The European Food Safety Authority has produced this Guidance on human and animal health aspects (Part 1) of the risk assessment of nanoscience and nanotechnology applications in the food and feed chain. It covers the application areas within EFSA's remit, e.g. novel foods, food contact materials, food/feed additives and pesticides. The Guidance takes account of the new developments that have taken place since publication of the previous Guidance in 2011. Potential future developments are suggested in the scientific literature for nanoencapsulated delivery systems and nanocomposites in applications such as novel foods, food/feed additives, biocides, pesticides and food contact materials. Therefore, the Guidance has taken account of relevant new scientific studies that provide more insights to physicochemical properties, exposure assessment and hazard characterisation of nanomaterials. It specifically elaborates on physicochemical characterisation of nanomaterials in terms of how to establish whether a material is a nanomaterial, the key parameters that should be measured, the methods and techniques that can be used for characterisation of nanomaterials and their determination in complex matrices. It also details the aspects relating to exposure assessment and hazard identification and characterisation. In particular, nanospecific considerations relating to in vivo/in vitro toxicological studies are discussed and a tiered framework for toxicological testing is outlined. It describes in vitro degradation, toxicokinetics, genotoxicity as well as general issues relating to testing of nanomaterials. Depending on the initial tier results, studies may be needed to investigate reproductive and developmental toxicity, immunotoxicity, allergenicity, neurotoxicity, effects on gut microbiome and endocrine activity. The possible use of read-across to fill data gaps as well as the potential use of integrated testing strategies and the knowledge of modes/mechanisms of action are also discussed. The Guidance proposes approaches to risk characterisation and uncertainty analysis, and provides recommendations for further research in this area.
Stereolithography (SL) additive manufacturing process provides increased dimensional precision, smooth surface finish and printing resolution range in the order of magnitude of 100 μm, allowing to obtain intricate 3D geometries. The incorporation of ceramic-based inclusions within liquid resins enhances the thermal and mechanical properties of the final 3D printed component while improving the surface finishing of the final parts; in this way, it expands the range of process applications and reduces the post-processing steps. The proposed approach investigates the bulk modification of commercial SLA resins mixed with ceramic powders of Al2O3 (grain size 1–10 μm) and SiO2 (grain size 55–75 nm) aiming to improve 3D printed parts performance in terms of mechanical properties, dimensional stability and surface finishing compared with pure, unmodified resins. The produced materials were used for the development of inserts for injection moulding and were examined for their performance during the injection moulding process. The addition of particles in the nano- and micro-range is being employed to improve parts performance for rapid tooling applications whilst maintaining 3D printing accuracy, thermal and mechanical properties as well as achieving a smooth surface finishing compared with unmodified resins.
The COVID-19 pandemic instigated massive production of critical medical supplies and personal protective equipment. Injection moulding (IM) is considered the most prominent thermoplastic part manufacturing technique, offering the use of a large variety of feedstocks and rapid production capacity. Within the context of the European Commission-funded imPURE project, the benefits of IM have been exploited in repurposed IM lines to accommodate the use of nanocomposites and introduce the unique properties of nanomaterials. However, these amendments in the manufacturing lines highlighted the need for targeted and thorough occupational risk analysis due to the potential exposure of workers to airborne nanomaterials and fumes, as well as the introduction of additional occupational hazards. In this work, a safety-oriented failure mode and effects analysis (FMEA) was implemented to evaluate the main hazards in repurposed IM lines using acrylonitrile butadiene styrene (ABS) matrix and silver nanoparticles (AgNPs) as additives. Twenty-eight failure modes were identified, with the upper quartile including the seven failure modes presenting the highest risk priority numbers (RPN), signifying a need for immediate control action. Additionally, a nanosafety control-banding tool allowed hazard classification and the identification of control actions required for mitigation of occupation risks due to the released airborne silver nanoparticles.
Nanoparticles are being used in novel applications of the thermoplastics industry, including automotive parts, the sports industry and leisure and consumer goods, which can be produced nowadays through additive manufacturing. However, there is limited information on the health and safety aspects during the production of these new materials, mainly from recycled sources. This study covers the exposure assessment to nano- and micro-size particles emitted from the nanocomposites during the production of filaments for 3D printing through a compounding and extrusion pilot line using recycled (post-industrial) thermoplastic polyurethane (TPU) and recycled polyamide 12 (PA12), which have been also upcycled through reinforcement with iron oxide nanoparticles (Fe3O4 NPs), introducing matrix healing properties triggered by induction heating. The assessment protocol included near- and far-field measurements, considering the extruder as the primary emission source, and portable measuring devices for evaluating particulate emissions reaching the inhalable zone of the lab workers. A Failure Modes and Effects Analysis (FMEA) study for the extrusion process line was defined along with a Failure Tree Analysis (FTA) process in which the process deviations, their sources and the relations between them were documented. FTA allowed the identification of events that should take place in parallel (simultaneously) or in series for the failure modes to take place and the respective corrective actions to be proposed (additional to the existing control measures).
A vinyl‐modified anthraquinone (AQ) derivative (Vinyl‐AQ) is synthesized through a palladium‐mediated Suzuki coupling reaction between vinylphenylboronic acid and 2‐chloromethylanthraquinone and, subsequently, copolymerized with N,N‐dimethylacrylamide (DMAM) through free radical copolymerization in organic solvent. The chemical structure of the resulting water‐soluble copolymer, P(DMAM‐co‐AQ), is verified using techniques such as proton nuclear magnetic resonance, attenuated total reflection‐infrared spectroscopy, thermogravimetric analysis, and UV–vis spectroscopy. The evolution of the oxygen scavenging abilities of aqueous P(DMAM‐co‐AQ) solutions after UV irradiation is monitored as a function of UV irradiation time, concentration of AQ moieties, and pH. The copolymer is proved an effective UV‐triggered oxygen scavenger, leading to dissolved oxygen contents below 1 ppm for the optimized experimental conditions. This behavior is related with the appearance of novel chemical species with interesting optical properties, as suggested by the respective evolution of the UV–vis absorption and photoluminescence spectra after UV irradiation.
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