Aluminum doping tunes band gap energy level as well as oxidative stress-mediated cytotoxicity of ZnO nanoparticles in MCF-7 cells

Chemically sprayed pristine and Cd 2+ incorporated Co2SnO4 thin films for low ppm level enhanced chemi - resistive behaviour towards dimethylamine detection at room temperature

The surge in hazardous volatile organic liquid emissions driven by the rapid growth of the manufacturing industry has compelled a rising demand for gas sensors, which exhibit remarkable sensitivity, selectivity, and room temperature operation. Ternary metal oxide spinel has indeed garnered significant attention in chemi-resistive gas sensors due to their large reactive surface area, physicochemical, and other unique properties. In this work, we have studied chemically sprayed pristine and Cd 2+ incorporated Co2SnO4 thin film as a sensing layer under room temperature (300 K) conditions. The 5 wt% Cd 2+ incorporated Co2SnO4 films unveiled a high sensor response to dimethylamine (DMA) gas (S = Igas/Iair = 6153 at 1 ppm), which was boosted by 8.89-fold times compared to pristine Co2SnO4 film, due to the large reactive surface area and enhanced defective oxygen vacancies. It has superior selectivity towards DMA gas, good response time (154 s) / recovery time (90 s), superior pro-longevity (S = 6138) after 60 days, stable repeatability (7 cycles), excellent cross-selectivity, and relative humid resistance at 300 K. This research work provides insights on Cd 2+ incorporated Co2SnO4 thin films and their feasibility in real-time gas sensing devices.

Aluminum enhances the oxidative damage of ZnO NMs in the human neuroblastoma SH-SY5Y cell line

Bare and doped zinc oxide nanomaterials (ZnO NMs) are of great interest as multifunctional platforms for biomedical applications. In this study, we systematically investigate the physicochemical properties of Aluminum doped ZnO (AZO) and its bio-interactions with neuroblastoma (SH-SY5Y) and red blood (RBCs) cells. We provide a comprehensive chemical and structural characterization of the NMs. We also evaluated the biocompatibility of AZO NMs using traditional toxicity assays and advanced microscopy techniques. The toxicity of AZO NMs towards SH-SY5Y cells, decreases as a function of Al doping but is higher than the toxicity of ZnO NMs. Our results show that N-acetyl cysteine protects SH-SY5Y cells against reactive oxygen species toxicity induced by AZO NMs. ZnO and AZO NMs do not exert hemolysis in human RBCs at the doses that cause toxicity (IC50) in neuroblastoma cells. The Atomic force microscopy qualitative analysis of the interaction of SH-SY5Y cells with AZO NMs shows evidence that the affinity of the materials with the cells results in morphology changes and diminished interactions between neighboring cells. The holotomographic microscopy analysis demonstrates NMs' internalization in SH-SY5Y cells, changes in their chemical composition, and the role of lipid droplets in the clearance of toxicants.

The combined effects of polystyrene nanoplastics with nickel on oxidative stress and related toxic effects to earthworms from individual and cellular perspectives

Nanoplastics may adsorb other pollutants in the environment due to their high specific surface area and small size. We used earthworms as experimental organisms to evaluate the ecotoxicity of NPs and Ni combined pollution at the individual and cellular levels. The results showed that when only 20 mg/L Ni2+ was added to the combined pollution system, the antioxidant system of earthworm coelomocytes was destroyed to a certain extent, the ROS level increased, the cell viability decreased significantly, and the redox balance was destroyed. With the introduction of PS-NPs and the increase of concentration, the oxidative damage in the coelomocytes of earthworms gradually increased, and finally tended to be stable when the maximum concentration of 50 mg/L PS-NPs and Ni were exposed together. At the animal level, the activities of CAT and SOD decreased within 28 days of exposure, and the combined pollution showed a synergistic effect. At the same time, it promoted the synthesis of GST in earthworms, improved their detoxification ability and reduced oxidative damage. The changes of T-AOC and MDA showed that the combined pollution caused the accumulation of ROS and caused more serious toxicological effects. With the increase of exposure time, the antioxidant system of earthworms was continuously destroyed, and the oxidative damage was serious, which induced more serious lipid peroxidation and caused the damage of earthworm body wall structure.

Estimating the in vitro cytotoxicity of the newly emerged zinc oxide (ZnO) doped chromium nanoparticles using the human fetal lung fibroblast cells (WI38 cells)

Advances in nanotechnology have been increased for more smart applications and getting the highest level of benefits, recently modification of the surface characters of nanoparticles is a new trend to get the optimal benefits, one of these modification is doping of zinc oxide with chromium nanoparticles (ZnO doped Cr NPs), the present study aimed to identify the surface characters of doped ZnO and their possible cytotoxic effects. The doped NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Field emission scanning electron microscope (FESEM), and Electromagnetic Data Exchange (EDX). Human fetal lung fibroblast cells (WI38 Cells) was treated with variable concentrations of pure ZnO and ZnO doped Cr (0.01 %, 0.02 %, 0.03 % and 0.04 %) for 24 hr at 37 °C followed by the MTT assay. The cells treated with the obtained half-maximal inhibitory concentration (IC50). The supernatant and cells were collected for oxidant/anti-oxidant and molecular analysis.The observed FESEM features are in line with the reported XRD analysis confirming the hexagonal crystal symmetry of all samples. The findings revealed that pure ZnO exhibited potent cytotoxic effects followed by (0.03 % and 0.04 %). All tested NPs produce lipid peroxidation significantly (0.03 % and 0.04 %). The significant up regulation of Bcl-2-associated X protein (BAX) and apoptotic Caspase (Cas-3) transcription level were reported in ZnO and 0.03 % and 0.04 % in contrast the anti apoptitic B-cell lymphoma 2 (Bcl-2) is elevated in 0.01 % and 0.02 %. Doping of ZnO with Cr causing significant morphological changes which effect on their toxicity especially with 0.03 % and 0.04 %.

Impact of resveratrol and zinc on biomarkers of oxidative stress induced by Trichinella spiralis infection

Trichinellosis is a re-emerging worldwide foodborne zoonosis. Oxidative stress is one of the most common detrimental effects caused by trichinellosis. In addition, Trichinella infection poses an infinite and major challenge to the host's immune system. Resistance and side effects limit the efficiency of the existing anti-trichinella medication. Given that concern, this work aimed to investigate the anti-helminthic, antioxidant, anti-inflammatory and immunomodulatory effects of resveratrol and zinc during both phases of Trichinella spiralis infection. Sixty-four Swiss albino mice were divided into four equal groups: non-infected control, infected control, infected and treated with resveratrol, and infected and treated with zinc. Animals were sacrificed on the 7th and 35th days post-infection for intestinal and muscular phase assessments. Drug efficacy was assessed by biochemical, parasitological, histopathological, immunological, and immunohistochemical assays. Resveratrol and zinc can be promising antiparasitic, antioxidant, anti-inflammatory, and immunomodulatory agents, as evidenced by the significant decrease in parasite burden, the significant improvement of liver and kidney function parameters, the increase in total antioxidant capacity (TAC), the reduction of malondialdehyde (MDA) level, the increase in nuclear factor (erythroid-derived 2)-like-2 factor expression, and the improvement in histopathological findings. Moreover, both drugs enhanced the immune system and restored the disturbed immune balance by increasing the interleukin 12 (IL-12) level. In conclusion, resveratrol and zinc provide protection for the host against oxidative harm and the detrimental effects produced by the host's defense response during Trichinella spiralis infection, making them promising natural alternatives for the treatment of trichinellosis.

AlCl3@ZnO nanostructured material: an efficient green catalyst for the one-pot solvent-free synthesis of 1,4-dihydropyridines

AlCl3-loaded ZnO nanoparticles have been explored as an efficient catalyst for 1,4-dihydropyridine synthesis under ambient temperature and solvent-free conditions. For this purpose, ZnO nanoparticles were synthesized by a simple solution-based precipitation technique using a stoichiometric amount of zinc sulfate and oxalic acid. The AlCl3@ZnO nanocrystalline catalyst was prepared by loading 20% AlCl3 on ZnO nanoparticles by a simple wet-impregnation technique. This catalyst efficiently performed Hantzsch pyridine reactions with various aromatic aldehydes, ethyl acetoacetate and ammonium acetate. The nanostructured AlCl3-loaded ZnO catalyst was characterized by UV-DRS, XRD, FESEM, EDS, FETEM-STEM-EDS and XPS techniques. The comprehensive characterization reveals the formation of AlCl3-loaded ZnO catalysts with an average particle size of 70-80 nm. The loading of AlCl3 on the ZnO surface was confirmed by minor shifts in the XPS and XRD peaks. FETEM-STEM-EDS also indicates reasonable AlCl3 loading on ZnO nanoparticles. The 20% AlCl3-loaded ZnO nanocatalyst (AlCl3@ZnO) confers 92% yield for the synthesis of 1,4-dihydropyridine under solvent-free and ambient temperature conditions. The synthesized 1,4-dihydropyridines were characterized by 1H-NMR, 13C-NMR, HRMS and FT-IR spectroscopic techniques. The reported catalyst is highly efficient, environmentally friendly and could become an alternative to homogenous and heterogenous catalytic reactions.

Effect of Na and Al doping on ZnO nanoparticles for potential application in sunscreens

This study investigated the environment-friendly production and characterization of zinc oxide nanoparticles (ZnO NPs) doped with sodium (Na) and aluminum (Al) metals to decrease the photocatalytic activity of ZnO for use in sunscreen. The metal-doped zinc oxide (ZnO) materials were prepared by the microwave method using extracts of Averrhoa carambola, also known as star fruit, as a reducing agent. The effects of metal-ion doping on the crystal structure, morphology, and optical characteristics of ZnO were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), transmission electron microscopy (TEM), and ultraviolet-visible (UV-Vis) spectroscopy. The sun protection factor (SPF) of the sunscreen formulations containing undoped ZnO, Na-doped ZnO (Na/ZnO), and Al-doped ZnO (Al/ZnO) NPs were found to be 10.10, 25.10, and 43.08, respectively. Therefore, Na/ZnO and Al/ZnO showed increased SPF. Additionally, the prepared nanomaterials and sunscreens were effective against Gram-positive and Gram-negative bacteria and showed antioxidant activities. The methylene blue (MB) degradation was used to evaluate the photocatalytic activities of the undoped ZnO, Na/ZnO, and Al/ZnO NPs, which were found to be 66%, 46%, and 38%, respectively. Therefore, due to the structural defects of ZnO NPs, their photocatalytic activity was decreased with Na- and Al- doping. Additionally, Al/ZnO is an ideal candidate as an ingredient in sunscreens.

In vitro anticancer and antibacterial performance of biosynthesized Ag and Ce co-doped ZnO NPs

The great potential of zinc oxide nanoparticles (ZnO NPs) for biomedical applications is attributed to their physicochemical properties. In this work, pure and Ag and Ce dual-doped ZnO NPs were synthesized through a facile and green route to examine their cytotoxicity in breast cancer and normal cells. The initial preparation of dual-doped nanoparticles was completed by the usage of taranjabin. The synthesis of Ag and Ce dual-doped ZnO NPs was started with preparing the Ce:Ag ratios of 1:1, 1:2, and 1:4. The cytotoxicity effects of synthesized nanoparticles against breast normal cells (MCF-10A) and breast cancer cells (MDA-MB-231) were examined. The hexagonal structure of synthesized nanoparticles was observed through the results of X-ray diffraction (XRD). Scanning electron microscopy (SEM) images exhibited the spherical shape and smooth surfaces of prepared particles along with the homogeneous distribution of Ag and Ce in ZnO with high-quality lattice fringes without any distortions. According to the cytotoxic results, the effects of Ag/Ce dual-doped ZnO NPs on breast cancer (MDA-MB-231) cells were significantly more than of pure ZnO NPs, while dual-doped and pure nanoparticles remained indifferent towards breast normal (MCF-10A) cells. In addition, we investigated the antimicrobial activity against harmful bacteria.

Synthesis and electrochemical performance of α-Al2O3 and M-Al2O4 spinel nanocomposites in hybrid quantum dot-sensitized solar cells

The aim of this study is to describe the performance of the aluminum oxide nanoparticle and metal aluminate spinel nanoparticle as photo-anodes in quantum dot photovoltaic. By using a sol–gel auto combustion method, Al₂O₃ NPs, CoAl₂O₄, CuAl₂O₄, NiAl₂O₄, and ZnAl₂O₄ were successfully synthesized. The formation of Al₂O₃ NPs and MAl₂O₄ (M=Co, Cu, Ni, Zn) nanocomposite was confirmed by using several characteristics such as XRD, UV–Vis, FTIR, FE-SEM, and EDX spectra. The XRD shows that the CoAl₂O₄ has a smaller crystallite size (12.37 nm) than CuAl₂O_4, NiAl₂O₄, and ZnAl₂O₄. The formation of a single-phase spinel structure of the calcined samples at 1100 °C was confirmed by FTIR. Our studies showed that the pure Al₂O₃ NP_s have a lower energy gap (1.37 eV) than synthesized MAl₂O₄ under UV–Vis irradiation. Due to the well separation between the light-generated electrons and the formed holes, the cell containing ZnAl₂O₄ nanocomposite with CdS QDs has the highest efficiency of 8.22% and the current density of 22.86 mA cm⁻², while the cell based on NiAl₂O₄ as a photoelectrode, six cycles of CdS/ZnS QDs, and P-rGO as a counter electrode achieved the best (PCE) power conversion efficiency of 15.14% and the current density of 28.22 mA cm⁻². Electrochemical impedance spectroscopy shows that ZnAl₂O₄ and NiAl₂O₄ nanocomposites have the highest life times of the photogenerated electrons (τ_n) of 11*10⁻² and 96*10⁻³ ms, respectively, and the lowest diffusion rates (K_eff) of 9.09 and 10.42 ms⁻¹, respectively.

Mitochondrial Dysfunction Induced by Zinc Oxide Nanoparticles

The constant evolution and applications of metallic nanoparticles (NPs) make living organisms more susceptible to being exposed to them. Among the most used are zinc oxide nanoparticles (ZnO-NPs). Therefore, understanding the molecular effects of ZnO-NPs in biological systems is extremely important. This review compiles the main mechanisms that induce cell toxicity by exposure to ZnO-NPs and reported in vitro research models, with special attention to mitochondrial damage. Scientific evidence indicates that in vitro ZnO-NPs have a cytotoxic effect that depends on the size, shape and method of synthesis of ZnO-NPs, as well as the function of the cells to which they are exposed. ZnO-NPs come into contact with the extracellular region, leading to an increase in intracellular [Zn2+] levels. The mechanism by which intracellular ZnO-NPs come into contact with organelles such as mitochondria is still unclear. The mitochondrion is a unique organelle considered the “power station” in the cells, participates in numerous cellular processes, such as cell survival/death, multiple biochemical and metabolic processes, and holds genetic material. ZnO-NPs increase intracellular levels of reactive oxygen species (ROS) and, in particular, superoxide levels; they also decrease mitochondrial membrane potential (MMP), which affects membrane permeability and leads to cell death. ZnO-NPs also induced cell death through caspases, which involve the intrinsic apoptotic pathway. The expression of pro-apoptotic genes after exposure to ZnO-NPs can be affected by multiple factors, including the size and morphology of the NPs, the type of cell exposed (healthy or tumor), stage of development (embryonic or differentiated), energy demand, exposure time and, no less relevant, the dose. To prevent the release of pro-apoptotic proteins, the damaged mitochondrion is eliminated by mitophagy. To replace those mitochondria that underwent mitophagy, the processes of mitochondrial biogenesis ensure the maintenance of adequate levels of ATP and cellular homeostasis.

Number 2 Feibi Recipe Ameliorates Pulmonary Fibrosis by Inducing Autophagy Through the GSK-3β/mTOR Pathway

Number 2 Feibi Recipe (N2FBR) is a traditional Chinese medicine formula for treating idiopathic pulmonary fibrosis. N2FBR inhibits H₂O₂-mediated oxidative stress damage in alveolar epithelial cells by increasing autophagy, as we previously demonstrated. However, it is unknown if similar mechanisms occur in vivo. We established a pulmonary fibrosis model by instilling bleomycin (BLM) from the airway to examine the effects of N2FBR on pulmonary fibrosis and investigate its probable mechanism in this work. We discovered that N2FBR treatment effectively alleviated interstitial fibrosis as well as collagen deposition, primarily in upregulating SOD, GSH-Px, T-AOC and downregulating MDA content. N2FBR also increased the expression of LC3B, Beclin-1, LAMP1, TFEB and downregulated the expression of p62, legumain. N2FBR treatment boosted the production of autophagosomes, according to the results of the TEM observation. Furthermore, we explored that N2FBR exerted its anti-oxidative stress and pro-autophagy effects via GSK-3β/mTOR signalling pathway. Therefore, these results provide further evidence for the protective effect of N2FBR in pulmonary fibrosis. Our findings could have ramifications for the development of antifibrosis therapies.

Recent trends in the application of nanoparticles in cancer therapy: The involvement of oxidative stress

In the biomedical area, the interdisciplinary field of nanotechnology has the potential to bring numerous unique applications, including better tactics for cancer detection, diagnosis, and therapy. Nanoparticles (NPs) have been the topic of many research and material applications throughout the last decade. Unlike small-molecule medications, NPs are defined by distinct physicochemical characteristics, such as a large surface-to-volume ratio, which allows them to permeate live cells with relative ease. The versatility of NPs as both therapeutics and diagnostics makes them ideal for a broad spectrum of illnesses, from infectious diseases to cancer. A significant amount of data has been participated in the current scientific publications, emphasizing the concept that NPs often produce reactive oxygen species (ROS) to a larger degree than micro-sized particles. It is important to note that oxidative stress governs a wide range of cell signaling cascades, many of which are responsible for cancer cell cytotoxicity. Here, we aimed to provide insight into the signaling pathways triggered by oxidative stress in cancer cells in response to several types of nanomaterials, such as metallic and polymeric NPs and quantum dots. We discuss recent advances in developing integrated anticancer medicines based on NPs targeted to destroy malignant cells by increasing their ROS setpoint.

The Study of Chemical Profile and Antioxidant Properties of Poplar-Type Polish Propolis Considering Local Flora Diversity in Relation to Antibacterial and Anticancer Activities in Human Breast Cancer Cells

Nine samples of ethanolic extracts of poplar-type propolis (EEP) originated from South-Eastern Poland were analyzed in terms of the diversity of the flora around the apiary. The mineral composition, antioxidant properties, polyphenolic profile (HPTLC), and main polyphenolic constituents (HPLC-DAD) were determined. Only minor differences in chemical composition and antioxidant capacity between tested EEPs were found regardless of their botanical origin. However, the biological activity of the EEPs was more diversified. The tested EEPs showed stronger antibacterial activity against Gram-negative bacteria (Escherichia coli) compared to Gram-positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis). Staphylococci biofilm inhibition occurred as a result of exposure to the action of four out of nine EEPs (P1–P4). Due to the various compositions of individual EEPs, a different MCF-7 cellular response was observed according to inhibition of cells migration and proliferation. Almost every sample inhibited the migration of breast cancer cells at a low concentration (0.04 µg/mL) of propolis. Even at the lowest concentration (0.02 µg/mL), each EEP inhibited the proliferation of MCF-7 cells, however, the level of inhibition varied between samples.

Protein-corona formation on aluminum doped zinc oxide and gallium nitride nanoparticles

The interaction of semiconductor nanoparticles with bio-molecules attracts increasing interest of researchers, considering the reactivity of nanoparticles and the possibility to control their properties remotely giving mechanical, thermal, or electrical stimulus to the surrounding bio-environment. This work reports on a systematic comparative study of the protein-corona formation on aluminum doped zinc oxide and gallium nitride nanoparticles. Bovine serum albumin was chosen as a protein model. Dynamic light scattering, transmission electron microscopy and X-ray photoelectron spectroscopy techniques have been used to demonstrate the formation of protein-corona as well as the stability of the colloidal suspension given by BSA, which also works as a surfactant. The protein adsorption on the NPs surface studied by Bradford Assay showed the dependence on the quantity of proteins adsorbed to the available sites on the NPs surface, thus the saturation was observed at ratio higher than 5:1 (NPs:Proteins) in case of ZnO, these correlating with DLS results. Moreover, the kinetics of the proteins showed a relatively fast adsorption on the NPs surface with a saturation curve after about 25 min. GaN NPs, however, showed a very small amount of proteins adsorbed on the surface, a change in the hydrodynamic size being not observable with DLS technique or differential centrifugal sedimentation. The Circular Dichroism analysis suggests a drastic structural change in the secondary structure of the BSA after attaching on the NPs surface. The ZnO nanoparticles adsorb a protein-corona, which does not protect them against dissolution, and in consequence, the material proved to be highly toxic for Human keratinocyte cell line (HaCaT) at concentration above 25 µg/mL. In contrast, the GaN nanoparticles which do not adsorb a protein-corona, show no toxicity signs for HaCaT cells at concentration as high as 50 µg/mL, exhibiting much lower concentration of ions leakage in the culture medium as compared to ZnO nanoparticles.

Nanosilver reinforced Parmelia sulcata extract efficiently induces apoptosis and inhibits proliferative signalling in MCF-7 cells

The Lichen, Parmelia sulcata synthesizes various secondary metabolites, in which phenolic based compounds received much attention due to their importance in biomedical application. Especially the phenolic compound was effective against the cancer treatment. An effective administration of such plant natural product can represent a significant conventional management of cancer in terms of chemoprevention. The nanomedicines are group of agents that selectively interfere the cancer cells which leads to reduction of side effect thereby reducing the doses. Silver nanoparticles is a promising antitumor agent, however, the conventional production of silver nanoparticles have many drawbacks which led to increase in need of eco-friendly biological production methods. In this study, we made an attempt to synthesise a nano silver (Ps-AgNPs) from phenolic extract of lichen Parmelia sulcata extract. The Ps-AgNps was applied for anticancer activity using MCF-7 cells and the effect was characterised by western blotting method. The FTIR, XRD, UV and TEM results confirms the presence of silver nanoparticles in phenolic extract of lichen Parmelia sulcata. The cytotoxicity assay shows that the Ps-AgNPs is toxic against cancer cells (MCF-7) but not to normal cells (NIH3T3), which confirm the selective induction of cell death (apoptosis) against cancer cells. The Western blot analysis also clearly indicates the down regulation of inflammatory genes (TNF-alpha and IL-6) and cell cycle genes (PCNA and Cyclin-D1) thus promoting intrinsic apoptotic pathway. The results suggest that Ps-AgNPs can effectively kill cancer cells and can be used as an alternative therapeutic agent for cancer treatment.

Silver Nanoparticles Synthesized Using Carica papaya Leaf Extract (AgNPs-PLE) Causes Cell Cycle Arrest and Apoptosis in Human Prostate (DU145) Cancer Cells

Treatment of cancer has been limited by the poor efficacy and toxicity profiles of available drugs. There is a growing demand to develop alternative approaches to combat cancer such as use of nano-formulation-based drugs. Here, we report biosynthesis and characterization of silver nanoparticles (AgNPs) with papaya leaf extract (PLE) and its anti-cancer properties against different human cancer cells. Purified nanoparticles were characterized by standard techniques, such as TEM, STM, SEM, EDS, XRD, and FTIR. Furthermore, cytotoxic activity of AgNPs-PLE was carried out against different human cancer cells and non-tumorigenic human keratinocytes cells. AgNPs-PLE when compared with AgNPs-citric acid or PLE showed better efficacy against cancer cells and was also relatively less toxic to normal cells. Treatment of DU145 cells with AgNPs-PLE (0.5-5.0 μg/ml) for 24-48 h lowered total cell number by 24-36% (P < 0.05). Inhibition of cell growth was linked with arrest of cell cycle at G2/M phase at 24 h, while G1 and G2/M phase arrests at 48 h. ROS production was observed at earlier time points in presence of AgNPs-PLE, suggesting its role behind apoptosis in DU145 cells. Induction of apoptosis (57%) was revealed by AO/EB staining in DU145 cells along with induction of Bax, cleaved caspase-3, and cleaved PARP proteins. G1-S phase cell cycle check point marker, cyclin D1 was down-regulated along with an increase in cip1/p21 and kip1/p27 tumor suppressor proteins by AgNPs-PLE. These findings suggest the anti-cancer properties of AgNPs-PLE.

Sono-synthesis approach improves anticancer activity of ZnO nanoparticles: reactive oxygen species depletion for killing human osteosarcoma cells

Aim: To investigate the effect of ultrasound during the synthesis of ZnO nanoparticles (NPs) on their anticancer activity. Materials & methods: ZnO NPs were synthesized in the presence and absence of ultrasonic irradiation. Biological tests were performed on human osteosarcoma cancer cells (Saos-2). Results: The sono-synthesized sample indicated higher cytotoxicity than the conventional one. (IC₅₀ = 16.48 ± 0.41 μg/ml for sonochemical ZnO; 26.96 ± 0.33 μg/ml for conventional ZnO). Both sonochemical and conventional samples acted like antioxidants and reduced intracellular reactive oxygen species level. This reduction was more significant in cells treated with the sono-synthesized sample. The sono-synthesized ZnO NPs showed more tumor selectivity than the conventional sample. Conclusion: Sono-synthesis of ZnO NPs by a bath sonicator could improve their anticancer activity.

SnO2-Doped ZnO/Reduced Graphene Oxide Nanocomposites: Synthesis, Characterization, and Improved Anticancer Activity via Oxidative Stress Pathway

BACKGROUND

Therapeutic selectivity and drug resistance are critical issues in cancer therapy. Currently, zinc oxide nanoparticles (ZnO NPs) hold considerable promise to tackle this problem due to their tunable physicochemical properties. This work was designed to prepare SnO2-doped ZnO NPs/reduced graphene oxide nanocomposites (SnO2-ZnO/rGO NCs) with enhanced anticancer activity and better biocompatibility than those of pure ZnO NPs.

MATERIALS AND METHODS

Pure ZnO NPs, SnO2-doped ZnO (SnO2-ZnO) NPs, and SnO2-ZnO/rGO NCs were prepared via a facile hydrothermal method. Prepared samples were characterized by field emission transmission electron microscopy (FETEM), energy dispersive spectroscopy (EDS), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), ultraviolet-visible (UV-VIS) spectrometer, and dynamic light scattering (DLS) techniques. Selectivity and anticancer activity of prepared samples were assessed in human breast cancer (MCF-7) and human normal breast epithelial (MCF10A) cells. Possible mechanisms of anticancer activity of prepared samples were explored through oxidative stress pathway.

RESULTS

XRD spectra of SnO2-ZnO/rGO NCs confirmed the formation of single-phase of hexagonal wurtzite ZnO. High resolution TEM and SEM mapping showed homogenous distribution of SnO2 and rGO in ZnO NPs with high quality lattice fringes without any distortion. Band gap energy of SnO2-ZnO/rGO NCs was lower compared to SnO2-ZnO NPs and pure ZnO NPs. The SnO2-ZnO/rGO NCs exhibited significantly higher anticancer activity against MCF-7 cancer cells than those of SnO2-ZnO NPs and ZnO NPs. The SnO2-ZnO/rGO NCs induced apoptotic response through the upregulation of caspase-3 gene and depletion of mitochondrial membrane potential. Mechanistic study indicated that SnO2-ZnO/rGO NCs kill cancer cells through oxidative stress pathway. Moreover, biocompatibility of SnO2-ZnO/rGO NCs was also higher against normal breast epithelial (MCF10A cells) in comparison to SnO2-ZnO NPs and ZnO NPs.

CONCLUSION

SnO2-ZnO/rGO NCs showed enhanced anticancer activity and better biocompatibility than SnO2-ZnO NPs and pure ZnO NPs. This work suggested a new approach to improve the selectivity and anticancer activity of ZnO NPs. Studies on antitumor activity of SnO2-ZnO/rGO NCs in animal models are further warranted.

Single-composition Al3+-singly doped ZnO phosphors for UV-pumped warm white light-emitting diode applications

The development of full-visible-spectrum phosphors is essential for next-generation light-emitting devices with better light quality. Herein, we report on a novel broad-band-emitting phosphor based on single-composition Al-doped ZnO phosphors. Under the UV excitation of 325 nm, the ZnO : Al phosphor exhibits a full spectrum emission in the visible wavelength range from 400 to 800 nm with a CIE chromaticity coordinate of (0.42, 0.48), a quantum efficiency of 43%, a color rendering index (CRI) of 74, a correlated color temperature (CCT) value of 3873 K and an activation energy of 0.22 eV. A prototype of a UV-pumped warm WLED with a high CRI of 87 and a CCT of 4067 K has been achieved by using only this broad-band-emitting Al3+-doped ZnO phosphor. The obtained results indicate that the single-composition Al3+-singly doped warm white emitting phosphor is a promising candidate for UV-pump warm white light-emitting diodes.

Barium Titanate (BaTiO3) Nanoparticles Exert Cytotoxicity through Oxidative Stress in Human Lung Carcinoma (A549) Cells

Barium titanate (BaTiO3) nanoparticles (BT NPs) have shown exceptional characteristics such as high dielectric constant and suitable ferro-, piezo-, and pyro-electric properties. Thus, BT NPs have shown potential to be applied in various fields including electro-optical devices and biomedicine. However, very limited knowledge is available on the interaction of BT NPs with human cells. This work was planned to study the interaction of BT NPs with human lung carcinoma (A549) cells. Results showed that BT NPs decreased cell viability in a dose- and time-dependent manner. Depletion of mitochondrial membrane potential and induction of caspase-3 and -9 enzyme activity were also observed following BT NP exposure. BT NPs further induced oxidative stress indicated by induction of pro-oxidants (reactive oxygen species and hydrogen peroxide) and reduction of antioxidants (glutathione and several antioxidant enzymes). Moreover, BT NP-induced cytotoxicity and oxidative stress were effectively abrogated by N-acetyl-cysteine (an ROS scavenger), suggesting that BT NP-induced cytotoxicity was mediated through oxidative stress. Intriguingly, the underlying mechanism of cytotoxicity of BT NPs was similar to the mode of action of ZnO NPs. At the end, we found that BT NPs did not affect the non-cancerous human lung fibroblasts (IMR-90). Altogether, BT NPs selectively induced cytotoxicity in A549 cells via oxidative stress. This work warrants further research on selective cytotoxicity mechanisms of BT NPs in different types of cancer cells and their normal counterparts.

Enhancement of NOx photo-oxidation by Fe- and Cu-doped blue TiO2

The present work is focused on the removal of NOx with reduced blue TiO₂ with Fe (blue Fe-TiO₂)- and Cu (blue Cu-TiO₂)-doped photocatalyst. TiO₂ was reduced via lithium in EDA (blue TiO₂). Fe and Cu ions were doped in the reduced TiO₂ (blue Fe-TiO₂ and blue Cu-TiO₂). The material resulted in a core-shell structure of amorphous and anatase phase. XPS suggests the existence of Ti³⁺ species and oxygen vacancies within the structure of TiO₂. Additionally, valence bond (VB)-XPS shows the generation of intermediate levels at the band edge of the doped photocatalyst. Photocurrent, electrochemical impedance spectroscopy and cyclic voltammetry confirmed the enhanced charge-separation process in doped reduced TiO₂. The photocatalysts were tested for the photo-oxidation of NOx. Blue Fe-TiO₂ reveals the efficiency of 70% for NO elimination and 44.74% for NO₂ formation. The improved efficiency of the doped photocatalyst is related to the re-engineered structure with Ti³⁺ species, oxygen vacancies, and charge traps. Electron spin resonance (ESR) measurement was carried out for blue Fe-TiO₂ to confirm the formation of reactive oxygen species (ROS). Furthermore, ion chromatography was used to investigate the mechanism of NOx oxidation. In conclusion, the doped blue TiO₂ has a strong tendency to photo-oxidize NOx gasses.

Cytotoxic effects in transformed and non-transformed human breast cell lines after exposure to silver nanoparticles in combination with selected aluminium compounds, parabens or phthalates

This study was undertaken to assess cytotoxic effects of selected aluminium compounds, parabens and phthalates in combination with silver nanoparticles (AgNP, 15 and 45 nm by STEM, Ag15 and Ag45, respectively) on cell lines of the human breast epithelium, normal (MCF-10A) and transformed (MDA-MB-231 and MCF-7). Combination indices were the most spectacular at effective concentrations (ED) inducing 25 % decrease in viability for the combinations of Ag15 with AlCl₃ for MDA-MB-231 cells or aluminium zirconium tetrachlorohydrex Gly (AlZr) for MCF-10A and MCF-7 cells, where rather strong antagonism was revealed. As the ED values increased, those effects were enhanced (e.g. Ag15+AlCl₃ for MDA-MB-231) or reversed into synergism (e.g. Ag15+AlZr for MCF-7). Another strong effect was observed for aluminium chloride hydroxide, which increasing ED, induced synergistic effect with both Ag15 and Ag45 on MCF-10A cells. Another interesting synergistic effect was observed for DBPh, but only in combination with Ag45 on MCF-10A and MCF-7. The results on cytotoxicity, cell cycle and oxidative stress induction indicate complex response of the cell lines to combined treatment with silver nanoparticles and the chemicals, which were influenced by diverse factors, such as physico-chemical characteristics of AgNP, method of their synthesis, concentrations used, and finally cell type.

High Surface Reactivity and Biocompatibility of Y2O3 NPs in Human MCF-7 Epithelial and HT-1080 FibroBlast Cells

This study aimed to generate a comparative data on biological response of yttrium oxide nanoparticles (Y₂O₃ NPs) with the antioxidant CeO₂ NPs and pro-oxidant ZnO NPs. Sizes of Y₂O₃ NPs were found to be in the range of 35±10 nm as measured by TEM and were larger from its hydrodynamic sizes in water (1004 ± 134 nm), PBS (3373 ± 249 nm), serum free culture media (1735 ± 305 nm) and complete culture media (542 ± 108 nm). Surface reactivity of Y₂O₃ NPs with bovine serum albumin (BSA) was found significantly higher than for CeO₂ and ZnO NPs. The displacement studies clearly suggested that adsorption to either BSA, filtered serum or serum free media was quite stable, and was dependent on whichever component interacted first with the Y₂O₃ NPs. Enzyme mimetic activity, like that of CeO₂ NPs, was not detected for the NPs of Y₂O₃ or ZnO. Cell viability measured by MTT and neutral red uptake (NRU) assays suggested Y₂O₃ NPs were not toxic in human breast carcinoma MCF-7 and fibroblast HT-1080 cells up to the concentration of 200 μg/mL for a 24 h treatment period. Oxidative stress markers suggested Y₂O₃ NPs to be tolerably non-oxidative and biocompatible. Moreover, mitochondrial potential determined by JC-1 as well as lysosomal activity determined by lysotracker (LTR) remained un-affected and intact due to Y₂O₃ and CeO₂ NPs whereas, as expected, were significantly induced by ZnO NPs. Hoechst-PI dual staining clearly suggested apoptotic potential of only ZnO NPs. With high surface reactivity and biocompatibility, NPs of Y₂O₃ could be a promising agent in the field of nanomedicine.

Zinc oxide nanoparticles induce human tenon fibroblast apoptosis through reactive oxygen species and caspase signaling pathway

Glaucoma is the leading cause of irreversible blindness in the world and trabeculectomy remains still the most commonly performed filtration surgery. Failure of trabeculectomy is due to the formation of scarring, which is associated with the increased fibroblast proliferation, activation, and collagen deposition at the site of the drainage channel with subconjunctival fibrosis. Our previous study has revealed that zinc oxide (ZnO) nanoparticles could efficiently decrease the expressions of TGF-β1 and inhibit fibroblast-mediated collagen lattice contraction. However, the mechanism underlying ZnO nanoparticle-induced fibroblast apoptosis is still unclear. In the present study, we investigated the effect of ZnO nanoparticles on the reactive oxygen species (ROS) and mitochondrial membrane potential (Δψm) in human Tenon fibroblasts (HTFs). Moreover, we also explored the influence of ZnO nanoparticles on the expression of Caspase-3, Caspase-9, apoptotic protease-activating factor-1 (Apaf-1), fibroblast-specific protein-1 (FSP-1), collagen III, and E-cadherin. The results indicated that ZnO nanoparticles markedly inhibit HTFs viability and decrease the Δψm in a concentration-dependent pattern. Exposure of HTFs to ZnO nanoparticles could also induce the elevated Caspase-3, Caspase-9, and Apaf-1 expression, decrease the levels of FSP-1, collagen III, and E-cadherin expression, leading to HTFs apoptosis. Our results suggested that elevated ROS and activated Caspase signaling play a fundamental role in ZnO nanoparticle-induced HTFs apoptosis.

Effect of Ag-doping on cytotoxicity of SnO2 nanoparticles in tobacco cell cultures

SnO2 nanoparticles (NPs) are promising materials for electrochemical, catalytic, and biomedical applications due to their high photosensitivity, suitable stability characteristics, wide band gap energy potential, and low cost. Doping SnO2 NPs with metallic elements such as Ag has been used to improve their efficiency. Despite their commercial importance, the current literature lacks investigations to determine their toxic effects on plant systems. In this study, SnO2 and Ag/SnO2 NPs were synthesized using polymer pyrolysis method and characterized by means of XRD, TEM, SEM, EDX, and DLS techniques. Subsequently, the toxicity of the synthesized NPs on cell viability, cell proliferation, and a number of oxidative stress markers were measured in tobacco cell cultures. SnO2 and Ag/SnO2 NPs were found to be polygonal in shape with the size range of 10-30 nm. Both NPs induced cytotoxicity by reducing the cell viability and cell proliferation in a dose-dependent manner. Furthermore, the generation of H2O2, phenolics, flavonoids, and increased activities of superoxide dismutase (SOD) and peroxidase (POD) were observed. According to the results, Ag-doping played a key role in the induction of toxicity in tobacco cell cultures. The obtained results confirmed that SnO2 and Ag/SnO2 NPs induced cytotoxicity in tobacco cells through oxidative stress.

A Safe-by-Design Strategy towards Safer Nanomaterials in Nanomedicines

The marriage of nanotechnology and medicine offers new opportunities to fight against human diseases. Benefiting from their unique optical, thermal, magnetic, or redox properties, a wide range of nanomaterials have shown potential in applications such as diagnosis, drug delivery, or tissue repair and regeneration. Despite the considerable success achieved over the past decades, the newly emerging nanomedicines still suffer from an incomplete understanding of their safety risks, and of the relationships between their physicochemical characteristics and safety profiles. Herein, the most important categories of nanomaterials with clinical potential and their toxicological mechanisms are summarized, and then, based on this available information, an overview of the principles in developing safe-by-design nanomaterials for medical applications and of the recent progress in this field is provided. These principles may serve as a starting point to guide the development of more effective safe-by-design strategies and to help identify the major knowledge and skill gaps.

The Interaction of Zinc Oxide/Green Tea Extract Complex Nanoparticles and its Effect on Monosodium Glutamate Toxicity in Liver of Rats

BACKGROUND

Zinc oxide nanoparticles (ZnO NPs) are increasingly utilized in both industrial and medical applications. Therefore, the study was aimed to investigate the effect of green nanoparticle complex (green tea extract/zinc oxide nanoparticles complex, GTE/ZnO NPs) on oxidative stress induced by monosodium glutamate (MSG) on the liver of rats.

METHODS

Wistar male rats (n=64) weighing between 200-250 g were divided randomly into eight groups: control group was given physiological saline (1 mg/kg), two groups were treated with two different doses of MSG (MSG-LD, MSG-HD; 6 and 17.5 mg/Kg, respectively), GTE was given 1 mg/mL, 5th group was treated with ZnO NPs and 6th group was treated with GTE/ZnO NPs complex while, 7th and 8th groups were treated with MSG-LD + GTE/ZnO NPs complex and MSG-HD + GTE/ZnO NPs complex, respectively. All substances were given orally for 30 consecutive days. At the end of the study, the liver was homogenized for measurement of the oxidative stress status and anti-inflammatory biomarkers as well as histological and transmission alternations.

RESULTS

Results showed that the antioxidant enzymes activity and glutathione level were significantly decreased in MSG groups than control in a dose-dependent manner. Conversely, the malondialdehyde and inflammatory cytokines levels were significantly increased in MSG groups than the control group. The liver indicated no evidence of alteration in oxidative status, anti-inflammatory and morphological parameters in GTE, ZnO NPs and GTE/ZnO NPs complex groups.

CONCLUSION

In conclusion, MSG at both doses caused oxidative stress and inflammation on liver after 28 days of exposure that supported histological analysis and transmission view of hepatic parenchyma. GTE/ZnO NPs act as partial hepato-protective against MSG.

Antibacterial activity of ultra-small copper oxide (II) nanoparticles synthesized by mechanochemical processing against S. aureus and E. coli

In this paper, ultra-small CuO nanoparticles (NPs) were synthesized through a mechanochemical method using two different Cu-containing precursors (i.e. CuSO₄·5H₂O and CuCl₂·2H₂O), and their structure and antibacterial activity were studied. From the microstructural studies, it was observed that CuO NPs have a spherical morphology and a narrow size distribution with 7 and 14 nm median particle sizes for CuCl₂·2H₂O and CuSO₄.5H2O precursors, respectively. The CuCl₂·2H₂O derived nanoparticles showed more antibacterial activity than CuSO₄.5H₂O derived nanoparticles. The minimum inhibitory concentration (MIC) of the synthesized nanoparticles (derived from both precursors) against E. coli and S.aureus were 3.75 and 2.50 mg/ml, respectively, which are higher than those reported in the literature for CuO NPs synthesized by other methods. This difference may be originated from ultra-small size of the synthesized nanoparticles, high bandgap energy and Fe inclusion entering from milling media and their effect on oxidative stress-mediated cytotoxicity of CuO NPs. The higher MIC value reported in this work indicates that the synthesized NPs not only show good antibacterial activity, but also they yield lower cytotoxicity, which extends their applications in the biomedical field.

Understanding Nanoparticle Toxicity Mechanisms To Inform Redesign Strategies To Reduce Environmental Impact

There has been a surge of consumer products that incorporate nanoparticles, which are used to improve or impart new functionalities to the products based on their unique physicochemical properties. With such an increase in products containing nanomaterials, there is a need to understand their potential impacts on the environment. This is often done using various biological models that are abundant in the different environmental compartments where the nanomaterials may end up after use. Beyond studying whether nanomaterials simply kill an organism, the molecular mechanisms by which nanoparticles exhibit toxicity have been extensively studied. Some of the main mechanisms include (1) direct nanoparticle association with an organism's cell surface, where the membrane can be damaged or initiate internal signaling pathways that damage the cell, (2) dissolution of the material, releasing toxic ions that impact the organism, generally through impairing important enzyme functions or through direct interaction with a cell's DNA, and (3) the generation of reactive oxygen species and subsequent oxidative stress on an organism, which can also damage important enzymes or an organism's genetic material. This Account reviews these toxicity mechanisms, presenting examples for each with different types of nanomaterials. Understanding the mechanism of nanoparticle toxicity will inform efforts to redesign nanoparticles with reduced environmental impact. The redesign strategies will need to be chosen based on the major mode of toxicity, but also considering what changes can be made to the nanomaterial without impacting its ability to perform in its intended application. To reduce interactions with the cell surface, nanomaterials can be designed to have a negative surface charge, use ligands such as polyethylene glycol that reduce protein binding, or have a morphology that discourages binding with a cell surface. To reduce the nanoparticle dissolution to toxic ions, the toxic species can be replaced with less toxic elements that have similar properties, the nanoparticle can be capped with a shell material, the morphology of the nanoparticle can be chosen to minimize surface area and thus minimize dissolution, or a chelating agent can be co-introduced or functionalized onto the nanomaterial's surface. To reduce the production of reactive oxygen species, the band gap of the material can be tuned either by using different elements or by doping, a shell layer can be added to inhibit direct contact with the core, or antioxidant molecules can be tethered to the nanoparticle surface. When redesigning nanoparticles, it will be important to test that the redesign strategy actually reduces toxicity to organisms from relevant environmental compartments. It is also necessary to confirm that the nanomaterial still demonstrates the critical physicochemical properties that inspired its inclusion in a product or device.

The impact of photocatalytic Ag/TiO2 and Ag/N-TiO2 nanoparticles on human keratinocytes and epithelial lung cells

The potential human health risks following the exposure to inorganic nanoparticles (NPs) is a very important issue for their application in leather finishing industry. The aim of our study was to investigate the cytotoxic effect of silver (Ag)/titanium dioxide (TiO₂) NPs on human cells. Photocatalytic NPs were prepared by electrochemical deposition of Ag on the surface of TiO₂ and nitrogen (N)-TiO₂ NPs and, subsequently, physico-chemical characterized. Then, a set of experiments have been performed to study the cytotoxicity and cell death mechanisms involved, the changes in cell morphology and the production of ROS induced in human keratinocytes (HaCaT) and human lung epithelial cells (A549) by exposure to NPs. Moreover, the changes in major signaling pathways and the inflammatory response induced by Ag/N-TiO₂ NPs in A549 cells were investigated. The data showed that cell death by late apoptosis/necrosis is induced in cells as function of the dose and the type of NPs and is characterized by morphological changes and cytoskeletal disorganization and an increase in reactive oxygen species (ROS) production. The exposure of A549 cells to Ag/N-TiO₂ NPs determine the activation of ERK1/2 MAP-kinase pathway and the release of pro-inflammatory mediators CXCL1, GM-CSF and MIF, known to be involved in the recruitment of circulating neutrophils and monocytes.

Carbon-dot wrapped ZnO nanoparticle-based photoelectrochemical sensor for selective monitoring of H2O2 released from cancer cells

This study reports on a simple approach for the fabrication of an electrode modified with biocompatible C-dot wrapped ZnO nanoparticles for selective photoelectrochemical monitoring of H₂O₂ released from living cells. The biocompatibility of the ZnO nanoparticles was confirmed through in-vitro cellular testing using the MTT assay on Huh7 cell lines. The ZnO nanoparticles wrapped with dopamine-derived C-dots possess numerous catalytically active sites, excessive surface defects, good electrical conductivity, and efficient separation ability of photo-induced electrons and holes. These properties offer highly sensitive and selective non-enzymatic photo-electrochemical monitoring of H₂O₂ released from HeLa cells after stimulation with N-formylmethionyl-leucyl-phenylalanine. The sensor has a wide linear range (20-800 nM), low detection limit (2.4 nM), and reliable reproducibility, this implying its suitability for biological and biomedical applications. Graphical abstract Schematic of the fabrication of ZnO nanoparticles by using a plant extract as a reducing agent. Wrapping of ZnO with C-dots enhances the photoelectrocatalytic efficacy. Sensitive and selective photoelectrochemical monitoring of H₂O₂ released from cancer cells is demonstrated.

Challenges facing nanotoxicology and nanomedicine due to cellular diversity

This review examines the interaction of nanomaterials (NMs) with cells from the perspective of major cellular differentiations. The structure and composition of cells reflect their role and function in a particular organ or environment. The normal differentiated-state and diseased cells may respond to NMs very differently. This review progresses with due care on nanotoxicology while emphasizing the potential of NMs in treating stress-associated disorders, including cancer and degeneration. The striking potential of NMs in inducing ROS, scavenging ROS, depleting cellular antioxidants, replenishing antioxidants, mimicking antioxidant enzyme activity, and modulating the immune system all show their considerable potential in treating cancer and other aging-associated disorders. It is now clear that NMs become more active and versatile when they come into contact with biological machinery, surprisingly in some cases, in a manner dependent on cell type. The mechanisms leading to the contrasting bioresponse of NMs ranging from toxicity to anticancer and from cell survival to carcinogenicity followed by their immuno-modulating potential show NMs to be a highly promising agent in biomedical therapy. This first-of-its-kind article seeks the challenges to be addressed that could provide a solid rationale in translating the promises of nanomedicine. A thorough understanding of normal and cancer biology could help to minimize the gap between basic and translational research in nanotechnology-based therapy.

Intracellular ROS Induction by Ag@ZnO Core-Shell Nanoparticles: Frontiers of Permanent Optically Active Holes in Breast Cancer Theranostic

In this study, we investigated whether ZnO coating on Ag nanoparticles (NPs) tunes electron flux and hole figuration at the metal-semiconductor interface under UV radiation. This effect triggers the photoactivity and generation of reactive oxygen species from Ag@ZnO NPs, which results in enhanced cytotoxic effects and apoptotic cell death in human breast cancer cells (MDA-MB231). In this context, upregulation of apoptotic cascade proteins (i.e., Bax/Bcl2 association, p53, cytochrome c, and caspase-3) along with activation of oxidative stress proteins suggested the occurrence of apoptosis by Ag@ZnO NPs in cancer cells through the mitochondrial pathway. Also, preincubation of breast cancer cells with Ag@ZnO NPs in dark conditions muted NP-related toxic effects and consequent apoptotic fate, highlighting biocompatible properties of unexcited Ag@ZnO NPs. Furthermore, the diagnostic efficacy of Ag@ZnO NPs as computed tomography (CT)/optical nanoprobes was investigated. Results confirmed the efficacy of the photoactivated system in obtaining desirable outcomes from CT/optical imaging, which represents novel theranostic NPs for simultaneous imaging and treatment of cancer.

Ag-doping regulates the cytotoxicity of TiO2 nanoparticles via oxidative stress in human cancer cells

We investigated the anticancer potential of Ag-doped (0.5-5%) anatase TiO2 NPs. Characterization study showed that dopant Ag was well-distributed on the surface of host TiO2 NPs. Size (15 nm to 9 nm) and band gap energy (3.32 eV to 3.15 eV) of TiO2 NPs were decreases with increasing the concentration of Ag dopant. Biological studies demonstrated that Ag-doped TiO2 NP-induced cytotoxicity and apoptosis in human liver cancer (HepG2) cells. The toxic intensity of TiO2 NPs was increases with increasing the amount of Ag-doping. The Ag-doped TiO2 NPs further found to provoke reactive oxygen species (ROS) generation and antioxidants depletion. Toxicity induced by Ag-doped TiO2 NPs in HepG2 cells was efficiently abrogated by antioxidant N-acetyl-cysteine (ROS scavenger). We also found that Ag-doped TiO2 NPs induced cytotoxicity and oxidative stress in human lung (A549) and breast (MCF-7) cancer cells. Interestingly, Ag-doped TiO2 NPs did not cause much toxicity to normal cells such as primary rat hepatocytes and human lung fibroblasts. Overall, we found that Ag-doped TiO2 NPs have potential to selectively kill cancer cells while sparing normal cells. This study warranted further research on anticancer potential of Ag-doped TiO2 NPs in various types of cancer cells and in vivo models.

Green synthesis of anisotropic zinc oxide nanoparticles with antibacterial and cytofriendly properties

Zinc oxide nanoparticles (ZnONPs) exhibit abundant biomedical applications. Anisotropic ZnONPs with a defined shape and size were synthesized using Bacillus megaterium (NCIM 2326) cell free extract as a bio-reductant. The study investigated the multidimensional effect of ZnONPs on Helicobacter pylori strains and assessed its biosafety in normal human mesenchymal stem cells (hMSc). The highly stable ZnONPs were produced using B. megaterium and Zinc nitrate as a precursor. The phase of ZnONPs formation and structural characterization were performed by UV- visible (UV-Vis), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and Field Emission Scanning electron microscopy (FESEM) analysis. Furthermore, the ZnONPs exhibited higher biocompatibility against human mesenchymal stem cells (hMSC) and proved to be potentially safe in mammalian cells. Corroborating the current investigation, we described the anti-H. Pylori dosage of ZnONPs was safe to hMSC and could efficiently use as nano-antibiotic.

Synthesis and evaluation of the cytotoxic and anti-proliferative properties of ZnO quantum dots against MCF-7 and MDA-MB-231 human breast cancer cells

Current trends in therapeutic research are the application of nanomaterial carriers for cancer therapy. One such molecule, ZnO, originally used in diagnosis and as a drug carrier, is gaining importance for its biological properties. Here, we report for the first time, the scope of ZnO QDs for enhanced cytotoxicity against MCF-7 and metastatic MDA-MB-231 human breast cancer cells. Unlike other ZnO nanostructures, ZnO QDs are dispersed and small sized (8-10nm) which is believed to greatly increase the cellular uptake. Furthermore, the acidic tumor microenvironment attracts ZnO QDs enhancing targeted therapy while leaving normal cells less affected. Results from MTT assay demonstrated that ZnO QDs induced cytotoxicity to MCF-7 and metastatic MDA-MB-231 breast cancer cells at very low concentrations (10 and 15μg/ml) as compared to other reported ZnO nanostructures. HEK-293 cells showed less toxicity at these concentrations. Confocal microscope images from DAPI staining and TUNEL assay demonstrated that ZnO QDs induced nuclear fragmentation and apoptosis in MCF-7 and MDA-MB-231. FACS results suggested ZnO QDs treatment induced cell cycle arrest at the G0/G1 phase in these cells. ZnO QDs drastically decreased the proliferation and migration of MCF-7 and MDA-MB-231 as seen from the results of the clonogenic and wound healing assays respectively. Furthermore, our data suggested that ZnO QDs regulated apoptosis via Bax and Bcl-2 proteins as validated by immunofluorescence and western blot. Taken together, our findings demonstrate that these ultra-small sized ZnO QDs destabilize cancer cells by using its acidic tumor microenvironment thereby inducing apoptosis and controlling the cell proliferation and migration at low dosages.

Modulation-Doped In2 O3 /ZnO Heterojunction Transistors Processed from Solution

This paper reports the controlled growth of atomically sharp In₂ O₃ /ZnO and In₂ O₃ /Li-doped ZnO (In₂ O₃ /Li-ZnO) heterojunctions via spin-coating at 200 °C and assesses their application in n-channel thin-film transistors (TFTs). It is shown that addition of Li in ZnO leads to n-type doping and allows for the accurate tuning of its Fermi energy. In the case of In₂ O₃ /ZnO heterojunctions, presence of the n-doped ZnO layer results in an increased amount of electrons being transferred from its conduction band minimum to that of In₂ O₃ over the interface, in a process similar to modulation doping. Electrical characterization reveals the profound impact of the presence of the n-doped ZnO layer on the charge transport properties of the isotype In₂ O₃ /Li-ZnO heterojunctions as well as on the operating characteristics of the resulting TFTs. By judicious optimization of the In₂ O₃ /Li-ZnO interface microstructure, and Li concentration, significant enhancement in both the electron mobility and TFT bias stability is demonstrated.

A combustion synthesis route for magnetically separable graphene oxide–CuFe2O4–ZnO nanocomposites with enhanced solar light-mediated photocatalytic activity

A novel GO–CuFe₂O₄–ZnO ternary nanocomposite has been designed as an efficient photocatalyst for the degradation of four toxic organic pollutants.

Nanotoxicity of cobalt induced by oxidant generation and glutathione depletion in MCF-7 cells

There are very few studies regarding the biological activity of cobalt-based nanoparticles (NPs) and, therefore, the possible mechanism behind the biological response of cobalt NPs has not been fully explored. The present study was designed to explore the potential mechanisms of the cytotoxicity of cobalt NPs in human breast cancer (MCF-7) cells. The shape and size of cobalt NPs were characterized by scanning and transmission electron microscopy (SEM and TEM). The crystallinity of NPs was determined by X-ray diffraction (XRD). The dissolution of NPs was measured in phosphate-buffered saline (PBS) and culture media by atomic absorption spectroscopy (AAS). Cytotoxicity parameters, such as [3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide] (MTT), neutral red uptake (NRU), and lactate dehydrogenase (LDH) release suggested that cobalt NPs were toxic to MCF-7 cells in a dose-dependent manner (50-200μg/ml). Cobalt NPs also significantly induced reactive oxygen species (ROS) generation, lipid peroxidation (LPO), mitochondrial outer membrane potential loss (MOMP), and activity of caspase-3 enzymes in MCF-7 cells. Moreover, cobalt NPs decreased intracellular antioxidant glutathione (GSH) molecules. The exogenous supply of antioxidant N-acetyl cysteine in cobalt NP-treated cells restored the cellular GSH level and prevented cytotoxicity that was also confirmed by microscopy. Similarly, the addition of buthionine-[S, R]-sulfoximine, which interferes with GSH biosynthesis, potentiated cobalt NP-mediated toxicity. Our data suggested that low solubility cobalt NPs could exert toxicity in MCF-7 cells mainly through cobalt NP dissolution to Co²⁺.

Cobalt iron oxide nanoparticles induce cytotoxicity and regulate the apoptotic genes through ROS in human liver cells (HepG2)

Cobalt iron oxide (CoFe₂O₄) nanoparticles (CIO NPs) have been one of the most widely explored magnetic NPs because of their excellent chemical stability, mechanical hardness and heat generating potential. However, there is limited information concerning the interaction of CIO NPs with biological systems. In this study, we investigated the reactive oxygen species (ROS) mediated cytotoxicity and apoptotic response of CIO NPs in human liver cells (HepG2). Diameter of crystalline CIO NPs was found to be 23nm with a band gap of 1.97eV. CIO NPs induced cell viability reduction and membrane damage, and degree of induction was dose- and time-dependent. CIO NPs were also found to induce oxidative stress revealed by induction of ROS, depletion of glutathione and lower activity of superoxide dismutase enzyme. Real-time PCR data has shown that mRNA level of tumor suppressor gene p53 and apoptotic genes (bax, CASP3 and CASP9) were higher, while the expression level of anti-apoptotic gene bcl-2 was lower in cells following exposure to CIO NPs. Activity of caspase-3 and caspase-9 enzymes was also higher in CIO NPs exposed cells. Furthermore, co-exposure of N-acetyl-cysteine (ROS scavenger) efficiently abrogated the modulation of apoptotic genes along with the prevention of cytotoxicity caused by CIO NPs. Overall, we observed that CIO NPs induced cytotoxicity and apoptosis in HepG2 cells through ROS via p53 pathway. This study suggests that toxicity mechanisms of CIO NPs should be further investigated in animal models.