In vitromechanistic study towards a better understanding of ZnO nanoparticle toxicity

Synthesis and Characterization of Naproxen Intercalated Zinc Oxide Stacked Nanosheets for Enhanced Hepatoprotective Potential

Liver diseases pose a significant global health burden, with limited therapeutic options for chronic cases. Zinc oxide (ZnO) nanomaterials have emerged as promising candidates for hepatoprotection due to their antioxidant, anti-inflammatory, and regenerative properties. However, their potential remains hampered by insufficient drug loading and controlled release. The current study explores the intercalation of Naproxen (Nx), a potent anti-inflammatory and analgesic drug, within ZnO stacked nanosheets (SNSs) to address these limitations. Herein, an easy and solution-based synthesis of novel Nx intercalated ZnO SNSs was established. The obtained Nx intercalated ZnO SNSs were encapsulated with poly(vinyl acetate) (PVA) to make them biocompatible. The synthesized biocomposite was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR), which confirm the successful synthesis and intercalation of Nx within the ZnO SNSs. The obtained outcomes showed that the configuration of ZnO nanosheets was altered when Nx was introduced, resulting in a more organized stacking pattern. An in vivo investigation of mice liver cells unveiled that the Nx intercalated ZnO SNss had increased hepatoprotective properties. The study's results provide valuable insights into using Nx intercalated ZnO SNss for targeted drug delivery and improved treatment effectiveness, particularly for liver-related illnesses.

Antibacterial Efficacy of ZnO/Bentonite (Clay) Nanocomposites against Multidrug-Resistant Escherichia coli

The emergence of multidrug-resistant (MDR) bacteria has spurred the exploration of therapeutic nanomaterials such as ZnO nanoparticles. However, the inherent nonspecific toxicity of ZnO has posed a significant obstacle to their clinical utilization. In this research, we propose a novel approach to improve the selectivity of the toxicity of ZnO nanoparticles by impregnating them onto a less toxic clay mineral, Bentonite, resulting in ZB nanocomposites (ZB NCs). We hypothesize that these ZB NCs not only reduce toxicity toward both normal and carcinogenic cell lines but also retain the antibacterial properties of pure ZnO nanoparticles. To test this hypothesis, we synthesized ZB NCs by using a precipitation technique and confirmed their structural characteristics through X-ray diffraction and Raman spectroscopy. Electron microscopy revealed composite particles in the size range of 20-50 nm. The BET surface area of ZB NCs, within a relative pressure (P/P0) range of 0.407-0.985, was estimated to be 31.182 m2/g. Notably, 50 mg/mL ZB NCs demonstrated biocompatibility with HCT 116 and HEK 293 cell lines, supported by flow cytometry and fluorescence microscopy analysis. In vitro experiments further confirmed a remarkable five-log reduction in the population of MDR Escherichia coli in the presence of 50 mg/mL of ZB NCs. Antibacterial activity of the nanocomposites was also validated in the HEK293 and HCT 116 cell lines. These findings substantiate our hypothesis and underscore the effectiveness of ZB NCs against MDR E. coli while minimizing nonspecific toxicity toward healthy cells.

Novel Antibacterial, Cytotoxic and Catalytic Activities of Silver Nanoparticles Synthesized from Acidophilic Actinobacterial SL19 with Evidence for Protein as Coating Biomolecule

Silver nanoparticles (AgNPs) have potential applications in medicine, photocatalysis, agriculture, and cosmetic fields due to their unique physicochemical properties and strong antimicrobial activity. Here, AgNPs were synthesized using actinobacterial SL19 strain, isolated from acidic forest soil in Poland, and confirmed by UV-vis and FTIR spectroscopy, TEM, and zeta potential analysis. The AgNPs were polydispersed, stable, spherical, and small, with an average size of 23 nm. The FTIR study revealed the presence of bonds characteristic of proteins that cover nanoparticles. These proteins were then studied by using liquid chromatography with tandem mass spectrometry (LC-MS/ MS) and identified with the highest similarity to hypothetical protein and porin with molecular masses equal to 41 and 38 kDa, respectively. Our AgNPs exhibited remarkable antibacterial activity against Escherichia coli and Pseudomonas aeruginosa. The combined, synergistic action of these synthesized AgNPs with commercial antibiotics (ampicillin, kanamycin, streptomycin, and tetracycline) enabled dose reductions in both components and increased their antimicrobial efficacy, especially in the case of streptomycin and tetracycline. Furthermore, the in vitro activity of the AgNPs on human cancer cell lines (MCF-7, A375, A549, and HepG2) showed cancer-specific sensitivity, while the genotoxic activity was evaluated by Ames assay, which revealed a lack of mutagenicity on the part of nanoparticles in Salmonella Typhimurium TA98 strain. We also studied the impact of the AgNPs on the catalytic and photocatalytic degradation of methyl orange (MO). The decomposition of MO was observed by a decrease in intensity of absorbance within time. The results of our study proved the easy, fast, and efficient synthesis of AgNPs using acidophilic actinomycete SL19 strain and demonstrated the remarkable potential of these AgNPs as anticancer and antibacterial agents. However, the properties and activity of such particles can vary by biosynthesized batch.

A novel inactivated virus system (InViS) for a fast and inexpensive assessment of viral disintegration

The COVID-19 pandemic has caused considerable interest worldwide in antiviral surfaces, and there has been a dramatic increase in the research and development of innovative material systems to reduce virus transmission in the past few years. The International Organization for Standardization (ISO) norms 18,184 and 21,702 are two standard methods to characterize the antiviral properties of porous and non-porous surfaces. However, during the last years of the pandemic, a need for faster and inexpensive characterization of antiviral material was identified. Therefore, a complementary method based on an Inactivated Virus System (InViS) was developed to facilitate the early-stage development of antiviral technologies and quality surveillance of the production of antiviral materials safely and efficiently. The InViS is loaded with a self-quenched fluorescent dye that produces a measurable increase in fluorescence when the viral envelope disintegrates. In the present work, the sensitivity of InViS to viral disintegration by known antiviral agents is demonstrated and its potential to characterize novel materials and surfaces is explored. Finally, the InViS is used to determine the fate of viral particles within facemasks layers, rendering it an interesting tool to support the development of antiviral surface systems for technical and medical applications.

Copper oxide nanoparticles trigger macrophage cell death with misfolding of Cu/Zn superoxide dismutase 1 (SOD1)

Background

Copper oxide (CuO) nanoparticles (NPs) are known to trigger cytotoxicity in a variety of cell models, but the mechanism of cell death remains unknown. Here we addressed the mechanism of cytotoxicity in macrophages exposed to CuO NPs versus copper chloride (CuCl₂).

Methods

The mouse macrophage cell line RAW264.7 was used as an in vitro model. Particle uptake and the cellular dose of Cu were investigated by transmission electron microscopy (TEM) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. The deposition of Cu in lysosomes isolated from macrophages was also determined by ICP-MS. Cell viability (metabolic activity) was assessed using the Alamar Blue assay, and oxidative stress was monitored by a variety of methods including a luminescence-based assay for cellular glutathione (GSH), and flow cytometry-based detection of mitochondrial superoxide and mitochondrial membrane potential. Protein aggregation was determined by confocal microscopy using an aggresome-specific dye and protein misfolding was determined by circular dichroism (CD) spectroscopy. Lastly, proteasome activity was investigated using a fluorometric assay.

Results

We observed rapid cellular uptake of CuO NPs in macrophages with deposition in lysosomes. CuO NP-elicited cell death was characterized by mitochondrial swelling with signs of oxidative stress including the production of mitochondrial superoxide and cellular depletion of GSH. We also observed a dose-dependent accumulation of polyubiquitinated proteins and loss of proteasomal function in CuO NP-exposed cells, and we could demonstrate misfolding and mitochondrial translocation of superoxide dismutase 1 (SOD1), a Cu/Zn-dependent enzyme that plays a pivotal role in the defense against oxidative stress. The chelation of copper ions using tetrathiomolybdate (TTM) prevented cell death whereas inhibition of the cellular SOD1 chaperone aggravated toxicity. Moreover, CuO NP-triggered cell death was insensitive to the pan-caspase inhibitor, zVAD-fmk, and to wortmannin, an inhibitor of autophagy, implying that this was a non-apoptotic cell death. ZnO NPs, on the other hand, triggered autophagic cell death.

Conclusions

CuO NPs undergo dissolution in lysosomes leading to copper-dependent macrophage cell death characterized by protein misfolding and proteasomal insufficiency. Specifically, we present novel evidence for Cu-induced SOD1 misfolding which accords with the pronounced oxidative stress observed in CuO NP-exposed macrophages. These results are relevant for our understanding of the consequences of inadvertent human exposure to CuO NPs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00467-w.

Long-term exposure to zinc oxide nanoparticles improves PAOs function in enhanced biological phosphorus removal

As the most widely applied process for biological phosphorus removal, enhanced biological phosphorus removal (EBPR) relies on phosphorus accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs), whose function is crucial for the removal of phosphorus. In this study, the effect of zinc oxide nanoparticles (ZnO NPs, 0-50 mg/L) on EBPR performance was investigated in both long-term reactors and batch experiments. It was found that the performance of biological phosphorus removal was recovered from 0% (day 0) to >99% (day 70) after long-term exposure of ZnO NPs (50 mg/L). Further studies revealed that ZnO NPs treatment caused no significant effects on the morphology and settleability of activated sludge, but enhanced the release and uptake of phosphorus as well as the transformations of polyhydroxyalkanoates and glycogen in activated sludge, which suggested that PAOs were re-activated during long-term exposure to ZnO NPs. Fluorescence in-situ hybridization (FISH) analysis showed that the relative abundance of PAOs was increased after long-term exposure. Meanwhile, the enzymatic activities of PPX and PPK were also enhanced. These results indicated that compared with short-term exposure, long-term exposure to ZnO NPs favours PAOs function and thus led to the recovery of biological phosphorus removal.

Assessing Genotoxicity of Ten Different Engineered Nanomaterials by the Novel Semi-Automated FADU Assay and the Alkaline Comet Assay

Increased engineered nanomaterial (ENM) production and incorporation in consumer and biomedical products has raised concerns about the potential adverse effects. The DNA damaging capacity is of particular importance since damaged genetic material can lead to carcinogenesis. Consequently, reliable and robust in vitro studies assessing ENM genotoxicity are of great value. We utilized two complementary assays based on different measurement principles: (1) comet assay and (2) FADU (fluorimetric detection of alkaline DNA unwinding) assay. Assessing cell viability ruled out false-positive results due to DNA fragmentation during cell death. Potential structure–activity relationships of 10 ENMs were investigated: three silica nanoparticles (SiO₂-NP) with varying degrees of porosity, titanium dioxide (TiO₂-NP), polystyrene (PS-NP), zinc oxide (ZnO-NP), gold (Au-NP), graphene oxide (GO) and two multi-walled carbon nanotubes (MWNT). SiO₂-NPs, TiO₂-NP and GO were neither cytotoxic nor genotoxic to Jurkat E6-I cells. Quantitative interference corrections derived from GO results can make the FADU assay a promising screening tool for a variety of ENMs. MWNT merely induced cytotoxicity, while dose- and time-dependent cytotoxicity of PS-NP was accompanied by DNA fragmentation. Hence, PS-NP served to benchmark threshold levels of cytotoxicity at which DNA fragmentation was expected. Considering all controls revealed the true genotoxicity for Au-NP and ZnO-NP at early time points.

Molecular characterization of superoxide dismutase and catalase genes, and the induction of antioxidant genes under the zinc oxide nanoparticle-induced oxidative stress in air-breathing magur catfish (Clarias magur)

The deduced amino acid sequences from the complete cDNA coding sequences of three antioxidant enzyme genes (sod1, sod2, and cat) demonstrated that phylogenetically the magur catfish (Clarias magur) is very much close to other bony fishes with complete conservation of active site residues among piscine, amphibian, and mammalian species. The three-dimensional structures of three antioxidant enzyme proteins are very much similar to mammalian counterparts, thereby suggesting the functional similarities of these enzymes. Exposure to ZnO NPs resulted in an oxidative stress as evidenced by an initial sharp rise of intracellular concentrations of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) but decreased gradually at later stages. The level of glutathione (GSH) also increased gradually in all the tissues examined after an initial decrease. Biochemical and gene expression analyses indicated that the magur catfish has the ability to defend the ZnO NP-induced oxidative stress by inducing the SOD/CAT enzyme system and also the GSH-related enzymes that are mediated through the activation of various antioxidant-related genes both at the transcriptional and translational levels in various tissues. Furthermore, it appeared that the stimulation of NO, as a consequence of induction nos2 gene, under NP-induced oxidative stress serves as a modulator to induce the SOD/CAT system in various tissues of magur catfish as an antioxidant strategy. Thus, it can be contemplated that the magur catfish possesses a very efficient antioxidant defensive mechanisms to defend against the oxidative stress and also from related cellular damages during exposure to ZnO NPs into their natural environment.

An updated overview on metal nanoparticles toxicity

Although thousands of different nanoparticles (NPs) have been identified and synthesized to date, well-defined, consistent guidelines to control their exposure and evaluate their potential toxicity have yet to be fully established. As potential applications of nanotechnology in numerous fields multiply, there is an increased awareness of the issue of nanomaterials' toxicity among scientists and producers managing them. An updated inventory of customer products containing NPs estimates that they currently number over 5.000; ten years ago, they were one fifth of this. More often than not, products bear no information regarding the presence of NPs in the indicated list of ingredients or components. Consumers are therefore largely unaware of the extent to which nanomaterials have entered our lives, let alone their potential risks. Moreover, the lack of certainties with regard to the safe use of NPs is curbing their applications in the biomedical field, especially in the diagnosis and treatment of cancer, where they are performing outstandingly but are not yet being exploited as much as they could. The production of radical oxygen species is a predominant mechanism leading to metal NPs-driven carcinogenesis. The release of particularly reactive metal ions capable of crossing cell membranes has also been implicated in NPs toxicity. In this review we discuss the origin, behavior and biological toxicity of different metal NPs with the aim of rationalizing related health hazards and calling attention to toxicological concerns involved in their increasingly widespread use.

Development of Antimicrobial PLA Composites for Fused Filament Fabrication

In addition to possessing the desirable properties of being a biodegradable and biocompatible polymer fabricated from renewable resources, poly (lactic acid) (PLA) has useful mechanical and thermal attributes that has enabled it to be one of the most widely-used plastics for medicine, manufacturing, and agriculture. Yet, PLA composites have not been heavily explored for use in 3D-printing applications, and the range of feasible materials for the technology is limited, which inhibits its potential growth and industry adoption. In this study, tunable, multifunctional antimicrobial PLA composite filaments for 3D-printing have been fabricated and tested via chemical, thermal, mechanical, and antimicrobial experiments. Thermally stable antimicrobial ceramics, ZnO and TiO₂, were used as fillers up to 30 wt%, and poly (ethylene glycol) (PEG) was used as a plasticizer to tune the physical material properties. Results demonstrate that the PLA composite filaments exhibit the thermal phase behaviors and thermal stability suitable for 3D-printing. Additionally, PEG can be used to tune the mechanical properties while not affecting the antimicrobial efficacy that ZnO and TiO₂ imbue.

Combined Toxicity of Metal Nanoparticles: Comparison of Individual and Mixture Particles Effect

Toxicity of metal nanoparticles (NPs) are closely associated with increasing intracellular reactive oxygen species (ROS) and the levels of pro-inflammatory mediators. However, NP interactions and surface complexation reactions alter the original toxicity of individual NPs. To date, toxicity studies on NPs have mostly been focused on individual NPs instead of the combination of several species. It is expected that the amount of industrial and highway-acquired NPs released into the environment will further increase in the near future. This raises the possibility that various types of NPs could be found in the same medium, thereby, the adverse effects of each NP either could be potentiated, inhibited or remain unaffected by the presence of the other NPs. After uptake of NPs into the human body from various routes, protein kinases pathways mediate their toxicities. In this context, family of mitogen-activated protein kinases (MAPKs) is mostly efficient. Despite each NP activates almost the same metabolic pathways, the toxicity induced by a single type of NP is different than the case of co-exposure to the combined NPs. The scantiness of toxicological data on NPs combinations displays difficulties to determine, if there is any risk associated with exposure to combined nanomaterials. Currently, in addition to mathematical analysis (Response surface methodology; RSM), the quantitative-structure-activity relationship (QSAR) is used to estimate the toxicity of various metal oxide NPs based on their physicochemical properties and levels applied. In this chapter, it is discussed whether the coexistence of multiple metal NPs alter the original toxicity of individual NP. Additionally, in the part of "Toxicity of diesel emission/exhaust particles (DEP)", the known individual toxicity of metal NPs within the DEP is compared with the data regarding toxicity of total DEP mixture.

A review on nanotoxicity and nanogenotoxicity of different shapes of nanomaterials

Nanomaterials (NMs) generally display fascinating physical and chemical properties that are not always present in bulk materials; therefore, any modification to their size, shape, or coating tends to cause significant changes in their chemical/physical and biological characteristics. The dramatic increase in efforts to use NMs renders the risk assessment of their toxicity highly crucial due to the possible health perils of this relatively uncharted territory. The different sizes and shapes of the nanoparticles are known to have an impact on organisms and an important place in clinical applications. The shape of nanoparticles, namely, whether they are rods, wires, or spheres, is a particularly critical parameter to affect cell uptake and site-specific drug delivery, representing a significant factor in determining the potency and magnitude of the effect. This review, therefore, intends to offer a picture of research into the toxicity of different shapes (nanorods, nanowires, and nanospheres) of NMs to in vitro and in vivo models, presenting an in-depth analysis of health risks associated with exposure to such nanostructures and benefits achieved by using certain model organisms in genotoxicity testing. Nanotoxicity experiments use various models and tests, such as cell cultures, cores, shells, and coating materials. This review article also attempts to raise awareness about practical applications of NMs in different shapes in biology, to evaluate their potential genotoxicity, and to suggest approaches to explain underlying mechanisms of their toxicity and genotoxicity depending on nanoparticle shape.

Chronic sublethal effects of ZnO nanoparticles on Tigriopus fulvus (Copepoda, Harpacticoida)

This study investigated for the first time the effects of ZnO nanoparticle (NP) chronic exposure (28 days) on Tigriopus fulvus. Acute toxicity (48 h) of three Zn chemical forms was assessed as well including the following: (a) ZnO nanoparticles (NPs), (b) Zn2+ from ZnO NP suspension after centrifugation (supernatant) and (c) ZnSO4 H2O. Physical-chemical and electronic microscopies were used to characterize spiked exposure media. Results showed that the dissolution of ZnO NPs was significant, with a complete dissolution at lowest test concentrations, but nano- and micro-aggregates were always present. Acute test evidenced a significant higher toxicity of Zn2+ and ZnSO4 compared to ZnO NPs. The chronic exposure to ZnO NPs caused negative effects on the reproductive traits, i.e. brood duration, brood size and brood number at much lower concentrations (≥ 100 μg/L). The appearance of ovigerous females was delayed at higher concentrations of ZnO NPs, while the time required for offspring release and the percentage of non-viable eggs per female were significantly increased. ZnO NP subchronic exposure evidenced its ability to reduce T. fulvus individual reproductive fitness, suggesting that ZnO NPs use and release must be carefully monitored. Graphical abstract Graphical Abstract.

Unravelling the ZnO-NPs mechanistic pathway: Cellular changes and altered morphology in the gastrointestinal tract of the earthworm Eisenia andrei

A major uptake route of nanoparticles (NPs) occurs via the gastrointestinal (GI) tract. When GI tract cells are exposed, NPs cytotoxic effects are observed that subsequently adversely affect the GI tract morphology and have consequences for the whole organism. The aim of this study was to understand the mechanism of effects caused by ZnO-NPs compared to Zn ions on the earthworm Eisenia andrei. The following aspects of individually exposed earthworms were investigated: 1) qualitative structural alterations in the gut epithelium and chloragogen cells of the GI tract, 2) quantitative changes within chloragogen tissues after 48 h of exposure (using morphometric analysis), and 3) the ADP/ATP ratio in homogenized tissue of the whole organism after 21 days of exposure to contaminated soil (contamination phase) followed by 14 days of elimination in clean soil (decontamination phase) to identify possible recovery. Both ZnO-NPs and Zn ions adversely affect the gut epithelium and chloragogen tissue of earthworms after 48 h of exposure to contaminated soil. Morphometric measurements revealed that the proportions of debris vesicles in the chloragocytes were significantly lower in worms exposed to ZnO-NPs than in worms exposed to Zn ions. Moreover, numerous spherite granules were observed in the chloragocytes of ionic Zn-treated worms, but not the ZnO-NPs-treated worms, suggesting differential regulation of these Zn forms. The Zn cytotoxic effect was not reflected in ADP/ATP ratio measurements. Our study provides new insights into nano-specific effects that are distinctive from ion regulation inside the GI tract and furthers our understanding of the relationship between effects at the cellular and whole-body levels.

Dynamic cytotoxicity of ZnO nanoparticles and bulk particles to Escherichia coli: A view from unfixed ZnO particle:Zn2+ ratio

ZnO nanoparticles (NPs) form binary mixtures of ZnO particles and released Zn²⁺ in the environment, and the quantitative contributions of these components to toxicity are still uncertain. Herein, quantitative contribution of ZnO particle and Zn²⁺ to cytotoxicity of ZnO NPs to Escherichia coli were determined during 48 h bioassay. The cytotoxicity and mechanisms of ZnO NPs were dynamic and affected by ionic strength, Fe³⁺, humic acid, and temperature due to the unfixed ZnO particle:Zn²⁺ ratio. ZnO NPs and ZnO bulk particles (BPs) had comparable cytotoxicity but distinct cytotoxic mechanisms. ZnO NPs cytotoxicity arises mainly from ZnO particles for 3 h and from Zn²⁺ afterwards (8-48 h). The cytotoxicity of ZnO BPs depends predominantly on ZnO particles for 12 h and on Zn²⁺ from 24 to 48 h. The cytotoxicity of ZnO NPs and BPs is partially attributable to Zn accumulation, and dependent on ZnO particle:Zn²⁺ ratio. The linear regressions of acute toxicity for ZnO NPs vs. BPs and Zn²⁺ yielded excellent r² (0.9994 and 0.9998) from literature data and good r² (≥ 0.714) under certain environmental factors, which can be applied to assess environmental risk of ZnO NPs. Furthermore, dynamic cytotoxicity and mechanisms should be seriously considered during the environmental risk assessment of ZnO NPs.

Cancer immunotherapy with immunoadjuvants, nanoparticles, and checkpoint inhibitors: Recent progress and challenges in treatment and tracking response to immunotherapy

Chemotherapy, surgery, and radiation are accepted as the preferred treatment modalities against cancer, but in recent years the use of immunotherapeutic approaches has gained prominence as the fourth treatment modality in cancer patients. In this approach, a patient's innate and adaptive immune systems are activated to achieve clearance of occult cancerous cells. In this review, we discuss the preclinical and clinical immunotherapeutic (e.g., immunoadjuvants (in-situ vaccines, oncolytic viruses, CXC antagonists, device activated agents), organic and inorganic nanoparticles, and checkpoint blockade) that are under investigation for cancer therapy and diagnostics. Additionally, the innovations in imaging of immune cells for tracking therapeutic responses and limitations (e.g., toxicity, inefficient immunomodulation, etc.) are described. Existing data suggest that if immune therapy is optimized, it can be a real and potentially paradigm-shifting cancer treatment frontier.

Antileishmanial activity and cytotoxicity of ZnO-based nano-formulations

INTRODUCTION

Nanoparticles (NPs) can be toxic due to their nano-range sizes. Zinc oxide (ZnO) has good biocompatibility and is commercially used in cosmetics. Moreover, ZnO NPs have potential biomedical uses, but their safety remains unclear.

METHODS

A range of doped ZnO NPs was evaluated for antileishmanial activity and in vitro toxicity in brine shrimp and human macrophages, and N-doped ZnO NPs were evaluated for in vivo toxicity in male BALB/C mice. N-doped ZnO NPs were administered via two routes: intra-peritoneal injection and topically as a paste. The dosages were 10, 50, and 100 mg/kg/day for 14 days.

RESULTS

Topical administration was safe at all dosages, but intra-peritoneal injection displayed toxicity at higher doses, namely, 50 and 100 mg/kg/day. The pathological results for the i.p. dose groups were mild to severe degenerative changes in parenchyma cells, increases in Kupffer cells, disappearance of hepatic plates, increases in cell size, ballooning, cytoplasmic changes, and nuclear pyknosis in the liver. Kidney histology was also altered in the i.p. administration group (dose 100 mg/kg/day), with inflammatory changes in the focal area. We associate pathological abnormalities with the presence of doped ZnO NPs at the diseased site, which was verified by PIXE analysis of the liver and kidney samples of the treated and untreated mice groups.

CONCLUSION

The toxicity of the doped ZnO NPs can serve as an essential determinant for the effects of ZnO NPs on environmental toxicity and can be used for guidelines for safer use of ZnO-based nanomaterials in topical treatment of leishmaniasis and other biomedical applications.

Mixture Effects of Diesel Exhaust and Metal Oxide Nanoparticles in Human Lung A549 Cells

Airborne ultrafine particles (UFP) mainly derive from combustion sources (e.g., diesel exhaust particles—DEP), abrasion sources (non-exhaust particles) or from the unintentional release of engineered nanoparticles (e.g., metal oxide nanoparticles—NPs), determining human exposure to UFP mixtures. The aim of the present study was to analyse the combined in vitro effects of DEP and metal oxide NPs (ZnO, CuO) on human lung A549 cells. The mixtures and the relative single NPs (DEP, ZnO, CuO) were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and inductively coupled plasma-optic emission spectroscopy (ICP-OES). Cells were exposed for different times (3–72 h) to mixtures of standard DEP at a subcytotoxic concentration and ZnO and CuO at increasing concentrations. At the end of the exposure, the cytotoxicity was assessed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and clonogenic tests, the pro-inflammatory potential was evaluated by interleukin-8 (IL-8) release and the cell morphology was investigated by fluorescence and transmission electron microscopy. The obtained results suggest that the presence of DEP may introduce new physico-chemical interactions able to increase the cytotoxicity of ZnO and to reduce that of CuO NPs.

Defect Engineering of ZnO Nanoparticles for Bioimaging Applications

Many promising attributes of ZnO nanoparticles (nZnO) have led to their utilization in numerous electronic devices and biomedical technologies. nZnO fabrication methods can create a variety of intrinsic defects that modulate the properties of nZnO, which can be exploited for various purposes. Here we developed a new synthesis procedure that controls certain defects in pure nZnO that are theorized to contribute to the n-type conductivity of the material. Interestingly, this procedure created defects that reduced the nanoparticle band gap to ∼3.1 eV and generated strong emissions in the violet to blue region while minimizing the defects responsible for the more commonly observed broad green emissions. Several characterization techniques including thermogravimetric analysis, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, Raman, photoluminescence, and inductively coupled plasma mass spectrometry were employed to verify the sample purity, assess how modifications in the synthesis procedure affect the various defects states, and understand how these alterations impact the physical properties. Since the band gap significantly decreased and a relatively narrow visible emissions band was created by these defects, we investigated utilizing these new nZnO for bioimaging applications using traditional fluorescent microscopy techniques. Although most nZnO generally require UV excitation sources to produce emissions, we demonstrate that reducing the band gap allows for a 405 nm laser to sufficiently excite the nanoparticles to detect their emissions during live-cell imaging experiments using a confocal microscope. This work lays the foundation for the use of these new nZnO in various bioimaging applications and enables researchers to investigate the interactions of pure nZnO with cells through fluorescence-based imaging techniques.

Assessment of the structural reorganization of liver and biochemical parameters of blood serum after introduction of zinc nanoparticles and its oxides

The demand for nanoparticles of metals and their oxides in medicine and biology is indisputable. To ensure the safe use of the unique capabilities of nanostructures, in particular, essential metals and their oxides, and to further search for ways leveling side effects of toxic effects in biomedical applications, a multifaceted approach to the study of their properties is needed, primarily affecting the effects on the organism level. In this connection, the purpose of the present research was to study the effect of zinc nanoparticles (ZnNPs) and zinc oxide nanoparticles (ZnONPs) on structural reorganization of the liver and morpho-biochemical parameters of rat blood. The test substances exhibit a hepatotoxic effect upon their single intraperitoneal administration to rats. In the experiment, increased activity of gamma glutamyltransferase (GGT) and lactate dehydrogenase (LDH), increased expression of caspase-3, the presence of signs of oxidative stress, inflammation, and capillary-trophic insufficiency, and induction of tumor necrosis factor (TNF-α), and colony stimulating factor 2 (granulocyte-macrophage) (GM-CSF) were registered in the experiment. The level of interferon-γ in the experimental groups tended to decrease in comparison with the control group. The observed effects progressed in time, most noticeably manifested in the case of ZnONPs. Comparing the dosages, ZnNPs are less toxic than ZnONPs.

INSIdE NANO: a systems biology framework to contextualize the mechanism-of-action of engineered nanomaterials

Engineered nanomaterials (ENMs) are widely present in our daily lives. Despite the efforts to characterize their mechanism of action in multiple species, their possible implications in human pathologies are still not fully understood. Here we performed an integrated analysis of the effects of ENMs on human health by contextualizing their transcriptional mechanism-of-action with respect to drugs, chemicals and diseases. We built a network of interactions of over 3,000 biological entities and developed a novel computational tool, INSIdE NANO, to infer new knowledge about ENM behavior. We highlight striking association of metal and metal-oxide nanoparticles and major neurodegenerative disorders. Our novel strategy opens possibilities to achieve fast and accurate read-across evaluation of ENMs and other chemicals based on their biosignatures.

Human keratinocytes adapt to ZnO nanoparticles induced toxicity via complex paracrine crosstalk and Nrf2-proteasomal signal transduction

Zinc oxide nanoparticles (Nano-ZnO) is currently one of the most extensively used inorganic particles in a wide range of skin care and consumable products. Therefore, examining the biological effects of Nano-ZnO, especially in the non-cytotoxic levels, thus holds important contemporary practical implications. Herein, our study demonstrates that long-term conditioning of human keratinocytes (HaCaTs) to non-cytoxic dose of Nano-ZnO (∼100 nm) can induce an adaptive response, leading to an enhancement of the cells tolerance against cytotoxic level of Nano-ZnO. It was found that the Nano-ZnO induced adaptive alteration is mediated by a strong synergism between the generation of reactive oxygen species (ROS) flares by a sub-population of cells that are loaded with Nano-ZnO and upregulation of several pro-inflammatory transcripts. Further studies revealed activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf-2) stress response pathway and the associated downstream sustained augmented level of chymotrypsin-like 20 s proteasome activity to be the major mechanism underpinning this phenomenon. Interestingly, these cytoprotective responses can further aid the Nano-ZnO conditioned HaCaT cells to cross-adapt to harmful effects of ultraviolet-A (UVA) by reducing radiation-induced DNA damage. Our findings have unveiled a range of previously undocumented potent and exploitable bioeffects of Nano-ZnO induced ROS mediated signaling within the framework of nano-adaptation.

Cytotoxicity and global transcriptional responses induced by zinc oxide nanoparticles NM 110 in PMA-differentiated THP-1 cells

Despite a wide production and use of zinc oxide nanoparticles (ZnONP), their toxicological study is only of limited number and their impact at a molecular level is seldom addressed. Thus, we have used, as a model, zinc oxide nanoparticle NM110 (ZnO110NP) exposure to PMA-differentiated THP-1 macrophages. The cell viability was studied at the cellular level using WST-1, LDH and Alamar Blue^® assays, as well as at the molecular level by transcriptomic analysis. Exposure of cells to ZnO110NP for 24 h decreased their viability in a dose-dependent manner with mean inhibitory concentrations (IC₅₀) of 8.1 μg/mL. Transcriptomic study of cells exposed to two concentrations of ZnO110NP: IC₅₀ and a quarter of it (IC₅₀/4) for 4 h showed that the expressions of genes involved in metal metabolism are perturbed. In addition, expression of genes acting in transcription regulation and DNA binding, as well as clusters of genes related to protein synthesis and structure were altered. It has to be noted that the expressions of metallothioneins genes (MT1, MT2) and genes of heat-shock proteins genes (HSP) were strongly upregulated for both conditions. These genes might be used as an early marker of exposure to ZnONP. On the contrary, at IC₅₀ exposure, modifications of gene expression involved in inflammation, apoptosis and mitochondrial suffering were noted indicating a less specific cellular response. Overall, this study brings a resource of transcriptional data for ZnONP toxicity for further mechanistic studies.

Ameliorative Effects of Selenium in ZnO NP-Induced Oxidative Stress and Hematological Alterations in Catla catla

Various applications of zinc oxide nanoparticles (ZnO NPs) can increase pollution in aquatic environments. Consequently, pollution can cause toxicity in fish as indicated by oxidative stress, hematotoxicity, and changes in gill and liver histology. Selenium is known for its antioxidant potential in scavenging the free radicals generated during ZnO NP-induced oxidative stress. This study tested the ameliorative role of selenium against ZnO NP-induced toxicity in freshwater fish Catla catla. Four groups of replicated fish, representing control, selenium-treated, ZnO NP-treated, and ZnO NPs+selenium-treated, were used in this study. The ZnO NPs (40 mg l^-1) were given to fish in water whereas selenium (50 μg kg^-1) was given as sodium selenite in feed. After 28 days of exposure, the fish specimens were processed to collect samples of blood, gills, and liver. The results demonstrated that the consumption of selenium containing feeds protected the C. catla from ZnO NP-induced toxicity and oxidative stress. The use of selenium containing feeds appeared to have reduced the contents of glutathione S-transferase (GST) and glutathione reduced (GSH), and increased the level of catalase (CAT) and superoxide dismutase (SOD). Furthermore, the consumption of selenium in feeds improved the hematological parameters in ZnO NP-treated fish. This study suggests that dietary selenium might be able to ameliorate ZnO NP-induced toxicity in fish.

Autophagy-dependent release of zinc ions is critical for acute lung injury triggered by zinc oxide nanoparticles

Pulmonary exposure to zinc oxide nanoparticles (ZnONPs) could cause acute lung injury (ALI), but the underlying molecular mechanism remains unclear. Herein, we established a ZnONPs-induced ALI mouse model, characterized by the histopathological changes (edema and infiltration of inflammatory cells in lung tissues), and the elevation of total protein and cytokine interleukin-6 in bronchoalveolar lavage fluid in time- and dose-dependent manners. This model also exhibited features like the disturbance of redox-state (reduced of glutathione to glutathione disulfide ratio, elevation of heme oxygenase-1 and superoxide dismutase 2), the decrease of adenosine triphosphate synthesis and the release of zinc ions in the lung tissues. Interestingly, we found that ZnONPs exposure caused the accumulation of autophagic vacuoles and the elevation of microtubule-associated proteins 1A/1B light chain (LC)3B-II and p62, indicating the impairment of autophagic flux. Our data indicated that the above process might be regulated by the activation of AMP-activated protein kinase but not the mammalian target of rapamycin pathway. The association between ZnONPs-induced ALI and autophagy was further verified by a classical autophagy inhibitor, 3-methyladenine (3-MA). 3-MA administration reduced the accumulation of autophagic vacuoles, the expression of LC3B-II and p62, followed by a significant attenuation of histopathological changes, inflammation, and oxidative stress. More importantly, 3-MA could directly decrease the release of zinc ions in lung tissues. Taken together, our study provides the evidence that ZnONPs-induced pulmonary toxicity is autophagy-dependent, suggests that limiting the release of zinc ions by inhibiting autophagy could be a feasible strategy for the prevention of ZnONPs-associated pulmonary toxicity.

Nanomaterial-involved neural stem cell research: Disease treatment, cell labeling, and growth regulation

Neural stem cells (NSCs) have been widely investigated for their potential in the treatment of various diseases and transplantation therapy. However, NSC growth regulation, labeling, and its application to disease diagnosis and treatment are outstanding challenges. Recently, nanomaterials have shown promise for various applications including genetic modification, imaging, and controlled drug release. Here we summarize the recent progress in the use of nanomaterials in combination with NSCs for disease treatment and diagnosis, cell labeling, and NSC growth regulation. The toxicity of nanomaterials to NSCs is also discussed.

Potential anti-cancer and anti-Candida activity of Zn-derived foams

Zinc (Zn)-derived foams have been prepared from an alkaline electrolyte solution by galvanostatic electrodeposition under different conditions. A detailed physico-chemical characterization was performed by Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). A pioneer application of these foams in medical implant-related applications was investigated. The in vitro behaviour of these Zn-derived foams in simulated physiological conditions was studied. The results revealed that the presence of zinc oxide was important enough to change the in vitro behaviour of these materials. The potential of these Zn-derived foams in inhibiting bone cancer cell proliferation - osteoscarcoma cells - and important pathogenic fungi responsible for implant-related infections -Candida albicans- was examined. Furthermore, the foams were evaluated for cytocompatibility with normal human osteoblasts. The results obtained allowed us to conclude that Zn-derived foams have an interesting potential for anti-cancer and anti-Candida activity, targeted for bone-related implant applications, suggesting that this novel material may have potential for further clinical studies.

Properties of Zinc Oxide Nanoparticles and Their Activity Against Microbes

Zinc oxide is an essential ingredient of many enzymes, sun screens, and ointments for pain and itch relief. Its microcrystals are very efficient light absorbers in the UVA and UVB region of spectra due to wide bandgap. Impact of zinc oxide on biological functions depends on its morphology, particle size, exposure time, concentration, pH, and biocompatibility. They are more effective against microorganisms such as Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus, Sarcina lutea, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Pseudomonas vulgaris, Candida albicans, and Aspergillus niger. Mechanism of action has been ascribed to the activation of zinc oxide nanoparticles by light, which penetrate the bacterial cell wall via diffusion. It has been confirmed from SEM and TEM images of the bacterial cells that zinc oxide nanoparticles disintegrate the cell membrane and accumulate in the cytoplasm where they interact with biomolecules causing cell apoptosis leading to cell death.

Toxicological characterization of ZnO nanoparticles in malignant and non-malignant cells

The increasing usage of zinc oxide nanoparticles (ZnO-NPs) in industrial applications as well as in consumer products raises concern regarding their potential adverse effects to a greater extend. Numerous studies have demonstrated toxic properties of NPs, however there is still a lack of knowledge concerning the underlying mechanisms. This study was designed to systematically investigate cytotoxicity, apoptosis, cell cycle alterations, and genotoxicity induced by ZnO-NP. Moreover, it was an aim of the investigations to specify the diverse effects of nanoparticle exposure in malignant in comparison with non-malignant cells. Therefore, human head and neck squamous cell carcinoma-derived FaDu cells were incubated with 4-20 µg/ml of ZnO-NPs for 1-48 hr and tested for cell viability, cell cycle alterations, apoptosis and caspase-3 gene expression as a sensitive marker of molecular apoptotic processes with regard to time- and dose-dependent effects. Human mesenchymal bone marrow stem cells were used as non-malignant representatives to examine oxidative stress-related genotoxicity. Results showed a significant reduction in cell viability as well as dose- and time-dependent increase of apoptotic cells following nanoparticle treatment. Likewise, caspase-3 gene expression enhanced already before first apoptotic cells were detectable. It could be observed that doses that were cytotoxic in tumor cells did not reduce viability in stem cells. However, the same concentrations already induced significant DNA damage. The findings of the study suggest to keep a more critical eye on the use of nanoparticles as anti-cancer agents. Yet, additional in vivo studies are needed to assess safety concerns for consumers and patients. Environ. Mol. Mutagen. 59:247-259, 2018. © 2017 Wiley Periodicals, Inc.

The size of zinc oxide nanoparticles controls its toxicity through impairing autophagic flux in A549 lung epithelial cells

Zinc oxide nanoparticles (ZnONPs) widely used in various products, have been concerned with its impact on human health, in particular, on the risk of pulmonary toxicity. Our previous study indicated that ZnONPs could harness autophagy and impair the autophagic flux, which was positively linked to ZnONPs-induced toxicity. The objective of this study was to investigate whether ZnONPs-induced impairment of autophagic flux and cell death in lung epithelial cells is related to the size of ZnONPs. We demonstrate that ZnONPs with the average size of 50 nm could induce toxic effects in A549 lung epithelial cells, including accumulation of autophagosomes (the elevation of LC3B-II/LC3B-I ratio), impaired autophagic flux (the increase of p62 expression), the release of intracellular zinc ions (the increase of FluoZin-3 signal and ZnT1 mRNA expression), mitochondrial damage (the decrease of TMRE signal), lysosomal dysfunction (the aberrant expression of LAMP-2), oxidative stress (the increase of DCFH-DA signal and HO-1 expression) and cell death. Interestingly, ZnONPs with the average size of 200 nm failed to induce autophagy-mediated toxicity. Taken together, our results indicate that the size of ZnONPs is closely correlated with its toxicity, which is probably mediated by induction of impaired autophagic flux. This finding provides an insight into better understating of ZnONPs-associated toxicity, and mitigating the risk to humans and allowing the safer application.

ZnO nanoparticles modulate the ionic transport and voltage regulation of lysenin nanochannels

Background

The insufficient understanding of unintended biological impacts from nanomaterials (NMs) represents a serious impediment to their use for scientific, technological, and medical applications. While previous studies have focused on understanding nanotoxicity effects mostly resulting from cellular internalization, recent work indicates that NMs may interfere with transmembrane transport mechanisms, hence enabling contributions to nanotoxicity by affecting key biological activities dependent on transmembrane transport. In this line of inquiry, we investigated the effects of charged nanoparticles (NPs) on the transport properties of lysenin, a pore-forming toxin that shares fundamental features with ion channels such as regulation and high transport rate.

Results

The macroscopic conductance of lysenin channels greatly diminished in the presence of cationic ZnO NPs. The inhibitory effects were asymmetrical relative to the direction of the electric field and addition site, suggesting electrostatic interactions between ZnO NPs and a binding site. Similar changes in the macroscopic conductance were observed when lysenin channels were reconstituted in neutral lipid membranes, implicating protein-NP interactions as the major contributor to the reduced transport capabilities. In contrast, no inhibitory effects were observed in the presence of anionic SnO₂ NPs. Additionally, we demonstrate that inhibition of ion transport is not due to the dissolution of ZnO NPs and subsequent interactions of zinc ions with lysenin channels.

Conclusion

We conclude that electrostatic interactions between positively charged ZnO NPs and negative charges within the lysenin channels are responsible for the inhibitory effects on the transport of ions. These interactions point to a potential mechanism of cytotoxicity, which may not require NP internalization.

Electronic supplementary material

The online version of this article (10.1186/s12951-017-0327-9) contains supplementary material, which is available to authorized users.

Human lung adenocarcinoma cells with an EGFR mutation are sensitive to non-autophagic cell death induced by zinc oxide and aluminium-doped zinc oxide nanoparticles

Lung cancer, mostly non-small cell lung cancer (NSCLC), is the leading cause of cancer deaths; however, efficient treatments for NSCLC remain insufficient. The objective of this study was to investigate the effects of an epidermal growth factor receptor (EGFR) mutation on autophagic cell death in human lung adenocarcinoma cells by 20-nm zinc oxide nanoparticles (ZnONP20) and aluminum-doped ZnONPs (Al-ZnONP20). Two types of human lung adenocarcinoma cells were used throughout the study: wild-type EGFR A549 cells and EGFR-mutated CL1-5 cells. We observed that a significant reduction in cell viability resulting from ZnONP20 and Al-ZnONP20 occurred in A549 and CL1-5 cells after 18 and 24 hr of exposure. A colony formation analysis showed that A549 cells re-grew after exposure to 20 μg/mL Al-ZnONP20. Levels of light chain 3 (LC3) II conversion were activated by ZnONP20 and Al-ZnONP20 in A549 cells, whereas LC3 II was inhibited by ZnONP20 and Al-ZnONP20 in CL1-5 cells. In conclusion, we have shown that human lung adenocarcinoma cells with an EGFR mutation are sensitive to ZnONP20 and Al-ZnONP20, which may have resulted in non-autophagic cell death. ZnONP20 and Al-ZnONP20 may have the potential for personalized therapeutics in NSCLC with an EGFR mutation.

Rapid Dissolution of ZnO Nanoparticles Induced by Biological Buffers Significantly Impacts Cytotoxicity

Zinc oxide nanoparticles (nZnO) are one of the most highly produced nanomaterials and are used in numerous applications including cosmetics and sunscreens despite reports demonstrating their cytotoxicity. Dissolution is viewed as one of the main sources of nanoparticle (NP) toxicity; however, dissolution studies can be time-intensive to perform and complicated by issues such as particle separation from solution. Our work attempts to overcome some of these challenges by utilizing new methods using UV/vis and fluorescence spectroscopy to quantitatively assess nZnO dissolution in various biologically relevant solutions. All biological buffers tested induce rapid dissolution of nZnO. These buffers, including HEPES, MOPS, and PIPES, are commonly used in cell culture media, cellular imaging solutions, and to maintain physiological pH. Additional studies using X-ray diffraction, FT-IR, X-ray photoelectron spectroscopy, ICP-MS, and TEM were performed to understand how the inclusion of these nonessential media components impacts the behavior of nZnO in RPMI media. From these assessments, we demonstrate that HEPES causes increased dissolution kinetics, boosts the conversion of nZnO into zinc phosphate/carbonate, and, interestingly, alters the structural morphology of the complex precipitates formed with nZnO in cell culture conditions. Cell viability experiments demonstrated that the inclusion of these buffers significantly decrease the viability of Jurkat leukemic cells when challenged with nZnO. This work demonstrates that biologically relevant buffering systems dramatically impact the dynamics of nZnO including dissolution kinetics, morphology, complex precipitate formation, and toxicity profiles.

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.

Multifunctional electrospun polymeric nanofibrous mats for catalytic reduction, photocatalysis and sensing

Fabrication and decoration of flexible Nylon 6,6 polymeric nanofibrous mats for production of multifunctional electrospun material was accomplished via visible light-emitting surface-protected silicon quantum dots (Si QD), ZnO nanoparticles (ZnO NP) and Pd nanocubes (Pd NC). UV-range light was utilized for Si QD production and, after hydrolysis/condensation together with nucleation and growth reactions, amine-modified, fluorescent Si QD were obtained. Additionally, available molecular groups on the Si QD coated onto the polymeric nanofibrous mats provided further attachment of metal oxide and metal NP for various catalytic purposes. Analytical investigations showed that visible-light emission could be maintained on the Nylon 6,6 mats for trinitrotoluene (TNT) sensing. Also, due to consecutive NP decoration, multifunctional, polymeric, flexible nanofibrous mats were obtained. Experiments revealed that fabricated multifunctional mats could reduce molecules such as paranitrophenol effectively or decompose waste dyes such as methylene blue via photocatalytic experiments, and sense the pollutant TNT in aqueous solutions as an all-in-one concept.

Surface modification of acetaminophen particles by atomic layer deposition

Active pharmaceutical ingredients (APIs) are predominantly organic solid powders. Due to their bulk properties many APIs require processing to improve pharmaceutical formulation and manufacturing in the preparation for various drug dosage forms. Improved powder flow and protection of the APIs are often anticipated characteristics in pharmaceutical manufacturing. In this work, we have modified acetaminophen particles with atomic layer deposition (ALD) by conformal nanometer scale coatings in a one-step coating process. According to the results, ALD, utilizing common chemistries for Al₂O₃, TiO₂ and ZnO, is shown to be a promising coating method for solid pharmaceutical powders. Acetaminophen does not undergo degradation during the ALD coating process and maintains its stable polymorphic structure. Acetaminophen with nanometer scale ALD coatings shows slowed drug release. ALD TiO₂ coated acetaminophen particles show cytocompatibility whereas those coated with thicker ZnO coatings exhibit the most cytotoxicity among the ALD materials under study when assessed in vitro by their effect on intestinal Caco-2 cells.

Differential dose-dependent effects of zinc oxide nanoparticles on oxidative stress-mediated pancreatic β-cell death

AIM

To study the effects of zinc oxide nanoparticles (ZON) on oxidative stress-mediated pancreatic β-cell death.

METHODS

Cellular uptake of ZON, effects on antioxidant factors and apoptosis were studied.

RESULTS

ZON get internalized by endocytosis and increase intracellular zinc ion levels. ZON treatment (30 and 100 μg/ml) to RIN5f cells resulted in cytotoxicity, oxidative stress and apoptosis. ZON (1, 3, 10 μg/ml, subcytotoxic concentrations) increased super oxide dismutase activity and levels of reduced glutathione in RIN5f cells. Furthermore, ZON (subcytotoxic concentrations) protected RIN5f cells from H₂O₂-induced oxidative stress as evidenced by reduced reactive oxygen species levels; increased super oxide dismutase activity and glutathione levels; and reduced apoptotic death.

CONCLUSION

ZON (subcytotoxic concentrations) protect pancreatic β cells from oxidative-stress-mediated cell death.