Nanotechnology is poised to play a crucial role in both scientific development and economic growth; however, regulations on commercial nanoscale substances are still needed, especially as new nanoproducts are being rapidly developed. To help to solve regulatory challenges in the future, this study focuses on the so-called “next generation” (2nd and higher) of relatively new nanomaterials defined as:Definitions of three generation of nanomaterials: Two widely used types of definitions of different generations of nanomaterials are from Roco and Tour, respectively. The project team evaluated them based on literature review as well as experts’ advice and gave proposed refined definitions of different generations of nanotechnology applications:
- First generation: Passive nanomaterials, which means they will neither react with the surrounding system nor change intentionally;
- Second generation: Reactive nanostructures. They are stimuli-responsive and are artificially designed to react with the environment in the form of stimulus;
- Third generation: Multifunctional nanosystems. Stimuli-responsive nanoparticles are used to build complex networks and synthetic life-like systems.
- Inventory & market assessment of 2nd or higher generation of nanomaterials:Though there has been an increase in research on higher generation nanomaterials recently, the absolute contribution of that to the whole nanoscale products market is still limited and the 3rd generation is at the conceptual phase. The search has yielded 48 examples of the 2nd generation products and eight of the 3rd ones.
- Assessment of terms (“substance”, “mixture” and “article”): The initial identification of generations refers to nanotechnology products rather than nanomaterials that have already been defined. Most 2nd products can still be identified by nanomaterial regulations. However, such regulations may not work for assembly structures (so-called “nanostructured particulate materials”) like core-shell particle and 3rd products. They can be identified through a specific six-step workflow.
- Evaluation of characterization parameters: Parameters required by the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) allow to characterize different nanoforms. Nevertheless, guidance is still needed to distinguish between organic and inorganic compounds, solid and fluid materials. Relevant work is currently ongoing.