Toxicity Assessment Of Nanoparticles Research Articles

TOXICITY OF NANOPARTICLES ON ANIMAL AND HUMAN ORGANISM: CELL RESPONSE

The review focuses on research related to the effect of nanoparticles on cells in the animal and human body and on the analysis of potential biological effects that may be caused by exposure to these materials. This review deals with the mechanisms through which nanoparticles interact with cells and analyses their potential consequences for an individual's health. The main mechanisms of toxicity are oxidative stress, inflammatory responses, cell damage, and genetic changes that can lead to apoptosis or other cellular responses. These effects are often modified by various factors, including the size and shape of the nanoparticles, their surface treatment and chemical composition. The work highlights significant differences in the responses of cells of different organ systems to nanoparticles, thereby pointing the need for a more precise examination of toxic effects depending on the biological context. This review also discusses important methods for assessing nanoparticle toxicity, including in vitro experiments, in vivo animal studies, and various clinical studies. The aim of this review was to provide a comprehensive overview of this important issue, which has significant implications for public health and the environment. Research into nanoparticles and their interaction with cells is crucial for a better understanding the risks associated with their exposure and for the development of safe technologies and applications that use these materials.

Unveiling the molecular networks underlying cellular impairment in Saccharomyces cerevisiae: investigating the effects of magnesium oxide nanoparticles on cell wall integrity and endoplasmic reticulum stress response.

Nanoparticles, particularly magnesium oxide nanoparticles (MgO-NPs), are increasingly utilized in various fields, yet their potential impact on cellular systems remains a topic of concern. This study aimed to comprehensively investigate the molecular mechanisms underlying MgO-NP-induced cellular impairment in Saccharomyces cerevisiae, with a focus on cell wall integrity, endoplasmic reticulum (ER) stress response, mitochondrial function, lipid metabolism, autophagy, and epigenetic alterations. MgO-NPs were synthesized through a chemical reduction method, characterized for morphology, size distribution, and elemental composition. Concentration-dependent toxicity assays were conducted to evaluate the inhibitory effect on yeast growth, accompanied by propidium iodide (PI) staining to assess membrane damage. Intracellular reactive oxygen species (ROS) accumulation was measured, and chitin synthesis, indicative of cell wall perturbation, was examined along with the expression of chitin synthesis genes. Mitochondrial function was assessed through Psd1 localization, and ER structure was analyzed using dsRed-HDEL marker. The unfolded protein response (UPR) pathway activation was monitored, and lipid droplet formation and autophagy induction were investigated. Results demonstrated a dose-dependent inhibition of yeast growth by MgO-NPs, with concomitant membrane damage and ROS accumulation. Cell wall perturbation was evidenced by increased chitin synthesis and upregulation of chitin synthesis genes. MgO-NPs impaired mitochondrial function, disrupted ER structure, and activated the UPR pathway. Lipid droplet formation and autophagy were induced, indicating cellular stress responses. Additionally, MgO-NPs exhibited differential cytotoxicity on histone mutant strains, implicating specific histone residues in cellular response to nanoparticle stress. Immunoblotting revealed alterations in histone posttranslational modifications, particularly enhanced methylation of H3K4me. This study provides comprehensive insights into the multifaceted effects of MgO-NPs on S. cerevisiae, elucidating key molecular pathways involved in nanoparticle-induced cellular impairment. Understanding these mechanisms is crucial for assessing nanoparticle toxicity and developing strategies for safer nanoparticle applications.

In silico assessment of nanoparticle toxicity powered by the Enalos Cloud Platform: Integrating automated machine learning and synthetic data for enhanced nanosafety evaluation

The rapid advance of nanotechnology has led to the development and widespread application of nanomaterials, raising concerns regarding their potential adverse effects on human health and the environment. Traditional (experimental) methods for assessing the nanoparticles (NPs) safety are time-consuming, expensive, and resource-intensive, and raise ethical concerns due to their reliance on animals. To address these challenges, we propose an in silico workflow that serves as an alternative or complementary approach to conventional hazard and risk assessment strategies, which incorporates state-of-the-art computational methodologies. In this study we present an automated machine learning (autoML) scheme that employs dose-response toxicity data for silver (Ag), titanium dioxide (TiO2), and copper oxide (CuO) NPs. This model is further enriched with atomistic descriptors to capture the NPs’ underlying structural properties. To overcome the issue of limited data availability, synthetic data generation techniques are used. These techniques help in broadening the dataset, thus improving the representation of different NP classes. A key aspect of this approach is a novel three-step applicability domain method (which includes the development of a local similarity approach) that enhances user confidence in the results by evaluating the prediction’s reliability. We anticipate that this approach will significantly expedite the nanosafety assessment process enabling regulation to keep pace with innovation, and will provide valuable insights for the design and development of safe and sustainable NPs. The ML model developed in this study is made available to the scientific community as an easy-to-use web-service through the Enalos Cloud Platform (www.enaloscloud.novamechanics.com/sabydoma/safenanoscope/), facilitating broader access and collaborative advancements in nanosafety.

Effects of copper nanoparticles on oxidative stress genes and their enzyme activities in common carp (Cyprinus carpio)

Copper nanoparticles (Cu-NPs) are becoming increasingly prevalent in the environment due to their wide range of applications, posing potential threats to living organisms. Negative effects of Cu-NP exposure have been confirmed in many fish species, and they include disorders in the expression of oxidative stress genes and the activity of enzymes they encode. Common carp, known for its sensitivity to nanopollutants in water, serves as a valuable model organism for nanoparticle toxicity assessment. This study investigated the effects of specific Cu-NPs – copper nanopowder (Cu-NPs), colloidal copper nanoparticles (Cu), and copper oxide nanoparticles (CuO-NPs) – on gene expression and enzyme activity (GPX, CYP1A, HSP70, SOD, CAT) in C. carpio hatchlings, utilizing molecular biology tools and biochemical analyses. Results showed that Cu increased the expression of the hsp70 gene, Cu-NPs elevated the expression of the cyp1a and hsp70 genes, and CuO increased cyp1a expression. Conversely, sod and cat exhibited reduced expression across all samples (Cu, Cu-NPs, CuO). All Cu forms induced significant ROS accumulation and notable alterations in oxidative stress biomarkers (SOD, CAT, GPX).

Interactive effects of temperature and salinity on toxicity of zinc oxide nanoparticles towards the marine mussel Xenostrobus securis

Growing application of zinc oxide nanoparticles (ZnO-NPs) in global market has led to the concern over their potential environmental impacts. Filter feeders like mussels are prone to nanoparticles due to their superior filter-feeding ability. Temperature and salinity of coastal and estuarine seawaters often vary seasonally and spatially, and their changes may jointly influence physicochemical properties of ZnO-NPs and thus their toxicity. This study, therefore, aimed to investigate the interactive effect of temperatures (15, 25 and 30 °C) and salinities (12 and 32 PSU) on physicochemical properties and sublethal toxicity of ZnO-NPs towards a marine mussel Xenostrobus securis, and to compare that with the toxicity caused by Zn2+ ions (zinc sulphate heptahydrate). The results revealed increased particle agglomeration but decreased zinc ion release of ZnO-NPs at the highest temperature and salinity condition (30 °C and 32 PSU). After exposure, ZnO-NPs significantly reduced survival, byssal attachment rate and filtration rate of the mussels at high temperature and salinity (30 °C and 32 PSU). Glutathione S-transferase and superoxide dismutase activities in the mussels were suppressed at 30 °C. These aligned with the augmented zinc accumulation with increasing temperature and salinity which could likely be attributable to increased particle agglomeration of ZnO-NP and enhanced intrinsic filtration rate of the mussels under these conditions. Together with the observed lower toxic potency of Zn2+ compared to ZnO-NPs, our results suggested that the mussels might accumulate more zinc through particle filtration under higher temperature and salinity, eventually resulting in elevated toxicity of ZnO-NPs. Overall, this study demonstrated the necessity to consider the interactive effect of environmental factors such as temperature and salinity during the toxicity assessment of nanoparticles.

Nanoparticles in ocular applications and their potential toxicity.

Nanotechnology has been developed rapidly in recent decades and widely applied in ocular disease therapy. Nano-drug delivery systems overcome the bottlenecks of current ophthalmic drug delivery and are characterized with strong biocompatibility, stability, efficiency, sustainability, controllability, and few side effects. Nanoparticles have been identified as a promising and generally safe ophthalmic drug-delivery system based on the toxicity assessment in animals. Previous studies have found that common nanoparticles can be toxic to the cornea, conjunctiva, and retina under certain conditions. Because of the species differences between humans and animals, advanced in vitro cell culture techniques, such as human organoids, can mimic the human organism to a certain extent, bringing nanoparticle toxicity assessment to a new stage. This review summarizes the advanced application of nanoparticles in ocular drug delivery and the potential toxicity, as well as some of the current challenges and future opportunities in nanotoxicological evaluation.

Toxicity assessment of nanoparticles in contact with the skin

Toxicity assessment of nanoparticles in contact with the skin

Tear of lipid membranes by nanoparticles.

Health concerns associated with the advent of nanotechnologies have risen sharply when it was found that particles of nanoscopic dimensions reach the cell lumina. Plasma and organelle lipid membranes, which are exposed to both the incoming and the engulfed nanoparticles, are the primary targets of possible disruptions. However, reported adhesion, invagination and embedment of nanoparticles (NPs) do not compromise the membrane integrity, precluding direct bilayer damage as a mechanism for toxicity. Here it is shown that a lipid membrane can be torn by small enough nanoparticles, thus unveiling mechanisms for how lipid membrane can be compromised by tearing from nanoparticles. Surprisingly, visualization by cryo transmission electron microscopy (cryo-TEM) of liposomes exposed to nanoparticles revealed also that liposomal laceration is prevented by particle abundance. Membrane destruction results thus from a subtle particle-membrane interplay that is here elucidated. This brings into a firmer molecular basis the theorized mechanisms of nanoparticle effects on lipid bilayers and paves the way for a better assessment of nanoparticle toxicity.

Effects of microenvironmental factors on assessing nanoparticle toxicity

Nanoparticles, such as dust or fine particles, are regarded as hazardous materials to human organs, and the interest in understanding their biological mechanisms and cellular response of nanoparticles is growing.

Co-exposures of acid rain and ZnO nanoparticles accelerate decomposition of aquatic leaf litter

The pattern of acid rain is dependent on the ratio of SO42− and NO3−, which change may affect the dissolution activity of dull heavy metals in the aquatic environment and further complicate the ongoing challenge of ecosystem stability and increase risks. In this study, we assessed the combined effects of acid rain (SO42-: NO3- was 2:1, 1:1, and 1:2) and ZnO nanoparticles (30 ng L-1) on plant litter decomposition through a microcosm experiment. The highest dissolution of ZnO nanoparticles was achieved when the SO42-: NO3- ratio was 1:2, and there were no significant differences among other treatments. The fungal biomass showed significant decreases under acute exposures but tended to be adaptive during chronic exposures. The co-exposure significantly stimulated the activities of leucine-aminopeptidase, glycine-aminopeptidase, polyphenol oxidase, and cellobiohydrolase. Besides, the fungal diversity and the relative abundance of some functional genera (e.g. Anguillospora) were enhanced when the SO42-: NO3- ratio was 1:2 and 2:1. In conclusion, the decomposition rate of plant litter was increased by 123–204% by co-exposures. Collectively, the findings underline the importance of considering environmental context to assess nanoparticle toxicity.

Fate and removal of silver nanoparticles during sludge conditioning and their impact on soil health after simulated land application

The growing use of silver nanoparticles (AgNPs) in personal care products and clothing has increased their concentrations in wastewater and subsequently in sludge raising concerns about their fate and toxicity during wastewater treatment and after land application of sludge. This research investigated the fate and removal of AgNPs during chemical conditioning of anaerobically digested sludge and their impact on soil bacteria and health after land application. Ferric chloride (FeCl3), alum (Al2 (SO4)3 • (14–18) H2O), and synthetic (polyacrylamide) polymer were used for sludge conditioning. All conditioners effectively removed AgNPs from the liquid phase and concentrated them in sludge solids. Concentration analyses showed that out of 53.0 mg/L of silver in the sludge, only 0.1 to 0.003 mg/L of silver remained in the sludge supernatant after conditioning and 12 to 20% of this value were particulates. Morphological analyses also showed that AgNPs went through physical, chemical, and morphological changes in sludge that were not observed in nanopure water and the resulting floc structures and the incorporation of nanoparticles were different for each conditioner. The impact of conditioned AgNPs on the biological activities of soil was evaluated by investigating its impact on the presence of five important phyla (Acidobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria). The results showed that AgNPs at a concentration of 20 mg AgNPs/g soil had a minimal impact on the presence and diversity of the assessed phyla. Also, using different chemicals for sludge conditioning resulted in different growth behavior of studied phyla. This study provides new insight into how the presence of AgNPs and different chemicals used for sludge conditioning might impact the soil biological activities and hence plant growth. The study also provides a solid basis for further research in the risk assessment of nanoparticle toxicity in biosolids amended soils.

Therapeutic nanostructures and nanotoxicity.

Nanotechnology, with its continuous advancement, leads to the development of nanoscale-level therapeutics to mitigate many complex diseases. This results in the emergence of numerous novel nanomaterials and its composite products into the market such as liposome, polymeric nanoparticles, dendrimers, and nanostructured lipid carrier. However, their application is always determined by a high benefit to risk ratio. Very few research have been done on the toxicity assessment of nanoparticles in the biological system; therefore, the limited knowledge regarding the toxicity profile of nanotherapeutics is available leading to the ignorance of its side effects. Nanoparticles can distribute in the whole body through translocating in the bloodstream by crossing membrane barriers efficiently and shows effect in organs and tissues at cellular and molecular levels. The interaction of nanoparticle with cell may consequences into nanotoxicity. The narrow size distribution, large surface area to mass ratio and surface properties of nanoparticle are significantly associated with nanotoxicity. Nanoparticles can enter into the tissue and cell by invading the membranes and cause cellular injury as well as toxicity. Therefore, the exploration of mechanisms of nanotoxicity has prime importance now a day. The toxicity assessment should be an integral part of the development of nanotherapeutics using various toxicity evaluation models. This review has focused on the exploration of different nanostructures for therapeutic delivery system along with its physicochemical characteristics responsible for adverse effects on human biology, various toxicity evaluation models, and environmental and regulatory hurdles.

Changes in Serum Physiological and Biochemical Parameters of Male Swiss Albino Mice After Oral Administration of Metal Oxide Nanoparticles (ZnO, CuO, and ZnO+CuO).

Zinc oxide (ZnO) and copper oxide (CuO) nanoparticles (NPs) are widely used in medicine and industrial fields. They have negative effects such as hematoxic, cytotoxic, and genotoxic on animals. This research aimed to investigate the blood physiological and biochemical responses induced by ZnO-NP and CuO-NP individually or in combination in male Swiss albino mice. For purpose, NPs were given to mice with 100 μl of water by oral gavage for 14 days. Three sublethal NP dose groups (1, 5, 25 mg/kg/day) and one control group (only received 100 μl of water) were used in the experiments and serum metabolite (glucose, total protein, total cholesterol, triglyceride, cortisol, blood urea nitrogen, immunoglobulin G, and M), ions (Na, K, Cl, Mg, and Ca), and enzyme (ALT, AST, ALP, and LDH) levels were measured. ZnO-, CuO-, and ZnO+CuO-NPs especially higher doses (5 and 25 mg/kg/day) decreased all serum metabolite (except blood urea nitrogen), ions, and ALP while these nanoparticles increased ALT, AST, LDH, and blood urea nitrogen. These increases/decreases in all serum parameters were generally higher in mice treated with the ZnO+CuO-NP mixture compared to the ZnO-NP and CuO-NP groups alone. The study shows that serum biochemistry profiles can be used as indicators to assess nanoparticle toxicity on lipid, protein, and energy metabolisms, immune and enzyme systems, ion regulation, and tissue functions.

Electrodynamic assisted self-assembled fibrous hydrogel microcapsules: a novel 3D in vitro platform for assessment of nanoparticle toxicity.

Nanoparticle (NP) toxicity assessment is a critical step in assessing the health impacts of NP exposure to both consumers and occupational workers. In vitro assessment models comprising cells cultured in a two-dimensional tissue culture plate (2D-TCP) are an efficient and cost-effective choice for estimating the safety risks of NPs. However, in vitro culture of cells in 2D-TCPs distorts cell–integrin and cell–cell interactions and is not able to replicate an in vivo phenotype. Three-dimensional (3D) in vitro platforms provide a unique alternative to bridge the gap between traditional 2D in vitro and in vivo models. In this study, novel microcapsules of alginate hydrogel incorporated with natural polymeric nanofibers (chitin nanofibrils) and synthetic polymeric nanofibers poly(lactide-co-glycolide) are designed as a 3D in vitro platform. This study demonstrates for the first time that electrodynamic assisted self-assembled fibrous 3D hydrogel (3D-SAF hydrogel) microcapsules with a size in the range of 300–500 μm in diameter with a Young's modulus of 12.7–42 kPa can be obtained by varying the amount of nanofibers in the hydrogel precursor solutions. The 3D-SAF microcapsules were found to mimic the in vivo cellular microenvironment for cells to grow, as evaluated using A549 cells. Higher cellular spreading and prolonged proliferation of A549 cells were observed in 3D-SAF microcapsules compared to control microcapsules without the nanofibers. The 3D-SAF microcapsule integrated well plate was used to assess the toxicity of model NPs, e.g., Al2O3 and ZnO. The toxicity levels of the model NPs were found to be dependent on the chemistry of the NPs and their physical agglomeration in the test media. Our results demonstrate that 3D-SAF microcapsules with an in vivo mimicking microenvironment can be developed as a physiologically relevant platform for high-throughput toxicity screening of NPs or pharmaceutical drugs.

Pulmonary surfactant inhibition of nanoparticle uptake by alveolar epithelial cells

Pulmonary surfactant forms a sub-micrometer thick fluid layer that covers the surface of alveolar lumen and inhaled nanoparticles therefore come in to contact with surfactant prior to any interaction with epithelial cells. We investigate the role of the surfactant as a protective physical barrier by modeling the interactions using silica-Curosurf-alveolar epithelial cell system in vitro. Electron microscopy displays that the vesicles are preserved in the presence of nanoparticles while nanoparticle-lipid interaction leads to formation of mixed aggregates. Fluorescence microscopy reveals that the surfactant decreases the uptake of nanoparticles by up to two orders of magnitude in two models of alveolar epithelial cells, A549 and NCI-H441, irrespective of immersed culture on glass or air–liquid interface culture on transwell. Confocal microscopy corroborates the results by showing nanoparticle-lipid colocalization interacting with the cells. Our work thus supports the idea that pulmonary surfactant plays a protective role against inhaled nanoparticles. The effect of surfactant should therefore be considered in predictive assessment of nanoparticle toxicity or drug nanocarrier uptake. Models based on the one presented in this work may be used for preclinical tests with engineered nanoparticles.

Validation of an air/liquid interface device for TiO2 nanoparticle toxicity assessment on NR8383 cells: preliminary results

nvestigations on adverse biological effects of nanoparticles (NP) are performed usually either in vivo on rodents or in vitro under submerged conditions where NP are in suspension into cell culture media. However, sedimentation of NP in vitro is a continuous process and to assess the exact deposited cellular dose remains difficult, as the cellular internal dose is a function of time. Moreover, the cellular responses to NP under submerged culture conditions or by exposing rodents by nose-only to NP aerosols might differ from those observed at physiological settings at the air-liquid interface (ALI). Rat alveolar NR8383 macrophages were exposed to aerosols at the air-liquid interface. We studied TiO2 NM105, a mixture of anatase and rutile. NR8383 cells were exposed to a single dose of 3.0 cm2/cm2 of TiO2 aerosol. Following RNA extraction, transcriptome allowing full coverage of the rat genome was performed, and differentially expressed genes were retrieved. Their products were analyzed for functions and interaction with String DB. Only 126 genes were differentially expressed and 98 were recognized by String DB and give us the gene expression signature of exposed rat alveolar NR8383 macrophages. Among them, 13 display relationships at a high confidence level and the ten most differentially expressed compared to unexposed cells were: Chac1, Ccl4, Zfp668, Fam129b, Nab2, Txnip, Id1, Cdc42ep3, Dusp6 and Myc, ranked from the most overexpressed to the most under-expressed. Some of them were previously described as over or under-expressed in NP exposed cell systems. We validated in our laboratory an easy-to-use device and a physiological relevant paradigm for studying the effects of cell exposure to TiO2. Ccl4 gene expression seems to be a positive marker of exposure evidenced as well as in vivo or in both in vitro conditions.

Determination of the bioavailability of zinc oxide nanoparticles using ICP-AES and associated toxicity

Advancement in nanotechnology has brought abundant number of products and materials in multiple fields including biomedicine owing to their unique physico-chemical properties. This further necessitates toxicity assessment of nanoparticles (NPs) before they are employed for product fabrication, medicinal, environmental or industrial purposes. Zinc oxide nanoparticles (ZnONPs) belong to the category of metal oxide NPs and hold quite a lot of possibilities to be applied in aforementioned scenarios. Present study addresses the probable outcomes of bio-nano interaction of ZnONPs with healthy adult Wistar rats. Sphere head shaped ZnONPs were synthesized via wet chemical method. Physico-chemical characterization was performed using number of sophisticated techniques including HR-TEM, Zeta potential analysis, TGA and XRD. Size of the particles was found to be 43 nm and ensured homogenous distribution with high purity. For in vivo studies, as synthesized NPs were administered into rats via intravenous (i.v.) and intraperitoneal (i.p.) routes. Animals were sacrificed on 3rd, 14th and 21st day of exposure. Metabolically relevant tissues like brain, liver, kidneys and spleen were isolated and analyzed for different parameters like gross pathology, haematology, neurotoxicity, target organ toxicity, immunotoxicity etc. Results suggests that ZnONPs did not elicit significant toxic responses in rat except a few anomalies with histology, ion content and antioxidant system within liver; thereby confirming potent hepatotoxicity. Hence the study recommends adopting surface functionalization strategies for reducing toxic response of ZnONPs during various application rationales.

In Vitro Methods for Assessing Nanoparticle Toxicity.

As a consequence of their increase in annual production and widespread distribution in the environment, nanoparticles potentially pose a significant public health risk. The sought-after catalytic activity granted by their physiochemical properties doubles as a hazard to physiological processes following exposure through inhalation, oral, transdermal, subcutaneous, and intravenous uptake. Upon uptake into the body, their size, morphology, surface charge, coating, and chemical composition augment the response of biological systems to the materials and enhance their toxicity. Identification of each property is necessary to predict the harm imposed by foreign nanomaterials in the body. Assay methods ranging from endotoxin and lactate dehydrogenase (LDH) signaling to apoptosis and oxidative stress detection supply valuable techniques for exposing biomarkers of nanoparticle-induced cellular damage. Spectroscopic investigation of epithelial barrier permeation and distribution within living cells reveals the proclivity of nanoparticles to penetrate the body's natural defensive boundaries and deposit themselves in cytotoxic locations. Combination of the various characterization methodologies and assays is required for every new nanoparticulate system despite preexisting data for similar systems due to the lack of deterministic trends among investigated nanoparticles. The propensity of nanomaterials to denature proteins and oxidize substrates in their local environment generates significant concern for the applicability of several traditional in vitro assays, and the modification of susceptible approaches into novel methods suitable for the evaluation of nanoparticles comprises the focus of future work centered on nanoparticle toxicity analysis.

Zebrafish as a Model to Evaluate Nanoparticle Toxicity.

Nanoparticles are increasingly being developed for in vivo use, from targeted drug delivery to diagnostics, where they have enormous potential, while they are also being used for a variety of applications that can result in environmental exposure for humans. Understanding how specific nanoparticles interact with cells and cell systems is essential to gauge their safety with respect to either clinical or environmental exposure. Zebrafish is being increasingly employed as a model to evaluate nanoparticle biocompatibility. This review describes this model and how it can be used to assess nanoparticle toxicity at multiple levels, including mortality, teratogenicity, immunotoxicity, genotoxicity, as well as alterations in reproduction, behavior and a range of other physiological readouts. This review also provides an overview of studies using this model to assess the toxicity of metal, metal oxide and carbon-based nanoparticles. It is anticipated that this information will inform research aimed at developing biocompatible nanoparticles for a range of uses.

Novel method for rapid toxicity screening of magnetic nanoparticles

Iron oxide nanoparticles have attracted a great deal of research interest and have been widely used in bioscience and clinical research including as contrast agents for magnetic resonance imaging, hyperthermia and magnetic field assisted radionuclide therapy. It is therefore important to develop methods, which can provide high-throughput screening of biological responses that can predict toxicity. The use of nanoelectrodes for single cell analysis can play a vital role in this process by providing relatively fast, comprehensive, and cost-effective assessment of cellular responses. We have developed a new method for in vitro study of the toxicity of magnetic nanoparticles (NP) based on the measurement of intracellular reactive oxygen species (ROS) by a novel nanoelectrode. Previous studies have suggested that ROS generation is frequently observed with NP toxicity. We have developed a stable probe for measuring intracellular ROS using platinized carbon nanoelectrodes with a cavity on the tip integrated into a micromanipulator on an upright microscope. Our results show a significant difference for intracellular levels of ROS measured in HEK293 and LNCaP cancer cells before and after exposure to 10 nm size iron oxide NP. These results are markedly different from ROS measured after cell incubation with the same concentration of NP using standard methods where no differences have been detected. In summary we have developed a label-free method for assessing nanoparticle toxicity using the rapid (less than 30 minutes) measurement of ROS with a novel nanoelectrode.