Cellular interactions of zinc oxide nanoparticles with human embryonic kidney (HEK 293) cells

Farnesol and Selected Nanoparticles (Silver, Gold, Copper, and Zinc Oxide) as Effective Agents Against Biofilms Formed by Pathogenic Microorganisms

Purpose

Biofilms, which are created by most microorganisms, are known for their widely developed drug resistance, even more than planktonic forms of microorganisms. The aim of the study was to assess the effectiveness of agents composed of farnesol and nanoparticles (silver, gold, copper, and zinc oxide) in the degradation of biofilms produced by pathogenic microorganisms.

Methods

Escherichia coli, Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans were used to create the biofilm structure. Colloidal suspensions of silver, gold, copper, and zinc oxide (Ag, Au, Cu, ZnO) with the addition of farnesol (F) were used as the treatment factor. The size distribution of those composites was analyzed, their zeta potential was measured, and their structure was visualized by transmission electron microscopy. The viability of the microorganism strains was assessed by an XTT assay, the ability to form biofilms was analyzed by confocal microscopy, and the changes in biofilm structure were evaluated by scanning electron microscopy. The general toxicity toward the HFFF2 cell line was determined by a neutral red assay and a human inflammation antibody array.

Results

The link between the two components (farnesol and nanoparticles) caused mutual stability of both components. Planktonic forms of the microorganisms were the most sensitive when exposed to AgF and CuF; however, the biofilm structure of all microorganism strains was the most disrupted (both inhibition of formation and changes within the structure) after AgF treatment. Composites were not toxic toward the HFFF2 cell line, although the expression of several cytokines was higher than in the not-treated group.

Conclusion

The in vitro studies demonstrated antibiofilm properties of composites based on farnesol and nanoparticles. The greatest changes in biofilm structure were triggered by AgF, causing an alteration in the biofilm formation process as well as in the biofilm structure.

Zinc Oxide Nanoparticles Trigger Autophagy in the Human Multiple Myeloma Cell Line RPMI8226: an In Vitro Study

Multiple myeloma (MM) is a malignant clonal proliferative plasma cell tumor. Zinc oxide nanoparticles (ZnO NPs) are used for antibacterial and antitumor applications in the biomedical field. This study investigated the autophagy-induced effects of ZnO NPs on the MM cell line RPMI8226 and the underlying mechanism. After RPMI8226 cells were exposed to various concentrations of ZnO NPs, the cell survival rate, morphological changes, lactate dehydrogenase (LDH) levels, cell cycle arrest, and autophagic vacuoles were monitored. Moreover, we investigated the expression of Beclin 1 (Becn1), autophagy-related gene 5 (Atg5), and Atg12 at the mRNA and protein levels, as well as the level of light chain 3 (LC3). The results showed that ZnO NPs could effectively inhibit the proliferation and promote the death of RPMI8226 cells in vitro in a dose- and time-dependent manner. ZnO NPs increased LDH levels, enhanced monodansylcadaverine (MDC) fluorescence intensity, and induced cell cycle arrest at the G2/M phases in RPMI8226 cells. Moreover, ZnO NPs significantly increased the expression of Becn1, Atg5, and Atg12 at the mRNA and protein levels and stimulated the production of LC3. We further validated the results using the autophagy inhibitor 3-methyladenine (3‑MA). Overall, we observed that ZnO NPs can trigger autophagy signaling in RPMI8226 cells, which may be a potential therapeutic approach for MM.

The Addition of Co into CuO-ZnO Oxides Triggers High Antibacterial Activity and Low Cytotoxicity

In the present work, a simple two-step method is proposed for mixed oxide synthesis aimed at the achievement of antibacterial nanomaterials. In particular, Cu, Zn and Co have been selected to achieve single-, double- and triple-cation oxides. The synthesized samples are characterized by XRD, IR, SEM and EDX, indicating the formation of either crystalline or amorphous hydrocarbonate precursors. The oxides present one or two crystalline phases, depending on their composition; the triple-cation oxides form a solid solution of tenorite. Also, the morphology of the samples varies with the composition, yielding nanoparticles, filaments and hydrangea-like microaggregates. The antibacterial assays are conducted against E. coli and indicate an enhanced efficacy, especially displayed by the oxide containing 3% Co and 9% Zn incorporated into the CuO lattice. The oxides with the highest antibacterial properties are tested for their cytotoxicity, indicating a low toxicity impact, in line with literature data.

Ampicillin-resistant bacterial pathogens targeted chitosan nano-drug delivery system (CS-AMP-P-ZnO) for combinational antibacterial treatment

Drug-resistant microorganisms are defeated using combinational drug delivery systems based on biopolymer chitosan (CS) and metal nanoparticles. Hence, PEGylated zinc oxide nanoparticles (P-ZnO NPs) decorated chitosan-based nanoparticles (CS NPs) were prepared to deliver ampicillin (AMP) for improved antibacterial activity. In comparison to ZnO NPs, P-ZnO NPs exhibit less aggregation and more stable rod morphologies in TEM. The size of the P-ZnO NPs decreased and was engulfed by the spherical CS-AMP NPs. The zeta potential of the CS-AMP-P-ZnO NPs was determined to be -32.93 mV and the hydrodynamic size to be 210.2 nm. Further, DEE and DLE of CS-AMP (2.0:0.2 w/w) showed 79.60 ± 2.62 % and 15.14 ± 2.11 %, respectively. The cumulative AMP release was observed at >50 % at 48 h at pH 5.4 and 7.4. Additionally, when compared to AMP, CS-AMP-P-ZnO NPs had better antibacterial activity against E. coli, due to the alternation of cell membrane permeability by CS and ZnO NPs. Moreover, the hemolytic properties of ZnO NPs were attenuated because of PEGylation and CS. Furthermore, due to the biocompatible effect of CS, CS-AMP-P-ZnO NPs did not exhibit toxicity on cells and chick embryos. Hence, this study concludes that CS-AMP-P-ZnO NPs could be a promising antibacterial agent.

Chromone-based benzohydrazide derivatives as potential α-glucosidase inhibitor: Synthesis, biological evaluation and molecular docking study

In order to find new α-glucosidase inhibitors with high efficiency and low toxicity, novel chromone-based benzohydrazide derivatives 6a-6s were synthesized and characterized through ¹H NMR, ¹³C NMR, and HRMS. All the new synthesized compounds were tested for inhibitory activities against α-glucosidase. Compounds 6a-6s with IC₅₀ values ranging from 4.51 ± 0.09 to 27.21 ± 0.83 μM, showed a potential α-glucosidase inhibitory activity as compared to the positive control (acarbose: IC₅₀ = 790.40 ± 0.91 μM). Compound 6i exhibited the highest α-glucosidase inhibitory activity with an IC₅₀ value of 4.51 ± 0.09 μM. Theinteractionbetween α-glucosidase and 6i was further confirmed by enzyme kinetic, fluorescence quenching, circular dichroism, and molecular docking study. In vivo experiment showed that 6i could suppress the rise of blood glucose levels after sucrose loading. The cytotoxicity result indicated that 6i exhibited low cytotoxicity in vitro.

A Nanocomposite with Extracellular Vesicles from Lactobacillus paracasei as a Bioinspired Nanoantibiotic Targeting Staphylococcus aureus

The utilization of biomimetic materials that merge functional nanoparticles (NPs) with a cell-derived nanosized membrane is a state-of-the-art approach to harnessing cellular properties for biomedical applications. However, the development of biocompatible and species-selective biomimetic agents against hazardous pathogens threatening human health is still in its early stages. Herein, we report the synthesis and functional analysis of a novel nanoplatform in which a PEGylated MoS2-ZnO (MZ) nanocomposite was cloaked with a generally regarded as safe (GRAS)-grade Lactobacillus paracasei-derived extracellular vesicle (LPEV) for MZ-LPEV nanocomposite and evaluated its activity against Staphylococcus aureus. The MZ nanocomposite was characterized via X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The coating of MZ with LPEV was confirmed through nanoparticle tracking analysis and zeta potential measurements. MZ-LPEV exhibited 5- to 20-fold higher antibacterial activity than that of ZO NPs and MZ nanocomposite against S. aureus. Reactive oxygen species (ROS) production and bacterial membrane disruption were confirmed as antibacterial mechanisms of MZ-LPEV. Finally, MZ-LPEV exhibited enhanced biocompatibility and selectivity for S. aureus. All our results showed that LPEV could be utilized for developing synergistic nanoantibiotics against S. aureus.

NMR-Based Metabolomic Imprinting Elucidates Macrophage Polarization of THP-1 Cell Lines Stimulated by Zinc Oxide Nanoparticles

Zinc oxide (ZnO) nanoparticles (NPs) have been widely used in industry, cosmetics, drugs, bioimaging, and drug delivery. ZnO NPs have been found to interact and interfere with cellular physiology via macrophages, thereby resulting in macrophage polarization. The functional reprogramming of the cells is synchronized through cellular metabolic adaptations. The current study, therefore, aims to establish crosstalk between ZnO-NP-induced metabolic alterations and macrophage polarization in PMA-activated THP-1 cell lines. We observed moderate to heightened cytotoxic response in terms of cell viability and proliferation. The results also revealed increased Th1-type cytokine and chemokine expression. In order to characterize the changes in metabolite concentration in treatment groups, we employed multivariate data analysis (principal component analysis and partial least-squares discriminant analysis) of 1H NMR spectra. The results revealed biologically relevant patterns and alterations in many metabolic pathways. These alterations and patterns were found to be in line across the immune-cytotoxic axis. Furthermore, the results also implicate the role of carbon metabolism toward the classical activation of macrophage polarization. The omics approach could identify the markers involved in NP-induced toxicity, thus elaborating our vision of cytotoxicity that is currently limited to end-point and cytokine assays. Also, it could be emphasized that metabolic reconfiguration upon NP stimulation could direct macrophage polarization toward classical activation.

Recent advances in ZnO-based photosensitizers: Synthesis, modification, and applications in photodynamic cancer therapy

Zinc oxide nanoparticles (ZnO NPs) are important semiconductor materials with interesting photo-responsive properties. During the past, ZnO-based NPs have received considerable attention for photodynamic therapy (PDT) due to their biocompatibility and excellent potential of generating tumor-killing reactive oxygen species (ROS) through gentle photodynamic activation. This article provides a comprehensive review of the recent developments and improvements in optical properties of ZnO NPs as photosensitizers for PDT. The optical properties of ZnO-based photosensitizers are significantly dependent on their charge separation, absorption potential, band gap engineering, and surface area, which can be adjusted/tuned by doping, compositing, and morphology control. Here, we first summarize the recent progress in the charge separation capability, absorption potential, band gap engineering, and surface area of nanosized ZnO-based photosensitizers. Then, morphology control that is closely related to their synthesis method is discussed. Following on, the state-of-art for the ZnO-based NPs in the treatment of hypoxic tumors is comprehensively reviewed. Finally, we provide some outlooks on common targeted therapy methods for more effective tumor killing, including the attachment of small molecules, antibodies, ligands molecules, and receptors to NPs which further improve their selective distribution and targeting, hence improving the therapeutic effectiveness. The current review may provide useful guidance for the researchers who are interested in this promising dynamic cancer treatment technology.

The nephrotoxic potential of polystyrene microplastics at realistic environmental concentrations

As microplastics (MPs) dispersed into the environment, people might be exposed to MPs. Most pollutants either pass through or concentrate in the kidney. Therefore, nephrotoxicity tests are needed to verify the toxic potential of MPs. Here we used human embryonic kidney 293 (HEK293) cells to determine the association between nephrotoxicity and round-shape polystyrene MPs (PSMPs) (3.54 ± 0.39 μm) under realistic environmental exposure concentrations. Results revealed that PSMPs can adhere to the cell membrane and get entirely engulfed by HEK293 cells. PSMPs can induce cytotoxicity by oxidative stress via inhibition of the antioxidant haem oxygenase-1. Depolarisation of the mitochondrial membrane potential and formation of autophagosomes confirmed that apoptosis and autophagy can be simultaneously induced by PSMPs. The inflammatory factor was only activated (33 cytokines) by noncytotoxic concentration of PSMPs (3 ng/mL); however, the cytotoxic concentration (300 ng/mL) of PSMPs induced autophagy, which might further reduce NLRP3 expression, thus contributing to dampening inflammation (35 cytokines) in HEK293 cells. PSMPs (300 ng/mL) can impair kidney barrier integrity and increase the probability of developing acute kidney injury through the depletion of the zonula occludens-2 proteins and α1-antitrypsin. Altogether, our results demonstrated that environmental exposure to PSMPs may lead to an increased risk of renal disease.

Advancements in nanomedicines for the detection and treatment of diabetic kidney disease

In the diabetic kidneys, morbidities such as accelerated ageing, hypertension and hyperglycaemia create a pro-inflammatory microenvironment characterised by extensive fibrogenesis. Radiological techniques are not yet optimised generating inconsistent and non-reproducible data. The gold standard procedure to assess renal fibrosis is kidney biopsy, followed by histopathological assessment. However, this method is risky, invasive, subjective and examines less than 0.01% of kidney tissue resulting in diagnostic errors. As such, less than 10% of patients undergo kidney biopsy, limiting the accuracy of the current diabetic kidney disease (DKD) staging method. Standard treatments suppress the renin-angiotensin system to control hypertension and use of pharmaceuticals aimed at controlling diabetes have shown promise but can cause hypoglycaemia, diuresis and malnutrition as a result of low caloric intake. New approaches to both diagnosis and treatment are required. Nanoparticles (NPs) are an attractive candidate for managing DKD due to their ability to act as theranostic tools that can carry drugs and enhance image contrast. NP-based point-of-care systems can provide physiological information previously considered unattainable and provide control over the rate and location of drug release. Here we discuss the use of nanotechnology in renal disease, its application to both the treatment and diagnosis of DKD. Finally, we propose a new method of NP-based DKD classification that overcomes the current systems limitations.

Biosynthesis and bioactivities of metal nanoparticles mediated by Helichrysum aureonitens

Biosynthesis of nanoparticles is the preferred route for the fabrication of biocompatible and cheaper drugs. In this study, the extract and major secondary metabolite from Helichrysum aureonitens, 3,5-dihydroxy-6,7,8-trimethoxyflavone, were used to synthesize silver and zinc oxide nanoparticles. Spectroscopic and microscopic techniques confirmed the formation of the nanoparticles. The flavone alone showed higher DPPH radical scavenging ability (IC50 = 487.1 μg mL−1) relative to the control, butylated hydroxytoluene. In addition, silver nanoparticles synthesized using the flavone had higher ferric reducing potential (Fe3+ to Fe2+) compared to the other test samples. The cytotoxic activity of the plant extract, the flavone, and their biosynthesized nanoparticles was also investigated using the MTT assay against the cancerous MCF-7 (breast adenocarcinoma) and A549 (human lung adenocarcinoma)), and non-cancerous HEK293 (human embryonic kidney) cell lines. The plant extract decreased the cell viability of A549 (IC50 = 68.6 μg mL−1) without being cytotoxic against HEK293, even at high concentrations. Silver nanoparticles significantly decreased cell viability of A549 and moderately decreased cell viability of MCF-7 but induced cell death of HEK293 even at low concentrations. This study provides a green synthesis route for silver and zinc oxide nanoparticles and confirms the therapeutic effectiveness of H. aureonitens, thereby validating its use in ethnomedicine.

L-Cysteine capped zinc oxide nanoparticles induced cellular response on adenocarcinomic human alveolar basal epithelial cells using a conventional and organ-on-a-chip approach

Zinc oxide nanoparticles (ZnO NPs) are among the well-characterized nanomaterials with multifaceted biomedical applications, including biomedical imaging, drug delivery, and pharmaceutical preparations. The high surface charge of ZnO NPs leads to the agglomeration of the particles. Therefore, surface coating with a suitable ligand can increase colloidal stability. In this present study, in-vitro responses of ZnO NPs capped with a sulfur-containing amino acid, L-cysteine (Cys-ZnO NPs), on A549 cells was investigated. Fourier Transform Infrared Spectroscopy (FTIR) studies were carried out to confirm the capping of ZnO NPs with L-cysteine. Cytotoxic studies using A549 cells demonstrated reduced cytotoxicity in comparison with already reported pristine Zinc Oxide nanoparticles. The cellular uptake is confirmed by fluorescent cytometry. However, a higher concentration (160 µg/mL) of Cys-ZnO NPs led to apoptotic cell death marked by nuclear condensation, mitochondrial membrane depolarization, actin filament condensation, lysosomal damage LDH leakage, intracellular ROS production, blebbing, upregulation of Bax and downregulation of Bcl-2 gene expression. Cys-ZnO NPs treatment was also carried out in cells cultured in a microfluidic lung-on-a-chip device under a physiologically relevant flow rate. The study concluded that the microfluidic-based lung-on-a-chip culture resulted in reduced cell death compared to the conventional condition.

Mitochondria-Dependent Oxidative Stress Mediates ZnO Nanoparticle (ZnO NP)-Induced Mitophagy and Lipotoxicity in Freshwater Teleost Fish

Due to many special characteristics, zinc oxide nanoparticles (ZnO NPs) are widely used all over the world, leading to their wide distribution in the environment. However, the toxicities and mechanisms of environmental ZnO NP-induced changes of physiological processes and metabolism remain largely unknown. Here, we found that addition of dietary ZnO NPs disturbed hepatic Zn metabolism, increased hepatic Zn and lipid accumulation, downregulated lipolysis, induced oxidative stress, and activated mitophagy; N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN, Zn²⁺ ions chelator) alleviated high ZnO NP-induced Zn and lipid accumulation, oxidative stress, and mitophagy. Mechanistically, the suppression of mitochondrial oxidative stress attenuated ZnO NP-activated mitophagy and ZnO NP-induced lipotoxicity. Taken together, our study elucidated that mitochondrial oxidative stress mediated ZnO NP-induced mitophagy and lipotoxicity; ZnO NPs could be dissociated to free Zn²⁺ ions, which partially contributed to ZnO NP-induced changes in oxidative stress, mitophagy, and lipid metabolism. Our study provides novel insights into the impacts and mechanism of ZnO NPs as harmful substances inducing lipotoxicity of aquatic organisms, and accordingly, metabolism-relevant parameters will be useful for the risk assessment of nanoparticle materials in the environment.

Zinc oxide nanoparticles: potential effects on soil properties, crop production, food processing, and food quality

The use of zinc oxide nanoparticles (ZnO NPs) is expected to increase soil fertility, crop productivity, and food quality. However, the potential effects of ZnO NP utilization should be deeply understood. This review highlights the behavior of ZnO NPs in soil and their interactions with the soil components. The review discusses the potential effects of ZnO NPs on plants and their mechanisms of action on plants and how these mechanisms are related to their physicochemical properties. The impact of current applications of ZnO NPs in the food industry is also discussed. Based on the literature reviewed, soil properties play a vital role in dispersing, aggregation, stability, bioavailability, and transport of ZnO NPs and their release into the soil. The transfer of ZnO NPs into the soil can affect the soil components, and subsequently, the structure of plants. The toxic effects of ZnO NPs on plants and microbes are caused by various mechanisms, mainly through the generation of reactive oxygen species, lysosomal destabilization, DNA damage, and the reduction of oxidative stress through direct penetration/liberation of Zn2+ ions in plant/microbe cells. The integration of ZnO NPs in food processing improves the properties of the relative ZnO NP-based nano-sensing, active packing, and food/feed bioactive ingredients delivery systems, leading to better food quality and safety. The unregulated/unsafe discharge concentrations of ZnO NPs into the soil, edible plant tissues, and processed foods raise environmental/safety concerns and adverse effects. Therefore, the safety issues related to ZnO NP applications in the soil, plants, and food are also discussed.

A New Surface Charge Neutralizing Nano-Adjuvant to Potentiate Polymyxins in Killing Mcr-1 Mediated Drug-Resistant Escherichia coli

Resistance to polymyxins when treating multidrug-resistant (MDR) Gram-negative bacterial infections limit therapeutic options. Here, we report the synthesis of a nickel (Ni) doped Zinc oxide (NZO) combined with black phosphorus (BP) (NZB) nanocomposite and its synergistic action with polymyxin B (PolB) against polymyxin-resistant Escherichia coli harboring mobilized colistin resistance (mcr-1) gene. NZB and PolB combination therapy expressed a specific and strong synergy against Mcr-1 expressing E. coli cells. The underlying mechanism of the synergy is the charge neutralization of the E. coli cell surface by NZB, resulting in a more feasible incorporation of PolB to E. coli. The synergistic concentration of NZB with PolB was proved biocompatible. Thus, the NZB is the first biocompatible nano-adjuvant to polymyxins against polymyxin-resistant E. coli cells, recognizing the physical status of bacteria instead of known adjuvants targeting cellular gene products. Therefore, NZB has the potential to revive polymyxins as leading last-resort antibiotics to combat polymyxin-resistant Gram-negative bacterial infections.

Facile Use of ZnO Nanopowders to Protect Old Manual Paper Documents

One of the main problems faced by libraries, archives and collectors is the mold degradation of the paper-based documents, books, artworks etc. Microfungi (molds) emerge in regular storage conditions of such items (humidity, usually over 50%, and temperatures under 21 °C). If the removal of the visible mycelium is relatively easy, there is always the problem of the subsequent appearance of mold as the spores remain trapped in the cellulosic, fibrillary texture, which acts as a net. Moreover, due to improper hand hygiene bacteria contamination, old books could represent a source of biohazard, being colonized with human pathogens. An easy and accessible method of decontamination, which could offer long term protection is therefore needed. Here, we present a facile use of the ZnO nanopowders as antimicrobial agents, suitable for cellulose-based products, conferring an extended antibacterial and anti-microfungal effect. The proposed method does not adversely impact on the quality of the cellulose documents and could be efficiently used for biodegradation protection.

Interactions of Zinc Oxide Nanostructures with Mammalian Cells: Cytotoxicity and Photocatalytic Toxicity

This article presents a state-of-the-art review and analysis of literature studies on the morphological structure, fabrication, cytotoxicity, and photocatalytic toxicity of zinc oxide nanostructures (nZnO) of mammalian cells. nZnO with different morphologies, e.g., quantum dots, nanoparticles, nanorods, and nanotetrapods are toxic to a wide variety of mammalian cell lines due to in vitro cell-material interactions. Several mechanisms responsible for in vitro cytotoxicity have been proposed. These include the penetration of nZnO into the cytoplasm, generating reactive oxygen species (ROS) that degrade mitochondrial function, induce endoplasmic reticulum stress, and damage deoxyribonucleic acid (DNA), lipid, and protein molecules. Otherwise, nZnO dissolve extracellularly into zinc ions and the subsequent diffusion of ions into the cytoplasm can create ROS. Furthermore, internalization of nZnO and localization in acidic lysosomes result in their dissolution into zinc ions, producing ROS too in cytoplasm. These ROS-mediated responses induce caspase-dependent apoptosis via the activation of B-cell lymphoma 2 (Bcl2), Bcl2-associated X protein (Bax), CCAAT/enhancer-binding protein homologous protein (chop), and phosphoprotein p53 gene expressions. In vivo studies on a mouse model reveal the adverse impacts of nZnO on internal organs through different administration routes. The administration of ZnO nanoparticles into mice via intraperitoneal instillation and intravenous injection facilitates their accumulation in target organs, such as the liver, spleen, and lung. ZnO is a semiconductor with a large bandgap showing photocatalytic behavior under ultraviolet (UV) light irradiation. As such, photogenerated electron-hole pairs react with adsorbed oxygen and water molecules to produce ROS. So, the ROS-mediated selective killing for human tumor cells is beneficial for cancer treatment in photodynamic therapy. The photoinduced effects of noble metal doped nZnO for creating ROS under UV and visible light for killing cancer cells are also addressed.

Mitochondrial toxicity of nanomaterials

In recent years, nanomaterials have been widely applied in electronics, food, biomedicine and other fields, resulting in increased human exposure and consequent research focus on their biological and toxic effects. Mitochondria, the main target organelle for nanomaterials (NM), play a critical role in their toxic activities. Several studies to date have shown that nanomaterials cause alterations in mitochondrial morphology, mitochondrial membrane potential, opening of the mitochondrial permeability transition pore (MPTP) and mitochondrial respiratory function, and promote cytochrome C release. An earlier mitochondrial toxicity study of NMs additionally reported induction of mitochondrial dynamic changes. Here, we have reviewed the mitochondrial toxicity of NMs and provided a scientific basis for the contribution of mitochondria to the toxicological effects of different NMs along with approaches to reduce mitochondrial and, consequently, overall toxicity of NMs.

Zinc oxide nanoparticles for therapeutic purposes in cancer medicine

Zinc oxide nanoparticles are characterized by a good biocompatibility while providing a versatile potential as innovative therapeutic agents in cancer medicine.

Zinc oxide nanoparticles induce human multiple myeloma cell death via reactive oxygen species and Cyt-C/Apaf-1/Caspase-9/Caspase-3 signaling pathway in vitro

BACKGROUND

Human multiple myeloma (MM) is a malignant and incurable B cell tumor. Zinc oxide nanoparticles (ZnO NPs) have been widely used in biomedical fields including anti-bacterial and anti-tumor. However, the influence of ZnO NPs on MM cells is still unclear. The present study aimed to investigate the effect of ZnO NPs on MM cell (a human myeloma-derived RPMI8226 cell line) death in vitro and the underlying mechanism.

METHODS

The morphology of ZnO NPs was characterized by transmission electron microscopy (TEM), and the inhibitory and apoptotic effect of ZnO NPs on human MM cells was monitored by a CCK-8 method and an Annexin V-FITC/PI assay. Meanwhile, the morphological change in the cells after exposure to ZnO NPs was observed by a light field microscope. Moreover, the effects of ZnO NPs on the ATP level, reactive oxygen species (ROS) generation, and apoptosis were separately explored by the DCFH-DA fluorescent probe, flow cytometry, and ATP bioluminescence assay. Moreover, the expression of cytochrome C (Cyt-C), Apaf-1, Caspase-9 and Caspase-3 at mRNA and protein levels was further determined by using quantitative PCR (Q-PCR) and western blotting. In the present study, the human peripheral blood mononuclear cells (PBMCs) were used as normal control samples for the relevant experiment.

RESULTS

The results indicated that ZnO NPs could significantly inhibit human MM cell proliferation and cell death in a time- and dose-dependent manner in vitro, and this outcome can be confirmed by cell morphology and apoptosis assay. Meanwhile, the results also showed that ZnO NPs could effectively increase ROS production and decrease ATP levels in human MM cells. ZnO NPs could also significantly elevate the expression of Cyt-C, Apaf-1, Caspase-9 and Caspase-3 at mRNA and protein levels, leading to cell death. By contrast, ZnO NPs showed little cytotoxic influence on PBMCs.

CONCLUSION

ZnO NPs can significantly induce human MM cell death in a time- and dose-dependent manner in vitro, decrease the ATP production and enhance the ROS generation. ZnO NPs can also increase Cyt-C, Apaf-1, Caspase-9 and Caspase-3 expression at mRNA and protein levels in human MM cells, and initiate MM cell apoptosis, indicating that Cyt-C, Apaf-1, Caspase-9 and Caspase-3 play crucial roles in ZnO NPs-induced, mitochondria-mediated apoptosis in human MM cells. Overall, ZnO NPs may be a potential agent in treating human multiple myeloma in clinical practice.

ZnO Nanostructures and Electrospun ZnO-Polymeric Hybrid Nanomaterials in Biomedical, Health, and Sustainability Applications

ZnO-based nanomaterials are a subject of increasing interest within current research, because of their multifunctional properties, such as piezoelectricity, semi-conductivity, ultraviolet absorption, optical transparency, and photoluminescence, as well as their low toxicity, biodegradability, low cost, and versatility in achieving diverse shapes. Among the numerous fields of application, the use of nanostructured ZnO is increasingly widespread also in the biomedical and healthcare sectors, thanks to its antiseptic and antibacterial properties, role as a promoter in tissue regeneration, selectivity for specific cell lines, and drug delivery function, as well as its electrochemical and optical properties, which make it a good candidate for biomedical applications. Because of its growing use, understanding the toxicity of ZnO nanomaterials and their interaction with biological systems is crucial for manufacturing relevant engineering materials. In the last few years, ZnO nanostructures were also used to functionalize polymer matrices to produce hybrid composite materials with new properties. Among the numerous manufacturing methods, electrospinning is becoming a mainstream technique for the production of scaffolds and mats made of polymeric and metal-oxide nanofibers. In this review, we focus on toxicological aspects and recent developments in the use of ZnO-based nanomaterials for biomedical, healthcare, and sustainability applications, either alone or loaded inside polymeric matrices to make electrospun composite nanomaterials. Bibliographic data were compared and analyzed with the aim of giving homogeneity to the results and highlighting reference trends useful for obtaining a fresh perspective about the toxicity of ZnO nanostructures and their underlying mechanisms for the materials and engineering community.

Metal-containing nanoparticles derived from concealed metal deposits: An important source of toxic nanoparticles in aquatic environments

The potential environmental risks of engineered nanoparticles in aquatic environment have attracted considerable attention, but naturally produced nanoparticles have relatively been ignored, such as ore-related nanoparticles. To obtain more information about the natural ore-related nanoparticles, deep groundwater and well water samples were respectively collected in or around four major metal deposits in Inner Mongolia, China. These water samples were tested with high resolution transmission electron microscopy (TEM) and abundant metal-containing nanoparticles were found. Major ore-forming elements of corresponding metal deposits, such as Fe, Pb, Zn and Cu, and even associated elements, such as As, Sb, Sn and Cr, significantly contributed to the chemical compositions of these detected nanoparticles. Through comparison analyses, these metal-containing nanoparticles were shown to be originally from deep concealed metal deposits. They were the products of faulting and oxidation of ore minerals, and were transported long distances by water flow. Notably, these ore-related nanoparticles happened to have similar components with those nanoparticles of high environmental risks. Coupled with the analytical results of Atomic absorption spectroscopy (AAS) and inductively coupled plasma mass spectrometry (ICP-MS), it is recommended that the concentration limits of metal-containing nanoparticles should be considered in the safety assessment of drinking water. This is the first time, so far as we know, that naturally produced ore-related nanoparticles in the aquatic environment were listed as a kind of material with environmental risks. Considering the wide distribution of concealed metal deposits, more attention on related studies was urgently required for establishing specialized risk assessment and monitoring system.

Mesoporous superparamagnetic hydroxyapatite nanocomposite: A multifunctional platform for synergistic targeted chemo-magnetotherapy

In the present study, the aim was to develop a magneto-responsive nanocomposite for application in drug delivery by the integration of magnetic nanoparticles into an inorganic architecture, hydroxyapatite. The magnetic mesoporous hydroxyapatite nanocomposites, MMHAPs, were synthesized using a template-free method and fully characterized by XRD, FT-IR, TEM, FE-SEM, VSM, ICP, BET, and UV-Vis spectroscopy. MMHAPs exhibited a rod-like shape with a structure of large mesopores and high surface area. A sample of the nanocomposites with well-defined properties, MMHAP(2), was selected as a carrier for delivery of chemotherapy drug, doxorubicin (Dox). Then, it was coated with polyethylene glycol (P) and folic acid (F), providing aqueous stability and tumor targeting, respectively. The evaluation of drug release profile revealed that the release of drug occurs in a time-staggered manner under low pH conditions, which simulate the internal condition of lysosome. More important, a significant drug release was observed under a static magnetic field (SMF), displaying a magnetically triggered release. According to the toxicity assessment, MMHAP(2) did not show any noticeable toxic effect against the tumor cells (Saos-2) and normal cells (HEK-293) up to 100 μg ml^-1 in the presence or absence of SMF. In contrast, the drug-loaded nanocomposite, F.P.D@MMHAP(2), possesses high antitumor efficacy particularly in the presence of SMF. Moreover, it was found that the cellular internalization of F.P.D@MMHAP(2) could be increased by SMF, providing therapeutic efficiency enhancement. The high cytotoxic effect of F.P.D@MMHAP(2) with the help of SMF caused apoptosis in the tumor cells, which was preceded by a disturbance in the intracellular redox state and then caspase activation. Based on the data obtained, F.P.D@MMHAP(2) is a pH- and magneto-responsive platform opening up a new perspective in terms of its exploitation in cancer therapy.

Ecotoxicological assessment of perchlorate using in vitro and in vivo assays

Perchlorate is an inorganic ion widespread in the environment, generated as a natural and anthropogenic pollutant, with known endocrine disruption properties in the thyroid gland. Nonetheless, there are few reports of its ecotoxicological impact on wildlife. The aim of this study was to evaluate the adverse effects of KClO₄ exposure on different cell lines, HEK, N2a, and 3T3, as well as in ecological models such as Vibrio fischeri, Pseudokirchneriella subcapitata, Daphnia magna, and Eisenia fetida. Perchlorate exhibited similar toxicity against tested cell lines, with LC₅₀ values of 19, 15, and 19 mM for HEK, N2a, and 3T3, respectively; whereas in V. fischeri, the toxicity, examined as bioluminescence reduction, was considerably lower (EC₅₀ = 715 mM). The survival of the freshwater algae P. subcapitata was significatively impaired by perchlorate (LC₅₀ = 72 mM), and its effect on the lethality in the crustacean D. magna was prominent (LC₅₀ = 5 mM). For the earthworm E. fetida, the LC₅₀ was 56 mM in soil. In this organism, perchlorate induced avoidance behavior, weight loss, and decreased egg production and hatchling, as well as morphological and histopathological effects, such as malformations, dwarfism, and necrosis. In conclusion, perchlorate toxicity varies according to the species, although E. fetida is a sensitive model to generate information regarding the toxicological impact of KClO₄ on biota.

Varied dose exposures to ultrafine particles in the motorcycle smoke cause kidney cell damages in male mice

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Exposure to ultrafine particles has significant effect on kidney cell deformation.

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The exposure results in alterations in glomerular and tubular epithelial cells.

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Ultrafine particle concentration determines kidney cell deformation.

Ultrafine particles (UFPs) are one of motorcycle exhaust emissions which can penetrate the lung alveoli and deposit in the kidney. This study was aimed to investigate mice kidney cell physical damage (deformation) due to motorcycle exhaust emission exposures. The motorcycle exhaust emissions were sucked from the muffler with the rate of 33 cm³/s and passed through an ultrafine particle filter system before introduced into the mice exposure chamber. The dose concentration of the exhaust emissions was varied by setting the injected time of the 20s, 40s, 60s, 80s, and 100s. The mice were exposed to the smoke in the chamber for 100 s twice a day. The impact of the ultrafine particles on the kidney was observed by identifying the histological image of the kidney cell deformation using a microscope. The exposure was conducted for 10 days. The kidney observations were carried out on day 11. The results showed that there was a significant linear correlation between the total concentration of ultrafine particles deposited in the kidneys and the physical damage percentages. The increased concentrations of ultrafine particles caused larger cell deformation to the kidneys.

Responses and recovery assessment of continuously cultured Nitrosomonas europaea under chronic ZnO nanoparticle stress: Effects of dissolved oxygen

Although the antibacterial performances of emerging nanoparticles (NPs) have been extensively explored in the nitrifying systems, the impacts of dissolved oxygen (DO) levels on their bio-toxicities to the nitrifiers and the impaired cells' recovery potentials have seldom been addressed yet. In this study, the physiological and transcriptional responses of the typical ammonia oxidizers - Nitrosomonas europaea in a chemostat to the chronic ZnO NP exposure under different DO conditions were investigated. The results indicated that the cells in steady-growth state in the chemostat were more persevering than batch cultured ones to resist ZnO NP stress despite the dose-dependent NP inhibitory effects were observed. In addition, the occurred striking over-expressions of amoA and hao genes at the initial NP exposure stage suggested the cells' self-regulation potentials at the transcriptional level. The low DO (0.5 mg/L) cultured cells displayed higher sensitivity to NP stress than the high DO (2.0 mg/L) cultured ones, probably owning to the inefficient oxygen-dependent electron transfer from ammonia oxidation for energy conversion/production. The following 12-h NP-free batch recovery assays revealed that both high and low DO cultured cells possessed the physiological and metabolic activity recovery potentials, which were in negative correlation with the NP exposure time. The duration of NP stress and the resulting NP dissolution were critical for the cells' damage levels and their performance recoverability. The membrane preservation processes and the associated metabolism regulations were expected to actively participate in the cells' self-adaption to NP stress and thus be responsible for their metabolic activities recovery.