Cytotoxicity Of Zinc Oxide Nanoparticles Research Articles

Betanin inspired zinc oxide nanoparticles: The potential antioxidant and anticancer activity against human lung cancer cell line (A549)

Background informationLung cancer is the most frequently reported disease on a global scale. The bioactive substances are less successful in specifically destroying cancer cells. To prevent early inactivation and ensure targeted delivery of bioactive chemicals to cancer cells. Betanin is known as nitrogenous water-soluble molecule which possess anti-inflammatory, hepatoprotective, antioxidant, and anticancer properties. Aim of the studyThis work evaluates the anti-cancer and anti-oxidant properties of Betanin coated zinc oxide nanoparticles on the A549 lung cancer cell line. Materials and methodsIn the current work, Betanin coated Zinc oxide nanoparticles (Betanin coated ZnO NPs) were made utilizing Betanin, a phytochemical. SEM, FTIR, DLS, and UV–Vis were used to evaluate their properties. Trypan blue and MTT were used to confirm cell survival and cytotoxicity of ZnO nanoparticles at various dosages. The morphological evaluation of A549 cells was investigated by phase contrast microscopy and apoptosis by propidium iodide staining. The membrane integrity of mitochondria was investigated by rhodamine 123 staining and observed under fluorescence microscope. The anti-oxidant ability of ZnO nanoparticles was analyzed by level of catalase, glutathione, nitric oxide, lipid peroxidation, and superoxide dismutase using UV spectrophotometric analysis. Studies on gene expression (Bcl2, P53and BAX) were conducted to assess the molecular mechanism of apoptosis mediated by synthesized nanoparticle and level of matrix metalloproteinase −2 (MMP-2) by gelatin zymography. ResultsAt the peak of 383 nm in the UV band, zinc oxide NP synthesis was confirmed. The FT-IR data demonstrated that zinc oxide nanoparticles were effectively coated with Betanin and by dynamic light scattering analysis confirmed particle size to be 100.8 nm. The presence of cubic, spherical, and platelet-shaped zinc oxide nanoparticles has been observed by SEM analysis. The nanoparticles of zinc oxide (ZnO) were synthesized chemically and exhibited decreasing cell viability and increasing cytotoxicity and apoptosis in dose dependent manner. The levels of LPO activity increased significantly and NO, antioxidant enzymes (GSH, SOD, and CAT) activity decreased significantly (P <0.0001). Our results demonstrated that A549 cells treated with Betanin loaded ZnO nanoparticles to prevent oxidation by scavenging free radicals and increased levels of gene expression related to apoptotic proteins BAX, p53 and decreased level of expression in Bcl2. Further, level of matrix metalloproteinase −2 (MMP-2) decreased with increase in concentration of nanoparticle. ConclusionAs per the research described above, lung cancer cells were effectively targeted by the anticancer and antioxidant abilities of ZnO nanoparticles inspired by Betanin (A549).

Comparative Evaluation of Cytotoxicity of Zinc Oxide Nanoparticles Mixed With Herbal Extract as an Intracanal Medicament: A Zebrafish Model Study.

Objective In this study, zebrafish embryos are used to study the cytotoxic effects of a novel intracanal medication (ICM) based on zinc oxide nanoparticles (ZnO NPs) loaded with polyherbal extracts (Azadirachta indica and Solanum xanthocarpum). Material and methods In the present study, a green and sustainable method was employed for the synthesis of ZnO NPs mixed with bark and seed extracts of Azadirachta indica and Solanum xanthocarpum to be used as a polyherbal ICM. Formulation of ZnO NPs was confirmed with color change in mixture produced upon dissolving zinc acetate dihydrate in distilled water followed by slow addition of sodium hydroxide solution and herbal extracts. The effects of these green synthesized ZnO NPs were evaluated through a zebrafish embryo toxicity test. Embryos were exposed to different concentrations (25, 50, and 100 µg/mL) of synthesized experimental doses of ZnO NP and compared with the control embryos. Toxicological endpoints, such as the zebrafish embryo's survival rate, hatching rate, and heart rate, were noted and described. Results A concentration-dependent increase in mortality rate and hatching delay followed by declined heart rate was observed in green synthesized ZnO NP-treated embryos. The maximum toxicity was observed with an increase in the concentration of 100 µg/mL of the experimental dose, and at a low concentration of 25 µg/mL, it does not effectively show any developmental alteration in zebrafish embryos. Conclusion A novel polyherbal ICM loaded with ZnO NPs exhibited a dose-dependent effect on the heart rate, hatching, and mortality rate of the embryos. At optimal concentrations, the medication demonstrated minimal developmental malformations and cytotoxic effects, indicating its safety for use. However, increasing concentrations of the medication resulted in severe developmental malformations.

Machine-learning Assisted Insights into Cytotoxicity of Zinc Oxide Nanoparticles

Zinc oxide nanoparticles (ZnO NPs) are commercially used as an active ingredient or a color additive in foods, pharmaceuticals, sun protection lotions, and cosmetic products. While the use of ZnO NPs in everyday products has not been linked to any serious health issues so far, the scientific evidence generated for their safety is not conclusive and, in most cases, could not be validated further in in vivo settings. To settle controversies arising from inconsistent in vitro findings in previous research focusing on the toxicity ZnO NPs, we combined the results of 25+ independent studies. One way analysis of variance (ANOVA) and classification and regression tree (CART) algorithm were used to pinpoint intrinsic and extrinsic factors influencing cytotoxic potential of ZnO in nanoscale. Particle size was found to have the most significant impact on the cytotoxic potential of ZnO NPs, with 10 nm identified as a critical diameter below which cytotoxic effects were elevated. As expected, strong cell type-, exposure duration- and dose-dependency were observed in cytotoxic response of ZnO NPs, highlighting the importance of assay optimization for each cytotoxicity screening. Our findings also suggested that ≥12 hours exposure to NPs resulted in cytotoxic responses irrespective of the concentration. Considering the cumulative nature of research processes where advances are made through subsequent investigations over time, such meta-analytical approaches are critical to maximizing the use of accumulated data in nano-safety research.

Food Additive Solvents Increase the Dispersion, Solubility, and Cytotoxicity of ZnO Nanoparticles.

Zinc oxide (ZnO) nanoparticles (NPs) are utilized as a zinc (Zn) fortifier in processed foods where diverse food additives can be present. Among them, additive solvents may strongly interact with ZnO NPs by changing the dispersion stability in food matrices, which may affect physico-chemical and dissolution properties as well as the cytotoxicity of ZnO NPs. In this study, ZnO NP interactions with representative additive solvents (methanol, glycerin, and propylene glycol) were investigated by measuring the hydrodynamic diameters, solubility, and crystallinity of ZnO NPs. The effects of these interactions on cytotoxicity, cellular uptake, and intestinal transport were also evaluated in human intestinal cells and using in vitro human intestinal transport models. The results revealed that the hydrodynamic diameters of ZnO NPs in glycerin or propylene glycol, but not in methanol, were significantly reduced, which is probably related to their high dispersion and increased solubility under these conditions. These interactions also caused high cell proliferation inhibition, membrane damage, reactive oxygen (ROS) generation, cellular uptake, and intestinal transport. However, the crystal structure of ZnO NPs was not affected by the presence of additive solvents. These findings suggest that the interactions between ZnO NPs and additive solvents could increase the dispersion and solubility of ZnO NPs, consequently leading to small hydrodynamic diameters and different biological responses.

Selective cytotoxicity of zinc oxide nanoparticles synthesized from Putranjiva roxburghii leaf extract

Selective cytotoxicity of zinc oxide nanoparticles synthesized from Putranjiva roxburghii leaf extract

Effects of Adding Cinnamon, ZnO, and CuO Nanoparticles on the Antibacterial Properties of a Glass Ionomer Cement as the Luting Agent for Orthodontic Bands and Their Cytotoxicity

This study was conducted to evaluate the effects of adding cinnamon nanoparticles (NPs), Zinc oxide (ZnO) nanoparticles (NPs), and Copper oxide (CuO) NPs on the antibacterial property of a luting and lining glass ionomer cement (GIC) that was used for the cementation of orthodontic bands to the tooth. Cinnamon NPs, ZnO NPs, and CuO NPs were added into a luting and lining GIC in weight percentages of 1%, 2%, and 4%, respectively while a non-modified GIC was considered as the control group. Agar disc diffusion test was applied to assess the antimicrobial property of samples against Streptococcus mutans (S. mutans). The cytotoxicity of the nanoparticles was examined through the MTT assay for gingival fibroblasts. Data showed that GIC containing cinnamon and ZnO NPs displayed a larger inhibition zone diameter and greater antibacterial activity against S. mutans than CuO NPs. Meanwhile, there were no significant differences in the inhibition zone diameter of cinnamon NPs and ZnO NPs. The cytotoxicity assessment revealed the lower cytotoxicity of cinnamon NPs and the higher cytotoxicity of CuO NPs while the cytotoxicity of ZnO NPs was observed to be higher than cinnamon NPs and lower than CuO NPs. GIC containing cinnamon NPs exhibited noticeable antibacterial activity against S. mutans and cinnamon NPs revealed less cytotoxicity and it is can be labeled as a favorable option for further assessment to be applied in fixed orthodontic treatments for the cementation of bands to teeth.

Cytotoxicity of zinc oxide nanoparticles coupled with folic acid and polyethylene glycol

The anticancer mediators claim their activity in liquid form as a biocompatible and use in bios stems, which are mostly collected in fluid form. Control on the stability of metal oxide nanoparticles in parallel reducing the effect of large amount on their biological and cytotoxicity activities, remains a challenge. Here anticancer activity and cytotoxicity zinc oxide nanoparticles (NPs) have been presented that are coated with folic acid (F.A) and polyethylene glycol (PEG). The nanoparticles were synthesized by wet chemical method and characterized by x-ray diffraction; scanning electron microscopy and Fourier transform infrared spectroscopy. The cytotoxicity studies were performed on HepG2 cells.MMT assay was used to check the cell viability. The PEG and F.A capped ZnO NPs have shown reduction in cytotoxicity as compare to bare ZnO nanoparticles.

Cytotoxic Activity of Zinc Oxide Nanoparticle Synthesis Using Leaves Extract of Abies webbiana

Aim: The present study aimed to analyse the cytotoxicity of zinc oxide nanoparticles (ZnO NPs) that are biosynthesized using extract of Abies webbiana&#x0D; Methodology: Zinc oxide nanoparticles were synthesized by green approach using A. webbiana and were characterized by UV- vis spectroscopy. The powdered A. webbiana mediated ZnO NPs were subjected to cytotoxic tests for different concentrations by brine shrimp lethality assay.&#x0D; Results: ZnO NPs synthesized from A. webbiana showed reduced toxicity at lower concentrations. After 48 hours, it was found that at a minimal concentration of 5 µl, 90% of the nauplii and in concentration of 10 µl and 20 µl, 80% of the nauplii were alive. At a concentration of 40 µl and 80 µl, 70% of the nauplii were alive. Whereas the control showed 100% of the nauplii to be alive.&#x0D; Conclusion: Various nanoformulations of A. webbiana mediated ZnO NPs can be developed at optimal concentrations for therapeutics that are safe and economical.

The cytotoxicity of zinc oxide nanoparticles to 3D brain organoids results from excessive intracellular zinc ions and defective autophagy.

Although the neurotoxicity of ZnO nanoparticles (NPs) has been evaluated in animal and nerve cell culture models, these models cannot accurately mimic human brains. Three-dimensional (3D) brain organoids based on human-induced pluripotent stem cells have been developed to study the human brains, but this model has rarely been used to evaluate NP neurotoxicity. We used 3D brain organoids that express cortical layer proteins to investigate the mechanisms of ZnO NP-induced neurotoxicity. Cytotoxicity caused by high levels of ZnO NPs (64μg/mL) correlated with high intracellular Zn ion levels but not superoxide levels. Exposure to a non-cytotoxic concentration of ZnO NPs (16μg/mL) increased the autophagy-marker proteins LC3B-II/I but decreased p62 accumulation, whereas a cytotoxic concentration of ZnO NPs (64μg/mL) decreased LC3B-II/I proteins but did not affect p62 accumulation. Fluorescence micro-optical sectioning tomography revealed that 64μg/mL ZnO NPs led to decreases in LC3B proteins that were more obvious at the outer layers of the organoids, which were directly exposed to the ZnO NPs. In addition to reducing LC3B proteins in the outer layers, ZnO NPs increased the number of micronuclei in the outer layers but not the inner layers (where LC3B proteins were still expressed). Adding the autophagy flux inhibitor bafilomycin A1 to ZnO NPs increased cytotoxicity and intracellular Zn ion levels, but adding the autophagy inducer rapamycin only slightly decreased cellular Zn ion levels. We conclude that high concentrations of ZnO NPs are cytotoxic to 3D brain organoids via defective autophagy and intracellular accumulation of Zn ions.

Nanoencapsulation of thyme essential oil: a new avenue to enhance its protective role against oxidative stress and cytotoxicity of zinc oxide nanoparticles in rats.

Although the green synthesis of nanometals is eco-friendly, the toxicity or safety of these biosynthesized nanoparticles in living organisms is not fully studied. This study aimed to evaluate the potential protective role of encapsulated thyme oil (ETO) against zinc oxide nanoparticles (ZnO-NPs). ETO was prepared using a mixture of whey protein isolate, maltodextrin, and gum Arabic, and ZnO-NPs were synthesized using parsley extract. Six groups of male Sprague-Dawley rats were treated orally for 21 days which included the control group, ZnO-NP-treated group (25 mg/kg body weight (b.w.)), ETO-treated groups at low or high dose (50, 100 mg/kg b.w.), and the groups that received ZnO-NPs plus ETO at the two tested doses. Blood and tissue samples were collected for different assays. The results showed that carvacrol and thymol were the major components in ETO among 13 compounds isolated by GC-MS. ZnO-NPs were nearly spherical and ETOs were round in shape with an average size of 38 and 311.8 nm, respectively. Administration of ZnO-NPs induced oxidative stress, DNA damage, biochemical, ctyogentical, and histological changes in rats. ETO at the tested doses alleviated these disturbances and showed protective effects against the hazards of ZnO-NPs. It could be concluded that encapsulation of thyme oil using whey protein isolate, maltodextrin, and gum Arabic improved the antioxidant properties of ETO, probably possess synergistic effects, and can be used as a promising tool in pharmaceutical and food applications.

Cytotoxicity of zinc oxide nanoparticles to innate and adaptive human immune cells.

Zinc oxide nanoparticles (ZnO-NPs) are widely used in almost every area of life. Therefore, exposure to them is unavoidable, which makes it necessary to assess their safety for humans. This paper aims to determine toxicity of ZnO-NPs of two diameters toward human immune cells responsible for: innate response (U-937 and HL-60) and acquired response (COLO-720L and HUT-78). Mitochondrial activity, membrane integrity, degree of cellular lipid oxidation, induction of inflammation, and activation of the apoptosis pathway were evaluated to determine differences in cellular response to the tested nanoparticles. ZnO-NPs with a diameter of 100 and 130nm cause significant cell mortality at 25 and 12mg/L, respectively. Mitochondrial damage leads to the activation of the caspase cascade and, consequently, to cell apoptosis. ZnO-NPs also cause peroxidation of membrane lipids. Due to the photocatalytic properties of ZnO-NPs, the effect of ultraviolet (UV) irradiation on the degree of their toxicity was also investigated. However, UV irradiation enhances the toxic effect of nanoparticles mainly by weakening the cell's defense capabilities. ZnO-NPs are cytotoxic to human immune system, and they may cause both long-term and short-term negative effects.

In vitro cytotoxicity of zinc oxide nanoparticles in mouse ovarian germ cells

Recently, metal oxide nanoparticles such as zinc oxide nanoparticles (ZnO-NPs) have received considerable attention and humans are exposed to them in everyday life. The increasing use of ZnO-NPs may lead to human health issues. However, little is known about their effects on female reproductive systems, particularly on female germ cells. Germ cells differentiation is a complex biological process that is sensitive to environmental insults and any negative effect on germ cells development may inhibit fertility. Therefore, this study aimed to determine the impact of ZnO-NPs on mouse ovarian germ cells in an in vitro system. The effects of ZnO-NPs on these cells were evaluated using light microscopy, cell proliferation assessment, reactive oxygen species (ROS) level determination, standard cytotoxicity assessment (cell viability assessed by PI staining) and gene expression analysis. Our results demonstrated that ZnO-NPs have cytotoxic effects in a concentration- and time-dependent manner in mouse ovarian germ cells. Exposure of cells to ZnO-NPs concentration-dependently enhanced ROS generation. Furthermore, molecular analysis of ZnO-NPs-treated cells showed a significant increase in expression of premeiotic germ cells markers but a decrease in meiotic and post-meiotic markers compared to un-treated cells. Taken together, our data provides a preliminary insight into possible adverse effects of ZnO-NPs on mouse ovarian germ cells differentiation even at low concentrations.

The Influences of Aqueous Dispersion Media on the Cytotoxic Effect of Zinc Oxide Nanoparticles

Zinc oxide nanoparticles (ZnO-NPs) are widely utilized in many applications due to distinct physical and chemical characteristics. There are growing concerns that abundant use of ZnO-NPs can cause harm to humans and the environment. There is a substantial problem with reproducibility in nanotoxicology research due to the inherent properties of nanoparticles. Dispersion media are used for the preparation of nanoparticles. However, the physical and biological behaviors of ZnO-NPs in aqueous dispersion media are poorly understood. In this study, we investigated the effect of ZnO-NPs on the viability of SH-SY5Y cells. Our results showed that ZnO-NPs diluted from water-dispersed stock solution caused significant cell death at a much lower dose compared to their counterpart diluted from the phosphate-buffered saline (PBS)-dispersed stock solution. Electron microscopic data indicated that ZnO-NPs from the PBS-dispersed stock solution form much larger agglomerates compared to the one from the water-dispersed stock solution. From these data, we can conclude that the types of media used for particle dispersion impact the change in the physical property and cytotoxicity of ZnO-NPs.

Synthesis, characterization and cytotoxicity of zinc oxide nanoparticles by green synthesis method

The use of engineered nanoparticles (NPs) has increased considerably because of their almost universal applications, such as electronics, optical, pharmaceutical, biomedical and energy fields, which have been expanding rapidly during the past few decades. Due to the widespread applications of zinc oxide nanoparticles (ZnONPs), the potential exposure of workers, consumers and scientists to these particles has increased. We conducted a ZnONPs synthesis through a low cost, eco-friendly and sustainable method, where Beta vulgaris extract was utilized as a reducing agent. Characterization of ZnONPs was conducted by High-Resolution Transmission Electron Microscopy (HRTEM), Fourier-Transform Infrared Spectroscopy (FTIR) and X-ray diffraction analysis (XRD) to obtain the morphological properties. In this study, we evaluate ZnONPs toxicity in vitro in two mouse fibroblast cell lines C2C12 and L929 myoblast cell lines and human lymphocytes from peripheral blood (HLPB), using Trypan blue dye exclusion method. MTT assay method only in cell lines C2C12 and L929 after 24 h of exposure. The results show the ZnONPs size was between 16 and 24 nm, with hexagonal crystal structure and semi-spherical morphology. The toxic effects of ZnONPs were analyzed in the two cell lines after a 24 and 48 h incubation period. The value of TC50 ZnONPs was calculated after a 24 h exposure, which was found to be between 28 and 37 μg/mL and 20–30 μg/mL at a 48 h exposure. The viability value was reported non toxic at concentrations of 1 × 10−6-1x10−3 μg/mL.

Corrigendum to facile biofabrication, characterization, evaluation of photocatalytic, antipathogenic activity and in vitro cytotoxicity of zinc oxide nanoparticles

Corrigendum to facile biofabrication, characterization, evaluation of photocatalytic, antipathogenic activity and in vitro cytotoxicity of zinc oxide nanoparticles

Facile biofabrication, characterization, evaluation of photocatalytic, antipathogenic activity and in vitro cytotoxicity of zinc oxide nanoparticles

Abstract Zinc oxide nanoparticles (ZnO NPs) are gaining interest due to their multifunctional properties and desirable biological activities. The present study reports the formulation and characterization of ZnO NPs using an aqueous extract of dry onion peels (Allium cepa L) and further investigates their photocatalytic, in vitro antipathogenic activity and cytotoxicity against human lung cancer A549 cell line. The results of XRD analysis showed the presence of nine intense peaks indicating the crystallized hexagonal phase of ZnO NPs with a size of about 35 nm. Field-emission scanning electron micrographs and the results of EDS showed the hexagonal morphological feature, and the presence of zinc and oxygen in phytogenically synthesized ZnO NPs. The synthesized ZnO NPs showed potent catalytic activity in the degradation of organic dyes (crystal violet and methylene blue). The formulated ZnO NPs indicated a significant bactericidal activity against Bacillus sp., Escherichia coli, Staphylococcus aureus, Vibrio cholerea, Corynebacterium sp., and Salmonella sp. that are common foodborne pathogens. In this study, the obtained IC50 concentration of 51.25 μg/mL exhibits significant anticancer activity against A549 cells than other tested concentrations because of the release of zinc ions, which induce the cell apoptosis. Furthermore, studies on cell cycle validate that ZnO NPs arrest the cell cycle at the sub-G1 phase of A549 cells. These results suggest the utility of phytogenic ZnO NPs for various biomedical applications.

The time-dependent cellular response mechanism upon exposure to zinc oxide nanoparticles

Zinc oxide nanoparticle is one of the nanomaterials people engaged most in their life and its health effect has been taken into concern. In this work, A549 cell line was used as cell model, and the cytotoxicity of zinc oxide nanoparticles was revealed to be concentration-dependent. Through the measurement of cellular proteome, much more differentially expressed proteins were observed after the cells being treated for 9 h than 24 h. Also, most of these proteins expressed in the pattern which showed a significant decrease after exposure to zinc oxide nanoparticles and then an increase at 24 h. Intracellular reactive oxygen species and glutathione determination indicated that high level of oxidative stress was presented in cell after treatment with zinc oxide nanoparticles for 9 h. It can be observed from western blot analysis that the expression of NF-κB p65, PNPase, and HSP90 rose significantly after 9 h of exposure. Thus, a deduction was reached that toxicity of nanoparticles consists both of particle toxicity and ion toxicity, and a long-time treatment may conceal the toxicity induced by particles. The conclusion we made highlighted the importance of exposure time in the study of nanoparticle toxicity and would provide a new perspective for studying toxicity mechanism of nanoparticles.

Zinc oxide nanoparticles harness autophagy to induce cell death in lung epithelial cells

Although zinc oxide nanoparticles (ZnONPs) are widely used, they have raised concerns of toxicity in humans. Previous studies have indicated that reactive oxygen species (ROS) and autophagy are involved in the cytotoxicity of ZnONPs, but the regulatory mechanisms between autophagy and ROS remain to be elucidated. Herein, we comprehensively investigated the regulatory mechanism of autophagy and the link between autophagy and ROS in ZnONPs-treated lung epithelial cells. We demonstrated that ZnONPs could induce autophagy, and this process could enhance the dissolution of ZnONPs in lysosomes to release zinc ions. Sequentially, zinc ions released from ZnONPs were able to damage not only lysosomes, leading to impaired autophagic flux, but also mitochondria. Impaired autophagic flux resulted in the accumulation of damaged mitochondria, which could generate excessive ROS to cause cell death. We further demonstrated that the inhibition of autophagy by either pharmacological inhibitors or small interfering RNA (siRNA)-mediated knockdown of Beclin-1 and AMP-activated protein kinase could ameliorate ZnONPs-induced cell death. Moreover, we found that lysosomal-associated membrane protein 1/2 (LAMP-1/2), which were the most abundant highly glycosylated protein in late endosomes/lysosomes, exhibited aberrant expression pattern upon treatment with ZnONPs. Intriguingly, LAMP-2 knockdown, but not LAMP-1 knockdown, could exacerbate the ROS generation and cell death induced by ZnONPs treatment. Meanwhile, LAMP-2 overexpression alleviated ZnONPs-induced cell death, suggesting that LAMP-2 was linked to this toxic phenotype induced by ZnONPs. Our results indicate that autophagic dysfunction could contribute to excessive ROS generation upon treatment with ZnONPs in lung epithelial cells, suggesting that modulating the autophagy process would minimize ZnONPs-associated toxicity.

Charge and agglomeration dependent in vitro uptake and cytotoxicity of zinc oxide nanoparticles

The influence of the surface charge and the state of agglomeration of ZnO nanoparticles on cellular uptake and viability are investigated. For this purpose, ZnO nanoparticles were synthesized by colloidal routes and their physicochemical properties were investigated in detail. Three different surface modifications were investigated, involving coatings with the amphiphilic polymer poly(isobutylene-alt-maleic anhydride)-graft-dodecyl, mercaptoundecanoic acid, and l-arginine, which provide the nanoparticles with either a negative or a positive zeta-potential. The hydrodynamic diameters and zeta-potentials of all three nanoparticle species were investigated at different pH values and NaCl concentrations by means of dynamic light scattering and laser Doppler anemometry, respectively. The three differently modified ZnO nanoparticle species of similar sizes were also investigated in respect to their cellular uptake by 3T3 fibroblasts and HeLa cells, and their effect on cell viability.

In vitro cytotoxicity of SiO2 or ZnO nanoparticles with different sizes and surface charges on U373MG human glioblastoma cells.

Silicon dioxide (SiO2) and zinc oxide (ZnO) nanoparticles are widely used in various applications, raising issues regarding the possible adverse effects of these metal oxide nanoparticles on human cells. In this study, we determined the cytotoxic effects of differently charged SiO2 and ZnO nanoparticles, with mean sizes of either 100 or 20 nm, on the U373MG human glioblastoma cell line. The overall cytotoxicity of ZnO nanoparticles against U373MG cells was significantly higher than that of SiO2 nanoparticles. Neither the size nor the surface charge of the ZnO nanoparticles affected their cytotoxicity against U373MG cells. The 20 nm SiO2 nanoparticles were more toxic than the 100 nm nanoparticles against U373MG cells, but the surface charge had little or no effect on their cytotoxicity. Both SiO2 and ZnO nanoparticles activated caspase-3 and induced DNA fragmentation in U373MG cells, suggesting the induction of apoptosis. Thus, SiO2 and ZnO nanoparticles appear to exert cytotoxic effects against U373MG cells, possibly via apoptosis.