Interactions Of Engineered Nanomaterials Research Articles

The impacts of metal-based engineered nanomaterial mixtures on microbial systems: A review.

The last decade has witnessed tremendous growth in the commercial use of metal-based engineered nanomaterials (ENMs) for a wide range of products and processes. Consequently, direct and indirect release into environmental systems may no longer be considered negligible or insignificant. Yet, there is an active debate as to whether there are real risks to human or ecological health with environmental exposure to ENMs. Previous research has focused primarily on the acute effects of individual ENMs using pure cultures under controlled laboratory environments, which may not accurately reveal the ecological impacts of ENMs under real environmental conditions. The goal of this review is to assess our current understanding of ENM effects as we move from exposure of single to multiple ENMs or microbial species. For instance, are ENMs' impacts on microbial communities predicted by their intrinsic physical or chemical characteristics or their effects on single microbial populations; how do chronic ENM interactions compare to acute toxicity; does behavior under simplified laboratory conditions reflect that in environmental media; finally, is biological stress modified by interactions in ENM mixtures relative to that of individual ENM? This review summarizes key findings and our evolving understanding of the ecological effects of ENMs under complex environmental conditions on microbial systems, identifies the gaps in our current knowledge, and indicates the direction of future research.

The Era of Nanomaterials: A Safe Solution or a Risk for Marine Environmental Pollution?

In recent years, the application of engineered nanomaterials (ENMs) in environmental remediation gained increasing attention. Due to their large surface area and high reactivity, ENMs offer the potential for the efficient removal of pollutants from environmental matrices with better performances compared to conventional techniques. However, their fate and safety upon environmental application, which can be associated with their release into the environment, are largely unknown. It is essential to develop systems that can predict ENM interactions with biological systems, their overall environmental and human health impact. Until now, Life-Cycle Assessment (LCA) tools have been employed to investigate ENMs potential environmental impact, from raw material production, design and to their final disposal. However, LCA studies focused on the environmental impact of the production phase lacking information on their environmental impact deriving from in situ employment. A recently developed eco-design framework aimed to fill this knowledge gap by using ecotoxicological tools that allow the assessment of potential hazards posed by ENMs to natural ecosystems and wildlife. In the present review, we illustrate the development of the eco-design framework and review the application of ecotoxicology as a valuable strategy to develop ecosafe ENMs for environmental remediation. Furthermore, we critically describe the currently available ENMs for marine environment remediation and discuss their pros and cons in safe environmental applications together with the need to balance benefits and risks promoting an environmentally safe nanoremediation (ecosafe) for the future.

MESOCOSM: A mesocosm database management system for environmental nanosafety

Engineered nanomaterials (ENMs) are intentionally designed and produced by humans to revolutionize the manufacturing sector, such as electronic goods, paints, tires, clothes, cosmetic products, and biomedicine. With the spread of these ENMs in our daily lives, scientific research have generated a huge amount of data related to their potential impacts on human and environment health. To date, these data are gathered in databases mainly focused on the (eco)toxicity and occupational exposure to ENMs. These databases are therefore not suitable to build well-informed environmental exposure scenarios covering the life cycle of ENMs. In this paper, we report the construction of one of the first centralized mesocosm database management system for environmental nanosafety (called MESOCOSM) containing experimental data collected from mesocosm experiments suited for understanding and quantifying both the environmental hazard and exposure. The database, which is publicly available through https://aliayadi.github.io/MESOCOSM-database/, contains 5200 entities covering tens of unique experiments investigating Ag, CeO2, CuO, TiO2-based ENMs as well as nano-enabled products. These entities are divided into different groups i.e. physicochemical properties of ENMS, environmental, exposure and hazard endpoints, and other general information about the mesocosm testing, resulting in more than forty parameters in the database. The MESOCOSM database is equipped with a powerful application, consisting of a graphical user interface (GUI), allowing users to manage and search data using complex queries without relying on programmers. MESOCOSM aims to predict and explain ENMs behavior and fate in different ecosystems as well as their potential impacts on the environment at different stages of the nanoproducts lifecycle. MESOCOSM is expected to benefit the nanosafety community by providing a continuous source of critical information and additional characterization factors for predicting ENMs interactions with the environment and their risks.

Advanced In Vitro Testing Strategies and Models of the Intestine for Nanosafety Research.

There is growing concern about the potential adverse effects of oral exposure to engineered nanomaterials (ENM). Recent years have witnessed major developments in and advancement of intestinal in vitro models for nanosafety evaluation. The present paper reviews the key factors that should be considered for inclusion in nonanimal alternative testing approaches to reliably reflect the in vivo dynamics of the physicochemical properties of ENM as well the intestinal physiology and morphology. Currently available models range from simple cell line-based monocultures to advanced 3D systems and organoids. In addition, in vitro approaches exist to replicate the mucous barrier, digestive processes, luminal flow, peristalsis, and interactions of ENM with the intestinal microbiota. However, while the inclusion of a multitude of individual factors/components of particle (pre)treatment, exposure approach, and cell model approximates in vivo-like conditions, such increasing complexity inevitably affects the system's robustness and reproducibility. The selection of the individual modules to build the in vitro testing strategy should be driven and justified by the specific purpose of the study and, not least, the intended or actual application of the investigated ENM. Studies that address health hazards of ingested ENM likely require different approaches than research efforts to unravel the fundamental interactions or toxicity mechanisms of ENM in the intestine. Advanced reliable and robust in vitro models of the intestine, especially when combined in an integrated testing approach, offer great potential to further improve the field of nanosafety research.

Physical Properties of Carbon Nanomaterials and Nanoceria Affect Pathways Important to the Nodulation Competitiveness of the Symbiotic N2 -Fixing Bacterium Bradyrhizobium diazoefficiens.

The pathogenicity and antimicrobial properties of engineered nanomaterials (ENMs) are relatively well studied. However, less is known regarding the interactions of ENMs and agriculturally beneficial microorganisms that affect food security. Nanoceria (CeO2 nanoparticles (NPs)), multiwall carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), and carbon black (CB) have been previously shown to inhibit symbiotic N2 fixation in soybeans, but direct rhizobial susceptibility is uncertain. Here, Bradyrhizobium diazoefficiens associated with symbiotic N2 fixation in soybeans is assessed, evaluating the role of soybean root exudates (RE) on ENM-bacterial interactions and the effects of CeO2 NPs, MWCNTs, GNPs, and CB on bacterial growth and gene expression. Although bacterial growth is inhibited by 50 mg L-1 CeO2 NPs, MWCNTs, and CB, all ENMs at 0.1 and 10 mg L-1 cause a global transcriptomic response that is mitigated by RE. ENMs may interfere with plant-bacterial signaling, as evidenced by suppressed upregulation of genes induced by RE, and downregulation of genes encoding transport RNA, which facilitates nodulation signaling. MWCNTs and CeO2 NPs inhibit the expression of genes conferring B. diazoefficiens nodulation competitiveness. Surprisingly, the transcriptomic effects on B. diazoefficiens are similar for these two ENMs, indicating that physical, not chemical, ENM properties explain the observed effects.

Ligands and media impact interactions between engineered nanomaterials and clay minerals

The exponential growth in technologies incorporating engineered nanomaterials (ENMs) requires plans to handle waste ENM disposal and accidental environmental release throughout the material life cycle. These scenarios motivate efforts to quantify and model ENM interactions with diverse background particles and solubilized chemical species in a variety of environmental systems. In this study, quantum dot (QD) nanoparticles and clay minerals were mixed in a range of water chemistries in order to develop simple assays to predict aggregation trends. CdSe QDs were used as a model ENM functionalized with either negatively charged or zwitterionic small molecule ligand coatings, while clays were chosen as an environmentally relevant sorbent given their potential as an economical water treatment technology and ubiquitous presence in nature. In our unbuffered experimental systems, clay type impacted pH, which resulted in a change in zwitterionic ligand speciation that favored aggregation with kaolinite more than with montmorillonite. With kaolinite, the zwitterionic ligand-coated QD exhibited greater than ten times the relative attachment efficiency for QD-clay heteroaggregation compared to the negatively charged ligand coated QD. Under some conditions, particle oxidative dissolution and dynamic sorption of ions and QDs to surfaces complicated the interpretation of the removal kinetics. This work demonstrates that QDs stabilized by small molecule ligands and electrostatic surface charges are highly sensitive to changes in water chemistry in complex media. Natural environments enable rapid dynamic physicochemical changes that will influence the fate and mobility of ENMs, as seen by the differential adsorption of water-soluble QDs to our clay media.

Mechanisms involved in the impact of engineered nanomaterials on the joint toxicity with environmental pollutants

Emerging nanoscience and nanotechnology inevitably facilitate discharge of engineered nanomaterials (ENMs) into the environment. Owing to their versatile physicochemical properties, ENMs invariably come across and interact with various pollutants already existing in the environment, leading to considerable uncertainty regarding the risk assessment of pollutants. Nevertheless, the underlying mechanisms of the complicated joint toxicity are still largely unexplored. This review aims to aid in understanding the interaction of ENMs and pollutants from the perspective of ecological and environmental health risk assessment. Based on related research published from 2005 to 2018, this review focuses on summarizing the effect of ENMs on the toxicity of pollutants both in vivo and in vitro. Physicochemical interaction appears as a main factor affecting ENMs-pollutants joint toxicity, with the mechanisms and the resultants for ENM-pollutant adsorption been illustrated. Cellular and molecular mechanisms involved in the joint toxicity of ENMs and pollutants are discussed, including the effect of ENMs on the bioaccumulation, biodistribution, and metabolism of pollutants, as well as the defense responses of organisms against such pollutants. Future in-depth investigation are suggested to focus on further exploring biological mechanisms (especially for the antagonized effect of ENMs against pollutants), using more advanced mammalian models, and paying more attention to the realistic exposure scenarios.

Assessing plant uptake and transport mechanisms of engineered nanomaterials from soil

Abstract

Chemical basis of interactions between engineered nanoparticles and biological systems.

Chemical basis of interactions between engineered nanoparticles and biological systems.

From Immunotoxicity to Nanotherapy: The Effects of Nanomaterials on the Immune System

The potential for human exposure to the diverse and ever-changing world of nanoscale materials has raised concerns about their influence on health and disease. The novel physical and chemical properties of these materials, which are associated with their small size, complicate toxicological evaluations. Further, these properties may make engineered nanomaterials (ENMs) a prime target for interaction with the immune system following uptake by phagocytes. Undesired effects on antigen-presenting cells and other phagocytic cells are of concern due to the high likelihood of ENM uptake by these cells. In addition, ENM interactions with lymphocytes and other cell types can contribute to a varied spectrum of possible effects, including inflammation, hypersensitivity, and immunomodulation. Furthermore, the mast cell (a type of immune cell traditionally associated with allergy) appears to contribute to certain inflammatory and toxic effects associated with some ENMs. Although incidental exposure may be undesirable, nanomedicines engineered for various clinical applications provide opportunities to develop therapies that may or may not intentionally target the immune system. The interaction between ENMs and the immune system and the resulting pharmacokinetic and phenotypic responses are critical factors that dictate the balance between toxicity and clinical efficacy of nanotherapeutics.

Nano GO Consortium—A Team Science Approach to Assess Engineered Nanomaterials: Reliable Assays and Methods

Nano GO Consortium—A Team Science Approach to Assess Engineered Nanomaterials: Reliable Assays and Methods

Interactions of engineered nanomaterials in physiological media and implications for in vitro dosimetry

In vitro toxicity assays are efficient and inexpensive tools for screening the increasing number of engineered nanomaterials (ENMs) entering the consumer market. However, the data produced by in vitro studies often vary substantially among different studies and from in vivo data. In part, these discrepancies may be attributable to lack of standardisation in dispersion protocols and inadequate characterisation of particle–media interactions which may affect the particle kinetics and the dose delivered to cells. In this study, a novel approach for preparation of monodisperse, stabilised liquid suspensions is presented and coupled with a numerical model which estimates delivered dose values. Empirically derived material- and media-specific functions are presented for each media–ENM system that can be used to convert administered doses to delivered doses. The interactions of ENMs with a variety of physiologic media were investigated and the importance of this approach was demonstrated by in vitro cytotoxicity assays using THP-1 macrophages.

A novel comprehensive evaluation platform to assess nanoparticle toxicity in vitro

The amount of engineered nanomaterials (ENM) is constantly increasing. Their unique properties, compared to their bulk counterparts, render them suitable for various applications in many areas of life. Hence, nanomaterials appear in a variety of different consumer products leading to the exposure of human beings and the environment during their lifecycle. Even though results on biological effects of ENM are available, harmonized and validated test systems are still missing. One major problem concerning the reliable and robust toxicity testing arises from interactions of ENM with different assay systems. Modifications or damage to DNA can have fatal consequences, such as the formation of tumor cells and hence carcinogenesis. Therefore we focused on the re-evaluation of two genotoxicity assays concerning their nanomaterial compatibility; namely the cytokinesis-block micronucleus cytome assay (MN-assay) and the alkaline single cell gel electorphoresis assay (comet assay). We demonstrate the interference of ENM agglomerates with the read-out of both assays and discuss possibilities how to acquire relevant genotoxicity data.

The Need for Novel Approaches in Ecotoxicity of Engineered Nanomaterials

The discovery of new diverse and novel applications for engineered nanomaterials (ENMs) creates possibilities of inadvertent release in the environment. The interactions of ENMs with living systems and possible impact/adverse effects cannot be predicted due to novel size and physiochemical properties. The biological variability, dose dilemma, exposure methods, lack of suitable models and reference materials are certain important constraints in risk assessment of ENPs. Hence, we have explored the efficacy of microorganisms as models to understand uptake, accumulation and mechanism of adverse effects induced by selected nanoparticles.

Maximizing safe design of engineered nanomaterials: the NIH and NIEHS research perspective

Estimating potential risk of an emerging technology as its products are being developed offers the greatest potential for success of the technology. The National Nanotechnology Initiative was launched in 2000 to provide a federal framework to support safe and responsible development of nanotechnology.Within this framework, the National Institutes of Health (NIH) focuses resources and expertise on both the biomedical applications of nanotechnology and the possibility of adverse health effects, or implications research. NIH developed the NanoHealth and Safety Enterprise Initiative by identifying shared research needs across the nanotechnology applications and implications research communities to create an integrated research strategy to maximize resources and expedite the development of engineered nanomaterials (ENM) that are safe by design. The central goal of this program is to decipher the fundamental principles of ENM interactions with biological systems that are relevant to human exposure and physiological response. Program components include materials science, basic biology, pathobiology, and informatics, as well as a cross-disciplinary training program for new nanotechnology scientists. The magnitude of this program will be best supported by flexible, dynamic funding and research mechanisms including the formation of public-private partnerships that span the expertise and interests of government, industry, academia, public interest, and other stakeholders. It is through such innovative, integrated, and cross-disciplinary programs that the full promise of nanotechnology may be realized while ensuring that this emerging field does not succumb to hidden perils.