have shown that long-term starvation increases the concentration of free radicals and MnSOD concentration in the intestine and hepatopancreas, while return to feeding causes their decrease in both organs examined. Therefore, we concluded that a distinct relationship between MnSOD concentration, ROS activation, cell death activation and changes in the mitochondrial membrane potential occurred.

Size dependent oxidative stress response of the gut of Daphnia magna to functionalized nanodiamond particles

Nanodiamonds are a type of engineered nanomaterial with high surface area that is highly tunable and are being proposed for use as a material for medical imaging or drug delivery to composites. With their potential for widespread use they may potentially be released into the aquatic environment as are many chemicals used for these purposes. It is generally thought that nanodiamonds are innocuous, but toxicity may occur due to surface functionalization. This study investigated the potential oxidative stress and antioxidant response of enterocytes in a freshwater invertebrate, Daphnia magna, a common aquatic invertebrate for ecotoxicological studies, in response to two types of functionalized nanodiamonds (polyallylamine and oxidized). We also examined how the size of the nanomaterial may influence toxicity by testing two different sizes (5 nm and 15 nm) of nanodiamonds with the same functionalization. Adults of Daphnia magna were exposed to three concentrations of each of the nanodiamonds for 24 h. We found that both 5 and 15 nm polyallylamine nanodiamond and oxidized nanodiamond induced the production of reactive oxygen species in tissues. The smaller 5 nm nanodiamond induced a significant change in the expression of heat shock protein 70 and glutathione-S-transferase. This may suggest that daphnids mounted an antioxidant response to the oxidative effects of 5 nm nanodiamonds but not the comparative 15 nm nanodiamonds with either surface chemistry. Outcomes of this study reveal that functionalized nanodiamond may cause oxidative stress and may potentially initiate lipid peroxidation of enterocyte cell membranes in freshwater organisms, but the impact of the exposure depends on the particle size.

Chronic toxicity of nanodiamonds can disturb development and reproduction of Acheta domesticus L

The use of nanodiamonds in numerous materials designed for industry and medicine is growing rapidly. Consequently health and environmental risks associated with the exposure of humans and other biota to nanodiamonds-based materials are of the utmost importance. Scarcity of toxicological data for these particles led us to examine the potentially deleterious effects of nanodiamonds in model insect species, Acheta domesticus (Orthoptera) chronically exposed to ND in its diet. Organism-level end-point indices (lifespan, body weight, consumption, caloric value of faeces, reproduction) revealed adverse changes in the treated crickets in comparison with the control. Preliminary studies of oxidative stress level in the offspring of ND-treated crickets suggest toxicity of these particles limited to the exposed individuals. EPR analysis showing increase of radical signal in the faeces of ND-fed crickets led us to propose novel mechanism of nanodiamonds toxicity that is discussed in the light of literature data.

CAPSULE

Development and reproduction of Acheta domesticus can be disturbed by the chronic exposure to nanodiamonds.

Reduced fecundity and cellular changes in Acheta domesticus after multigenerational exposure to graphene oxide nanoparticles in food

Despite the fact that the demand for graphene and its derivatives in commercial applications is still growing, many aspects of its toxicity and biocompatibility are still poorly understood. Graphene oxide, which is released into the environment (air, soil and water) as so-called nanowaste or nanopollution, is able to penetrate living organisms. It is highly probable that, due to its specific nature, it can migrate along food chains thereby causing negative consequences. Our previous studies reported that short-term exposure to graphene oxide may increase the antioxidative defense parameters, level of DNA damage, which results in numerous degenerative changes in the gut and gonads. The presented research focuses on reproductive dysfunction and cellular changes in Acheta domesticus after exposure to GO nanoparticles in food (concentrations of 20 and 200 μg·g^-1 of food) throughout their entire life cycle. The results showed that long-term exposure to GO caused a significant decrease in the reproductive capabilities of the animals. Moreover, the next generation of A. domesticus had a lower cell vitality compared to their parental generation. It is possible that graphene oxide can cause multigenerational harmful effects.

Short-term in vivo exposure to graphene oxide can cause damage to the gut and testis

Graphene oxide (GO) has unique physicochemical properties and also has a potentially widespread use in every field of daily life (industry, science, medicine). Demand for nanotechnology is growing every year, and therefore many aspects of its toxicity and biocompatibility still require further clarification. This research assesses the in vivo toxicity of pure and manganese ion-contaminated GO that were administrated to Acheta domesticus with food (at 200mgkg^-1 of food) throughout their ten-day adult life. Our results showed that short-term exposure to graphene oxide in food causes an increase in the parameters of oxidative stress of the tested insects (catalase - CAT, total antioxidant capacity - TAC), induces damage to the DNA at a level of approximately 35% and contributes to a disturbance in the stages of the cell cycle and causes an increase of apoptosis. Moreover, upon analyzing histological specimens, we found numerous degenerative changes in the cells of the gut and testis of Acheta domesticus as early as ten days after applying GO. A more complete picture of the GO risk can help to define its future applications and methods for working with the material, which may help us to avoid any adverse effects and damage to the animal.