Nano- and microplastics (NMPs) are ubiquitous, persistent, and, as is now widely recognised, a global problem for humans and the environment. Because of the many different types of plastic from which NMPs are derived, conducting a general risk assessment is challenging. In addition, many plastics contain additives such as UV stabilisers or plasticisers that have hormonal effects – so-called endocrine disruptors (EDs) – and can easily be released from the plastics. Furthermore, some endocrine disruptors can strongly adhere to the surface of NMP particles and spread with them throughout the environment.
The effects of endocrine disruptors on humans and the environment remain partially unclear, as they can be very diverse and species-specific, making monitoring difficult. However, a causal link between exposure to endocrine disruptors and various human diseases has now been established. Adverse effects have also been observed in other organisms following exposure to endocrine disruptors, particularly in relation to reproduction.
Even if greener alternatives (e.g. bioplastics) could replace conventional plastics in the future, a significant influx of NMPs into the environment and the use of hormonally active substances can still be expected in the coming decades. Therefore, it is of utmost importance to establish additional test systems to protect human health and the environment, especially at the level of organisms that may facilitate the trophic transfer of EDs into the food chain.
This dossier explores general issues related to NMPs, EDs, and ecotoxicological risk assessment using the aquatic snail Biomphalaria glabrata.

Concluding this three-part series on Engineered Living Materials (ELMs), this dossier builds upon the previously discussed Biogenic Composition Ratio and production methodologies by analysing ELMs through the lens
of material features and hierarchical organisation across length scales. We explore how nano-, micro-, and macrostructural properties emerge from biological components, enabling functionalities such as self-healing and adaptivity. The dossier closes by identifying key challenges – such as vascularisation, scalability, and biosafety – that must be overcome to advance ELMs into practical applications.
This synthesis aims to inspire future research by providing a multidimensional perspective on the design and implementation of ELMs.

Building on the foundations, classifications and future potentials established in the NanoTrust-Dossier 64 ”Engineered Living Materials I”, this dossier explores the ELMs landscape in more detail, introducing the Biogenic Composition Ratio (BCR) as a categorisation scheme and providing an in-depth review of ELMs types ranging from fully biogenic to bioinspired materials. Additionally, production methodologies such as lamination, bioprinting, and electrospinning are discussed in ELMs fabrication. This dossier serves as a transition towards examining ELMs properties across length scales. It addresses the complex challenges inherent in designing and scaling ELMs, which are elaborated upon in the concluding part.

Engineered Living Materials (ELMs) incorporate living organisms in the synthesis process or seamlessly integrate them into conventional technological substrates, giving rise to novel functional materials. The transformative impact of ELMs spans various length scales and domains, such as construction, biomedicine and wearable technology. This impact arises from their exceptional attributes, including self-repair mechanisms, environmental responsiveness and inherent biocompatibility. This NanoTrust Dossier thoroughly examines the current state of ELMs production, offering a comprehensive systematic classification based on various parameters and elucidates recent strides in this dynamic field. Exploring ELMs unveils their scientific intricacies and underscores their potential to revolutionize and redefine material technologies in various applications.

Innovative chemicals and materials, such as advanced materials, are increasingly used in various applications. Advanced materials, like nanomaterials or biopolymers pose new challenges for established safety and risk assessments because of their unique properties, such as their size, shape, and surface characteristics, that distinguish them from conventional materials. In recent years, concepts such as “Safe by Design” (SbD) have been developed for nanomaterials to integrate safety aspects into the early stages of design and development. This concept has been further developed, extended to other advanced materials and chemicals in general, and expanded to include the aspect of sustainability in form of “Safe and Sustainable by Design” (SSbD). In 2022, the European Commission’s Joint Research Centre (JRC) presented a framework for safety and sustainability assessment aimed at helping to achieve the ambitious goals of the European Green Deal and the Chemical Strategy for Sustainability (CSS). The SSbD framework is intended to help companies and organisations assess not only safety but also environmental and socioeconomic sustainability, ensuring these factors are considered when (re)designing chemicals and materials. Application of the SSbD concept is currently voluntary. Because of the concept’s complexity and frequent lack of data, practical implementation remains a significant challenge for manufacturers. To effectively promote adoption of the SSbD concept, particularly amongst small and medium-sized enterprises (SMEs), appropriate framework conditions and additional measures to develop competence, cooperation, coordination, and support are needed.

Nanocarriers are innovative delivery and encapsulation systems with different chemical compositions and structures and are classified as advanced materials. They are used in a variety of applications, especially in medicine, cosmetics, and agriculture, as well as in food supplements and household products. Nanocarriers can protect sensitive active ingredients, delay their release, and even enable targeted delivery to the site of action, thereby increasing effectiveness and reducing any side effects. In the scientific literature, the term “nanocarrier” covers not only nanomaterials up to a size of 100 nm according to the definition proposed by the European Commission, but also structures up to 1,000 nm. At present, there is no uniform definition or categorisation of nanocarriers. In this dossier, they are classified on the basis of their origin and chemical composition, and categorised as organic, inorganic, and hybrid systems (material combinations of organic and inorganic materials) as well as supraparticles. To date, there has been little research on how nanocarrier systems behave in the various environmental compartments (soil, water, air). Analytical challenges and the lack of standardised test protocols make comprehensive risk assessments difficult.

The cosmetics industry uses a range of nanomaterials to improve the properties of products. Whilst there are no or only minor health concerns with soluble and biodegradable nanomaterials, such as those used to transport active ingredients into the skin, it is primarily the insoluble and persistent nanoparticles that give cause for concern. These are substances that are used, for example, as UV filters or dyes, or because of their antibacterial or antioxidant properties. To ensure the highest possible level of consumer protection, the EU Cosmetics Regulation was adapted in 2009, with special provisions introduced for nanomaterials. These include the notification of cosmetic products containing nanomaterials to the European Commission, a comprehensive safety assessment, and the labelling of nanoscale ingredients on the product label. Cosmetics are the only consumer products with such regulations in the EU. In the USA, for example, there are no such regulations to protect consumers. Technical progress, but also the experience gained during the implementation of the provisions for nanomaterials in the EU Cosmetics Regulation over the recent years, now necessitate their adaption and update. The definition of the term “nanomaterial” in the regulation, the safety assessment and notification procedures, and the labelling method are now subject to review at EU level.

Today, plastic is a ubiquitous material with good mechanical, chemical, and thermal properties and therefore used in many industrial sectors. The biggest challenge in recycling plastic waste is to separate the different types of plastic to a high degree of homogeneity. Waste sorting plants use automated sensorbased sorting systems to separate different plastics from each other. Many engineering plastics, such as polyoxymethylene (POM), end up in mixed waste streams, are not detected by sorting systems, and are therefore currently rarely or not at all recycled. Markerbased sorting is an innovative approach to improving recycling rates and achieving the recycling targets of the EU’s Circular Economy Action Plan (CEAP). For this, the marker materials are incorporated into plastics, which can only then be detected by automated sorting systems to subsequently achieve improved homogenisation. However, marker­based sorting is currently not economical because of the expected high implementation costs. Consequently, expensive technical plastics show the greatest potential for marker­based sorting. For example, POM from plastic components of waste electrical and electronic equipmentcould be separated by type and recycled. This dossier provides an overview of advanced materials with spectroscopic “fingerprints” and suitable detection methods that can be usedfor marker­based sorting.

To estimate the environmental sustainability of “advanced materials” (AdMs) in innovative solar cell technologies (emerging photovoltaics, EPVs), it is necessary to consider the entire life cycle. Life cycle assessments (LCAs) can identify those materials in a product that contribute the most to environmental damage in relation to the entire product when compared to the other materials used. This offers the opportunity to optimise the product in terms of sustainability. LCAs of EPVs carried out so far are hardly comparable because of different assumptions and system boundaries; they also have limitations, especially because of missing data. When compared with conventional photovoltaic (PV) technologies, EPVs can generally have a lower demand for energy and a shorter energy payback time because of simpler manufacturing methods and less demand of materials. When compared with solar glass or the (precious) metals or “critical raw materials” used for the electrodes, the AdMs assessed in the LCAs showed minor environmental impacts, primarily because they are used in relatively small quantities. EPVs have not yet reached marketability; consequently, no corresponding recycling technologies have been developed yet. Separating the composite materials represents a major challenge in recycling. Ideally, not only environmental compatibility (“prevention through design”, also known as “safety by design”) but also recyclability (“design for recycling”) should be taken into account already at the design stage. Furthermore, consideration should also be given to finding a suitable compromise between highest efficiency, best stability, cost-effectiveness, and sustainability (“sustainability by design”).

Titanium dioxide has been used as a food additive (E 171) in Europe since the 1960s. For a long time, it was assumed that this waterinsoluble material would not cause any negative health effects because of its low absorption rate. In recent years, however, animal studies have confirmed a dose-dependent toxic potential in the event of oral ingestion, with particular damage to the liver and kidneys, inflammatory reactions, and changes to the spleen and heart. The material was also found to accumulate in organs, and individual studies showed an effect on the intestinal flora and the immune system. One study also makes reference to a possible carcinogenic potential. The European Food Safety Authority (EFSA) rated the substance as safe when ingested orally. Up to 59% of the particles of E 171 can have a size of less than 100 nm. On the basis of the studies available to date, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) sees great uncertainties with regard to possible health effects, in particular because of the high proportion of nanoparticulates. The French government has therefore decided to ban E 171 for one year starting from 01.01.2020. Consumer protection organisations are calling for the ban to be extended to the entire European Union (EU). The industry stresses that E 171 is safe and fears negative economic consequences. However, some confectionery manufacturers have already changed their recipes and no longer use E 171. The European Commission is changing the specifications for E 171 so that it may only contain a maximum of 50% of nanoparticles in the future.

This dossier explores bio-inspired and biomimetic nanomaterials, differentiating between bio-inspired or biomimetic nanotechnology and bio-nanotechnology. Following a clarification of these terms, the basics of bio-inspired and biomimetic nanomaterials are then presented. Subsequently, a systematic classification of synthetic methods of bio-inspired and biomimetic nanomaterials is demonstrated. This classification is based on the method of manufacturing and not on the functionality of the materials. This enables a more coherent correlation with security aspects, which are yet to be defined in many cases. Due to the great variety, a categorization according to material properties or material compositions is not considered practical. In addition to chemical properties and behavior, physical parameters such as size, structure and surface quality also play an important role in the categorization. In summary, it can be said that bio-inspired and biomimetic nanomaterials represent important base materials as so-called functional advanced materials in research, development and industry – provided that the material development is accompanied by a corresponding safety and sustainability-oriented technology assessment.

Numerous research projects within the 8th Framework Programme for Research and Innovation of the European Commission – Horizon 2020 – are dedicated to environment, health and safety aspects of nanotechnologies, in continuation of the preceding 7th Framework Programme1. Many of the Horizon 2020 projects are devoted to the following subjects: risk assessment, regulation, standardization of measurement and analytical methods. Furthermore, some projects are focusing their research on production techniques and quality standards. Further research topics include life cycle analyses, safeby-design approaches and processes regarding sustainable production. Projects surrounding the subject of toxicity of nanomaterials are increasingly focusing on long-term studies and the (further) development of test methods. A number of Horizon 2020 projects are also dedicated to the consolidation and harmonization of data and databases. An increasing number of projects investigate computer models for the analysis of health risks and exposure scenarios, which are made available in the form of online platforms or tools for regulators, developers and researchers. Compared to the 7th Framework Programme, Horizon 2020 includes more projects dedicated to physicochemical characterization and the development of measurement and analysis methods of nanomaterials, as well as an increased number of nanoinformatic projects, which are intended to pool existing data on a European level.

Chemicals legislation is largely harmonisedwithin the European Union (EU), but even though nanomaterials have been in use for decades, they are often not specifically addressed in legislation. Information about how and where they are used on the EU market, and in what quantities, is scarce. As no common EU-wide nano-registry is in sight for the near future, many member states have launched national mandatory registries. The first such nano-registry was introduced in France in 2013, with four countries in the European Union and the European Economic Area (EEA) having since followed suit. Whilst the prevention of risks to human health and the environment is central to all national nano-registries, differences can be found with regard to the required information or the timing of registration.

A number of concepts address safety-relevant issues of innovative materials and products. The Safe-by-Design (SbD) concept is one of these, and aims to take account of these safety issues early on and during the entire product development process. The nano-specific concepts of SbD are intended to address prevailing uncertainties about potential risks to the environment and human health at the beginning stages in the development of new nanomaterials and products. The basic assumption of the SbD concept is that risks can be reduced through the choice of materials, products, tools and technologies, making them as safe as possible. Particular attention is paid to the product development stage, when it is still possible to intervene to control the selection of these factors. In line with the precautionary principle, the early integration of safety in the innovation process is generally seen as desirable.

Nanomaterials can improve the properties of food contact materials. Innovations of this kind are of particular interest for food packaging made out of plastic materials. The purpose of their use is to improve food storage and so to guarantee both freshness and quality. A further goal is to improve the technical properties of materials in order to make them sturdier more resistant to abrasion, and easier to process. Food contact materials are subject to a number of EU consumer protection regulations. Nanomaterials require authorisation by the European Food Safety Authority (EFSA), being responsible for assessing their safety. For nanomaterials authorised for use in the EU, specifications and restrictions are laid down in order to prevent consumers being exposed to them or to keep exposure as low as possible, and so to rule out any danger to health. At the end of the product lifetime, workers of recycling and waste treatment facilities may be exposed to higher levels of ultra ne particles or particulate matter may also be released unintentionally. To date, however, it has not been demonstrated that recycling polymers containing nanomaterials leads to any increased exposure of employees. With regard to environmental protection, little is known at present about the specific behaviour of nanomaterials and composites during waste treatment processes. There is also a need for comprehensive research on how far nanomaterials can be recycled, in order to develop sustainable nanotechnology.