Nanotechnology and Nanotoxicology

Global research landscape on nanotechnology in acute lung injury: a bibliometric analysis

Background

Acute lung injury is a common respiratory emergency that seriously affects the life, health and quality of life of patients, especially after the global COVID-19 pneumonia. The application of nanotechnology in acute lung injury is promising. In response to the knowledge explosion resulting from rapid publication growth, we applied bibliometric analysis to explore the research profile and thematic trends in the field.

Methods

Articles and reviews related to nanotechnology in acute lung injury from 2004 to 2023 were searched. Java-based Citespace, VOSviewer, and R software-based Bibiometrix were used to systematically evaluate publications by spatiotemporal distribution, author distribution, subject categories, topic distribution, references, and keywords.

Results

A total of 1,347 publications were included. The number of papers related to nanotechnology in acute lung injury has grown exponentially over the past 20 years. China was the most productive country out of all 53 countries, followed by the United States. The Chinese Academy of Sciences was the most productive institution with 76 papers. PARTICLE AND FIBRE TOXICOLOGY was the most productive journal. The top five high-frequency keywords were inflammation, oxidative stress, toxicity, in vitro, respiratory-distress-syndrome. And the top five emerging keywords were delivery, covid-19, extracellular vesicles, therapy, sars-cov-2. Drug delivery are the focus of current research. Two emerging research areas represented the development trends: novel nanocarriers with higher efficiency and lower biotoxicity, and the other is research related to impact of nanomaterials in the progression of acute lung injury.

Conclusion

The field of nanotechnology in acute lung injury has been in a period of rapid development in the last three years. Delivery,targeted delivery and exosm have been the focus of current research in this field. Two emerging research areas represented the development trends:novel nanocarriers with higher efficiency and lower biotoxicity such as extracellular vesicles, exosomes and solid lipid nanoparticles, and the other is research related to impact of nanomaterials in the progression of acute lung injury.

Comparative toxicity assessment of individual, binary and ternary mixtures of SiO2, Fe3O4, and ZnO nanoparticles in freshwater microalgae, Scenedesmus obliquus: Exploring the role of dissolved ions

Metal oxide nanoparticles (NPs) are considered among the most prevalent engineered nanomaterials. To have a deeper understanding of the mode of action of multiple metal oxide nanoparticles in mixtures, we have used a unicellular freshwater microalga Scenedesmus obliquus as a model organism. The toxicity of silicon dioxide (SiO2), iron oxide (Fe3O4), and zinc oxide (ZnO) NPs was studied individually as well as in their binary (SiO2 + Fe3O4, Fe3O4 + ZnO, and ZnO + SiO2) and ternary (SiO2 + Fe3O4 + ZnO) combinations. The effects of metal ions from ZnO and Fe3O4 were investigated as well. The results observed from the study, showed that a significant amount of toxicity was contributed by the dissolved ions in the mixtures of the nanoparticles. Decreases in the cell viability, ROS generation, lipid peroxidation, antioxidant enzyme activity, and photosynthetic efficiency were analyzed. Among all the individual particles, ZnO NPs showed the maximum effects and increased the toxicities of the binary mixtures. The binary and ternary mixtures of the NPs clearly showed increased toxic effects in comparison with the individual entities. However, the ternary combination had lesser toxic effects than the binary combination of Fe3O4 + ZnO. The decline in cell viability and photosynthetic efficiency were strongly correlated with various oxidative stress biomarkers emphasizing the crucial role of reactive oxygen species in inducing the toxic effects. The findings from this study highlight the importance of evaluating the combinatorial effects of various metal oxide NPs as part of a comprehensive ecotoxicity assessment in freshwater microalgae.

Polysaccharide-based nanoassemblies: From synthesis methodologies and industrial applications to future prospects

Polysaccharides, due to their remarkable features, have gained significant prominence in the sustainable production of nanoparticles (NPs). High market demand and minimal production cost, compared to the chemically synthesised NPs, demonstrate a drive towards polysaccharide-based nanoparticles (PSNPs) benign to environment. Various approaches are used for the synthesis of PSNPs including cross-linking, polyelectrolyte complexation, and self-assembly. PSNPs have the potential to replace a wide diversity of chemical-based agents within the food, health, medical and pharmacy sectors. Nevertheless, the considerable challenges associated with optimising the characteristics of PSNPs to meet specific targeting applications are of utmost importance. This review provides a detailed compilation of recent accomplishments in the synthesis of PSNPs, the fundamental principles and critical factors that govern their rational fabrication, as well as various characterisation techniques. Noteworthy, the multiple use of PSNPs in different disciplines such as biomedical, cosmetics agrochemicals, energy storage, water detoxification, and food-related realms, is accounted in detail. Insights into the toxicological impacts of the PSNPs and their possible risks to human health are addressed, and efforts made in terms of PSNPs development and optimising strategies that allow for enhanced delivery are highlighted. Finally, limitations, potential drawbacks, market diffusion, economic viability and future possibilities for PSNPs to achieve widespread commercial use are also discussed.

Mechanistic study of copper nanoparticle (CuNP) toxicity on the mouse uterus via apelin signaling

Copper nanoparticles (CuNPs) have been widely utilized in various applications. Due to its wider application, humans are at risk of its exposure. It has been reported that the exposure of CuNPs can lead to organ accumulation and affect organ toxicity. Recent study suggested that CuNPs can translocate into the uterus and affect uterine injury in rat, whereas uterine toxicity still remains unclear. The uterus is an important female organ which is required to sustain pregnancy. Thus, uterine structure and physiology are important. Therefore, this study hypothesized that CuNPs might have a toxic effect on the uterine features of mice. In this study, we have investigated the potential effects of CuNPs on the uterus of mice both in vivo and in vitro. In in vivo study, two groups of female mice were exposed to 5 and 50 mg/kg/day via oral exposure. In vivo results showed that CuNP treatment decreases the body weight and uterus weight and changes in antioxidant status with low estrogen and progesterone levels. Furthermore, CuNPs up-regulated the expression of caspase3 and down-regulated the expression of apelin receptor (APJ). Immunolocalization of apelin showed low abundance in the CuNP-treated uterus. These results suggest a poor apelin signaling in the uterus after CuNP treatment. The in vivo findings were further supported by the in vitro studies. Firstly, the uterus was cultured with 5 and 40 μg of CuNPs, and in the second in vitro experiment, the uterus was divided into 4 groups: control, 40 μg of CuNPs, 40 μg of CuNPs with apelin, and 40 μg of CuNPs with apelin receptor antagonist (ML221). In vitro study showed that CuNPs could directly induce the oxidative stress and apoptosis as well as changing antioxidant status in the uterus. The in vitro apelin 13 (APLN 13) treatments alleviated the expression of BCL2 and improved the antioxidant markers in CuNP-treated uterus. These results also provided an evidence of apelin-mediated signaling in the CuNP-treated uterus. In summary, our results present evidence that CuNPs can stimulate apoptotic pathways which may lead to uterine impairment due to weak apelin signaling.

An Overview of Essential Microelements and Common Metallic Nanoparticles and Their Effects on Male Fertility

Numerous factors affect reproduction, including stress, diet, obesity, the use of stimulants, or exposure to toxins, along with heavy elements (lead, silver, cadmium, uranium, vanadium, mercury, arsenic). Metals, like other xenotoxins, can cause infertility through, e.g., impairment of endocrine function and gametogenesis or excess production of reactive oxygen species (ROS). The advancement of nanotechnology has created another hazard to human safety through exposure to metals in the form of nanomaterials (NMs). Nanoparticles (NPs) exhibit a specific ability to penetrate cell membranes and biological barriers in the human body. These ultra-fine particles (<100 nm) can enter the human body through the respiratory tract, food, skin, injection, or implantation. Once absorbed, NPs are transported to various organs through the blood or lymph. Absorbed NPs, thanks to ultrahigh reactivity compared to bulk materials in microscale size, disrupt the homeostasis of the body as a result of interaction with biological molecules such as DNA, lipids, and proteins; interfering with the functioning of cells, organs, and physiological systems; and leading to severe pathological dysfunctions. Over the past decades, much research has been performed on the reproductive effects of essential trace elements. The research hypothesis that disturbances in the metabolism of trace elements are one of the many causes of infertility has been unquestionably confirmed. This review examines the complex reproductive risks for men regarding the exposure to potentially harmless xenobiotics based on a series of 298 articles over the past 30 years. The research was conducted using PubMed, Web of Science, and Scopus databases searching for papers devoted to in vivo and in vitro studies related to the influence of essential elements (iron, selenium, manganese, cobalt, zinc, copper, and molybdenum) and widely used metallic NPs on male reproduction potential.

Prospects of Nanotechnology in Improving the Productivity and Quality of Horticultural Crops

Nanotechnology shows high promise in the improvement of agricultural productivity thus aiding future food security. In horticulture, maintaining quality as well as limiting the spoilage of harvested fruit and vegetables is a very challenging task. Various kinds of nanomaterials have shown high potential for increasing productivity, enhancing shelf-life, reducing post-harvest damage and improving the quality of horticultural crops. Antimicrobial nanomaterials as nanofilm on harvested products and/or on packaging materials are suitable for the storage and transportation of vegetables and fruits. Nanomaterials also increase the vitality of the cut flower. Nanofertilizers are target-specific, slow releasing and highly efficient in increasing vegetative growth, pollination and fertility in flowers, resulting in increased yield and improved product quality for fruit trees and vegetables. Formulated nanopesticides are target-specific, eco-friendly and highly efficient. Nanosensors facilitate up-to-date monitoring of growth, plant disease, and pest attack in crop plants under field conditions. These novel sensors are used to precisely identify the soil moisture, humidity, population of crop pests, pesticide residues and figure out nutrient requirements. This review aimed to provide an update on the recent advancement of nanomaterials and their potential uses for enhancing productivity, quality of products, protection from pests and reduction of the postharvest losses of the horticultural crops. This study reveals that nanotechnology could be used to generate cutting-edge techniques towards promoting productivity and quality of horticultural crops to ensure food and nutritional security of ever-increasing population of the world.

Caco-2 in vitro model of human gastrointestinal tract for studying the absorption of titanium dioxide and silver nanoparticles from seafood

Titanium dioxide nanoparticles (TiO₂ NPs) are widely used in industry as a white pigment (paints, paper industry and toothpastes), photocatalysts (environmental decontamination and photovoltaic cells), inorganic UV filter (sunscreens and personal care products) and as a food additive (E171) and antimicrobial food packaging material. Silver nanoparticles (Ag NPs) are used in photonics, microelectronics, catalysis and medicine due to their catalytic activity, magnetic and optical polarizability, electrical and thermal conductivities and enhanced Raman scattering. They also have antibacterial, antifungal and antiviral activities, as well as anti-inflammatory potential. The huge increase in the use of nano-based products, mainly metallic NPs, implies the presence of nanomaterials in the environment, and hence, the unintentional human ingestion through water or foods (gastrointestinal tract is the main pathway of NPs intake in humans). The presence of TiO₂ NPs and Ag NPs in seafood samples was firstly established using an ultrasound assisted enzymatic hydrolysis procedure and sp-ICP-MS analysis. Several clams, cockles, mussels, razor clams, oysters and variegated scallops, which contain TiO₂ NPs and Ag NPs, were subjected to an in vitro digestion process simulating human gastrointestinal digestion in the stomach and in the small and large intestine to determine the bioaccessibility of these NPs. Caco-2 cells were selected as model of human intestinal epithelium for transport studies because of the development of membrane transporters that are responsible for the uptake of chemicals. Parameters as transepithelial electrical resistance (TEER) and permeability of Lucifer Yellow were studied for establishing cell monolayer integrity. TiO₂ NPs and Ag NPs transport as well as total Ti and Ag concentrations passing through the gastrointestinal epithelial barrier model (0-2 h) were assessed by sp-ICP-MS and ICP-MS in several molluscs.

Therapeutic nanostructures and nanotoxicity

Nanotechnology, with its continuous advancement, leads to the development of nanoscale-level therapeutics to mitigate many complex diseases. This results in the emergence of numerous novel nanomaterials and its composite products into the market such as liposome, polymeric nanoparticles, dendrimers, and nanostructured lipid carrier. However, their application is always determined by a high benefit to risk ratio. Very few research have been done on the toxicity assessment of nanoparticles in the biological system; therefore, the limited knowledge regarding the toxicity profile of nanotherapeutics is available leading to the ignorance of its side effects. Nanoparticles can distribute in the whole body through translocating in the bloodstream by crossing membrane barriers efficiently and shows effect in organs and tissues at cellular and molecular levels. The interaction of nanoparticle with cell may consequences into nanotoxicity. The narrow size distribution, large surface area to mass ratio and surface properties of nanoparticle are significantly associated with nanotoxicity. Nanoparticles can enter into the tissue and cell by invading the membranes and cause cellular injury as well as toxicity. Therefore, the exploration of mechanisms of nanotoxicity has prime importance now a day. The toxicity assessment should be an integral part of the development of nanotherapeutics using various toxicity evaluation models. This review has focused on the exploration of different nanostructures for therapeutic delivery system along with its physicochemical characteristics responsible for adverse effects on human biology, various toxicity evaluation models, and environmental and regulatory hurdles.

Eco friendly silver nanoparticles synthesis by Brassica oleracea and its antibacterial, anticancer and antioxidant properties

Production of environmentally amenable silver nanoparticles (AgNPs) has garnered the interest of the scientific community owing to their broad application primarily in the field of optronics, sensing and extensively in pharmaceuticals as promising antioxidant, antimicrobial and anticancer agents. The current study emphases on production of ecofriendly silver nanoparticles from Brassica oleracea (BO) and investigated their antibacterial, anticancer and antioxidant activity. The characteristics of synthesized BO-AgNPs were studied by ultraviolet-visible spectroscopy, particle size analysis, electro kinetic/zeta potential analysis, and Transmission electron microscope (TEM). A distinctive absorption maximum at 400 nm confirmed the formation of BO-AgNPs and data on TEM analysis have shown that the synthesized nanoparticles were predominantly spherical in shape. The BO-AgNPs obtained were assessed for antibacterial, antioxidant, and cytotoxic ability in MCF-7 cells. The antibacterial activity expressed was maximum against Staphylococcus epidermidis (Gram positive) and Pseudomonas aeruginosa (Gram negative) with DIZ of 14.33 ± 0.57 and 12.0 ± 0.20 mm respectively. Furthermore, the ability of the synthesized green nanoparticles to scavenge free radicals revealed a strong antioxidant activity. The cytotoxicity increased proportionately with increasing concentration of the green synthesized BO-AgNPs with maximum effect at 100 μg/ml and IC50 of 55 μg/ml. In conclusion, the data obtained in the study is reflective of the role of BO-AgNPs as potential and promising antimicrobial agent against bacterial infections and potential anticancer agent in cancer therapy.

Nanoparticles and Controlled Delivery for Bioactive Compounds: Outlining Challenges for New "Smart-Foods" for Health

Nanotechnology is a field of research that has been stressed as a very valuable approach for the prevention and treatment of different human health disorders. This has been stressed as a delivery system for the therapeutic fight against an array of pathophysiological situations. Actually, industry has applied this technology in the search for new oral delivery alternatives obtained upon the modification of the solubility properties of bioactive compounds. Significant works have been made in the last years for testing the input that nanomaterials and nanoparticles provide for an array of pathophysiological situations. In this frame, this review addresses general questions concerning the extent to which nanoparticles offer alternatives that improve therapeutic value, while avoid toxicity, by releasing bioactive compounds specifically to target tissues affected by specific chemical and pathophysiological settings. In this regard, to date, the contribution of nanoparticles to protect encapsulated bioactive compounds from degradation as a result of gastrointestinal digestion and cellular metabolism, to enable their release in a controlled manner, enhancing biodistribution of bioactive compounds, and to allow them to target those tissues affected by biological disturbances has been demonstrated.

Iron oxide nanoparticles induced cytotoxicity, oxidative stress and DNA damage in lymphocytes

Over the past few decades nanotechnology and material science has progressed extremely rapidly. Iron oxide nanoparticles (IONPs) owing to their unique magnetic properties have a great potential for their biomedical and bioengineering applications. However, there is an inevitable need to address the issue of safety and health effects of these nanoparticles. Hence, the present study was aimed to assess the cytotoxic effects of IONPs on rats' lymphocytes. Using different assays, we studied diverse parameters including mitochondrial membrane potential, intracellular accumulation of reactive oxygen species (ROS), lactate dehydrogenase activity, antioxidant enzymes activity and DNA damage measurements. Intracellular metal uptake and ultrastructure analysis were also carried out through inductively coupled plasma atomic emission spectroscopy, transmission electron microscopy respectively. The results show that the IONP-induced oxidative stress was concentration-dependent in nature, with significant (P < 0.05) increase in ROS levels, lipid peroxidation level as well as depletion of antioxidant enzymes and glutathione. Moreover, we observed morphological changes in the cell after intracellular uptake and localization of nanoparticles in cells. From the findings of the study, it may be concluded that IONPs induce ROS-mediated cytotoxicity in lymphocytes. Copyright © 2017 John Wiley & Sons, Ltd.

Engineered nanoparticles of titanium dioxide (TIO2): Uptake and biological effects in a sea bass cell line

With the rapid development of nanotechnology there has been a corresponding increase in the application of titanium dioxide nanoparticles (TiO₂-NPs) in various consumer and industrial products, consequently their potential health hazards and environmental effects are considered an aspect of great concern. In the present study, in order to assess the impact of TiO₂-NPs in the marine environment, the biological effects of TiO₂-NPs on a sea bass cell line (DLEC) were investigated. Cells were exposed for 24 h to different concentrations of TiO₂-NPs (1, 8, 40, 200 and 1000 μg/ml) or co-exposed with CdCl₂ (Cd). The effects of UV light irradiation were also investigated in cells treated with TiO₂-NPs and/or Cd. The internalization of TiO₂-NPs and the morphological cell modifications induced by the treatments were examined by transmission and scanning electron microscopy, this latter coupled with energy dispersive X-ray spectroscopy (EDS) for particle element detection. In addition, the effects of controlled exposures were studied evaluating the cytotoxicity, the DNA damage and the expression of inflammatory genes. Our study indicates that TiO₂-NPs were localized on the cell surface mainly as agglomerates revealed by EDS analysis and that they were uptaken by the cells inducing morphological changes. Photoactivation of TiO₂-NPs and/or co-exposure with Cd affects ATP levels and it contributes to induce acute cellular toxicity in DLEC cells dependent on Ti concentration. The inflammatory potential and the DNA damage, this latter displayed through a caspase-3 independent apoptotic process, were also demonstrated. Overall our data suggest that the interaction of TiO₂-NPs with marine water contaminants, such as cadmium, and the UV irradiation, may be an additional threat to marine organisms.

Toxicological Concerns of Engineered Nanosize Drug Delivery Systems

Matters when converted into nanosize provide some unique surface properties, which are different from those of the bulk materials. Nanomaterials show some extraordinary behavioral patterns because of those properties, such as supermagnetism, quantum confinement, etc. A great deal of implication of nanomaterials in nanomedicine has already been realized. Utility of nanomaterials as drug nanocarrier projects many potential advantages of them in drug delivery. Despite many such advantages, the potential risk of health and environmental hazards related to them cannot be ignored. Here various physicochemical factors, such as chemical nature, degradability, surface properties, surface charge, particle size, and shape, have been shown to play a crucial role in toxicity related to drug nanocarriers. Evidence-based findings of some drug nanocarriers have been incorporated to provide distinct knowledge to the readers in the field. A glimpse of current regulatory controls and measures required to combat the challenges of toxicological aspects of drug nanocarriers have been described.

Nanotechnology-based inhalation treatments for lung cancer: state of the art

Considering the challenges associated with conventional chemotherapy, targeted and local delivery of chemotherapeutics via nanoparticle (NP) carriers to the lungs is an emerging area of interest. Recent studies and growing clinical application in cancer nanotechnology showed the huge potential of NPs as drug carriers in cancer therapy, including in lung carcinoma for diagnosis, imaging, and theranostics. Researchers have confirmed that nanotechnology-based inhalation chemotherapy is viable and more effective than conventional chemotherapy, with lesser side effects. Recently, many nanocarriers have been investigated, including liposomes, polymeric micelles, polymeric NPs, solid lipid NPs, and inorganic NPs for inhalation treatments of lung cancer. Yet, the toxicity of such nanomaterials to the lungs tissues and further distribution to other organs due to systemic absorption on inhalation delivery is a debatable concern. Here, prospect of NPs-based local lung cancer targeting through inhalation route as well as its associated challenges are discussed.

Modeling of spherical silver nanoparticles in silicone-based nanocomposites for marine antifouling

A non-toxic foul-release model of silicone/spherical AgNP hybrid nanocomposites with enhanced hydrophobicity, self-cleaning, and marine fouling release performance.

How hydrophobic nanoparticles aggregate in the interior of membranes: A computer simulation

Lipid-based dispersion of hydrophobic nanoparticles (NPs) not only gives fundamental insight into how nanomaterials distribute in live cells and organisms, but also provides a quite general route to designing nanocarrier agents in triggered drug delivery and medical imaging. It is not clearly understood how hydrophobic NPs arrange in the interior of a membrane. In this paper, with computer simulation techniques, we demonstrate that hydrophobic NPs having a diameter compared to the hydrophobic thickness of the membrane are capable of clustering in the hydrophobic interior of a cell membrane. Except from the isotropic aggregation, an unexpected linear arrangement of spherical NPs, which is still not found from experiments, is identified here. The free-energy costs associated with linear and isotropic aggregations are computed explicitly to interpret aggregation behavior and the obtained phase diagrams give us a comprehensive understanding of where linear aggregation is expected. In this work we also shows that NP size and membrane tension play key roles in determining the NP aggregate, while the effects of NP concentration and membrane curvature seem to be relatively weak.

Synthesis, characterization and toxicological evaluation of a core-shell copper oxide/polyaniline nanocomposite

The newest generation of copper oxide NPs (CuO NPs) is the CuO core-shell (CS), which has potential applications in several areas (e.g., electronics and paint) and is able to provide a greater service life due to its coating; however, its toxicity is not fully understood. The objective of this study was to synthesize, characterize and evaluate the aquatic toxicology of CuO NPs and CuO core-shells through acute and chronic toxicity tests with the freshwater microcrustaceans Daphnia magna and to evaluate its acute toxicity with the marine bioluminescent bacteria Vibrio fischeri. The NPs were synthesized by direct thermal decomposition after being coated as a CS with polyaniline (PANI). With respect to acute toxicity with D. magna, the CuO NPs and CS CuO/PANI presented EC50 values of 0.32 mg L(-1) and 0.48 mg L(-1), respectively. For the tests with V. fischeri, the CuO NPs (EC50-15 min=7.79 mg L(-1)) exhibited behavior similar to that of the CS CuO/PANI (EC50-15 min=9.05 mg L(-1)) after 15 min of exposure. Regarding chronic toxicity, both forms showed a statistically significant effect (p<0.05) on the growth and reproduction parameters. Based on the characterization and toxicity results, it can be concluded that both forms of CuO were toxic and presented similar behaviors during the acute tests; however, after 21 d of exposure, CS CuO/PANI showed higher toxicity to the reproduction parameter, highlighting the importance of a complete study of the NP to better understand its toxicity mechanism.

Evaluation of toxicity and oxidative stress induced by copper oxide nanoparticles in the green alga Chlamydomonas reinhardtii

Copper oxide nanoparticles (CuO NP) are frequently employed for their antimicrobial properties in antifouling paints. Their extensive use can contaminate aquatic ecosystems. However, the toxicological effects of this NP in the environment are poorly known. In this study, we evaluated the toxicity and oxidative stress induced by CuO NP on Chlamydomonas reinhardtii using several toxicological assays. CuO NP was found to induce growth inhibition and a significant decrease in carotenoids levels. From data on cells density after 72 h of CuO NP exposure in light, the EC50 value was calculated to be 150.45±1.17 mg L(-1) and the NOEC≤100 mg L(-1). Evaluation of esterase activity demonstrates a decrease in cell metabolism activity with the increase of CuO NP concentration. The CuO NP induced an increase of reactive species level (190±0.45% at 1000 mg L(-1) after 72 h of exposition, compared to control) and lipid peroxidation of cellular membranes (73±2% at 1000 mg L(-1) of CuO NP in 72 h of exposition, compared to control). Investigation of CuO NP uptake showed the presence of NP into C. reinhardtii cells in different sites of the cell and, biomarkers of enzymatic antioxidants showed a change of activity after CuO NP exposition. In conclusion, C. reinhardtii was shown to be sensitive to the presence of CuO NP in their environment and CuO NP treatments induced a toxic response from 0.1 mg L(-1) after 72 h of treatment.

Toxicity and bio-accumulation of inhaled cerium oxide nanoparticles in CD1 mice

Male CD1 mice were subjected to nose-inhalation exposure of CeO2 nanoparticles (NPs) for 0, 7, 14 or 28 days with 14 or 28 days of recovery time at an aerosol concentration of 2 mg/m(3). Markers of lung injury and pro-inflammatory cytokines (interleukin-1beta, tumour necrosis factor-alpha, interleukin-6 and macrophage inflammatory protein-2) in bronchoalveolar lavage fluid (BALF), oxidative stress in lungs, bio-accumulation, and histopathology of pulmonary and extrapulmonary tissues were assessed. BALF analysis revealed the induction of pulmonary inflammation, as evident by an increase in the influx of neutrophils with a significant secretion of pro-inflammatory cytokines that lead to generation of oxidative stress and cytotoxicity, as is evident by induction of lipid peroxidation, depletion of glutathione and increased BALF lactate dehydrogenase and protein. The histopathological examination revealed that these inhaled CeO2 NPs were located all over the pulmonary parenchyma, inducing a severe, chronic, active inflammatory response characterised by necrosis, proteinosis, fibrosis and well-formed discrete granulomas in the pulmonary tissue and tubular degeneration leading to coagulative necrosis in kidneys. Inductively coupled plasma optical emission spectrometer results showed a significant bio-accumulation of these particles in the pulmonary and extrapulmonary tissues, even after one month of post-inhalation exposure. Together, these findings suggest that inhalation exposure of CeO2 NPs can induce pulmonary and extrapulmonary toxicity.

Nanotoxicity of Magnesium Oxide on Human Neuroblastoma SH-SY5Y Cell Lines

The use of magnesium oxide (MgO) nanoparticles in industrial applications has been raised over the last decade. However, there is limited toxicology information available regarding the effects of MgO nanoparticles. In this study, cytotoxicity and neurotoxicity of this nanoparticle on SH-SY5Y cell lines was investigated. In order to assess the cytotoxicity effect, SH-SY5Y cells were exposed to three different types of MgO nanoparticles (MgO 5, MgO 10 and MgO 24) for 24, 48 and 72 h. The concentration of nanoparticles ranges from 1nM to 1mM. Cell viability was determined by MTS assay. Neurotoxicity test was performed to determine the effects of MgO nanoparticles on human neural cells. Results indicated that MgO nanoparticles are not toxic to both undifferentiated and differentiated SH-SY5Y cells. With further exploration, the safety and health concern regarding exposure of MgO nanoparticles can be verified since the increasing of using this nanoparticle in industry over the time.

Health hazards associated with nanomaterials

Nanotechnology is a major scientific and economic growth area and presents a variety of hazards for human health and environment. It is widely believed that engineered nanomaterials will be increasingly used in biomedical applications (as therapeutics and as diagnostic tools). However, before these novel materials can be safely applied in a clinical setting, their toxicity needs to be carefully assessed. Nanoscale materials often behave different from the materials with a larger structure, even when the basic material is same. Many mammals get exposed to these nanomaterials, which can reach almost every cell of the mammalian body, causing the cells to respond against nanoparticles (NPs) resulting in cytotoxicity and/or genotoxicity. The important key to understand the toxicity of nanomaterials is that their minute size, smaller than cellular organelles, allows them to penetrate the basic biological structures, disrupting their normal function. There is a wealth of evidence for the noxious and harmful effects of engineered NPs as well as other nanomaterials. The rapid commercialization of nanotechnology field requires thoughtful, attentive environmental, animal and human health safety research and should be an open discussion for broader societal impacts and urgent toxicological oversight action. While ‘nanotoxicity’ is a relatively new concept to science, this comprehensive review focuses on the nanomaterials exposure through the skin, respiratory tract, and gastrointestinal tract and their mechanism of toxicity and effect on various organs of the body.

Polyaniline nanofibers: acute toxicity and teratogenic effect on Rhinella arenarum embryos

The fate and effect of nanomaterials in the environment is of paramount importance towards the technological application of the materials. This work shows the ecotoxicological potential of polyaniline (PANI) nanofibers in the larvae Rhinella arenarum by means of AMPHITOX test. Acute toxicity of PANI nanofibers towards embryos of the common South American toad R. arenarum (Anura: bufonidae) was evaluated in the premetamorphosis (stage 25) larvae. The exposure of R. arenarum larvae to at dose of 150, 250 and 400 mg L(-1) resulted in 100% viability within 96 h exposure. The embryos at 2-4 blastomers stage (early life stage teratogenic test) revealed that embryos were not killed and no teratogenic effects were observed when embryos were incubated with PANI nanofibers (150 and 250 mg L(-1)), while only a growth retardation of embryos was induced at levels of 250 mg PANI nanofibers L(-1). On the other hand, at 400 mg L(-1) concentration, a reduction in the body length of larvae and tail malformation was observed. This results suggest that a concentration-dependent toxicity is operative, typified by phenotypes that had abnormal body axes. The presence of PANI nanofibers in gut contents and its excretion by larval stages of R. arenarum was confirmed by UV-visible spectroscopy.

Layer-by-layer capsules for magnetic resonance imaging and drug delivery

Layer-by-layer (LbL) self-assembled polyelectrolyte capsules have demonstrated their unique advantages and capability in drug delivery applications. These ordered micro/nano-structures are also promising candidates as imaging contrast agents for diagnostic and theranostic applications. Magnetic resonance imaging (MRI), one of the most powerful clinical imaging modalities, is moving forward to the molecular imaging field and requires the availability of advanced imaging probes. In this review, we are focusing on the design of MRI visible LbL capsules, which incorporate either paramagnetic metal-ligand complexes or superparamagnetic iron oxide (SPIO) nanoparticles. The design criteria cover the topics of probe sensitivity, biosafety, long-circulation property, targeting ligand decoration, and drug loading strategies. Examples of MRI visible LbL capsules with paramagnetic or superparamagnetic moieties were given and discussed. This carrier platform can also be chosen for other imaging modalities.

Stability and in vivo evaluation of pullulan acetate as a drug nanocarrier

To develop pullulan acetate nanoparticles (PANs) as a drug nanocarrier, pullulan acetate (PA) was synthesized and characterized. Its acetylation degree determined by the proton nuclear magnetic resonance ((1)H NMR) was 2.6. PANs were prepared by the solvent diffusion method and characterized by transmission electron microscope (TEM), size distribution, and zeta potential techniques. PANs had nearly spherical shape with a size range of 200-450 nm and low zeta potentials both in distilled water and in 10% FBS. The storage stability of PANs was observed in distilled water. PANs were stored for at least 2 months with no significant size and zeta potential changes. The safety of PANs was studied through single dose toxicity test in mice, and the result showed that PANs were well tolerated at the dose of 200 mg/kg in mice. Epirubicin-loaded PANs (PA/EPI) were also prepared and characterized in this study. Moreover, the in vivo pharmacokinetics of PA/EPI was investigated. Compared with the free EPI group, the PA/EPI group exhibited higher plasma drug concentration, longer half-life time (t(1/2)) and the larger area under the curve (AUC). All results suggested that PANs were stable, safe, and showed a promising potential on improving the bioavailability of the loaded drug of the encapsulated drug.

Copper nanoparticles exert size and concentration dependent toxicity on somatosensory neurons of rat

Metal nanoparticles, due to their unique properties and important applications in optical, magnetic, thermal, electrical, sensor devices and cosmetics, are beginning to be widely manufactured and used. This new and rapidly growing field of technology warrants a thorough examination of the material's bio-compatibility and safety. Ultra-small particles may adversely affect living cells and organisms since they can easily penetrate the body through skin contact, inhalation and ingestion. Retrograde transport of copper nanoparticles from nerve endings on the skin can reach the somatosensory neurons in dorsal root ganglion (DRG). Since copper nanoparticles have industrial and healthcare applications, we determined the concentration and size-dependant effects of their exposure on survival of DRG neurons of rat in cell culture. The neurons were exposed to copper nanoparticles of increasing concentrations (10-100 muM) and sizes (40, 60 and 80 nm) for 24 h. Light microscopy, histochemical staining for copper, lactate dehydrogenase (LDH) assay for cell death, and MTS [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay for cell viability were performed to measure the resultant toxicity and cell survival. DRG neurons exposed to copper nanoparticles displayed vacuoles and detachment of some neurons from the substratum. Neurons also exhibited disrupted neurite network. LDH and MTS assays revealed that exposure to copper nanoparticles had significant toxic effect with all the sizes tested when compared to unexposed control cultures. Further analysis of the results showed that copper nanoparticles of smaller size and higher concentration exerted the maximum toxic effects. Rubeanic acid staining showed intracellular deposition of copper. These results demonstrate that copper nanoparticles are toxic in a size- and concentration-dependent manner to DRG neurons.

Toxicity assessments of multisized gold and silver nanoparticles in zebrafish embryos

The potential toxicity of nanoparticles is addressed by utilizing a putative attractive model in developmental biology and genetics: the zebrafish (Danio rerio). Transparent zebrafish embryos, possessing a high degree of homology to the human genome, offer an economically feasible, medium-throughput screening platform for noninvasive real-time assessments of toxicity. Using colloidal silver (cAg) and gold nanoparticles (cAu) in a panoply of sizes (3, 10, 50, and 100 nm) and a semiquantitative scoring system, it is found that cAg produces almost 100% mortality at 120 h post-fertilization, while cAu produces less than 3% mortality at the same time point. Furthermore, while cAu induces minimal sublethal toxic effects, cAg treatments generate a variety of embryonic morphological malformations. Both cAg and cAu are taken up by the embryos and control experiments, suggesting that cAg toxicity is caused by the nanoparticles themselves or Ag(+) that is formed during in vivo nanoparticle destabilization. Although cAg toxicity is slightly size dependent at certain concentrations and time points, the most striking result is that parallel sizes of cAg and cAu induce significantly different toxic profiles, with the former being toxic and the latter being inert in all exposed sizes. Therefore, it is proposed that nanoparticle chemistry is as, if not more, important than specific nanosizes at inducing toxicity in vivo. Ultimately such assessments using the zebrafish embryo model should lead to the identification of nanomaterial characteristics that afford minimal or no toxicity and guide more rational designs of materials on the nanoscale.

Zebrafish as a correlative and predictive model for assessing biomaterial nanotoxicity

The lack of correlative and predictive models to assess acute and chronic toxicities limits the rapid pre-clinical development of new therapeutics. This barrier is due in part to the exponential growth of nanotechnology and nanotherapeutics, coupled with the lack of rigorous and robust screening assays and putative standards. It is a fairly simple and cost-effective process to initially screen the toxicity of a nanomaterial by using invitro cell cultures; unfortunately it is nearly impossible to imitate a complimentary invivo system. Small mammalian models are the most common method used to assess possible toxicities and biodistribution of nanomaterials in humans. Alternatively, Daniorerio, commonly known as zebrafish, are proving to be a quick, cheap, and facile model to conservatively assess toxicity of nanomaterials.

Acute Toxicity and Tissue Distribution of Cerium Oxide Nanoparticles by a Single Oral Administration in Rats

Cerium oxide nanoparticles (size: 30 nm) were prepared by the supercritical synthesis method, Acute oral toxicity and tissue distribution of the nanoparticles were evaluated by a single administration in rats. Oral administration of the nanoparticles to the rats did not lead to death when the animals were treated by a dose of 5 g/kg (high dose) as well as 100 mg/kg (low dose). Abnormal clinical signs, changes in serum biochemistry and hematology were not observed in high-dose treated group compared to the vehicle control group. Lesions in liver, lung and kidney were not observed in high-dose treated group by histopathological examination. Tissue distribution analysis in liver, kidney, spleen, lung, testis and brain was performed on day 1, day 7 and day 14 after treatment. The average values of the accumulated cerium oxide nanoparticles were elevated in all tissues but statistical significance was only shown in lung. Low levels of tissue distributions after a single oral administration seem to be the low bioavailability of the nanoparticles.

On the toxicity of therapeutically used nanoparticles: an overview

Human beings have been exposed to airborne nanosized particles throughout their evolutionary stages, and such exposures have increased dramatically over the last century. The rapidly developing field of nanotechnology will result in new sources of this exposure, through inhalation, ingestion, and injection. Although nanomaterials are currently being widely used in modern technology, there is a serious lack of information concerning the human health and environmental implications of manufactured nanomaterials. Since these are relatively new particles, it is necessary to investigate their toxicological behavior. The objective of this review was to trace the cellular response to nanosized particle exposure. Therapeutic application of selected nanoparticles together with their range of toxic doses was also reviewed. Effect of therapeutically used nanoparticles on cell membrane, mitochondrial function, prooxidant/antioxidant status, enzyme leakage, DNA, and other biochemical endpoints was elucidated. This paper highlights the need for caution during the use and disposal of such manufactured nanomaterials to prevent unintended environmental impacts.