Safety‐by‐Design of Metal Oxide Nanoparticles Based on the Regulation of their Energy Edges
Yanlin Feng, Yun Chang, Keqiang Xu, Runxiao Zheng, Xiaqing Wu, Yan Cheng, Haiyuan Zhang
Abstract
Abstract The safety of metal oxide (MOx) nanoparticles (NPs) has been highly concerned because of their wide application and potential toxicological injury. The safe‐by‐design strategy is usually developed to make safer MOx NPs based on regulation of their physicochemical properties. In the present study, manganese oxide (Mn 3 O 4 ) NPs, as a representative of insoluble toxic MOx NPs, are doped with a series of transition metal to regulate their conduction band energy ( E c ) out of biological redox potential range (BRPR) or Fermi energy ( E f ) far away from valence band energy ( E v ), aiming at completely eliminating the toxicity or significantly reducing the toxicity. It is found that all these M‐doping cannot move E c of Mn 3 O 4 NPs out of the BRPR but zinc (Zn)‐, copper (Cu)‐, and chromium (Cr)‐doping do move E f far away from E v , where Zn‐doping results in the largest | E f − E v | value. Various abiotic, in vitro and in vivo assessments reveal that Zn‐, Cu‐, and Cr‐doped Mn 3 O 4 NPs can generate lower amount of •OH and trigger weaker injury than Mn 3 O 4 NPs, where Zn‐doped Mn 3 O 4 NPs show the lowest toxicity. Regulating E f far away from E v becomes a feasible safe‐by‐design approach to achieve safe MOx NPs.