Zinc oxide nanoparticles for selective destruction of tumor cells and potential for drug delivery applications

The cytotoxic properties of zinc oxide nanoparticles on the rat liver and spleen, and its anticancer impacts on human liver cancer cell lines

INTRODUCTION

Due to their unique properties including cellular uptake and the delivery efficiency to biological systems, nanoparticles are used in various preclinical and clinical applications. The aim of this study was to investigate the toxicity impacts of zinc oxide nanoparticles (ZnO-NPs) on morphology and functionality of the rat's liver and spleen and illustrated its safe-therapeutic doses.

METHODS

The 28 female Swiss albino rats (180-220 g) and two human hepatocyte cell lines (HepG2 and HUH7) were designed as an in vivo and in vitro study, respectively. Samples were treated with certain doses of ZnO-NPs. The rat's liver morphology and functionality and apoptotic genes expression profile (Bax, Bcl-2, and P53) were analyzed to detect the cytotoxicity and antitumor impacts of ZnO-NPs, respectively.

RESULTS

The results showed a positive significant association between the increasing doses of ZnO-NPs and alanine aminotransferase/aspartate aminotransferase values. Moreover, a meaningful correlation was detected between the rat's liver and spleen weight and ZnO-NPs doses. Furthermore, the histopathological analysis of rat's liver showed the individual cytotoxic properties of ZnO-NPs. Finally, the positive significant correlation was detected among the expression of Bax and P53 genes with ZnO-NPs. In addition, the negative correlation was demonstrated between the expression of Bcl-2 and ZnO-NPs.

CONCLUSION

In general, in the current study, the antitumor effects of ZnO-NPs were confirmed by the enhancement of P53 and Bax genes expression profile, which are indicated the apoptotic induction in HUH7 cell line. Moreover, we introduced a safe-clinical ZnO-NPs dosage, have antitumor effects.

Zinc-Doped Copper Oxide Nanocomposites Inhibit the Growth of Pancreatic Cancer by Inducing Autophagy Through AMPK/mTOR Pathway

Zinc doped copper oxide nanocomposites (Zn-CuO NPs) is a novel doped metal nanomaterial synthesized by our group using the sonochemical method. Our previous studies have shown that Zn-CuO NPs could inhibit cancer cell proliferation by inducing apoptosis via ROS-mediated pathway. In the present study, we studied the anticancer effect of Zn-CuO NPs on human pancreatic cancer cells. MTS assay revealed that Zn-CuO NPs was able to inhibit cancer cell growth. TEM, flow cytometry and fluorescence microscope analysis showed that Zn-CuO NPs induced autophagy significantly; the number of autophagosomes increased obviously in cells treated with Zn-CuO NPs. Western blot analysis revealed that treatment with the NPs resulted in activation of AMPK/mTOR pathway in both AsPC-1 and MIA Paca-2 cells in dose dependent manners. Moreover, in the presence of AMPK activator AMPKinone, the protein level of p-AMPK, p-ULK1, Beclin-1 and LC3-II/LC3-I increased, while the protein expression of p-AMPK, p-ULK1, Beclin-1 and LC3-II/LC3-I decreased in the presence of AMPK inhibitor Compound C. In vivo study using xenograft mice revealed that Zn-CuO NPs significantly inhibited tumor growth with low toxicity. Our study confirms that Zn-CuO NPs inhibit the tumor growth both in vitro and in vivo for pancreatic cancer. AMPK/mTOR pathway plays an important role in the NPs induced inhibition of tumor growth.

Targeting autophagy using metallic nanoparticles: a promising strategy for cancer treatment

Despite the extensive genetic and phenotypic variations present in the different tumors, they frequently share common metabolic alterations, such as autophagy. Autophagy is a self-degradative process in response to stresses by which damaged macromolecules and organelles are targeted by autophagic vesicles to lysosomes and then eliminated. It is known that autophagy dysfunctions can promote tumorigenesis and cancer development, but, interestingly, its overstimulation by cytotoxic drugs may also induce cell death and chemosensitivity. For this reason, the possibility to modulate autophagy may represent a valid therapeutic approach to treat different types of cancers and a variety of clinical trials, using autophagy modulators, are currently employed. On the other hand, recent progress in nanotechnology offers plenty of tools to fight cancer with innovative and efficient therapeutic agents by overcoming obstacles usually encountered with traditional drugs. Interestingly, nanomaterials can modulate autophagy and have been exploited as therapeutic agents against cancer. In this article, we summarize the most recent advances in the application of metallic nanostructures as potent modulators of autophagy process through multiple mechanisms, stressing their therapeutic implications in cancer diseases. For this reason, we believe that autophagy modulation with nanoparticle-based strategies would acquire clinical relevance in the near future, as a complementary therapy for the treatment of cancers and other diseases.

Ameliorative effect of zinc oxide nanoparticles against potassium bromate-mediated toxicity in Swiss albino rats

Potassium bromate (PB) is a commonly used food additive, a prominent water disinfection by-product, and a class IIB carcinogen. It exerts a various degree of toxicity depending on its dose and exposure duration consumed with food and water in the living organisms. The present investigation aims to demonstrate the protective efficacy of zinc oxide nanoparticles (ZnO NPs) derived from Ochradenus arabicus (OA) leaf extract by green technology in PB-challenged Swiss albino rats. The rodents were randomly distributed, under the lab-standardized treatment strategy, into the following six treatment groups: control (group I), PB alone (group II), ZnO alone (group III), ZnO NP alone (group IV), PB + ZnO (group V), and PB + ZnO NPs (group VI). The rats were sacrificed after completion of the treatment, and their blood and liver samples were collected for further analysis. Group II showed extensive toxic effects with altered liver function markers (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase, gamma-glutamyl transferase, glutathione-S-transferase, and thioredoxin reductase) and compromised redox status (SOD, CAT, GR, GPx, GSH, MDA, and total carbonyl content). The histopathological analysis and comet assay further supported the biochemical results of the same group. Besides, group III also showed moderate toxicity evidenced by an alteration in most of the studied parameters while group IV demonstrated mild toxicity after biochemical analysis indicating the excellent biocompatibility of the NPs. However, group VI exhibited attenuation of the PB-induced toxic insults to a significant level as compared to group II, whereas group V failed to show similar improvement in the studied parameters. All these findings entail that the ZnO NPs prepared by green synthesis have significant ameliorative property against PB-induced toxicity in vivo. Moreover, administration of the NPs improved the overall health of the treated animals profoundly. Hence, these NPs have significant therapeutic potential against the toxic effects of PB and similar compounds in vivo, and they are suitable to be used at the clinical and industrial levels.

Subchronic and chronic toxicity evaluation of inorganic nanoparticles for delivery applications

Inorganic nanoparticles provide the opportunity to localize bioactive agents to the target sites and protect them from degradation. In many cases, acute toxicities of inorganic nanoparticles used for delivery applications have been investigated. However, little information is available regarding the long-term toxicity of such materials. This review focuses on the importance of subchronic and chronic toxicity assessment of inorganic nanoparticles investigated for delivery applications. We have attempted to provide a comprehensive review of the available literature for chronic toxicity assessment of inorganic nanoparticles. Where possible correlations are made between particle composition, physiochemical properties, duration, frequency and route of administration, as well as the sex of animals, with tissue and blood toxicity, immunotoxicity and genotoxicity. A critical gap analysis is provided and important factors that need to be considered for long-term toxicology of inorganic nanoparticles are discussed.

Increased ZnO nanoparticle toxicity to wheat upon co-exposure to phenanthrene

Polycyclic aromatic hydrocarbons and zinc oxide nanoparticles are ubiquitous pollutants in the environment. However, little information is available about their toxicity interaction in food crops. In this study, seed germination and hydroponic experiments were conducted to assess the impact of ZnO (NPs and bulk at 250, 500 and 1000 mg L^-1) individual and combined with phenanthrene (1 mg L^-1) on wheat growth for 15 days. Under ZnO (NPs and bulk) alone and combined with phenanthrene exposure, dose-dependent toxicity in some indexes (germination rate, biomass, shoot height, root length) was observed. Both ZnO NPs and bulk inhibited plant growth at high concentrations, but no significant difference was observed between them (P > 0.05). The chlorophyll concentration of wheat leaves decreased by 0.43-0.60 fold when the levels of ZnO NPs and bulk treated were elevated. There was a negative correlation between ZnO (NPs and bulk) and total chlorophyll. Hill reaction activity also exhibited the same tendency. Through transmission electron microscopy, ZnO NPs were found in wheat seedling root apoplast and symplasm at 1000 mg L^-1 with or without phenanthrene. High doses (500 and 1000 mg L^-1) of ZnO (NPs and bulk) caused more DNA damage to wheat seedling root cells, and ZnO NPs induced stronger genotoxicity than bulk ones to wheat root cells. Superoxide dismutase (SOD) and catalase (CAT) activities of wheat seedling roots decreased at 1000 mg L^-1 ZnO (NPs and bulk), especially in the co-exposure treatments. Hence, ZnO (NPs and bulk) combined with phenanthrene cause more damage to wheat seedling roots, and even destroy the antioxidant system. Our findings are helpful for not only assessing the individual and combined toxicity between phenanthrene and ZnO (NPs and bulk), but also for understanding the different response of plants to individual and combined pollution.

Antibacterial and cytotoxic assessment of poly (methyl methacrylate) based hybrid nanocomposites

Poly (methyl methacrylate) (PMMA) is an extensively used implant material in biomedical devices. Biofilm formation creates issues in PMMA-based biomedical implants, while emergence of drug resistant pathogens poses an additional complication. Hence development of surfaces that resist bacterial colonisation is extremely desirable. In this context, nanomaterials are among the potential choices. In the present work, nanocomposites (NCs) were developed by incorporation of chemically synthesized nanoparticles of CuO, cetyl trimethyl ammonium bromide (CTAB) capped CuO and ZnO (singly and in combination) in PMMA. The efficacy of these NCs was assessed against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria which are prevalent in many implant-associated infections. Results revealed species-specific response of the bacteria towards nanomaterials. CuO NC (0.1% (w/v)) was more effective against E. coli, while CTAB capped CuO NC and ZnO NC were very effective against S. aureus. Furthermore, combination of nanoparticles improved efficacy of nanocomposites against both the bacterial species. In vitro cytotoxicity assay using L6 myoblast cell line showed that all NCs at 0.1% (w/v) were biocompatible, showing >85% cell viability. The present study suggests that combination of NPs is a promising option to combat implant infection by multiple organisms.

Cosmetic reconstruction in breast cancer patients: Opportunities for nanocomposite materials

The most common malignancy in women, breast cancer remains a major medical challenge that affects the life of thousands of patients every year. With recognized benefits to body image and self-esteem, the use of synthetic mammary implants for elective cosmetic augmentation and post-mastectomy reconstruction continues to increase. Higher breast implant use leads to an increased occurrence of implant-related complications associated with implant leakage and rupture, capsular contracture, necrosis and infections, which include delayed healing, pain, poor aesthetic outcomes and the need for revision surgeries. Along with the health status of the implant recipient and the skill of the surgeon, the properties of the implant determine the likelihood of implant-related complications and, in doing so, specific patient outcomes. This paper will review the challenges associated with the use of silicone, saline and "gummy bear" implants in view of their application in patients recovering from breast cancer-related mastectomy, and investigate the opportunities presented by advanced functional nanomaterials in meeting these challenges and potentially opening new dimensions for breast reconstruction. STATEMENT OF SIGNIFICANCE: Breast cancer is a significant cause of morbidity and mortality in women worldwide, which is difficult to prevent or predict, and its treatment carries long-term physiological and psychological consequences. Post-mastectomy breast reconstruction addresses the cosmetic aspect of cancer treatment. Yet, drawbacks of current implants contribute to the development of implant-associated complications, which may lead to prolonged patient care, pain and loss of function. Nanomaterials can help resolve the intrinsic biomechanical mismatch between implant and tissues, enhance mechanical properties of soft implantable materials, and provide an alternative avenue for controlled drug delivery. Here, we explore advances in the use of functionalized nanomaterials to enhance the properties of breast implants, with representative examples that highlight the utility of nanomaterials in addressing key challenges associated with breast reconstruction.

Sub-acute oral exposure of zinc oxide nanoparticles causes alteration in iron homeostasis through acute phase response: A protective effect by surface modification

Zinc oxide nanoparticles (ZnO NPs) are one of the most widely used nanomaterials. Following oral exposure, these NPs can accumulate in various organs and induce the toxicity due to their physiochemical characteristics. In present study to reduce the toxicity, surface engineered ZnO NPs (c-ZnO NPs) were in-situ synthesized by using polyacrylamide grafted guar gum (PAm-g-GG) polymer in alkaline media. Further, the comparative effect of bared ZnO NPs (b-ZnO NPs) and c-ZnO NPs were assessed on secondary target organ liver and kidneys of Swiss mice at doses of 10, 50 and 300 mg/kg following 28 days repeated oral treatment. The b-ZnO NPs were incited severe damages in liver and kidney tissue than c-ZnO NPs as seen by transmission electron microscopy and histopathology. The increased levels of serum biomarkers (AST, ALT, ALP, creatinine, uric acid, and urea) were also observed, that remarking a disturbance in the function of liver and kidney. After sub-acute oral treatment of b-ZnO NPs, the hepatic pro-inflammatory cytokines (IL-6, TNF-α, and MMP-9) were up-regulated that causes the activation of acute phase response (APR). We also observed significantly increased in expression of hepatic acute phase proteins (hepcidin and haptoglobin) and altered interlinked iron (Fe) signaling biomarkers (hephaestin, TF, TFR-1, LDH, and ferroportin). This study emphasizes that exposure to ZnO NPs may cause inflammation mediated APR through ultra-structural damage of tissue that could escort the progression of anemia. Nevertheless, the capping with PAm-g-GG in c- ZnO NPs has reduced the toxicity by altering the surface reactive property of ZnO NPs.

Vanadium Dioxide Nanocoating Induces Tumor Cell Death through Mitochondrial Electron Transport Chain Interruption

A biomaterials surface enabling the induction of tumor cell death is particularly desirable for implantable biomedical devices that directly contact tumor tissues. However, this specific antitumor feature is rarely found. Consequently, an antitumor-cell nanocoating comprised of vanadium dioxide (VO2) prepared by customized reactive magnetron sputtering has been proposed, and its antitumor-growth capability has been demonstrated using human cholangiocarcinoma cells. The results reveal that the VO2 nanocoating is able to interrupt the mitochondrial electron transport chain and then elevate the intracellular reactive oxygen species levels, leading to the collapse of the mitochondrial membrane potential and the destruction of cell redox homeostasis. Indeed, this chain reaction can effectively trigger oxidative damage in the cholangiocarcinoma cells. Additionally, this study has provided new insights into designing a tumor-cell-inhibited biomaterial surface, which is modulated by the mechanism of mitochondria-targeting tumor cell death.

Functionalized magnetic nanoparticles attenuate cancer cells proliferation: Transmission electron microscopy analysis

The penetration and transportation of nanoparticles (NPs) inside the cancer cells is critical to study. In this article, cancer cells (HCT-116) were treated with functionalized magnetic NPs for the period of 48 hr and studied their ultrastructure by transmission electron microscopy (TEM). The NPs-treated cells were prepared by chemical fixation and sliced into electron-transparent arbitrary sections (200 × 200 μm² ) by ultramicrotome. Major events of NPs-cell interaction, such as penetration of NPs, encapsulation of NPs into the intracellular compartments, transportation of NPs, and NPs exit, were examined by TEM to understand the mechanism of cell death. The NPs showed the uniform spherical shape with broad size distribution (100-400 nm), while cells displayed irregular morphology with average diameter ~5 μm. Our results showed the successful penetration of NPs deep into the cell, encapsulation, transportation, and exocytosis. Furthermore, we tested the different concentrations (0, 1.5, 12.5, and 50 μg/ml) of NPs on cancer cells and evaluated the cell viability. Laser confocal microscopy and colorimetric analysis together demonstrated that the cell viability is a dose-dependent phenomenon, where 50 μg/ml specimen showed the highest killing of cancer cells compared to other dosages.

A Systematic Study of the Effect of pH on the Initialization of Ca-deficient Hydroxyapatite to β-TCP Nanoparticles

The formation of β-tricalcium phosphate (β-TCP) nanoparticles via a wet precipitation technique was studied in a systematical way, taking reaction pH and sintering temperature parameters into account. A full transformation of Ca-deficient hydroxyapatite (CDHA) to β-TCP at 750 °C in under 3 hours from Ca++ and PO₄3- precursor solutions prepared under a pH of 5.5 was observed. For pH values higher than 6.5, CDHA can only partially transform into β-TCP and only at temperatures higher than 750 °C confirmed using X-Ray diffraction and Raman spectroscopy. The morphologies of the particles were also examined by Transmission electron microscopy. The lower temperatures and the shorter sintering time allow for a fine needle-like morphology, but with a high crystallinity, likely eliminating the possibility of excessive grain growth that is otherwise expected to occur under high-temperature treatment with long process times. We show that sintering of nanostructured, high crystallinity β-TCP at relatively low temperatures is possible via adjustment of the precursor solution parameters. Such an outcome is important for the use of β-TCP with a fine morphology imitating that of the skeletal tissues, enhancing the osteointegration of a base, load-bearing alloy to the host tissue. MTT analysis was used to test the effect of the obtained β-TCP particles on the viability of MG-63 human osteoblast-like cells.

Green synthesis of ZnO hierarchical microstructures by Cordia myxa and their antibacterial activity

In this study, the leaves extract of Cordia myxa, has been used for the first time to synthesize zinc oxide (ZnO) hierarchical microstructures. The solution combustion method was employed as a self-sustaining reaction between zinc nitrate and the leaves extract. The surface properties of leaves mediated ZnO microstructures were determined by UV–Visible spectral analysis, Fourier transform infrared (FT-IR), Cold field emission-scanning electron microscopy (CFE-SEM), Energy dispersive X-ray (EDX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). In addition, the effect of the leaves extract concentration on ZnO structures, size and surface properties was also studied. ZnO structures synthesized employing C. myxa were found to be hexagonal, triangular and round in shape which was determined using CFE-SEM. X-ray diffraction (XRD) analysis confirmed the crystalline nature of compounds. Furthermore, C. myxa mediated ZnO microstructures shows good bactericidal activity against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria.

Green synthesis of zinc oxide nanostructures and investigation of their photocatalytic and bactericidal applications

We report a facile one-pot green synthesis of zinc oxide (ZnO) nanostructures using aqueous leaf extract of Dolichos Lablab L. as the reducing and capping agent. The optical properties, structure and morphology of the as-synthesized ZnO nanostructures have been characterized by UV-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) supported with energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). TEM analysis revealed that the as-synthesized ZnO nanostructures have an average particle diameter of 29 nm. XRD patterns confirmed the formation of phase-pure ZnO nanostructures with a hexagonal wurtzite structure. The synthesized ZnO nanostructures were used as a catalyst in the photodegradation of methylene blue (MB), rhodamine B (RhB) and orange II (OII) under visible and near-UV irradiation. The results showed the highest efficiency of photodegradation of ZnO nanostructures for MB (80%), RhB (95%) and OII (66%) at pH values of 11, 9 and 5, respectively, in a 210 min time interval. In addition, the antimicrobial activity of the ZnO nanostructures using the agar well diffusion method against Bacillus pumilus and Sphingomonas paucimobilis showed the highest zones of inhibition of 18 mm and 20 mm, respectively. Hence, ZnO nanostructures have the potential to be used as a photocatalyst and bactericidal component.

We report a facile one-pot green synthesis of zinc oxide (ZnO) nanostructures using aqueous leaf extract of Dolichos Lablab L. as the reducing and capping agent.

Simulating graphene oxide nanomaterial phototransformation and transport in surface water

The production of graphene-family nanomaterials (GFNs) has increased appreciably in recent years. Graphene oxide (GO) has been found to be the most toxic nanomaterial among GFNs and, to our knowledge, no studies have been conducted to model its fate and transport in the environment. Lab studies show that GO undergoes phototransformation in surface waters under sunlight radiation resulting in formation of photoreduced GO (rGO). In this study, the recently updated Water Quality Analysis Simulation Program (WASP8) is used to simulate time-dependent environmental exposure concentrations of GO and its major phototransformation product, rGO, for Brier Creek, GA, USA at two flow scenarios under a constant loading of GO to the river for a period of 20 years. Analysis shows that the degree of phototransformation is closely associated with river flow condition: up to of 40% of GO undergoes phototransformation at low flow condition, whereas only 2.5% of GO phototransformation occurs at mean flow condition. River flow and heteroaggregation exhibit a 'competing' effect in determining the formation of rGO heteroagglomerates. Mass fraction analysis indicates that the vast majority of rGO heteroagglomerates settle to the sediment layers due to the settling of suspended solids. Simulation of natural recovery after removal of the GO source suggests that free GO and rGO are the immediate contaminants of concern in the studied surface water system, while rGO heteroaggregated with suspended solids can have a long-term ecological impact on both the water column and sediments.

Biogenesis of ZnO nanoparticles using Pandanus odorifer leaf extract: anticancer and antimicrobial activities

The continuously increasing incidence rates of cancer and infectious diseases are open threats to the sustainable survival of animals and humans.

A biomolecule-assisted one-pot synthesis of zinc oxide nanoparticles and its bioconjugate with curcumin for potential multifaceted therapeutic applications

Biodegradable ZnO nanoparticles with excellent biocompatibility prepared via a biogenic process have great potential as therapeutic agent-cum-drug carriers for cancer treatment.

Zinc overload mediated by zinc oxide nanoparticles as innovative anti-tumor agent

The predicted global cancer burden is expected to surpass 20 million new cancer cases by 2025. Despite recent advancement in tumor therapy, a successful cancer treatment remains challenging. The emerging field of nanotechnology offers great opportunities for diagnosis, imaging, as well as treatment of cancer. Zinc oxide nanoparticles (ZnO NP) were shown to exert selective cytotoxicity against tumor cells via a yet unknown mechanism, most likely involving the generation of reactive oxygen species (ROS). These nanoparticles are a promising therapeutic opportunity as zinc is a nontoxic trace element and its application in medically-related products is considered to be safe. We could show that ZnO NP can exert cytotoxic effects on several human tumor cell lines. There can be found ZnO NP concentrations which selectively damage tumor cells while human fibroblasts do not sustain lasting damage. Cytotoxicity is attributable to the release of zinc ions from the nanoparticles outside the cells as well as to a direct cell-nanoparticle interaction. This involves uptake of the particles into the tumor cells. With a silica shell the cytotoxicity can be delayed which can help in the future for a safe transport in the blood stream. Cellular damage finally cumulates in apoptotic cell death via zinc overload within 48 h after treatment with ZnO NP. A therapeutical perspective could be the targeted accumulation of ZnO NP at the tumor side to induce local zinc overload that substantially damages the tumor cells with no or low side effects. We suggest further studies to explore the potential of ZnO NP as an innovative anti-tumor agent.

The efficacy of chronic zinc oxide nanoparticles using on testicular damage in the streptozotocin-induced diabetic rat model

Testicular impairment is a common complication of Diabetes mellitus (DM). Zinc Oxide Nanoparticles (ZnO NPs) are a novel agent for Zn delivery with antidiabetic and antioxidant activities. However, few reports were recorded on it. The current study aimed to investigate the possible ameliorating effect of ZnO NPs treatment on testicular tissues alterations in streptozotocin (STZ)-induced diabetic rats. Therefore, thirty mature male Wistar rats were divided into three main groups: Control group (n = 18) was subdivided equally into three subgroups (negative control, vehicle and ZnO NPs), Diabetic group (n = 6) and ZnO NPs-treated diabetic group (n = 6). Induction of diabetes was done by a single intraperitoneal injection of STZ (60 mg/kg bw). The rats were orally treated by ZnO NPs (10 mg/kg bw) for 30 constitutive days. At the end of the experiment, blood glucose and serum testosterone levels were measured. Also, testicular tissues were obtained for histopathological investigations and immunohistochemical staining with anti-PCNA (proliferating cell marker), anti-ssDNA (apoptotic cell marker), anti-SOX9 (Sertoli cell marker), anti-Stella (spermatogonia marker), anti-STRA8 (preleptotene and early-leptotene spermatocytes marker), anti-DMC1 (leptotene and zygotene spermatocytes marker), anti-Dnmt3a (a marker for cells under DNA methylation) and anti-α-SMA (peritubular myoid cell marker). The biochemical analysis revealed that diabetes resulted in a significant elevation in blood glucose level and a reduction in serum testosterone level. Moreover, histopathological investigations revealed disorganized seminiferous epithelium and sever hyalinization with vacuolization of the testicular interstitium containing Leydig cells. The immunohistochemical findings support spermatogenesis impairment in the diabetic group. However, ZnO NPs treatment restores architecture of seminiferous epithelium and Leydig cells. Furthermore, more PCNA, SOX9, Stella, STRA8, DMC1 and Dnmt3a immunopositive cells with an improvement of peritubular α-SMA immunopositive expression, as well as few ssDNA-immunopositive cells were detected in the seminiferous epithelium. This study suggested the possible protective role of orally administered ZnO NPs on testicular alterations in the STZ-induced diabetic group via steroidogenesis and spermatogenesis enhancement. In addition, further researches are acquired for evaluation mechanism of ZnO NPs treatment via oral or parenteral routes in a dose-dependent manner to identify the more effective route and dose in the treatment of testicular diabetic complications.

Effect of ZnO Nanoparticles on Human Bone Marrow Mesenchymal Stem Cells: Viability, Morphology, Particles Uptake, Cell Cycle and Metabolites

Despite the growing interest in nanoparticles (NPs), the evaluation of their safety use has to be deeply considered, but standardized procedures for the evaluation of their toxicity have not been defined. In vitro methods are ideal in toxicology research because they can rapidly provide reproducible results while preventing the use of animals. Primary cells are considered a better option as model systems for predicting toxicological behavior, although several cell types do not survive enough in culture and isolated cells can have substantial variability when obtained from different donors. Recently, a new test for acute toxicity based on the use of human bone marrow mesenchymal stem cells (hBMMSCs) has been developed and successfully tested in our laboratory following the ICCVAM (Interagency Coordinating Committee on the Validation of Alternative Methods) guidelines [1]. Along these lines, the aim of this study is to evaluate the acute cytotoxicity of ZnO nanoparticles using the new toxicity test based on hBMMSCs, while comparing their behavior with respect to the toxicity of ZnO micrometer ones. For this reason, we assessed the citotoxicity by performing Neutral Red assay, the cellular uptake by transmission electron microscopy and the effects on hBMMSCs cycle by FACS analysis. Furthermore, we also analyzed by means of GC-MS the polar metabolite profile of hBMMSCs samples treated with ZnO micro- and nanoparticles. Our results show that despite the slight differences in terms of cytotoxicity, nano and microparticles show a very different behavior with respect to their effects on hBMMSCs cycle, metabolite profile and cellular uptake.

Synthesis and characterization of Zinc oxide nanoparticles utilizing seed source of Ricinus communis and study of its antioxidant, antifungal and anticancer activity

ZnO nanoparticles have been synthesized using solution combustion technique and its antioxidant, antifungal, anticancer activity was studied. Ricinus communis plant seed extract used as fuel in synthesis by the solution combustion technique. Powder X-ray diffraction (PXRD) demonstrates the arrangement of a crystalline hexagonal stage (ICDD card number 89-1397) with space aggregate P63mc (186) and cell parameters a = b = 3.253, c = 5.213 Å. The normal crystallite measure is 20 nm which is ascertained by Debye - Scherer's formula. The Purity of the sample and metal to oxygen bond development was affirmed by utilizing Fourier transformation infrared (FTIR) spectroscopy and the particle size and shape was confirmed by HRTEM. Antifungal action of ZnO NPs was studied against Aspergillus and Penicillium by well dispersion strategy. The antifungal activity shows that ZnO NPs constitute as an effective fungicidal agent against both Aspergillus (4 ± 0.5 mm) and Penicillium (3 mm ± 0.4 mm) at 30 μg/mL fixation. ZnO nanoparticles were subjected to antioxidant activity. The objective of the study was to analyze the anticancer property of ZnO NPs on MDA-MB 231 cancer cells. To check the efficacy of the synthesized drug ZnO NPs MTT assay was performed, that determines % viability and/or cytotoxicity. IC₅₀ of ZnO NPs in case of MDA-MB-231 breast cancer was 7.103 μg/mL. Anticancer outcome demonstrates that ZnO NPs is active against in MDA-MB-231 cells.

Exposure to ZnO nanoparticles alters neuronal and vascular development in zebrafish: Acute and transgenerational effects mitigated with dissolved organic matter

Exposure to ZnO-nanoparticles (NPs) in embryonic zebrafish reduces hatching rates which can be mitigated with dissolved organic material (DOM). Although hatching rate can be a reliable indicator of toxicity and DOM mitigation potential, a fish that has been exposed to ZnO-NPs or any other toxicant may also exhibit other abnormal phenotypes not readily detected by the unaided eye. In this study, we moved beyond hatching rate analysis to investigate the consequences of ZnO-NPs exposure on the nervous and vascular systems in developing zebrafish. Zebrafish exposed to ZnO-NPs (1-100 ppm) exhibited an array of cellular phenotypes including: abnormal secondary motoneuron (SMN) axonal projections, abnormal dorsal root ganglion development and abnormal blood vessel development. Dissolved Zn (<10 kDa) exposure also caused abnormal SMN axonal projections, but to a lesser extent than ZnO-NPs. The ZnO-NPs-induced abnormal phenotypes were reversed in embryos concurrently exposed with various types of DOM. In these acute mitigation exposure experiments, humic acid and carbohydrate, along with natural organic matter obtained from the Suwannee River in Georgia and Milwaukee River in Wisconsin, were the best mitigators of ZnO-NPs-induced motoneuron toxicity at 96 h post fertilization. Further experiments were performed to determine if the ZnO-NPs-induced, abnormal axonal phenotypes and the DOM mitigated axonal phenotypes could persist across generations. Abnormal SMN axon phenotypes caused by ZnO-NPs-exposure were detected in F1 and F2 generations. These are fish that have not been directly exposed to ZnO-NPs. Fish mitigated with DOM during the acute exposure (F0 generation) had a reduction in abnormal motoneuron axon errors in larvae of subsequent generations. Therefore, ZnO-NPs exposure results in neurotoxicity in developing zebrafish which can persist from one generation to the next. Mitigation with DOM can reverse the abnormal phenotypes in an acute embryonic exposure context, as well as across generations, resulting in healthy fish.

Cellulose Nanocrystal-ZnO Nanohybrids for Controlling Photocatalytic Activity and UV Protection in Cosmetic Formulation

A high-performance semiconductor zinc oxide (ZnO) on melamine formaldehyde-coated cellulose nanocrystals (MFCNCs) was synthesized and evaluated for its application in smart cosmetics. These ZnO@MFCNC hybrid nanostructures were evaluated for their in vitro sun protection factor performance and photocatalytic activity under simulated UV and solar radiation. The photodegradation kinetics of a model pigment (methylene blue) was fitted to the Langmuir-Hinshelwood model. A 4-fold increase in the photocatalytic activity of ZnO@MFCNCs was observed when compared to pure ZnO. This is associated with (i) increased specific surface area provided by the MFCNC template, (ii) confined surface energy and controlled growth of ZnO nanoparticles, and (iii) entrapment of photoinduced charge carriers in the pores of the core-shell MFCNC rod, followed by fast promotion of interfacial e-charge transfer to the surface of the catalyst. The present study demonstrates how an increase in photocatalytic activity can be engineered without the introduction of structural defects or band gap tailoring of the semiconductor. The aqueous-based ZnO@MFCNC hybrid system displayed attractive UV-absorption and photocatalytic characteristics, offering the conversion of this renewable and sustainable technology into intelligent cosmetic formulations.

Elemental zinc to zinc nanoparticles: is ZnO NPs crucial for life? Synthesis, toxicological, and environmental concerns

The semi-conducting material zinc is one of the essential trace elements for humans, is a co-factor of more than 300 enzymes, and plays an important role in maintaining vital cellular functions. Deficiency of zinc may lead to cancer initiation; however, a high concentration also has toxic effects that might be life threatening. The toxicity can be addressed by the disequilibrium of zinc-mediated proteins and oxidative stress that produce nascent oxygen, hydroxyl radicals, and other reactive oxygen species. Zinc-based nanoparticles (NPs) are among the most important and multifunctional compounds. Zinc oxide (ZnO) NPs exhibit attractive antimicrobial and photocatalytic properties due to the smaller particle size and increased particle surface reactivity. Further, these are more biocompatible compared to other metallic NPs, easily synthesizable, and have high selectivity, enhanced cytotoxicity, and are a promising anticancer agent. However, some of the pertinent concerns regarding nano-zinc still needs to be clarified. Current research also demonstrates their usage in wastewater treatment, textile, medicine, etc. This review covers the importance of zinc for living systems and its NPs, with more emphasis on ZnO NPs. A comprehensive overview of ZnO NPs, their synthesis, characterization techniques, crystal structure, properties, and brief industrial applications are presented.

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

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

Influence of bovine serum albumin pre-incubation on toxicity and ER stress-apoptosis gene expression in THP-1 macrophages exposed to ZnO nanoparticles

When entering a biological environment, proteins could be adsorbed onto nanoparticles (NPs), which can potentially influence the toxicity of NPs. This study used bovine serum albumin (BSA) as the model for serum protein and investigated its interactions with three different types of ZnO NPs, coded as XFI06 (pristine NPs of 20 nm), NM110 (pristine NPs of 100 nm) and NM111 (hydrophobic NPs of 130 nm). Atomic force microscope indicated the adsorption of BSA to ZnO NPs, leading to the increase of NP diameters. Pre-incubation with BSA did not significantly affect hydrodynamic size but decreased Zeta potential of NM110 and NM111. The fluorescence and synchronous fluorescence of BSA were quenched after pre-incubation with ZnO NPs, and the quenching effects were more obvious for XFI06 and NM110. Exposure to all types of ZnO NPs significantly induced cytotoxicity and lysosomal destabilization, which was slightly alleviated when NPs were pre-incubated with BSA. However, ZnO NPs with or without pre-incubation of BSA resulted in comparable intracellular Zn ions, glutathione and reactive oxygen species in THP-1 macrophages. Exposure to ZnO NPs promoted the expression of endoplasmic reticulum (ER) stress markers (DDIT3 and XBP-1s) and apoptosis genes (CASP9 and CASP12). Pre-incubation with BSA had minimal impact on ER stress gene expression but decreased apoptosis gene expression. Combined, these results suggested that pre-incubation with BSA could modestly alleviate the cytotoxicity and reduce ER stress related apoptosis gene expression in THP-1 macrophages after ZnO NP exposure.

In-Vitro cytotoxicity, antibacterial, and UV protection properties of the biosynthesized Zinc oxide nanoparticles for medical textile applications

Nowadays, medical textiles have become the most essential and developing part in human healthcare sector. This work was undertaken with a view to harness the bio-active macromolecules secreted by fungi e.g. proteins and enzymes in bio-synthesis of ZnO nanoparticles for multifunctional textiles such as antibacterial activity and UV protection with considering the cytotoxicity limitation. Herein, the isolated fungus, Aspergillus terreus, was allowed to produce proteins which has affinity to cape ZnO-NPs. Various factors affecting the behavior of the secreted proteins on the formed nanoparticles were investigated. Thorough characterizations of the protein capped ZnO-NPs were performed by the using of UV-Visible spectroscopy, transmission electron microscope (TEM) Fourier Transform-Infra Red (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis and Dynamic light scattering analysis (DLS). Prior treatment of cotton fabrics with ZnO-NPs, the cytotoxicity of the protein capped ZnO-NPs was examined. After that, the antibacterial activity of the ZnO-NPs before and after treating of cotton fabrics, besides, the UV-protection (UPF) properties were investigated. Results obviously demonstrated the ability of the bio-secreted protein to cape and reduce ZnO to spherical ZnO-NPs with particle size lied around 10-45 nm, as indicated form UV-vis., spectra TEM, Zeta sizer, FTIR and XRD. Regarding to the results of cytotoxicity, the treatment of the cotton fabrics with ZnO-NPs were performed at safe dose (20 ppm). At this dose, ZnO-NPs loaded samples exhibited reasonable antibacterial activity against both Gram positive and Gram negative bacteria; besides, good UV-protection with reasonable increase in UVA and UVB blocking values. Indeed, nanotechnology based microbiological active molecules opens up new opportunities for us to explore novel applications in terms of green technology.

Cross Talk Between Autophagy and Apoptosis Contributes to ZnO Nanoparticle-Induced Human Osteosarcoma Cell Death

Killing osteosarcoma cells by zinc oxide nanoparticles (NPs) and its underlying subcellular mechanism are never studied. Here, it is found that the NPs induce cross talk between apoptosis and autophagy, which leads to osteosarcoma cell death. Specifically, the NP uptake promotes autophagy by inducing accumulation of autophagosomes along with impairment of lysosomal functions. The autophagy further causes the uptaken NPs to release zinc ions by promoting their dissolution. These intracellular zinc ions, together with those that are originally released from the extracellular NPs and flowed into the cells, collectively target and damage mitochondria to produce reactive oxygen species (ROS). Then the ROS inhibit cell proliferation by arresting S phase and trigger apoptosis by extrinsic and intrinsic pathways, ultimately leading to cell death. More importantly, suppression of the early stage autophagy restores cell viability by abolishing apoptosis whereas blockade of the late stage autophagy inversely enhances apoptosis. In contrast, inhibition of apoptosis shows a limited ability to restore cell viability but obviously enhance autophagy. Notably, cell viability is strongly ameliorated by the combination of inhibitors for both the late stage autophagy and the apoptosis. These findings provide a mechanistic understanding of the NP-directed autophagy and apoptosis in osteosarcoma cells.

Effective Neural Photostimulation Using Indium-Based Type-II Quantum Dots

Light-induced stimulation of neurons via photoactive surfaces offers rich opportunities for the development of therapeutic methods and high-resolution retinal prosthetic devices. Quantum dots serve as an attractive building block for such surfaces, as they can be easily functionalized to match the biocompatibility and charge transport requirements of cell stimulation. Although indium-based colloidal quantum dots with type-I band alignment have attracted significant attention as a nontoxic alternative to cadmium-based ones, little attention has been paid to their photovoltaic potential as type-II heterostructures. Herein, we demonstrate type-II indium phosphide/zinc oxide core/shell quantum dots that are incorporated into a photoelectrode structure for neural photostimulation. This induces a hyperpolarizing bioelectrical current that triggers the firing of a single neural cell at 4 μW mm^-2, 26-fold lower than the ocular safety limit for continuous exposure to visible light. These findings show that nanomaterials can induce a biocompatible and effective biological junction and can introduce a route in the use of quantum dots in photoelectrode architectures for artificial retinal prostheses.

Extracts of Clove (Syzygium aromaticum) Potentiate FMSP-Nanoparticles Induced Cell Death in MCF-7 Cells

Both nanoparticles and cloves (Syzygium aromaticum) possess anticancer properties, but they do not elicit a significant response on cancer cells when treated alone. In the present study, we have tested fluorescent magnetic submicronic polymer nanoparticles (FMSP-nanoparticles) in combination with crude clove extracts on human breast cancer cells (MCF-7) to examine whether the combination approach enhance the cancer cell death. The MCF-7 cells were treated with different concentrations (1.25 μg/mL, 12.5 μg/mL, 50 μg/mL, 75 μg/mL, and 100 μg/mL) of FMSP-nanoparticles alone and in combination with 50 μg/mL crude clove extracts. The effects of FMSP-nanoparticles alone and combined with clove extracts were observed after 24 hrs and 48 hrs intervals. The response of FMSP-nanoparticles-treated cells was evaluated by Trypan Blue, 4',6-diamidino-2-phenylindole (DAPI), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, respectively. We have demonstrated that cancer cell viability was decreased to 55.40% when treated with FMSP-nanoparticles alone, whereas when cancer cells were treated with FMSP-nanoparticles along with crude clove extracts, the cell viability was drastically decreased to 8.50%. Both morphological and quantitative data suggest that the combination of FMSP-nanoparticles plus crude clove extracts are more effective in treating cancer cells and we suggest that the combination treatment of nanoparticles along with clove extracts hold a great promise for the cancer treatments.

Oxidative stress mediated cytotoxicity of tin (IV) oxide (SnO2) nanoparticles in human breast cancer (MCF-7) cells

Due to unique optical and electronic properties tin oxide nanoparticles (SnO₂ NPs) have shown potential for various applications including solar cell, catalyst, and biomedicine. However, there is limited information concerning the interaction of SnO₂ NPs with human cells. In this study, we explored the potential mechanisms of cytotoxicity of SnO₂ NPs in human breast cancer (MCF-7) cells. Results demonstrated that SnO₂ NPs induce cell viability reduction, lactate dehydrogenase leakage, rounded cell morphology, cell cycle arrest and low mitochondrial membrane potential in dose- and time-dependent manner. SnO₂ NPs were also found to provoke oxidative stress evident by generation of reactive oxygen species (ROS), hydrogen peroxide (H₂O₂) and lipid peroxidation, while depletion of glutathione (GSH) level and lower activity of several antioxidant enzymes. Remarkably, we observed that ROS generation, GSH depletion, and cytotoxicity induced by SnO₂ NPs were effectively abrogated by antioxidant N-acetylcycteine. Our data have shown that SnO₂ NPs induce toxicity in MCF-7 cells via oxidative stress. This study warrants further research to explore the genotoxicity of SnO₂ NPs in different types of cancer cells.