Enzyme-like CeO₂ Nanomaterials with Different Structure–Activity for Ulcerative Colitis Therapy

High Resolution Image Download MS PowerPoint Slide Cerium dioxide nanomaterials (CeO 2 NMs) have been widely reported as nanozymes to improve homeostasis of the gut microbiota in ulcerative colitis mice. However, the structure–activity relationship of CeO 2 NMs in terms of their physiochemical properties and biological activities remains unclear. This study showed that the gas–liquid interface played an important role in the synthesis of CeO 2 NMs by controlling crystal growth, leading to extension of the crystal nuclei in different directions. We therefore synthesized three CeO 2 NMs with different properties in nitrogen (CeO 2 –N 2 ), carbon dioxide (CeO 2 –CO 2 ), and oxygen (CeO 2 –O 2 ) conditions, respectively, and studied their structure–activity relationships. The results showed that all CeO 2 NMs helped to prevent and control microbial damage, including changes in microbial growth and metabolite contents, to varying extents. The repair capacities of CeO 2 NMs with different properties were mainly attributed to their nanozyme catalytic abilities. The codelivery of CeO 2 NMs loaded with 5-aminosalicylic acid (5-ASA), especially CeO 2 –N 2 NMs, could improve the metabolite products and homeostasis of the gut microbiota. These results showed that codelivery of CeO 2 NMs loaded with 5-ASA could help to alleviate gut inflammation in ulcerative colitis mice. We anticipate that CeO 2 NMs may provide a therapeutic option in future clinical trials.