Determination of the bioavailability of zinc oxide nanoparticles using ICP-AES and associated toxicity

Dextran-Graft-Polyacrylamide/Zinc Oxide Nanoparticles Inhibit of Cancer Cells in vitro and in vivo

Introduction

Tumor drug resistance and systemic toxicity are major challenges of modern anticancer therapy. Nanotechnology makes it possible to create new materials with the required properties for anticancer therapy.

Methods

In this research, Dextran-graft-Polyacrylamide/ZnO nanoparticles were used. The study was carried out using prostate (DU-145, LNCaP, PC-3), breast (MDA-MB-231, MCF-7, MCF-7 Dox) cancer cells and non-malignant (MAEC, BALB/3T3 clone A31) cells. Zinc was visualized with fluorescence in vitro and in vivo. ROS and apoptotic markers were identified by cytometry. Zinc accumulation and histopathological changes in the tumor, liver, kidney, and spleen were evaluated in a rat model.

Results

ZnO nanoparticles dissociation and release of Zn2+ into the cytosol occurs in 2-3 hours for cancerous and non-cancerous cells. ROS upregulation was detected in all cells. For non-malignant cells, the difference between the initial ROS level was insignificant. The rate of carbohydrate metabolism in cancer cells was reduced by nanosystems. Zinc level in the tumor was upregulated by 25% and 39% after treatment with nanosystems and doxorubicin combined, respectively. The tumor Walker-256 carcinosarcoma volume was reduced twice following mono-treatment with the nanocomplex and 65-fold lower when the nanocomplex was combined with doxorubicin compared with controls. In the liver, kidney and spleen, the zinc level increased by 10-15% but no significant pathological alterations in the tissues were detected.

Conclusion

D-PAA/ZnO NPs nanosystems were internalized by prostate, breast cancer cells and non-malignant cells via endocytosis after short time, but cytotoxicity against non-cancer cells were significantly lower in vitro and in vivo. D-PAA/ZnO NPs nanocomplex efficiently promoted cell death of tumor cells without showing cytotoxicity against non-malignant cells making it a promising anti-cancer agent.

Molecular mechanisms of zinc oxide nanoparticles neurotoxicity

Zinc oxide nanoparticles (ZnONPs) are widely used in industry and biomedicine. A growing body of evidence demonstrates that ZnONPs exposure may possess toxic effects to a variety of tissues, including brain. Therefore, the objective of the present review was to summarize existing evidence on neurotoxic effects of ZnONPs and discuss the underlying molecular mechanisms. The existing laboratory data demonstrate that both in laboratory rodents and other animals ZnONPs exposure results in a significant accumulation of Zn in brain and nervous tissues, especially following long-term exposure. As a result, overexposure to ZnONPs causes oxidative stress and cell death, both in neurons and glial cells, by induction of apoptosis, necrosis and ferroptosis. In addition, ZnONPs may induce neuroinflammation through the activation of nuclear factor kappa B (NF-κB), extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK), and lipoxygenase (LOX) signaling pathways. ZnONPs exposure is associated with altered cholinergic, dopaminergic, serotoninergic, as well as glutamatergic and γ-aminobutyric acid (GABA)-ergic neurotransmission, thus contributing to impaired neuronal signal transduction. Cytoskeletal alterations, as well as impaired autophagy and mitophagy also contribute to ZnONPs-induced brain damage. It has been posited that some of the adverse effects of ZnONPs in brain are mediated by altered microRNA expression and dysregulation of gut-brain axis. Furthermore, in vivo studies have demonstrated that ZnONPs exposure induced anxiety, motor and cognitive deficits, as well as adverse neurodevelopmental outcome. At the same time, the relevance of ZnONPs-induced neurotoxicity and its contribution to pathogenesis of neurological diseases in humans are still unclear. Further studies aimed at estimation of hazards of ZnONPs to human brain health and the underlying molecular mechanisms are warranted.

Intraperitoneal hepatorenal toxicity of zinc oxide and nickel oxide nanoparticles in rats: a systematic review

Zinc oxide (ZnO) and nickel oxide (NiO) nanoparticles (NPs) are widely used in various industries due to their distinctive physico-chemical and biological properties. However, concerns have been raised about their potential toxicity in humans. While many studies have reviewed their effects on visceral organs upon ingestion, inhalation, or skin contact, limited reviews are available regarding their adverse consequences on the liver and kidneys resulting from intraperitoneal administration in rats. Hence, this systematic review is the first to uniquely address this issue. A systematic search was performed on PubMed and Google scholar to identify articles that explored the toxic effects of ZnO-NPs and NiO-NPs in rats following intraperitoneal injection. The quality of the articles was assessed using SYCLE's risk of bias tool, leading to the selection of 16 articles; 14 for ZnO-NPs, 1 for NiO-NPs and 1 for both NPs. This review revealed that ZnO-NPs induces an acute toxicity in liver and kidney that is dose dependent. The impairments were marked by changes in organs functional markers, lipid and glucose levels and antioxidant deficiencies and lipid peroxidation. NiO-NPs also showed considerable toxicity, despite the limited studies. Further, variability of physico-chemical properties among studies complicated the toxicity assessment. To conclude, this study provides a novel contribution by summarizing the literature findings that suggest potential adverse intraperitoneal hepatorenal toxic outcomes associated with ZnO-NPs and NiO-NPs. Future research should focus on long-term effects and standardizing protocols to ensure the safe use of ZnO-NPs and NiO-NPs in industrial and clinical practices.

Intraperitoneal hepato-renal toxicity of zinc oxide and nickel oxide nanoparticles in male rats: biochemical, hematological and histopathological studies

In recent years, zinc oxide (ZnO) and nickel oxide (NiO) nanoparticles (NPs) have become more prevalent in commercial and industrial products. However, questions have been raised regarding their potential harm to human health. Limited studies have been conducted on their intraperitoneal toxicity in rats, and their co-exposure effects remain uncertain. Therefore, this study aimed to investigate some biological responses induced by a single intraperitoneal injection of ZnO-NPs (200 mg/kg) and/or NiO-NPs (50 mg/kg) in rats over time intervals. Blood and organ samples were collected from 36 male rats for hematological, biochemical, oxidative stress, and histological analysis. Results showed that the administration of NPs reduced the body and organ weights as well as red blood cell (RBC) indices and altered white blood cell (WBC) and platelet (PLT) counts. The experimental groups exhibited elevated levels of aspartate aminotransferase (AST), alanine transaminase (ALT), creatinine (CREA), urea, lipid profile, glucose (GLU), total protein (TP), albumin (ALB) and malondialdehyde (MDA), and decreased uric acid (UA), superoxide dismutase (SOD), and glutathione (GSH). Histological observations also revealed architectural damages in liver and kidneys. These alterations were time-dependent and varied in their degree of toxicity. Co-exposure of NPs initially lessened the damage but increased it afterwards compared to individual exposure. In conclusion, intraperitoneal injection of ZnO-NPs and/or NiO-NPs alters biological processes and induces oxidative stress in rats' liver and kidneys in a time-dependent manner, with NiO-NPs being more potent than ZnO-NPs. Furthermore, co-exposed NPs initially appeared to be antagonistic to one another while further aiming toward synergism.

Nanozinc and plant growth-promoting bacteria improve biochemical and metabolic attributes of maize in tropical Cerrado

INTRODUCTION

Plant growth-promoting bacteria (PGPBs) could be developed as a sustainable strategy to promote plant growth and yield to feed the ever-growing global population with nutritious food. Foliar application of nano-zinc oxide (ZnO) is an environmentally safe strategy that alleviates zinc (Zn) malnutrition by improving biochemical attributes and storage proteins of grain.

METHODS

In this context, the current study aimed to investigate the combined effect of seed inoculation with PGPBs and foliar nano-ZnO application on the growth, biochemical attributes, nutrient metabolism, and yield of maize in the tropical savannah of Brazil. The treatments consisted of four PGPB inoculations [i.e., without inoculation, Azospirillum brasilense (A. brasilense), Bacillus subtilis (B. subtilis), Pseudomonas fluorescens (P. fluorescens), which was applied on the seeds] and two doses of Zn (i.e., 0 and 3 kg ha-1, applied from nano-ZnO in two splits on the leaf).

RESULTS

Inoculation of B. subtilis with foliar ZnO application increased shoot dry matter (7.3 and 9.8%) and grain yield (17.1 and 16.7%) in 2019-20 and 2020-2021 crop seasons respectively. Inoculation with A. brasilense increased 100-grains weight by 9.5% in both crop seasons. Shoot Zn accumulation was improved by 30 and 51% with inoculation of P. fluorescens in 2019-20 and 2020-2021 crop seasons. Whereas grain Zn accumulation was improved by 49 and 50.7% with inoculation of B. subtilis and P. fluorescens respectively. In addition, biochemical attributes (chlorophyll a, b and total, carotenoids, total soluble sugar and amino acids) were improved with inoculation of B. subtilis along with foliar nano ZnO application as compared to other treatments. Co-application of P. fluorescens with foliar ZnO improved concentration of grains albumin (20 and 13%) and globulin (39 and 30%). Also, co-application of B. subtilis and foliar ZnO improved concentration of grains glutelin (8.8 and 8.7%) and prolamin (15 and 21%) in first and second seasons.

DISCUSSION

Therefore, inoculation of B. subtilis and P. fluorescens with foliar nano-ZnO application is considered a sustainable and environmentally safe strategy for improving the biochemical, metabolic, nutritional, and productivity attributes of maize in tropical Savannah regions.

Zinc-nutrient element based alloys for absorbable wound closure devices fabrication: Current status, challenges, and future prospects

The need for the development of load-bearing, absorbable wound closure devices is driving the research for novel materials that possess both good biodegradability and superior mechanical characteristics. Biodegradable metals (BMs), namely: magnesium (Mg), zinc (Zn) and iron (Fe), which are currently being investigated for absorbable vascular stent and orthopaedic implant applications, are slowly gaining research interest for the fabrication of wound closure devices. The current review presents an overview of the traditional and novel BM-based intracutaneous and transcutaneous wound closure devices, and identifies Zn as a promising substitute for the traditional materials used in the fabrication of absorbable load-bearing sutures, internal staples, and subcuticular staples. In order to further strengthen Zn to be used in highly stressed situations, nutrient elements (NEs), including calcium (Ca), Mg, Fe, and copper (Cu), are identified as promising alloying elements for the strengthening of Zn-based wound closure device material that simultaneously provide potential therapeutic benefit to the wound healing process during implant biodegradation process. The influence of NEs on the fundamental characteristics of biodegradable Zn are reviewed and critically assessed with regard to the mechanical properties and biodegradability requirements of different wound closure devices. The opportunities and challenges in the development of Zn-based wound closure device materials are presented to inspire future research on this rapidly growing field.

The Influence of Supplementation with Zinc in Micro and Nano Forms on the Metabolism of Fatty Acids in Livers of Rats with Breast Cancer

The aim of this study was to investigate the effect of zinc supplementation (in the form of nano or microparticles) on the profile and metabolism of fatty acids in the liver microsomes of rats with induced breast cancer. The activity of desaturases (Δ5, Δ6, Δ9) and the level of cholesterol and its oxidized derivatives were measured. The aim of this study was also to determine the effect of various forms of zinc supplements on rats that were on 5-, 12- and 15-hydroxyeicosatetraenoic (5-, 12- and 15-HETE) and hydroxyoctadecadienoic (HODE) acids, and the level of prostaglandin E2 (PGE2). Female Spraque-Dawley rats (n = 24) were divided into 2 groups that were supplemented with zinc in the micro form (342 nm) or nano form (99 nm) particles, respectively, and a group with a standard diet (control group). All animals received 7,12-dimethylbenz[a]anthracene twice for the induction of breast cancer. Dietary nano-Zn supplementation increased vaccenic acid content (p = 0.032) and decreased Δ6-desaturase activity (p = 0.006), whereas micro-Zn increased cholesterol (p = 0.006), ∑COPs (total cholesterol-oxidation products) (p = 0.019) and PGE2 (p = 0.028) content. Dietary enrichment with Zn microparticles resulted in lower concentrations of the metabolites 15-, 12- and 5-HETE and HODE. Our study indicates that the effect of zinc supplementation on the metabolism of fatty acids in the liver microsomes under neoplastic conditions depends on the form in which it is administered.

Cell-free extract assisted synthesis of ZnO nanoparticles using aquatic bacterial strains: Biological activities and toxicological evaluation

The introduction of novel bacterial strains and the development of microbial approaches for nanoparticles biosynthesis could minimize the negative environmental impact and eliminate the concern and challenges of the available approaches. In this study, a biological method based on microbial cell-free extract was used for biosynthesis of ZnO NPs using two new aquatic bacteria, Marinobacter sp. 2C8 and Vibrio sp. VLA. The synthesized ZnO NPs were characterized by UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscope (AFM), dynamic light scattering (DLS) and zeta potential. The UV-Visible absorption peak was found to be at 266 and 250 nm for ZnO-2C8 NPs and ZnO-VLA NPs, respectively. FTIR study suggested that the hydroxyl, amine, and carboxyl groups of bacterial proteins are mainly responsible for stabilizing the biosynthesized ZnO NPs. The formation of hexagonal wurtzite structure of ZnO NPs was confirmed by the XRD pattern. The morphology of the nanoparticles was found to be spherical with the average particle size of about 10.23 ± 2.48 nm and 20.26 ± 4.44 nm for ZnO-2C8 NPs and ZnO-VLA NPs, respectively. The values of zeta potential indicate the high stability of the biosynthesized ZnO NP. Zeta potential values indicated the high stability of the biosynthesized ZnO NP and were obtained -20.54 ± 7.15 and -23.87 ± 2.29 mV for ZnO-2C8 NPs and ZnO-VLA NPs, respectively. The biosynthesized ZnO NPs had antibacterial activity against Gram-negative and Gram-positive strains and possessed excellent antibiofilm activity with the maximum inhibition of about 96.55% at 250 µg/mL. The DPPH activity of ZnO-2C8 NPs and ZnO-VLA NPs were found 88.9% and 85.7% for 2500 μg/mL concentration, respectively. The toxicity test revealed the biocompatibility of the biosynthesized ZnO NPs. The results suggested that this approach is a very good route for synthesizing ZnO NPs with potential applications in biotechnology.

Comparative study of As (V) uptake in aqueous medium by a polymer inclusion membrane-based passive sampling device and two filamentous fungi (Aspergillus niger and Rhizopus sp.)

In this work a polymer inclusion membrane (PIM) is proposed as passive sampler material and compared with two filamentous fungi for As (V) uptake to evaluate its ability as chemical surrogate material for the monitoring of this metalloid in aquatic environments. Results show excellent passive sampling characteristics of the device since a linear uptake profile as a function of time was observed. The correlation coefficients between the PIM passive sampler with Aspergillus niger (r = 0.83) and Rhizopus sp. (r = 0.13) uptake, show that the first species is the best modeled by the PIM, suggesting its potential as a chemical substitute in bioavailability studies.

Recent Progress in Antimicrobial Strategies for Resin-Based Restoratives

Repairing tooth defects with dental resin composites is currently the most commonly used method due to their tooth-colored esthetics and photocuring properties. However, the higher than desirable failure rate and moderate service life are the biggest challenges the composites currently face. Secondary caries is one of the most common reasons leading to repair failure. Therefore, many attempts have been carried out on the development of a new generation of antimicrobial and therapeutic dental polymer composite materials to inhibit dental caries and prolong the lifespan of restorations. These new antimicrobial materials can inhibit the formation of biofilms, reduce acid production from bacteria and the occurrence of secondary caries. These results are encouraging and open the doors to future clinical studies on the therapeutic value of antimicrobial dental resin-based restoratives. However, antimicrobial resins still face challenges such as biocompatibility, drug resistance and uncontrolled release of antimicrobial agents. In the future, we should focus on the development of more efficient, durable and smart antimicrobial dental resins. This article focuses on the most recent 5 years of research, reviews the current antimicrobial strategies of composite resins, and introduces representative antimicrobial agents and their antimicrobial mechanisms.

Biosafety risk assessment of nanoparticles: Evidence from food case studies

Nanotechnology provides a wide range of benefits in the food industry in improving food tastes, textures, sensations, quality, shelf life, and food safety. Recently, potential adverse effects such as toxicity and safety concerns have been associated with the increasing use of engineered nanoparticles in food industry. Additionally, very limited information is known concerning the behavior, properties and effects of food nano-materials in the gastrointestinal tract. There is explores the current advances and provides insights of the potential risks of nanoparticles in the food industry. Specifically, characteristics of food nanoparticles and their absorption in the gastrointestinal tract, the effects of food nanoparticles against the gastrointestinal microflora, and the potential toxicity mechanisms in different organs and body systems are discussed. This review would provide references for further investigation of nano-materials toxicity effect in foods and their molecular mechanisms. It will help to develop safer foods and expand nano-materials applications in safe manner.

Metal- and metal/oxide-based engineered nanoparticles and nanostructures: a review on the applications, nanotoxicological effects, and risk control strategies

The production and demand of nanoparticles in the manufacturing sector and personal care products, release a large number of engineered nanoparticles (ENPs) into the atmosphere, aquatic ecosystems, and terrestrial environments. The intentional or involuntary incorporation of ENPs into the environment is carried out through different processes. The ENPs are combined with other compounds and release into the atmosphere, settling on the ground due to the water cycle or other atmospheric phenomena. In the case of aquatic ecosystems, the ENPs undergo hetero-aggregation and sedimentation, reaching different living organisms and flora, as well as groundwater. Accordingly, the high mobility of ENPs in diverse ecosystems is strongly related to physical, chemical, and biological processes. Recent studies have been focused on the toxicological effects of a wide variety of ENPs using different validated biological models. This literature review emphasizes the study of toxicological effects related to using the most common ENPs, specifically metal and metal/oxides-based nanoparticles, addressing different synthesis methodologies, applications, and toxicological evaluations. The results suggest negative impacts on biological models, such as oxidative stress, metabolic and locomotive toxicity, DNA replication dysfunction, and bioaccumulation. Finally, it was consulted the protocols for the control of risks, following the assessment and management process, as well as the classification system for technological alternatives and risk management measures of ENPs, which are useful for the transfer of technology and nanoparticles commercialization.

Evidence of a non-apoptotic mode of cell death in microglial BV-2 cells exposed to different concentrations of zinc oxide nanoparticles

Zinc oxide nanoparticles (ZnO NPs) possess huge application potential. However, the toxicity of ZnO NPs is a great cause of concern. Indeed, ZnO NPs have been found to cause neurotoxicity. As microglial dysfunctions have been linked to the neurotoxic potential of NPs, the physico-chemical properties of ZnO NPs were determined and their cytotoxic effects were characterised on murine microglial BV-2 cells. In-house prepared and meticulously characterised ZnO NPs exhibited narrow size distribution with an average size of around 20 nm and a zeta potential at physiological pH around 24 mV. ZnO NPs did not exhibit aggregation in the cell culture medium. When microglial BV-2 cells were exposed for 6 and 24 h to ZnO NPs (5, 10, 20, 40, and 80 μg/mL), several cell damages were observed. Cellular accumulation of NPs in microglial BV-2 cells was associated with cell growth inhibition and cell death induction, measured by the trypan blue exclusion and MTT assays. Mitochondrial dysfunction and lysosomal alteration were associated with increased plasma membrane permeability measured by staining with DiOC₆(3), acridine orange, and propidium iodide, respectively. In addition, an accumulation of reactive oxygen species (ROS) was detected after staining with dihydroethidium and dihydrorhodamine 123. No apoptotic features were present: no cells with condensed and/or fragmented nuclei (Hoechst staining) characteristic of apoptotic cells, absence of subG1 cells, absence of caspase-3 cleavage, and PARP fragmentation. With ZnO NPs (80 μg/mL), with the annexin V/propidium iodide (PI) assay, few apoptotic cells (annexin V+/PI- cells) were detected whereas (annexin V+/PI+ cells) evocating necrotic cells were mainly identified. No modification of the cells in the different phases of the cell cycle was found. Altogether, our data show that ZnO NPs induce a non-apoptotic mode of cell death associated with an accumulation of ROS, mitochondrial, and lysosomal dysfunction and plasma membrane damages in microglial BV-2 cells.Graphical abstract.

Metallic Antibacterial Surface Treatments of Dental and Orthopedic Materials

The oral cavity harbors complex microbial communities, which leads to biomaterial-associated infections (BAI) during dental and orthopedic treatments. Conventional antibiotic treatments have met great challenges recently due to the increasing emergency of drug-resistant bacteria. To tackle this clinical issue, antibacterial surface treatments, containing surface modification and coatings, of dental and orthopedic materials have become an area of intensive interest now. Among various antibacterial agents used in surface treatments, metallic agents possess unique properties, mainly including broad-spectrum antibacterial properties, low potential to develop bacterial resistance, relative biocompatibility, and chemical stability. Therefore, this review mainly focuses on underlying antibacterial applications and the mechanisms of metallic agents in dentistry and orthopedics. An overview of the present review indicates that much work remains to be done to deepen the understanding of antibacterial mechanisms and potential side-effects of metallic agents.

Enhancing ZnO-NP Antibacterial and Osteogenesis Properties in Orthopedic Applications: A Review

Prosthesis-associated infections and aseptic loosening are major causes of implant failure. There is an urgent need to improve the antibacterial ability and osseointegration of orthopedic implants. Zinc oxide nanoparticles (ZnO-NPs) are a common type of zinc-containing metal oxide nanoparticles that have been widely studied in many fields, such as food packaging, pollution treatment, and biomedicine. The ZnO-NPs have low toxicity and good biological functions, as well as antibacterial, anticancer, and osteogenic capabilities. Furthermore, ZnO-NPs can be easily obtained through various methods. Among them, green preparation methods can improve the bioactivity of ZnO-NPs and strengthen their potential application in the biological field. This review discusses the antibacterial abilities of ZnO-NPs, including mechanisms and influencing factors. The toxicity and shortcomings of anticancer applications are summarized. Furthermore, osteogenic mechanisms and synergy with other materials are introduced. Green preparation methods are also briefly reviewed.