Nanoparticles enable the treatment of lethal radiation

Despite the widespread use of radiological techniques in diagnosis and treatment, there is still no material that can protect people from radiation.

Recently, researchers at the Nanoparticle Research Center at the Korea Institute of Basic Science, in collaboration with colleagues at Seoul National University, the College of Dentistry, and the Institute of Dentistry, reported an efficient and safe nanocrystal that is effective against dangerous dose radiation.

By growing manganese oxide (Mn3O4) nanocrystals on cerium oxide (CeO2) nanocrystals, the group improved the catalytic activity of CeO2/Mn3O4 nanocrystals, thus avoiding the side effects of lethal radiation.

HYEON Taeghwan, director of the IBS Nanoparticle Research Center (Seoul National University), said: "Reactive oxygen species (ROS) are found in many major diseases, including sepsis, cancer, cardiovascular disease and Parkinson's disease. When our body is exposed to high levels of radiation, large amounts of ROS are generated within milliseconds due to the breakdown of water molecules. These ROS severely destroy cells and eventually lead to their death."

The research team used CeO2 and Mn3O4 nanoparticles for their excellent ROS scavenging ability. The challenge is how to use these antioxidant nanomaterials in a safe and economical way: although effective, CeO2 and Mn3O4 nanoparticles can only act to remove ROS at high doses, which is not only difficult to apply but also very wasteful.

In recent studies, researchers have borrowed from methods commonly employed in the field of catalysis: stacking nanoparticles with different lattice parameters results in surface strain and increases oxygen vacancies on the surface of nanocrystals.

"The synergistic effect of the strains produced on Mn3O4 and the increase in oxygen vacancies on the CeO2 surface improve the surface-binding affinity of ROS, thereby enhancing the catalytic activity of nanocrystals," said Han Shangen, lead author of this study. "Strain engineering of nanocrystals, which are mainly studied in the catalyst field, has now been extended to the medical field to protect cells from ROS-related diseases," said CHO Min Gee, co-first author of the study.

The team examined the safety and efficacy of this novel antioxidant nanocrystal. Molecular dynamics were analyzed using an acute radiation model of human intestinal organoids. "Genes expressed by organics pretreated with CeO2/Mn3O4 nanocrystals were associated with the proliferation and maintenance of intestinal stem cells compared with the group without pretreatment, while fewer genes were associated with cell death," explained Sang-woo Lee.

In a mouse study, with only a very small dose (1/360 of the amifostine injection dose), CeO2/Mn3O4 nanocrystals significantly increased the survival rate of animals to 67% and reduced oxidative stress to internal organs, circulatory system and bone marrow cells without obvious signs of toxicity.

"To ensure the safe and widespread use of radioprotectants in clinical practice, it is critical to maintain high catalytic efficacy at low doses." PARK Kyungpyo, a professor in the Department of Dentistry at Seoul University, said: "This CeO2/Mn3O4 nanocrystal demonstrates its strong antioxidant effect and effectively protects our entire body even in small doses."

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