Integration of ferrihydrite prepared by using an innovative method with oxidized activated carbon to construct a...

Inflammatory diseases are typically characterized by relatively high levels of reactive oxygen species (ROS). These persistent and abundant ROS cause irreversible damage to the body by directly destroying nucleic acids, proteins, and lipids. Therefore, effectively eliminating excess ROS is a crucial step in combating inflammatory injury. In recent years, nanozymes have opened up a new avenue in the study of mimicking natural enzyme properties, providing suitable alternatives to natural antioxidants. This study synthesized Fh using a novel copper oxide (CuO)-promoted ferric iron hydrolysis method, addressing the issue of product sensitivity to reaction parameters in previous methods. Using CAT activity as the standard, the effects of reactant concentration and ratio on Fh were investigated. The characterization results indicated that the oxidative carbon dot nanozyme (C-dot) bound with Fh through electrostatic and coordination interactions successfully formed the cascade nanozyme (Fh@C-dot). The activity of nanozymes in scavenging ROS in vitro and their anti-inflammatory activity in vivo were measured and evaluated. The results showed that Fh exhibited good CAT-like activity, while C-dots demonstrated excellent free radical scavenging activities, including SOD-like activity and hydroxyl radical scavenging activities. In contrast, the Fh@C-dot composite possessed both radical scavenging properties and CAT-like activity. Notably, its radical scavenging ability exhibited an enhanced effect. In addition, Fh@C-dot exhibited good biosafety and demonstrated significant therapeutic effects on irritant contact dermatitis in mice. In summary, this study provides valuable insights for the application of cascade nanozymes in the treatment of inflammatory diseases.