Designof MonovalentCerium-BasedMetalOrganicFrameworksasBioinspiredSuperoxideDismutaseMimicsfor IonizingRadiationProtection br

Superoxidedismutase(SOD)is one of the major antioxidantsin vivoand is expectedto play critical roles on the defenseagainst reactiveoxygen species(ROS)-mediateddamages,such as ionizingradiationdamages.Herein,inspiredbythe functionand structureof naturalSODs and ceriumoxide nanozymes,twomonovalentcerium-basedmetal organicframeworks(Ce-MOFs),CeIIIBTC andCeIVBTC, were designedfor superoxideradical (O2 center dot-) eliminationand ionizingradiationprotection.These two Ce-MOFsselectivelyscavengeO2 center dot-and areexcellentSOD mimics.Like natural SODs and cerium oxide nanozymes,the SOD-like catalyticmechanismof Ce-MOFsinvolvesa cycle betweenCe(IV)and Ce(III).Furthermore,by constructingmonovalentCe-MOFs,we found that high-valentCeIVBTC are more effectiveSOD-likenanozymescomparedto CeIIIBTC. Withsmallersize, better monodispersity,and more effectiveSOD-likeactivity,CeIVBTCnanozymeswere further appliedfor ionizingradiationprotection.Bothin vitroandin vivoresults demonstratedthat CeIVBTC nanozymescould efficientlyscavengeROS, preventcells from gamma-ray radiation-inducedcell viabilitydecreaseand DNA damages,and improvethe survivalrate of irradiatedmice by recoveringthe bone marrowDNA damageand alleviatingoxidativestress of tissues.The protectiveeffect and goodbiocompatibilityof CeIVBTC nanozymeswill enable the developmentof Ce-MOFs-basedradioprotectantsand facilitatetreatmentofother ROS-relateddiseases.

Automated summary

This study presents the design of two cerium-based metal organic frameworks, CeIIIBTC and CeIVBTC, which mimic the function of superoxide dismutase (SOD) and can effectively scavenge reactive oxygen species (ROS) and provide ionizing radiation protection. The CeIVBTC nanozymes show stronger SOD-like activity compared to CeIIIBTC, effectively scavenging ROS, improving cell viability, and enhancing the survival rate of irradiated mice.