Green hydrothermal synthesis and characterization of Ag2O-supported MgO/rGO nanocomposites by using Phoenix leaf extract: a promising approach for enhanced photocatalytic and anticancer activities.

The present work was designed to synthesize Ag2O-supported MgO/rGO nanocomposites (NCs) via green method using Phoenix leaf extract for improved photocatalytic and anticancer activity. Green synthesized Ag2O-supported MgO/rGO NCs were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Raman, ultraviolet-visible (UV-vis) spectroscopy, and photoluminescence (PL) spectroscopy, and gas chromatography-mass spectroscopy (GC-MS) was applied to examine the chemical components of the Phoenix leaf extract. Characterization data confirmed the preparation of MgO NPs, Ag2O-MgO NCs, and Ag2O-MgO/rGO NC with particle size of 26-28 nm. UV-vis study exhibited that the band gap energy of MgO NPs, Ag2O-MgO NCs, and Ag2O-MgO/rGO NC were in the range of 3.53-3.43 eV. The photocatalytic results showed that the photodegradation of Rh B dye of Ag2O-supported MgO/rGO NCs (82.81%) was significantly higher than pure MgO NPs. Additionally, the biological response demonstrates that the Ag2O-supported MgO/rGO NCs induced high cytotoxicity against MCF-7 cancer cells for 24 h and 48 h compared with both pure MgO NPs and Ag2O-MgO NCs. This study suggests that the adding of Ag2O and rGO sheets played significant role in the enhanced photocatalytic and anticancer performance of MgO NPs.

Green synthesis of ZnO-TiO2/RGO nanocomposites using Senna surattensis extract: a novel approach for enhanced anticancer efficacy and biocompatibility.

The purpose of the present study is to enhance the anticancer and biocompatibility performance of TiO2 NPs, ZnO NPs, ZnO-TiO2 (NCs), and ZnO-TiO2/reduced graphene oxide (RGO) NCs against two types of human cancer (HCT116) and normal (HUVCE) cells. A novel procedure for synthesizing ZnO-TiO2/RGO NCs has been developed using Senna surattensis extract. The improved physicochemical properties of the obtained samples were investigated using different techniques such as XRD, TEM, SEM, XPS, FTIR, DLS and UV-visible spectroscopy. XRD results showed that the addition of ZnO and RGO sheets affects the crystal structure and phase of TiO2 NPs. SEM and TEM images displayed that the TiO2 NPs and ZnO NPs were small with uniform spherical morphology in the prepared ZnO-TiO2/RGO NCs. Besides, it is shown that ZnO-TiO2 NCs anchored onto the surface of RGO sheets with a particle size of 14.80 ± 0.5 nm. XPS data confirmed the surface chemical composition and oxidation states of ZnO-TiO2/RGO NCs. Functional groups of prepared NPs and NCs were determined using FTIR spectroscopy. DLS data confirmed that the addition of ZnO and RGO sheets improves the negative surface charge of the prepared pure TiO2 NPs (-22.51 mV), ZnO NPs (-18.27 mV), ZnO-TiO2 NCs (-30.20 mV), and ZnO-TiO2/RGO NCs (-33.77 mV). Optical analysis exhibited that the bandgap energies of TiO2 NPs (3.30 eV), ZnO NPs (3.33 eV), ZnO-TiO2 NCs (3.03 eV), and ZnO-TiO2/RGO NCs (2.78 eV) were further enhanced by adding ZnO NPs and RGO sheets. This indicates that the synthesized samples can be applied to cancer therapy and environmental remediation. The biological data demonstrated that the produced ZnO-TiO2/RGO NCs show a more cytotoxic effect on HCT116 cells compared to pure TiO2 NPs and ZnO-TiO2 NCs. On the other hand, these NCs displayed the lowest level of toxicity towards normal HUVCE cells. These results indicate that the ZnO-TiO2/RGO NCs have strong toxicity against HCT116 cells and are compatible with normal cells. Our results show that the plant extract enhanced the physicochemical properties of NPs and NCs compared with the traditional chemical methods for synthesis. This study could open new avenues for developing more effective and targeted cancer treatments.

One-step preparation, characterization, and anticancer potential of ZnFe2O4/RGO nanocomposites.

Zinc ferrite nanoparticles (ZnFe2O4 NPs) have attracted extensive attention for their diverse applications including sensing, waste-water treatment, and biomedicine. The novelty of the present work is the fabrication of ZnFe2O4/RGO NCs by using a one-step hydrothermal process to assess the influence of RGO doping on the physicochemical properties and anticancer efficacy of ZnFe2O4 NPs. X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy-dispersive X-ray(EDX), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), UV-vis spectroscopy, and Photoluminescence (PL) spectroscopy were employed to characterize prepared pure ZnFe2O4 NPs and ZnFe2O4/ RGO NCs. XRD results showed that the synthesized samples have high crystallinity. Furthermore, the average crystal sizes of ZnFe2O4 nanoparticles (NPs) and ZnFe2O4/RGO nanocomposites (NCs) were 51.08 nm and 54.36 nm, respectively. SEM images revealed that pure ZnFe2O4 NPs were spherical in shape with uniformly loaded on the surface of the RGO nanosheet. XPS and EDX analysis confirmed the elemental compositions of ZnFe2O4/RGO NCs. Elemental mapping of SEM shows that the elemental compositions (Zn, Fe, O, and C) were homogeneously distributed in ZnFe2O4/RGO NCs. The intensity of FT-IR spectra depicted that pure ZnFe2O4 NPs were successfully anchored into the RGO nanosheet. An optical study suggested that the band gap energy of ZnFe2O4/RGO NCs (1.61 eV) was lower than that of pure ZnFe2O4 NPs (1.96 eV). PL spectra indicated that the recombination rate of the ZnFe2O4/ RGO NCs was lower than ZnFe2O4 NPs. MTT assay was used to evaluate the anticancer performance of ZnFe2O4 /RGO NCs and pure ZnFe2O4NPs against human cancer cells. In vitro study indicates that ZnFe2O4 /RGO NCs have higher anticancer activity against human breast (MCF-7) and lung (A549) cancer cells as compared to pure form ZnFe2O4 NPs. This work suggests that RGO doping enhances the anticancer activity of ZnFe2O4NPs by tuning its optical behavior. This study warrants future research on potential therapeutic applications of these types of nanocomposites.

Photocatalytic Degradation of Methylene Blue and Anticancer Response of In2O3/RGO Nanocomposites Prepared by a Microwave-Assisted Hydrothermal Synthesis Process.

The incorporation of graphene with metal oxide has been widely explored in various fields, including energy storage devices, optical applications, biomedical applications, and water remediation. This research aimed to assess the impact of reduced graphene oxide (RGO) doping on the photocatalytic and anticancer properties of In2O3 nanoparticles. Pure and In2O3/RGO nanocomposites were effectively synthesized using the single-step microwave hydrothermal process. XRD, TEM, SEM, EDX, XPS, Raman, UV-Vis, and PL spectroscopy were carefully utilized to characterize the prepared samples. XRD data showed that synthesized In2O3 nanoparticles had high crystallinity with a decreased crystal size after RGO doping. TEM and SEM images revealed that the In2O3 NPs were spherical and uniformly embedded onto the surface of RGO sheets. Elemental analysis of In2O3/RGO NC confirmed the presence of In, O, and C without impurities. Raman analysis indicated the successful fabrication of In2O3 onto the RGO surface. Uv-Vis analysis showed that the band gap energy was changed with RGO addition. Raman spectra confirmed that In2O3 nanoparticles were successfully anchored onto the RGO sheet. PL results indicated that the prepared In2O3/RGO NCs can be applied to enhance photocatalytic activity and biomedical applications. In the degradation experiment, In2O3/RGO NCs exhibited superior photocatalytic activity compared to that of pure In2O3. The degradation efficiency of In2O3/RGO NCs for MB dye was up to 90%. Biological data revealed that the cytotoxicity effect of In2O3/RGO NCs was higher than In2O3 NPs in human colorectal (HCT116) and liver (HepG2) cancer cells. Importantly, the In2O3/RGO NCs exhibited better biocompatibility against human normal peripheral blood mononuclear cells (PBMCs). All the results suggest that RGO addition improves the photocatalytic and anticancer activity of In2O3 NPs. This study highlights the potential of In2O3/RGO NCs as an efficient photocatalyst and therapeutic material for water remediation and biomedicine.

Bi2O3-Doped WO3 Nanoparticles Decorated on rGO Sheets: Simple Synthesis, Characterization, Photocatalytic Performance, and Selective Cytotoxicity toward Human Cancer Cells.

Graphene derivatives and metal oxide-based nanocomposites (NCs) are being studied for their diverse applications including gas sensing, environmental remediation, and biomedicine. The aim of the present work was to evaluate the effect of rGO and Bi2O3 integration on photocatalytic and anticancer efficacy. A novel Bi2O3-WO3/rGO NCs was successfully prepared via the precipitation method. X-ray crystallography (XRD) data confirmed the crystallographic structure and the phase composition of the prepared samples. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis confirmed the loading of Bi2O3-doped WO3 NPs on rGO sheets. Energy-dispersive X-ray (EDX) results confirmed that all elements of carbon (C), oxygen (O), tungsten (W), and bismuth (Bi) were present in Bi2O3-WO3/rGO NCs. The oxidation state and presence of elemental compositions in Bi2O3-WO3/rGO NCs were verified by the X-ray photoelectron spectroscopy (XPS) study. Raman spectra indicate a reduction in carbon-oxygen functional groups and an increase in the graphitic carbon percentage of the Bi2O3-WO3/rGO NCs. The functional group present in the prepared samples was examined by Fourier transform infrared (FTIR) spectroscopy. UV analysis showed that the band gap energy of the synthesized samples was slightly decreased with Bi2O3 and rGO doping. Photoluminescence (PL) spectra showed that the recombination rate of the electron-hole pair decreased with the dopants. Degradation of RhB dye under UV light was employed to evaluate photocatalytic performance. The results showed that the Bi2O3-WO3/rGO NCs have high photocatalytic activity with a degradation rate of up to 91%. Cytotoxicity studies showed that Bi2O3 and rGO addition enhance the anticancer activity of WO3 against human lung cancer cells (A549) and colorectal cancer cells (HCT116). Moreover, Bi2O3-WO3/rGO NCs showed improved biocompatibility in human umbilical vein endothelial cells (HUVECs) than pure WO3 NPs. The results of this work showed that Bi2O3-doped WO3 particles decorated on rGO sheets display improved photocatalytic and anticancer activity. The preliminary data warrants further research on such NCs for their applications in the environment and medicine.

Photodeposition mediated synthesis of silver-doped indium oxide nanoparticles for improved photocatalytic and anticancer performance.

Indium oxide nanoparticles (In2O3 NPs) are being investigated for a number of applications including gas-sensing, environmental remediation, and biomedicine. We aimed to examine the effect of silver (Ag) doping on photocatalytic and anticancer activity of In2O3 NPs. The Ag-doped (2%, 4%, and 6%weight) In2O3 NPs were synthesized by the photodeposition method. Prepared samples were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), UV-Vis spectroscopy, and the photoluminescence (PL). XRD data showed that Ag-doping increases the crystallinity of In2O3 NPs. SEM and TEM images indicated that In2O3 NPs have spherical morphology with smooth surfaces, and Ag-doping increases the size without affecting the particle's shape. XPS spectra showed the oxidation state and the presence of Ag in In2O3 NPs. Band gap energy of In2O3 NPs decreases with increasing the concentration of Ag (3.41 eV to 3.12 eV). The peak intensity of PL spectra of In2O3 NPs also reduces with the increment of Ag ions suggesting the hindrance of the recombination rate of e-/h+. The photocatalytic activity was measured by the degradation of Rh B dye under UV irradiation. The degradation efficiency of Ag-doped (6%) In2O3 NPs was 92%. Biochemical data indicated that Ag-doping enhances the anticancer performance of In2O3 NPs against human lung cancer cells (A549). Moreover, Ag-doped In2O3 NPs displayed excellent biocompatibility in normal human lung fibroblasts (IMR90). Overall, this study demonstrated that Ag-doping enhances the photocatalytic activity and anticancer efficacy of In2O3 NPs. This study warrants further investigation on the environmental and biomedical applications of Ag-In2O3 NPs.

High Performance of Carbon Monoxide Gas Sensor Based on a Novel PEDOT:PSS/PPA Nanocomposite.

In this work, the carbon monoxide (CO) detection property of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)/poly(p-anisidine) (PEDOT:PSS/PPA) nanocomposite was systematically investigated at room temperature. The PEDOT:PSS/PPA nanocomposite was synthesized by the cost-effective "in situ chemical oxidation polymerization" technique. The electric, optical, spectroscopic, and structural properties of the as-prepared nanomaterials were analyzed with I-V, UV-vis, Raman, Fourier transform infrared (FTIR), and X-ray diffraction (XRD) spectroscopies. Topological investigations of materials were conducted by atomic force microscopy (AFM). The gas-sensing performance of the PEDOT:PSS/PPA and PEDOT:PSS nanocomposites toward CO gas in the concentration range of 50-300 ppm at room temperature was explored, and their performances were compared. The PEDOT:PSS/PPA sensor shows a perfectly linear response to different concentrations (50-300 ppm) of CO gas (R 2 = 0.9885), and the response time and recovery time of the CO gas sensor (100 ppm) can be about 58 and 61 s, respectively, showing high sensitivity to CO gas and rapid response recovery with outstanding stability. Thus, the PEDOT:PSS/PPA-based sensors, with their impressive sensing performance, may give assurance for future high-performance CO-sensing applications.

Combined effect of single-walled carbon nanotubes and cadmium on human lung cancer cells.

Co-exposure of widely used single-walled carbon nanotubes (SWCNTs) and ubiquitous cadmium (Cd) to humans through ambient air is unavoidable. Studies on joint toxicity of SWCNTs and Cd in human cells are scarce. We aimed to investigate the joint effects of SWCNTs and Cd in human lung epithelial (A549) cells. Results showed that SWCNTs were safe while Cd induce significant toxicity to A549 cells. Remarkably, Cd-induced cell viability reduction, lactate dehydrogenase leakage, cell cycle arrest, dysregulation of apoptotic gene (p53, bax, bcl-2, casp3, and casp9), and mitochondrial membrane potential depletion were significantly mitigated following SWCNTs co-exposure. Cd-induced intracellular level of reactive oxygen species, hydrogen peroxide, and lipid peroxidation were significantly attenuated by SWCNT co-exposure. Moreover, glutathione depletion and lower activity of antioxidant enzymes after Cd exposure were also effectively abrogated by co-exposure of SWCNTs. Inductively coupled plasma-mass spectrometry study indicated that higher adsorption of Cd on SCWNTs might decreased cellular uptake and the toxic potential of Cd in A549 cells. Our work warranted further research to explore the potential mechanism of joint effects of SWCNTs and Cd at in vivo levels.

One-Pot Synthesis of SnO2-rGO Nanocomposite for Enhanced Photocatalytic and Anticancer Activity.

Metal oxide and graphene derivative-based nanocomposites (NCs) are attractive to the fields of environmental remediation, optics, and cancer therapy owing to their remarkable physicochemical characteristics. There is limited information on the environmental and biomedical applications of tin oxide-reduced graphene oxide nanocomposites (SnO2-rGO NCs). The goal of this work was to explore the photocatalytic activity and anticancer efficacy of SnO2-rGO NCs. Pure SnO2 NPs and SnO2-rGO NCs were prepared using the one-pot hydrothermal method. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), UV-Vis spectrometry, photoluminescence (PL), and Raman scattering microscopy were applied to characterize the synthesized samples. The crystallite size of the SnO2 NPs slightly increased after rGO doping. TEM and SEM images show that the SnO2 NPs were tightly anchored onto the rGO sheets. The XPS and EDX data confirmed the chemical state and elemental composition of the SnO2-rGO NCs. Optical data suggest that the bandgap energy of the SnO2-rGO NCs was slightly lower than for the pure SnO2 NPs. In comparison to pure SnO2 NPs, the intensity of the PL spectra of the SnO2-rGO NCs was lower, indicating the decrement of the recombination rate of the surfaces charges (e-/h+) after rGO doping. Hence, the degradation efficiency of methylene blue (MB) dye by SnO2-rGO NCs (93%) was almost 2-fold higher than for pure SnO2 NPs (54%). The anticancer efficacy of SnO2-rGO NCs was also almost 1.5-fold higher against human liver cancer (HepG2) and human lung cancer (A549) cells compared to the SnO2 NPs. This study suggests a unique method to improve the photocatalytic activity and anticancer efficacy of SnO2 NPs by fusion with graphene derivatives.

Enhanced Anticancer Performance of Eco-Friendly-Prepared Mo-ZnO/RGO Nanocomposites: Role of Oxidative Stress and Apoptosis.

ZnO nanoparticles (NPs) have attracted great attention in cancer therapy because of their novel and tailorable physicochemical features. Pure ZnO NPs, molybdenum (Mo)-doped ZnO NPs, and Mo-ZnO/reduced graphene oxide nanocomposites (Mo-ZnO/RGO NCs) were prepared using a facile, inexpensive, and eco-friendly approach using date palm (Phoenix dactylifera L.) fruit extract. Anticancer efficacy of green synthesized NPs/NCs was examined in two different cancer cells. The potential mechanism of the anticancer activity of green synthesized NPs/NCs was explored through oxidative stress and apoptosis. The syntheses of pure ZnO NPs, Mo-ZnO NPs, and Mo-ZnO/RGO NCs were confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and photoluminescence (PL). Dynamic light scattering (DLS) study indicated the excellent colloidal stability of green prepared samples. Mo-ZnO/RGO NCs exhibited threefold higher anticancer activity in human colon (HCT116) and breast (MCF7) cancer cells as compared to pure ZnO NPs. The anticancer activity of Mo-ZnO/RGO NCs was mediated through reactive oxygen species, p53, and the caspase-3 pathway. Moreover, cytocompatibility of Mo-ZnO/RGO NCs in human normal colon epithelial (NCM460) and normal breast epithelial cells (MCF10A) was much better than those of pure ZnO NPs. Altogether, green stabilized Mo-ZnO/RGO NCs exhibited enhanced anticancer performance and improved cytocompatibility because of green mediated good synergism between ZnO, Mo, and RGO. This study suggested the high nutritional value fruit-based facile preparation of ZnO-based nanocomposites for cancer therapy.

Facile green synthesis of ZnO-RGO nanocomposites with enhanced anticancer efficacy.

Drug resistance and inability to distinguish between cancerous and non-cancerous cells are important obstacles in the treatment of cancer. Zinc oxide nanoparticles (ZnO NPs) is now emerging as a crucial material to challenge this global issue due to its tunable properties. Developing an effective, inexpensive, and eco-friendly method in order to tailor the properties of ZnO NPs with enhanced anticancer efficacy is still challenging. For the first time, we reported a facile, inexpensive, and eco-friendly approach for green synthesis of ZnO-reduced graphene oxide nanocomposites (ZnO-RGO NCs) using garlic clove extract. Garlic has been playing one of the most important dietary and medicinal roles for humans since centuries. We aimed to minimize the use of toxic chemicals and enhance the anticancer potential of ZnO-RGO NCs with minimum side effects to normal cells. Aqueous extract of garlic clove was used as reducing and stabilizing agent for green synthesis of ZnO-RGO NCs from the zinc nitrate and graphene oxide (GO) precursors. A potential mechanism of ZnO-RGO NCs synthesis with garlic clove extract was also proposed. Preparation of pure ZnO NPs and ZnO-RGO NCs was confirmed by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and dynamic light scattering (DLS). The in vitro study showed that ZnO-RGO NCs induce two-fold higher cytotoxicity in human breast cancer (MCF7) and human colorectal cancer (HCT116) cells as compared to pure ZnO NPs. Besides, biocompatibility of ZnO-RGO NCs in non-cancerous human normal breast (MCF10A) and normal colon epithelial (NCM460) cells was higher than those of pure ZnO NPs. This work highlighted a facile and inexpensive green approach for the preparation of ZnO-RGO NCs with enhanced anticancer activity and improved biocompatibility.

A Novel Green Preparation of Ag/RGO Nanocomposites with Highly Effective Anticancer Performance.

The efficacy of current cancer therapies is limited due to several factors, including drug resistance and non-specific toxic effects. Due to their tuneable properties, silver nanoparticles (Ag NPs) and graphene derivative-based nanomaterials are now providing new hope to treat cancer with minimum side effects. Here, we report a simple, inexpensive, and eco-friendly protocol for the preparation of silver-reduced graphene oxide nanocomposites (Ag/RGO NCs) using orange peel extract. This work was planned to curtail the use of toxic chemicals, and improve the anticancer performance and cytocompatibility of Ag/RGO NCs. Aqueous extract of orange peels is abundant in phytochemicals that act as reducing and stabilizing agents for the green synthesis of Ag NPs and Ag/RGO NCs from silver nitrate and graphene oxide (GO). Moreover, the flavonoid present in orange peel is a potent anticancer agent. Green-prepared Ag NPs and Ag/RGO NCs were characterized by UV-visible spectrophotometry, transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and dynamic light scattering (DLS). The results of the anticancer study demonstrated that the killing potential of Ag/RGO NCs against human breast cancer (MCF7) and lung cancer (A549) cells was two-fold that of pure Ag NPs. Moreover, the cytocompatibility of Ag/RGO NCs in human normal breast epithelial (MCF10A) cells and normal lung fibroblasts (IMR90) was higher than that of pure Ag NPs. This mechanistic study indicated that Ag/RGO NCs induce toxicity in cancer cells through pro-oxidant reactive oxygen species generation and antioxidant glutathione depletion and provided a novel green synthesis of Ag/RGO NCs with highly effective anticancer performance and better cytocompatibility.

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.

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.

Reduced graphene oxide mitigates cadmium-induced cytotoxicity and oxidative stress in HepG2 cells.

Numerous applications of reduced graphene oxide (RGO) and pervasive cadmium (Cd) have led concern about their co-exposure to the environment and human. We studied the combined effects of RGO and Cd in human liver (HepG2) cells. Initially, we found that RGO (up to 50 µg/ml) did not harm to HepG2 cells while Cd induced dose-dependent (1-10 µg/ml) cytotoxicity. Exciting observations were that a non-cytotoxic concentration of RGO (25 µg/ml) effectively mitigates the toxic effects of Cd (2 µg/ml) such as cell viability reduction, lactate dehydrogenase release, and irregular cell morphology. Cd-induced cell cycle arrest, induction of caspases (3 and 9) enzymes activity, and loss of mitochondrial membrane potential were also significantly alleviated by RGO co-exposure. Moreover, generation of pro-oxidants (reactive oxygen species and hydrogen peroxide levels) and depletion of antioxidants (glutathione level and superoxide dismutase activity) due to Cd exposure was effectively attenuated by RGO co-exposure. Mitigating effect of RGO could be due to strong adsorption of Cd on the large surface area of RGO sheets, which decrease the cellular uptake and bioavailability of Cd for HepG2 cells. This study warrants future research on potential mechanisms of mitigating effects of RGO against Cd-induced toxicity in animal models.

Influence of silica nanoparticles on cadmium-induced cytotoxicity, oxidative stress, and apoptosis in human liver HepG2 cells.

Extensive application of amorphous silica nanoparticles (Si NPs) and ubiquitous cadmium (Cd) may increase their chances of coexposure to humans. Studies on combined effects of Si NPs and Cd in human cells are very limited. We investigated the potential mechanism of toxicity caused by coexposure of amorphous Si NPs and Cd in human liver (HepG2) cells. Results showed that Si NPs were not toxic to HepG2. However, Cd induced significant toxicity in HepG2 cells. Interestingly, we observed that a noncytotoxic concentration of Si NPs potentiated the cytotoxicity of Cd in HepG2 cells. We further noticed that coexposure of Si NPs and Cd augmented oxidative stress evidenced by the generation of oxidants (reactive oxygen species, hydrogen peroxide, and lipid peroxidation) and depletion of antioxidants (glutathione level and antioxidant enzyme activity). Coexposure of Si NPs and Cd also augmented mitochondria-mediated apoptosis in HepG2 cells indicated by altered regulation of apoptotic genes (p53, bax, bcl-2, caspase-3, and caspase-9) along with reduced mitochondrial membrane potential. Interaction data indicated that Si NPs facilitate the cellular uptake of Cd due to its strong adsorption on the surface of Si NPs. Hence, Si NPs increased the bioaccumulation and toxicity of Cd in HepG2 cells. This study warrants further research to explore the potential mechanisms of combined toxicity of Si NPs and Cd in animal models.

TiO2 nanoparticles potentiated the cytotoxicity, oxidative stress and apoptosis response of cadmium in two different human cells.

Widespread application of titanium dioxide nanoparticles (nTiO2) and ubiquitous cadmium (Cd) pollution may increase their chance of co-existence in the natural environment. Toxicological information on co-exposure of nTiO2 and Cd in mammalian models is largely lacking. Hence, we studied the combined effects of nTiO2 and Cd in human liver (HepG2) and breast cancer (MCF-7) cells. We observed that nTiO2 did not produce toxicity to HepG2 and MCF-7 cells. However, moderate concentration of Cd exposure caused cytotoxicity to both cells. Interestingly, non-cytotoxic concentration of nTiO2 effectively enhanced the oxidative stress response of Cd indicated by pro-oxidants generation (reactive oxygen species, hydrogen peroxide, and lipid peroxidation) and antioxidants depletion (glutathione level and glutathione reductase, superoxide dismutase, and catalase enzymes). Moreover, nTiO2 potentiated the Cd-induced apoptosis in both cells suggested by altered expression of p53, bax, and bcl-2 genes along with low mitochondrial membrane potential. Cellular uptake results demonstrated that nTiO2 facilitates the internalization of Cd into the cells. Overall, this study demonstrated that non-cytotoxic concentration of nTiO2 enhanced the toxicological potential of Cd in human cells. Therefore, more attention should be paid on the combine effects of nTiO2 and Cd on human health.

Mitochondrial dysfunction, autophagy stimulation and non-apoptotic cell death caused by nitric oxide-inducing Pt-coated Au nanoparticle in human lung carcinoma cells.

BACKGROUND: Reactive oxygen species (ROS)-mediated cancer therapeutic has been at higher appreciation than those mediated by reactive nitrogen species. Cytotoxic mechanism of a novel nitric oxide (NO) inducing-Pt coated Au nanoparticle (NP) has been comparatively studied with the well-established ROS inducing Pt-based anticancer drug cisplatin in human lung A549 carcinoma cells. METHODS: Cytotoxicity was evaluated by MTT assay, lactate dehydrogenase (LDH) release, thiobarbituric acid substances (TBARS) and C11-Boron dipyrromethene (BODIPY). ROS (O2·- and H2O2) was measured with dihydroethidium (DHE) and H2O2-specific sensor. Nitric oxide (NO) and mitochondrial dysfunction were evaluated respectively by NO-specific probe DAR-1 and JC-1. Autophagy was determined by lysotracker (LTR) and monodansylcadaverine (MDC) applied tandemly whereas apoptosis/necrosis by Hoechst/PI and caspase 3 activity. RESULTS: IC50 (concentration that inhibited cell viability by 50%) of Pt coated Au NP came to be 0.413 µM whereas IC50 of cisplatin came out to 86.5 µM in A549 cells treated for 24 h meaning NPs toxicity was over 200 times higher than cisplatin. However, no significant stimulation of intracellular ROS was observed at the IC50 of Pt coated Au NPs in A549 cells. However, markers like LDH release, TBARS, BODIPY and ROS were significantly higher due to cisplatin in comparison to Pt coated Au NP. CONCLUSIONS: Pt coated Au NP caused NO-dependent mitochondrial dysfunction and autophagy. Mode of cell death due to NP was much different from ROS-inducing cisplatin. GENERAL SIGNIFICANCE: Pt coated Au NP offer promising opportunity in cancer therapeutic and warrants advanced study in vivo models of cancer.

Co-Exposure to SiO2 Nanoparticles and Arsenic Induced Augmentation of Oxidative Stress and Mitochondria-Dependent Apoptosis in Human Cells.

Widespread application of silica nanoparticles (nSiO2) and ubiquitous metalloid arsenic (As) may increase their chances of co-exposure to human beings in daily life. Nonetheless, studies on combined effects of nSiO2 and As in human cells are lacking. We investigated the co-exposure effects of nSiO2 and As in human liver (HepG2) and human fibroblast (HT1080) cells. Results showed that nSiO2 did not cause cytotoxicity. However, exposure of As caused oxidative stress and apoptosis in both types of cells. Interesting results were that co-exposure of a non-cytotoxic concentration of nSiO2 significantly augmented the As induced toxicity in both cells. Intracellular level of As was higher in the co-exposure group (nSiO2 + As) than the As group alone, suggesting that nSiO2 facilitates the cellular uptake of As. Co-exposure of nSiO2 and As potentiated oxidative stress indicated by pro-oxidants generation (reactive oxygen species, hydrogen peroxide and lipid peroxidation) and antioxidants depletion (glutathione level, and glutathione reductase, superoxide dismutase and catalase activities). In addition, co-exposure of nSiO2 and As also potentiated mitochondria-mediated apoptosis suggested by increased expression of p53, bax, caspase-3 and caspase-9 genes (pro-apoptotic) and decreased expression of bcl-2 gene (anti-apoptotic) along with depleted mitochondrial membrane potential. To the best of our knowledge, this is the first study showing that co-exposure of nSiO2 and As induced augmentation of oxidative stress and mitochondria-mediated apoptosis in HepG2 and HT1080 cells. Hence, careful attention is required for human health assessment following combined exposure to nSiO2 and As.

Preventive effect of TiO2 nanoparticles on heavy metal Pb-induced toxicity in human lung epithelial (A549) cells.

Wide application of TiO2 nanoparticles (nTiO2) and ubiquitous lead (Pb) pollution in natural environment enhance the chance of co-exposure of humans to Pb and nTiO2. We investigated the effects of nTiO2 on Pb-induced toxicity in human lung epithelial (A549) cells. Results showed that nTiO2 was not toxic to A549 cells. Conversely, Pb-induced cytotoxicity and oxidative stress in A549 cells were evidenced by cell viability reduction, cell membrane damage, reactive oxygen species generation and depletion of antioxidants. The Pb was also found to alter the regulation of apoptotic genes and cell cycle. Interestingly, in co-exposure group (nTiO2 + Pb), nTiO2 effectively attenuated the cytotoxicity, oxidative stress and apoptotic responses of Pb in A549 cells. Cellular uptake experiments demonstrated that nTiO2 increased the bioaccumulation of Pb in cells. However, due to strong adsorption of Pb on nTiO2, free Pb ions were not available even inside the cells. Hence, nTiO2 significantly prevented the bioavailability and toxicity of Pb in A549 cells. This is the first report providing insight into understanding the mechanism of nTiO2 mediated prevention against Pb-induced toxicity in human cells. This study warranted further research on co-exposure effects of nTiO2 and Pb at in vivo mammalian models.