On September 13, 2022, the European Union (EU) Observatory for Nanomaterials (EUON) published a Nanopinion entitled “Can the Brain’s Gatekeeper Fight a Nano-Attack?” by Dr. Eugenia (Éva) Valsami-Jones, Professor of Environmental Nanoscience at the University of Birmingham, who co-authored an article entitled “Biotransformation modulates the penetration of metallic nanomaterials across an artificial