Safe(r)-by-design principles in the thermoplastics industry: guidance on release assessment during manufacture of nano-enabled products.

Background: The application of nanomaterials (NMs) and nano-enabled products (NEPs) across many industries has been extensive and is still expanding decades after first being identified as an emerging technology. Additive manufacturing has been greatly impacted and has seen the benefits of integrating NMs within products. With the expansion of nanotechnology, there has been a need to develop more adaptive and responsive methods to ascertain risks and ensure technology is developed safely.

Improving the dichloro-dihydro-fluorescein (DCFH) assay for the assessment of intracellular reactive oxygen species formation by nanomaterials.

To facilitate Safe and Sustainable by Design (SSbD) strategies during the development of nanomaterials (NMs), quick and easy in vitro assays to test for hazard potential at an early stage of NM development are essential. The formation of reactive oxygen species (ROS) and the induction of oxidative stress are considered important mechanisms that can lead to NM toxicity. In vitro assays measuring oxidative stress are therefore commonly included in NM hazard assessment strategies.

A comparison of dermal toxicity models; assessing suitability for safe(r)-by-design decision-making and for screening nanomaterial hazards.

The objective of Safe-by-Design (SbD) is to support the development of safer products and production processes, and enable safe use throughout a materials' life cycle; an intervention at an early stage of innovation can greatly benefit industry by reducing costs associated with the development of products later found to elicit harmful effects. Early hazard screening can support this process, and is needed for all of the expected nanomaterial exposure routes, including inhalation, ingestion and dermal. In this study, we compare in vitro and ex vivo cell models that represent dermal exposures (including HaCaT cells, primary keratinocytes, and reconstructed human epidermis (RhE)), and when possible consider these in the context of regulatory accepted OECD TG for in vitro dermal irritation.

The State of the Art and Challenges of In Vitro Methods for Human Hazard Assessment of Nanomaterials in the Context of Safe-by-Design.

The Safe-by-Design (SbD) concept aims to facilitate the development of safer materials/products, safer production, and safer use and end-of-life by performing timely SbD interventions to reduce hazard, exposure, or both. Early hazard screening is a crucial first step in this process. In this review, for the first time, commonly used in vitro assays are evaluated for their suitability for SbD hazard testing of nanomaterials (NMs).

Establishing relationships between particle-induced in vitro and in vivo inflammation endpoints to better extrapolate between in vitro markers and in vivo fibrosis.

Background: Toxicity assessment for regulatory purposes is starting to move away from traditional in vivo methods and towards new approach methodologies (NAM) such as high-throughput in vitro models and computational tools. For materials with limited hazard information, utilising quantitative Adverse Outcome Pathways (AOPs) in a testing strategy involving NAM can produce information relevant for risk assessment. The aim of this work was to determine the feasibility of linking in vitro endpoints to in vivo events, and moreover to key events associated with the onset of a chosen adverse outcome to aid in the development of NAM testing strategies.

Integrated approaches to testing and assessment for grouping nanomaterials following dermal exposure.

Exposure to different nanoforms (NFs) the dermal route is expected in occupational and consumer settings and thus it is important to assess their dermal toxicity and the contribution of dermal exposure to systemic bioavailability. We have formulated four grouping hypotheses for dermal toxicity endpoints which allow NFs to be grouped to streamline and facilitate risk assessment. The grouping hypotheses are developed based on insight into how physicochemical properties of NFs (i.

Bayesian based similarity assessment of nanomaterials to inform grouping.

Nanoforms can be manufactured in plenty of variants by differing their physicochemical properties and toxicokinetic behaviour which can affect their hazard potential. To avoid testing of each single nanomaterial and nanoform variation and subsequently save resources, grouping and read-across strategies are used to estimate groups of substances, based on carefully selected evidence, that could potentially have similar human health and environmental hazard impact. A novel computational similarity method is presented aiming to compare dose-response curves and identify sets of similar nanoforms.

Development of a standard operating procedure for the DCFH-DA acellular assessment of reactive oxygen species produced by nanomaterials.

Improved strategies are required for testing nanomaterials (NMs) to make hazard and risk assessment more efficient and sustainable. Including reduced reliance on animal models, without decreasing the level of human health protection. Acellular detection of reactive oxygen species (ROS) may be useful as a screening assay to prioritize NMs of high concern.

Simulated biological fluids - a systematic review of their biological relevance and use in relation to inhalation toxicology of particles and fibres.

The use of simulated biological fluids (SBFs) is a promising technique to better understand the release mechanisms and possible behaviour of materials, including fibres, metal-containing particles and nanomaterials. Applications of SBFs in dissolution tests allow a measure of material biopersistence or, conversely, bioaccessibility that in turn can provide a useful inference of a materials biodistribution, its acute and long-term toxicity, as well as its pathogenicity. Given the wide range of SBFs reported in the literature, a review was conducted, with a focus on fluids used to replicate environments that may be encountered upon material inhalation, including extracellular and intracellular compartments.

A Method to Assess the Relevance of Nanomaterial Dissolution During Reactivity Testing.

The reactivity of particle surfaces can be used as a criterion to group nanoforms (NFs) based on similar potential hazard. Since NFs may partially or completely dissolve over the duration of the assays, with the ions themselves inducing a response, reactivity assays commonly measure the additive reactivity of the particles and ions combined. Here, we determine the concentration of ions released over the course of particle testing, and determine the relative contributions of the released ions to the total reactivity measured.

Assessment of the physicochemical properties of chrysotile-containing brake debris pertaining to toxicity.

Grinding and drilling of chrysotile asbestos-containing brake pads during the 20 century led to release of chrysotile, resulting in varying levels of workplace exposures of mechanics. Despite exposures, excess risk of mesothelioma remains in doubt. The toxicity of particulates is primarily derived through a combination of physicochemical properties and dose and as such this study aimed to determine properties of asbestos-containing brake debris (BD) which may influence pathogenicity and potential of mesothelioma.

Assessing the bioactivity of crystalline silica in heated high-temperature insulation wools.

High-Temperature Insulation Wools (HTIW), such as alumino silicate wools (Refractory Ceramic Fibers) and Alkaline Earth Silicate wools, are used in high-temperature industries for thermal insulation. These materials have an amorphous glass-like structure. In some applications, exposure to high temperatures causes devitrification resulting in the formation of crystalline species including crystalline silica.

A Novel Exposure System Termed NAVETTA for In Vitro Laminar Flow Electrodeposition of Nanoaerosol and Evaluation of Immune Effects in Human Lung Reporter Cells.

A new prototype air-liquid interface (ALI) exposure system, a flatbed aerosol exposure chamber termed NAVETTA, was developed to investigate deposition of engineered nanoparticles (NPs) on cultured human lung A549 cells directly from the gas phase. This device mimics human lung cell exposure to NPs due to a low horizontal gas flow combined with cells exposed at the ALI. Electrostatic field assistance is applied to improve NP deposition efficiency.

Poly-lactic acid nanoparticles (PLA-NP) promote physiological modifications in lung epithelial cells and are internalized by clathrin-coated pits and lipid rafts.

Background: Poly-lactic acid nanoparticles (PLA-NP) are a type of polymeric NP, frequently used as nanomedicines, which have advantages over metallic NP such as the ability to maintain therapeutic drug levels for sustained periods of time. Despite PLA-NP being considered biocompatible, data concerning alterations in cellular physiology are scarce.

Methods: We conducted an extensive evaluation of PLA-NP biocompatibility in human lung epithelial A549 cells using high throughput screening and more complex methodologies.

Pan-European inter-laboratory studies on a panel of in vitro cytotoxicity and pro-inflammation assays for nanoparticles.

The rapid development of nanotechnologies and increased production and use of nanomaterials raise concerns about their potential toxic effects for human health and environment. To evaluate the biological effects of nanomaterials, a set of reliable and reproducible methods and development of standard operating procedures (SOPs) is required. In the framework of the European FP7 NanoValid project, three different cell viability assays (MTS, ATP content, and caspase-3/7 activity) with different readouts (absorbance, luminescence and fluorescence) and two immune assays (ELISA of pro-inflammatory cytokines IL1-β and TNF-α) were evaluated by inter-laboratory comparison.

Copper oxide nanoparticle toxicity profiling using untargeted metabolomics.

Background: The rapidly increasing number of engineered nanoparticles (NPs), and products containing NPs, raises concerns for human exposure and safety. With this increasing, and ever changing, catalogue of NPs it is becoming more difficult to adequately assess the toxic potential of new materials in a timely fashion. It is therefore important to develop methods which can provide high-throughput screening of biological responses.

Nanoparticle-allergen interactions mediate human allergic responses: protein corona characterization and cellular responses.

Background: Engineered nanomaterials (ENMs) interact with different biomolecules as soon as they are in contact, resulting in the formation of a biomolecule 'corona'. Hence, the 'corona' defines the biological identity of the ENMs and could affect the response of the immune system to ENM exposure. With up to 40 % of the world population suffering from type I allergy, a possible modulation of allergen effects by binding to ENMs is highly relevant with respect to work place and consumer safety.

Chitosan functionalisation of gold nanoparticles encourages particle uptake and induces cytotoxicity and pro-inflammatory conditions in phagocytic cells, as well as enhancing particle interactions with serum components.

Background: Gold nanoparticles (AuNPs) are a popular choice for use in medical and biomedical research applications. With suitable functionalisation AuNPs can be applied in drug delivery systems, or can aid in disease diagnosis. One such functionalisation is with chitosan, which enables efficient interaction and permeation of cellular membranes, providing an effective adjuvant.

Assessment of a panel of interleukin-8 reporter lung epithelial cell lines to monitor the pro-inflammatory response following zinc oxide nanoparticle exposure under different cell culture conditions.

Background: Stably transfected lung epithelial reporter cell lines pose an advantageous alternative to replace complex experimental techniques to monitor the pro-inflammatory response following nanoparticle (NP) exposure. Previously, reporter cell lines have been used under submerged culture conditions, however, their potential usefulness in combination with air-liquid interface (ALI) exposures is currently unknown. Therefore, the aim of the present study was to compare a panel of interleukin-8 promoter (pIL8)-reporter cell lines (i.

Multi-walled carbon nanotube induced frustrated phagocytosis, cytotoxicity and pro-inflammatory conditions in macrophages are length dependent and greater than that of asbestos.

The potential toxicity of carbon nanotubes (CNTs) has been compared to pathogenic fibres such as asbestos. It is important to test this hypothesis to ascertain safe methods for CNT production, handling and disposal. In this study aspects reported to contribute to CNT toxicity were assessed: length, aspect ratio, iron content and crystallinity; with responses compared to industrially produced MWCNTs and toxicologically relevant materials such as asbestos.

Enhanced Deposition by Electrostatic Field-Assistance Aggravating Diesel Exhaust Aerosol Toxicity for Human Lung Cells.

Air pollution is associated with increased risk of cardiovascular and pulmonary diseases, but conventional air quality monitoring gives no information about biological consequences. Exposing human lung cells at the air-liquid interface (ALI) to ambient aerosol could help identify acute biological responses. This study investigated electrode-assisted deposition of diesel exhaust aerosol (DEA) on human lung epithelial cells (A549) in a prototype exposure chamber.

Workflows for automated downstream data analysis and visualization in large-scale computational mass spectrometry.

MS-based proteomics and metabolomics are rapidly evolving research fields driven by the development of novel instruments, experimental approaches, and analysis methods. Monolithic analysis tools perform well on single tasks but lack the flexibility to cope with the constantly changing requirements and experimental setups. Workflow systems, which combine small processing tools into complex analysis pipelines, allow custom-tailored and flexible data-processing workflows that can be published or shared with collaborators.