Biocompatibility of gold nanoparticles in retinal pigment epithelial cell line

Gold nanoparticles (Au NPs) have been tested as targeted delivery agents because of their high chemical stability and surface plasmon properties. Here, we investigated the biocompatibility of Au spheres (5-, 10-, 20-, 30-, 50-. and 100-nm), cubes (50-nm), and rods (10 × 90 nm) on a retinal pigment epithelial (ARPE-19) cell line. The lethal dose for killing 50% of the cells (LD₅₀) was evaluated using an MTT (3-[4, 5 dimethyl-thiazoly-2-yl] 2-5 diphenyl tetrazolium bromide) assay. At and above LD₅₀, based on mass concentrations, the confluent cell layer began to detach, as shown by real-time measurements of electric impedance. We found that the biocompatibility of spheres improved with increasing nanoparticle size. The Au rods were less biocompatible than 10-nm spheres. Confocal microscopy showed that cubic (50-nm) and spherical NPs (50- and 100-nm) neither had cytotoxic effects nor entered cells. Lethal doses for internalized spherical NPs, which were toxic, were recalculated based on surface area (LD_50,A) concentrations. Indeed, when biocompatibility was expressed as the surface area concentration of NPs, the curve was independent of size. The LD_50,A of Au nanospheres was 23 cm²/ml. Our findings demonstrate that the sole modulation of the surface area would make it possible to use Au NPs for therapeutic purposes.     

Cytotoxicity of silica nanoparticles on HaCaT cells

Despite the widespread use of silica nanoparticles (SiO₂ NPs) in biological and medical fields, their adverse effects have not been clearly elucidated. In this study, spherical SiO₂ NPs with a 50 nm diameter were used to study their interaction with HaCaT cells. SiO₂ NPs were found to be readily internalized into HaCaT cells and localized in the cytoplasm, lysosomes and autophagosomes. Decreased cell viability and damaged cell membrane integrity showed the cytotoxicity of SiO₂ NPs. Significant glutathione depletion and reactive oxygen species generation, which reduced the cellular antioxidant level, could be the major factor of cytotoxicity induced by SiO₂ NPs. Copyright © 2013 John Wiley & Sons, Ltd.     

Toxicity assessment of anatase and rutile titanium dioxide nanoparticles: The role of degradation in different pH conditions and light exposure

Titanium dioxide nanoparticles (TiO₂NPs), in the two crystalline forms, rutile and anatase, have been widely used in many industrial fields, especially in cosmetics. Therefore, a lot of details about their safety issues have been discussed by the scientific community. Many studies have led to a general agreement about TiO₂NPs toxicity, in particular for anatase form, but no mechanism details have been proved yet. In this study, data confirm the different toxic potential of rutile and anatase TiO₂NPs in two cell lines up to 5 nM nanoparticles concentration. Moreover, we evaluated the role of titanium ions released by TiO₂NPs in different conditions, at pH = 4.5 (the typical lysosomal compartment pH) and at pH = 5.5 (the skin physiological pH) in conditions of darkness and light, to mimic the dermal exposure of cosmetics. Anatase nanoparticles were proner to degradation both in the acidic conditions and at skin pH. Our study demonstrates that pH and sunlight are dominant factors to induce oxidative stress, TiO₂NPs degradation and toxicity effects.     

Chitosan‐Coated Superparamagnetic Iron Oxide Nanoparticles for Doxorubicin Delivery: Synthesis and Anticancer Effect Against Human Ovarian Cancer Cells

Doxorubicin‐loaded chitosan‐coated superparamagnetic iron oxide nanoparticles (Fe₃O₄; SPIO‐NPs) were prepared by coprecipitation and emulsification cross‐linking method and uniform NPs with an average particle size of 82 nm, with high encapsulation efficiencies, were obtained. The drug‐loading efficiency of doxorubicin (3.2 mg/mg NPs) showed better results for the chitosan‐loaded SPIO‐NPs as compared to the bare ones (0.5 mg/mg; p < 0.05). The incubation of A2780 and OVCAR‐3 human ovarian cancer cells with doxorubicin‐loaded and doxorubicin‐loaded chitosan‐coated SPIO‐NPs, for 24, 48, 72, 96, and 120 h, showed significant IC₅₀ (2.0 ± 0.6 and 7.1 ± 2.7 mm doxorubicin) and IC₉₀ (4.0 ± 9.2 and 10 ± 0.5 mm doxorubicin), respectively, after 96 h of incubation. While, 95% and 98% growth inhibition was seen in A2780 and OVCAR‐3 cells after the 96‐h exposure to the doxorubicin‐chitosan‐SPIO‐NPs (p < 0.05). A 5‐day (120 h) incubation with doxorubicin‐chitosan‐SPIO‐NPs showed that A2780 and OVCAR‐3 cells were able to uptake 120 and 110 pg iron/cell, respectively, when treated with doxorubicin‐chitosan‐SPIO‐NPs for 72 h (p < 0.05).     

Varying the morphology of silver nanoparticles results in differential toxicity against micro-organisms,HaCaT keratinocytes and affects skin deposition

The use of silver nanoparticles (Ag NPs) within the healthcare sector and consumer products is rapidly increasing. There are now a range of diverse-shaped Ag NPs that are commercially available and many of the products containing nanosilver are topically applied to human skin. Currently, there is limited data on the extent to which the antimicrobial efficacy and cytotoxicity of Ag NPs is related to their shape and how the shape of the Ag NPs affects their distribution in both intact and burn wounded human skin after topical application. In this study, we related the relative Ag NP cytotoxicity to potential skin pathogens and HaCaT keratinocytes in vitro with the shape of the Ag NPs. We employed multiphoton fluorescence lifetime imaging to map the distribution of the native and unlabeled Ag NPs after topical application to both intact and burn wounded human skin using the localized surface plasmon resonance signal of the Ag NPs. Truncated plate shaped Ag NPs led to the highest cytotoxicity against both bacteria (IC₅₀ ranges from 31.25 to 125?μg/mL depending on the bacterial species) and HaCaT keratinocytes (IC₅₀ 78.65?μg/mL [95%CI 63.88, 96.83]) thus both with similar orders of magnitude. All Ag NPs were less cytotoxic than solutions of silver nitrate (IC₅₀ of 7.85?μg/mL [95%CI 1.49, 14.69]). Plate-shaped Ag NPs displayed the highest substantivity within the superficial layers of the stratum corneum when topically applied to intact skin and the highest deposition into the wound bed when applied to burned ex vivo human skin relative to other Ag NP shapes.     

Iron oxide nanoparticles mediated cytotoxicity via PI3K/AKT pathway: Role of quercetin

Recently Fe₂O₃ NPs (iron oxide nanoparticles) have been extensively used in medical imaging and in industry also. As a result, people are increasingly exposed day by day to those nanoparticles. The adverse effect of Fe₂O₃ NPs is not so significant at lower doses but at higher doses Fe₂O₃ NPs causes significant damage to cells. The present study investigates the cell signaling mechanism of Fe₂O₃ NPs induced oxidative stress and cytotoxicity in vitro using murine hepatocytes as the working model. In addition, the cytoprotective action of quercetin in this pathophysiology has also been investigated. Dose-dependent studies suggest that incubation of hepatocytes with 250 μg/ml Fe₂O₃ NPs for 4 h significantly decreased the cell viability and intra-cellular antioxidant ability. This study also showed that exposure to Fe₂O₃ NPs caused hepatocytes death via apoptotic pathway. Incubation of hepatocytes with quercetin (50 μmol/L) prior to 1 h of Fe₂O₃ NPs exposure protects the cells from the altering activities of antioxidant indices, cytotoxicity and apoptotic death. Results suggest that Fe₂O₃ NPs induced cellular damage and quercetin plays a protective role in Fe₂O₃ NPs induced cytotoxicity and apoptotic death.     

Design,synthesis and cytotoxic evaluation of nitric oxide‐releasing derivatives of isosteviol

Twenty‐six novel isosteviol derivatives coupled with two types of nitric oxide (NO) donors (furoxans and NONOates) were synthesized and screened for cytotoxic activities against four human cancer cell lines with sunitinib as the positive control. The results showed that seven furoxan‐based derivatives ( 8a , 8b , 8c , 8d , 8e , 9e , and 9f ) exhibited desirable cytotoxic activities, while NONOate‐based derivatives displayed poor potency because of unstability. Compared with sunitinib, compounds 8a and 8e were more active on all tested cell lines, especially in HCT116 ( 8a , IC₅₀ = 0.48 ± 0.02 μm ; 8e , IC₅₀ = 0.94 ± 0.01 μm ); compounds 8b and 8d were more potent on HCT116 (IC₅₀ = 3.39 ± 0.06 and 3.29 ± 0.03 μm ), HepG2 (IC₅₀ = 1.05 ± 0.03 and 5.37 ± 0.08 μm ), and SW620 (IC₅₀ = 1.33 ± 0.02 and 4.11 ± 0.05 μm ) cell lines, and 8c exhibited higher activities on HepG2 cells with an IC₅₀ = 4.76 ± 0.14 μm . NO‐releasing experiment of compounds 8a – e , 17a , 18a , 19a , and 21a reminded us that NO‐releasing amount of this series of isosteviol derivatives positively correlates with their cytotoxic activities.     

Folate-mediated poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) nanoparticles for targeting drug delivery

A novel targeting drug delivery system (TDDS) has been developed. Such a TDDS was prepared by W₁/O/W₂ solvent extraction/evaporation method, adopting poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) [P(HB-HO)] as the drug carrier, folic acid (FA) as the targeting ligand, and doxorubicin (DOX) as the model anticancer drug. The average size, drug loading capacity and encapsulation efficiency of the prepared DOX-loaded, folate-mediated P(HB-HO) nanoparticles (DOX/FA–PEG–P(HB-HO) NPs) were found to be around 240 nm, 29.6% and 83.5%. The in vitro release profile displayed that nearly 50% DOX was released in the first 5 days. The intracellular uptake tests of the nanoparticles (NPs) in vitro showed that the DOX/FA–PEG–P(HB-HO) NPs were more efficiently taken up by HeLa cells compared to non-folate-mediated P(HB-HO) NPs. In addition, DOX/FA–PEG–P(HB-HO) NPs (IC₅₀ = 0.87 μM) showed greater cytotoxicity to HeLa cells than other treated groups. In vivo anti-tumor activity of the DOX/FA–PEG–P(HB-HO) NPs showed a much better therapeutic efficacy in inhibiting tumor growth, and the final mean tumor volume was 178.91 ± 17.43 mm³, significantly smaller than normal saline control group (542.58 ± 45.19 mm³). All these results have illustrated that our techniques for the preparing of DOX/FA–PEG–P(HB-HO) NPs developed in present work are feasible and these NPs are effective in selective delivery of anticancer drug to the folate receptor-overexpressed cancer cells. The new TDDS may be a competent candidate in application in targeting treatment of cancers.     

Influence of agglomeration and specific lung lining lipid/protein interaction on short-term inhalation toxicity

Lung lining fluid is the first biological barrier nanoparticles (NPs) encounter during inhalation. As previous inhalation studies revealed considerable differences between surface functionalized NPs with respect to deposition and toxicity, our aim was to investigate the influence of lipid and/or protein binding on these processes. Thus, we analyzed a set of surface functionalized NPs including different SiO₂ and ZrO₂ in pure phospholipids, CuroSurf^TM and purified native porcine pulmonary surfactant (nS). Lipid binding was surprisingly low for pure phospholipids and only few NPs attracted a minimal lipid corona. Additional presence of hydrophobic surfactant protein (SP) B in CuroSurf^TM promoted lipid binding to NPs functionalized with Amino or PEG residues. The presence of the hydrophilic SP A in nS facilitated lipid binding to all NPs. In line with this the degree of lipid and protein affinities for different surface functionalized SiO₂ NPs in nS followed the same order (SiO₂ Phosphate?～?unmodified SiO₂?<?SiO₂ PEG?<?SiO₂ Amino NPs). Agglomeration and biomolecule interaction of NPs in nS was mainly influenced by surface charge and hydrophobicity. Toxicological differences as observed in short-term inhalation studies (STIS) were mainly influenced by the core composition and/or surface reactivity of NPs. However, agglomeration in lipid media and lipid/protein affinity appeared to play a modulatory role on short-term inhalation toxicity. For instance, lipophilic NPs like ZrO₂, which are interacting with nS to a higher extent, exhibited a far higher lung burden than their hydrophilic counterparts, which deserves further attention to predict or model effects of respirable NPs.     

Tissue distribution following 28 day repeated oral administration of aluminum‐based nanoparticles with different properties and the in vitro toxicity

The tissue distribution and toxicity of nanoparticles (NPs) depend on their physical and chemical properties both in the manufactured condition and within the biological system. We characterized three types of commercially available aluminum‐based NPs (Al‐NPs), two rod‐type aluminum oxide NPs (Al₂O₃, AlONPs), with different aspect ratios (short [S]‐ and long [L]‐AlONPs), and spherical aluminum cerium oxide NPs (AlCeO₃, AlCeONPs). The surface area was in order of the S‐AlONPs > L‐AlONPs > AlCeONPs. Very importantly, we found that AlCeONPs is Al₂O₃‐coated CeO₂ NPs, but not AlCeO₃ NPs, and that the Al level in AlCeONPs is approximately 20% of those in S‐ and L‐AlONPs. All three types of Al‐NPs were slightly ionized in gastric fluid and rapidly particlized in the intestinal fluid. There were no significant differences in the body weight gain following 28 days of repeated oral administration of the three different types of Al‐NPs. All Al‐NPs elevated Al level in the heart, spleen, kidney and blood at 24 hours after the final dose, accompanied by the altered tissue level of redox reaction‐related trace elements. Subsequently, in four types of cells derived from the organs which Al‐NPs are accumulated, H9C2 (heart), HEK‐293 (kidney), splenocytes and RAW264.7 (blood), S‐AlONPs showed a very low uptake level and did not exert significant cytotoxicity. Meanwhile, cytotoxicity and uptake level were the most remarkable in cells treated with AlCeONPs. In conclusion, we suggest that the physicochemical properties of NPs should be examined in detail before the release into the market to prevent unexpected adverse health effects.     

Combined effect of titanium dioxide nanoparticles and glucose on the cardiovascular system in young rats after oral administration

Titanium dioxide nanoparticles (TiO₂ NPs) have already been used as food additive in various products and are usually consumed with a considerable amount of sugar. Oral consumption of TiO₂ NPs poses concerning health risks; however, research on the combined effect of ingested TiO₂ NPs and glucose is limited. We examined young Sprague‐Dawley rats administrated TiO₂ NPs orally at doses of 0, 2, 10 and 50 mg/kg body weight per day with and without 1.8 g/kg body weight glucose for 30 and 90 days. Heart rate, systolic and diastolic blood pressure, blood biochemical parameters and histopathology of cardiac tissues was assessed to quantify cardiovascular damage. The results showed that oral exposure to TiO₂ NPs and high doses of glucose both could induce cardiovascular injuries. The toxic effects were dose‐, time‐ and gender‐dependent. The interaction effects between oral‐exposed TiO₂ NPs and glucose existed and revealed to be antagonism in most of the biological parameters. However, toxic effects of the high‐dose glucose seemed to be more severe than TiO₂ NPs and the interaction of TiO₂ NPs with glucose. These results suggest that it may be more important to control the sugar intake than TiO₂ NPs for protecting the health of TiO₂ NP consumers.     

Oxidative stress contributes to silica nanoparticle-induced cytotoxicity in human embryonic kidney cells

In order to elucidate the nanoparticle-induced cytotoxicity and its mechanism, the effects of 20 and 50 nm silica nanoparticles on cultured human embryonic kidney (HEK293) cells were investigated. Cell viability, mitochondrial function, cell morphology, reactive oxygen species (ROS), glutathione (GSH), thiobarbituric acid reactive substance (TBARS), cell cycle and apoptosis were assessed under control and silica exposed conditions. Exposure to 20 or 50 nm SiO₂ nanoparticles at dosage levels between 20 and 100 μg/ml decreased cell viability in a dose-dependent manner. Median lethal dose (LD₅₀) of 24 h exposure was 80.2 ± 6.4 and 140.3 ± 8.6 μg/ml for 20 and 50 nm SiO₂ nanoparticles, respectively. Morphological examination revealed cell shrinkage and nuclear condensation after SiO₂ nanoparticle exposure. Increase in intracellular ROS level and reduction in GSH content were also observed in SiO₂ nanoparticle-exposed HEK293 cells. Increase in the amount of TBARS suggested an elevated level of lipid peroxidation. Flow cytometric analysis showed that SiO₂ nanoparticles can cause G2/M phase arrest and apoptotic sub-G1 population increase in a dose-dependent manner. In summary, exposure to SiO₂ nanoparticles resulted in a dose-dependent cytotoxicity in cultured HEK293 cells that was associated with increased oxidative stress.     

Intracellular trafficking of nuclear localization signal conjugated nanoparticles for cancer therapy

Doxorubicin (DOX) is an anticancer drug with an intracellular site of action in the nucleus. For high antitumour activity, it should be effectively internalized into the cancer cells and accumulate in the nucleus. In this study, we have prepared a nuclear localization signal conjugated doxorubicin loaded Poly (d,l-lactide-co-glycolide) nanoparticles (NPs), to deliver doxorubicin to the nucleus efficiently. Physico-chemical characterization of these NPs showed that the drug is molecularly dispersed in spherical and smooth surfaced nanoparticles. NPs (～226 nm in diameter, 46% encapsulation efficiency) under in vitro conditions exhibited sustained release of the encapsulated drug (63% release in 60 days). Cell cytotoxicity results showed that NLS conjugated NPs exhibited comparatively lower IC₅₀ value (2.3 μM/ml) than drug in solution (17.6 μM/ml) and unconjugated NPs (7.9 μM/ml) in breast cancer cell line MCF-7 as studied by MTT assay. Cellular uptake studies by confocal laser scanning microscopy (CLSM) and fluorescence spectrophotometer showed that greater amount of drug is targeted to the nucleus with NLS conjugated NPs as compared to drug in solution or unconjugated NPs. Flow cytometry experiments results showed that NLS conjugated NPs are showing greater cell cycle (G2/M phase) blocking and apoptosis than native DOX and unconjugated NPs. In conclusion, these results suggested that NLS conjugated doxorubicin loaded NPs could be potentially useful as novel drug delivery system for breast cancer therapy.     

Phosphate-enhanced cytotoxicity of zinc oxide nanoparticles and agglomerates

Zinc oxide (ZnO) nanoparticles (NPs) have been found to readily react with phosphate ions to form zinc phosphate (Zn₃(PO₄)₂) crystallites. Because phosphates are ubiquitous in physiological fluids as well as waste water streams, it is important to examine the potential effects that the formation of Zn₃(PO₄)₂ crystallites may have on cell viability. Thus, the cytotoxic response of NIH/3T3 fibroblast cells was assessed following 24 h of exposure to ZnO NPs suspended in media with and without the standard phosphate salt supplement. Both particle dosage and size have been shown to impact the cytotoxic effects of ZnO NPs, so doses ranging from 5 to 50 μg/mL were examined and agglomerate size effects were investigated by using the bioinert amphiphilic polymer polyvinylpyrrolidone (PVP) to generate water-soluble ZnO ranging from individually dispersed 4 nm NPs up to micron-sized agglomerates. Cell metabolic activity measures indicated that the presence of phosphate in the suspension media can led to significantly reduced cell viability at all agglomerate sizes and at lower ZnO dosages. In addition, a reduction in cell viability was observed when agglomerate size was decreased, but only in the phosphate-containing media. These metabolic activity results were reflected in separate measures of cell death via the lactate dehydrogenase assay. Our results suggest that, while higher doses of water-soluble ZnO NPs are cytotoxic, the presence of phosphates in the surrounding fluid can lead to significantly elevated levels of cell death at lower ZnO NP doses. Moreover, the extent of this death can potentially be modulated or offset by tuning the agglomerate size. These findings underscore the importance of understanding how nanoscale materials can interact with the components of surrounding fluids so that potential adverse effects of such interactions can be controlled.     

Effects of SiO2 nanoparticles on HFL‐I activating ROS‐mediated apoptosis via p53 pathway

Silicon dioxide nanoparticles (SiO₂ NPs) have attracted increasing interest as nanovehicles for delivering drugs, genes and bio‐active molecules into cells. However, it is still unknown whether SiO₂ NPs could cause side‐effects to normal cells. In the present study, human lung fibroblasts (HFL‐Is) were directly exposed to two different sizes of SiO₂ NPs. The effect of size and concentration on cell response was studied by analyzing the cell viability, the ratio of apoptosis and the pathway of cell injury. The results demonstrated that a size‐associated and a dose‐dependent toxicity of HFL‐Is was induced by SiO₂ NPs. Meanwhile, the expression of reactive oxygen species in HFL‐I was significantly increased. This activation effect was accompanied by upregulation of p53 expression, release of cytochrome C from chondriosomes, inhibition of Bcl2, and activation of Bax and caspase 9. These findings implied that SiO₂ NPs might induce apoptosis of HFL‐Is by stimulating reactive oxygen species release and subsequently causing the activation of p53 pathway in vitro. Copyright © 2011 John Wiley & Sons, Ltd.     

The role of quercetin in the formation of titanium dioxide nanoparticles for nanomedical applications

The current work aimed to synthesize and characterize titanium dioxide nanoparticles (TiO₂NPs) using quercetin (QE) and evaluate their biological activities, i.e., anti-hemolytic, anti-inflammatory, and cytotoxicity effects. The crystallographic phase and morphology of biosynthesized QE-TiO₂NPs were characterized by XRD (X-Ray Diffraction) and TEM/FE-SEM (Transmission/Field-Emission Scanning Electron Microscopy) micrographs. Functional groups involved in the synthesis process were determined by FTIR spectroscopy (Fourier Transform-Infrared Spectroscopy). Based on the characterization results, selected QE-TiO₂NPs showed a rutile phase, spherical shape, and a size range of 7.3–39 nm. The QE-TiO₂NPs did not show a hemolytic effect. They indicated 95.3% red blood cells (RBCs) membrane stabilization activity and 82.6% inhibition of bovine serum albumin (BSA) denaturation, similar to a standard drug, which proved their anti-inflammatory effects. The attained results from cytotoxicity studies revealed the toxic effects of QE-TiO₂NPs with IC50 values below 100 and 50 μg/mL for human breast cancer cells of MCF-7 and melanoma cancer cells of A375, respectively. These NPs did not significantly affect normal skin fibroblast cells up to 50 μg/mL and only showed a 16% inhibition rate on the cell viability at 100 μg/mL. These NPs also induced excessive ROS generation. This work established the blood/biocompatibility and excellent nanomedical applications of biosynthesized QE-TiO₂NPs.     

Suppressing growth,migration, and invasion of human hepatocellular carcinoma HepG2 cells by Catharanthus roseus‑silver nanoparticles

Application of silver nanoparticles serves as a new approach in cancer treatment due to its unique features. Biosynthesis of silver nanoparticles using plant is advantageous since they are easily accessible, nontoxic and produce quicker reaction compared to other methods. To evaluate the cytotoxicity, mechanism of cell death and DNA damage of biosynthesized Catharanthus roseus-silver nanoparticles on human liver cancer (HepG2) cells. The antiproliferative activity of Catharanthus roseus‑silver nanoparticles was measured using MTT assay. The cytotoxic effects were further evaluated by measuring nitric oxide and reactive oxygen species (ROS). The mechanism of cell death was determined by annexin-FITC/propidium iodide, mitochondrial membrane potential (MMP) and cell cycle assays. The assessment of DNA damage was evaluated using Comet assay method. The uptake of the nanoparticles were evaluated by Transmission Electron Microscopy (TEM). Catharanthus roseus‑silver nanoparticles has inhibited the proliferation of HepG2 cells in a time-dependent manner with a median IC₅₀ value of 3.871 ± 0.18 μg/mL. The concentration of nitrite and ROS were significantly higher than control. The cell death was due to apoptosis associated with MMP loss, cell cycle arrest, and extensive DNA damage. TEM analysis indicated the presence of free nanoparticles and endosomes containing the nanoparticles. The findings show that Catharanthus roseus‑silver nanoparticles have produced cytotoxic effects on HepG2 cells and thus may have a potential to be used as an anticancer treatment, particularly for hepatocellular carcinoma.     

Copper oxide nanoparticles induce oxidative stress and cytotoxicity in airway epithelial cells

Metal oxide nanoparticles are often used as industrial catalysts and elevated levels of these particles have been clearly demonstrated at sites surrounding factories. To date, limited toxicity data on metal oxide nanoparticles are available. To understand the impact of these airborne pollutants on the respiratory system, airway epithelial (HEp-2) cells were exposed to increasing doses of silicon oxide (SiO₂), ferric oxide (Fe₂O₃) and copper oxide (CuO) nanoparticles, the leading metal oxides found in ambient air surrounding factories. CuO induced the greatest amount of cytotoxicity in a dose-dependent manner; while even high doses (400 μg/cm²) of SiO₂ and Fe₂O₃ were non-toxic to HEp-2 cells. Although all metal oxide nanoparticles were able to generate ROS in HEp-2 cells, CuO was better able to overwhelm antioxidant defenses (e.g. catalase and glutathione reductase). A significant increase in the level of 8-isoprostanes and in the ratio of GSSG to total glutathione in cells exposed to CuO suggested that ROS generated by CuO induced oxidative stress in HEp-2 cells. Co-treatment of cells with CuO and the antioxidant resveratrol increased cell viability suggesting that oxidative stress may be the cause of the cytotoxic effect of CuO. These studies demonstrated that there is a high degree of variability in the cytotoxic effects of metal oxides, that this variability is not due to the solubility of the transition metal, and that this variability appears to involve sustained oxidative stress possibly due to redox cycling.     

Genotoxicity and cytotoxicity of ZnO and Al2O3 nanoparticles

Abstract

Objectives: Metal oxide nanoparticles (ZnO-NPs and Al₂O₃-NPs) are used in many fields, including consumer products and biomedical applications. As a result, exposure to these NPs is highly frequent, however, no conclusive information on their potential cytotoxicity and genotoxicity mechanisms are available. For this reason, we studied cytotoxic and genotoxic effects of ZnO-NPs and Al₂O₃-NPs on human peripheral blood lymphocytes.

Materials and methods: We obtained our goals by using MTT assay, Annexin V-FITC flow cytometry, and alkaline, neural and pH 12.1 versions of comet assay.

Results: Exposure of lymphocytes to both NPs for 24?h slightly decreased viability of lymphocytes at ≥0.5?mM. For the first time, we revealed using the comet assays that both ZnO-NPs and Al₂O₃-NPs caused a concentration-dependent increase of DNA single-strand breaks, but not alkali-labile sites. Treatment with DNA glycosylases showed that the NPs induced oxidative DNA damage. DNA damage caused by both nanoparticles at 0.05?mM was removed within 120?min, however lymphocytes did not repair DNA damage induced by 0.5?mM NPs. Studied nanoparticles did not induce apoptosis in lymphocytes.

Conclusion: Our results suggest that ZnO-NPs and Al₂O₃-NPs at concentration up to 0.5?mM did not exhibit cytotoxic effect but may exert genotoxic effect on lymphocytes, at least partially by the generation of oxidative DNA damage and strand breaks.     

Cytotoxic and inflammatory responses of TiO2 nanoparticles on human peripheral blood mononuclear cells

Titanium dioxide nanoparticles (TiO₂‐NPs) have been widely used in many applications. Owing to their nanoscale size, interactions between cells and NPs have been expansively investigated. With the health concerns raised regarding the adverse effects of these interactions, closer examination of whether TiO₂‐NPs can induce toxicity towards human cells is greatly needed. Therefore, in this study, we investigated the cytotoxicity of TiO₂‐NPs towards human blood cells (peripheral blood mononuclear cells [PBMCs]) in serum‐free medium, for which there is little information regarding the cytotoxic effects of TiO₂‐NPs. Our results provide evidence that PBMCs treated with TiO₂‐NPs (at concentrations ≥25 μg ml^?1) for 24 h significantly reduced cell viability and significantly increased production of toxic mediators such as reactive oxygen species and inflammatory response cytokines such as interleukin‐6 and tumor necrosis factor‐α (P < 0.05). Cell apoptosis induction also occurred at these concentrations. Significant expressions of cyclooxygenase‐2 and interleukin‐1β were also observed in PBMCs treated with TiO₂‐NPs at concentrations ≥125 μg ml^?1. Our data presented here clearly indicate that the concentration of TiO₂‐NPs (at size ~26.4 ± 1.2 nm) applied to human blood cells has a strong impact on cytotoxic induction. Copyright © 2016 John Wiley & Sons, Ltd.