One-Pot Synthesis of Fe/N-Doped Hollow Carbon Nanospheres with Multienzyme Mimic Activities against Inflammation

Inflammation, including infectious and noninfectious inflammation, are a growing threat to public health worldwide. For different types of inflammation, more specific and intensified therapy is needed. Nanozymes are able to regulate levels of radical reactive oxygen species (ROS) to suppress inflammation, becoming potential anti-inflammatory agents. Herein, hollow porous carbon spheres codoped with nitrogen and iron (Fe/N-HCNs) are synthesized through a one-pot strategy, which exerted multienzyme mimicking activities, including peroxidase (POD)-, oxidase (OXD)-, catalase (CAT)-, and superoxide dismutase (SOD)-like activities. Moreover, these activities were promoted by the removal of iron oxides produced in the synthesis process. Based on the study of multienzyme activities, we designed two kinds of animal inflammatory models, bacteria-infected wound and inflammatory bowel disease, to evaluate the anti-inflammation ability of Fe/N-HCNs. The results indicated that Fe/N-HCNs could increase ROS levels through performing their POD-like activity in a weak acid environment to catalyze H₂O₂ against bacteria-infected wound healing, whereas Fe/N-HCNs with the capability of scavenging ROS in a neutral environment could also be unitized to treat noninfectious inflammatory bowel disease. Together, our study provided evidence that the prominent multienzyme activities of Fe/N-HCNs could be used as an anti-inflammatory alternative for both infectious and noninfectious inflammation.