"DIAGONAL will bring SbD knowledge and tools to a development stage which can be implemented in the MCNMs and HARNs related industries, relying on experimental (in-vitro) and modelling (in-silico) research, to study specific hazard and exposure properties that MCNMs & HARNs exhibit along their life cycle, with emphasis in the interactions between NM constituents, with other particles and the environment, as well as their release rate and fate. While hazard and exposure determination will allow gaining understanding on the MCNMs & HARNs behaviour and evolution, multi-scale modelling will answer the questions ""what are they?"" and ""where do they go?"", through novel predictors for properties estimation, resulting from additive and/or synergistic interactions between components, as well as system-dependent properties. Ultimately, the obtained results will serve as basis to provide adapted or novel risk management guidelines, ready to use SbD tools and strategies to increase nanomaterials safety, including Sustainable-by-Design considerations, and recommendations for risk governance.DIAGONAL partners are involved in current R&D projects (NMBP-12-2017, NMBP-13-2018, NMBP-14-2018, NMBP-15-2019), networks (e.g. NanoSafety Cluster and EMMC) and working groups (e.g. OECD - WPMN and BNCT). The project will establish cooperation lines with the US nanosafety research community involving a US partner and integrating renowned US institutions on its advisory board, guaranteeing resource-efficient working plans, aligned with current EU and international efforts in the nanosafety field, and facilitating the use of existing reference platforms and databases.7 industrial cases producing or using MCNMs/HARNs will participate providing data from scaled up scenarios, validating models, and implementing the novel SbD approaches and tools developed in the project. Exploitation activities and connection with Open Innovation Test Beds will allow mainstreaming SbD among targeted industries"