The EU Observatory for Nanomaterials (EUON) has released a study adding to the current knowledge of nanomaterials' behaviour in the human body and the environment. The study explored the current status, existing gaps, and research needs related to the (bio)degradation and persistence of nanomaterials and their relevant organic coatings. It also looked at the concept of safe-by-design (SbD) which relates to degradation and persistence.

Carried out by NIA member Novamechanics, the study found that work in this field has mainly focused on carbon-based and organic nanomaterials, several of which degrade more easily compared to inorganic nanomaterials, although with exceptions. Biopolymers and lipids are among the easiest to degrade, while carbon-based nanomaterials are found to be more persistent in vivo.

Most of the test guidelines currently available for studying the degradation and persistence of bulk chemicals have also been applied to nanomaterials, with or without adaptations; a wide range of techniques have been used, with enzymatic degradation as the most studied. According to the report, this points to a potential research gap in the study of cell and bacterial degradation.

The study also found that extensive work is being performed for SbD nanomaterials, in Europe and globally; however, there is no consensus on how to define 'safe-by-design' nanomaterials, mostly owing to the vagueness of the term 'safety', but also because of nanomaterials' different properties, which can vary considerably. Notwithstanding this, the study proposes that SbD for nanomaterials are already available, with application sectors such as nanomedicine leading the field thanks to more specific requirements being in place.

The concept of 'safe-by-degradation' is also discussed, looking at the optimized lifetime of a nanomaterial including its safe clearance from the body and the environment. Specifically in the case of carbon nanotubes (CNTs), it has been suggested that decreasing their length leads to decreased toxicity.

Finally, responses to the expert survey carried out as part of the study indicated that the sustainability dimension, mot limited to environmental considerations but also taking into account societal aspects, should be part of the SbD approach.

The full study can be read at this link.