Establishing bilateral modulation of radiation induced redox damage via biocatalytic single atom engineering at Au clusters

Modulation of radiation biological process at atomic and molecular level is closely related to biocatalytic process, redox biology and multisystem inflammation. Thus, it is necessary to clarify the exact relationship between the biocatalytic process and radiation biology, and further establish the corresponding intrinsic mechanism. In this work, we employed a serial of single atom substitutional gold clusters, which show different biocatalytic activity and selectivity for radiation induced redox modulation. The single atomic Er-substituted Au clusters show the highest antioxidant activity, and clearance rate to reactive oxygen and nitrogen species (RONS), such as peroxynitrite (ONOO-), nitric oxide ((NO)-N-center dot) and hydroxyl radicals ((OH)-O-center dot). Meanwhile, single atomic Cu- or Pt-substituted Au clusters exhibit excellent catalase-like (CAT-like) activity. Moreover, the single atomic Pt-substituted Au clusters also show the best ability to oxidate H2O molecules to OH-. Biological experiments show that Er-substituted Au clusters have good radioreduction ability, which can increase the survival rate of irradiated mice from 40% to 90%. On the contrary, Au clusters substituted by Cu or Pt have the effect of promoting radioxidation, reducing the survival rate of mice to 30% and 0%. These results suggest that antioxidant capacity, RONS scavenging ability and reducibility are closely related to radioreduction, while CAT-like activity and oxidativeness promote radioxidation.