A catalytic perspective to nanomaterials reactivity-based toxicity; implications for single- and multiple-component nanomaterials (nanocomposites)

The extended use of a given product normally precedes concerns about it. The reactivity-based nanotoxicity is a major concern that must be tackled from its fundamental understanding to its regulatory management. Moreover, concepts and ideas must seamlessly flow between relevant performers. Functional nanomaterials have been used in many fields; among these, catalysis is probably the earliest more extended application of nanomaterials, these are engineered to afford specific properties, and are typically known as Engineered Nanomaterials (ENMs). Heterogenous catalysis shares its basic features with reactivity-based toxicity. In both cases, we are dealing with phenomena triggered by reactions occurring at the surface of the nanomaterial. Therefore, the extensive knowledge in heterogeneous catalysis is key to understanding reactivity-based nanotoxicology. In this regard, determining surface exposure is fundamental to mechanistically comprehend dose-response, similar to how catalysis shifted from mass-based to surface-centered metrics. Catalysis science made a further refinement iteration: reactions occur at surfaces, though not all surfaces are necessarily reactive, making it crucial to normalize per reactive site. This perspective focuses on two key aspects that link heterogeneous catalysis and reactivity-based nanotoxicity: the reactive sites on the surface of nanomaterials and how different combinations of nanomaterials appear and perform. A comment is also made regarding the somewhat vague term ‘multicomponent nanomaterial,’ which is contrasted with the well-defined, established, and widely accepted term ‘nanocomposite’ within the chemical community. Clear and precise terminology and concepts are essential for effective research and regulation.