Reactive oxygen and nitrogen species (RONS), especially reactive nitrogen species (RNS) are intermediate products during incidence of nervous system diseases, showing continuous damage for traumatic brain injury (TBI). Here, we developed a carbogenic nanozyme, which shows an antioxidant activity 12 times higher than ascorbic acid (AA) and behaves as multienzyme mimetics. Importantly, the nanozyme exhibits an ultrahigh scavenging efficiency (∼16 times higher than AA) toward highly active RNS, such as •NO and ONOO– as well as traditional reactive oxygen species (ROS) including O2 •–, H2O2, and •OH. In vitro experiments show that neuron cells injured by H2O2 or lipopolysaccharide can be significantly recovered after carbogenic nanozyme treatment via scavenging all kinds of RONS. Moreover, the carbogenic nanozyme can serve as various enzyme mimetics and eliminate the harmful peroxide and glutathione disulfide from injured mice, demonstrating its potential as a therapeutic for acute TBI.

An oligomeric nanozyme with ultrafast electron transfer can achieve high catalytic activity and alleviate acute brain injury.

Homeostasis of gut microbiota is extremely essential for maintaining nutrient metabolism and regulating immunological function. The increasing evidence suggests that inflammatory bowel disease (IBD) is strongly associated with dysregulation of gut microbiota. During activated inflammation, excessive reactive oxygen species (ROS) and reactive nitrogen species (RNS) produced by inflammatory cells play a detrimental role in regulating IBD and gut microbiota. ROS/RNS cause damage to the surrounding tissues, including nutrient absorption disorders, intestinal dysmotility and barrier dysfunction. Meanwhile, ROS/RNS provide terminal electron receptors for anaerobic respiration and support the bloom of facultative anaerobes, eventually causing gut microbiota dysbiosis. Redox-active nanoparticles (NPs) with catalytic properties or enzyme-like activities can effectively scavenge ROS/RNS, and selectively target inflamed sites via ultrasmall size-mediated enhanced permeation and retention (EPR) effect, showing great potential to regulate IBD and maintain the homeostasis of gut microbiota. In addition, the widespread application of NPs in commercial products has increased their accumulation in healthy organisms, and the biological effects on normal microbiota resulting from long-term exposure of NPs to gastrointestinal tract also need attention.

Mn clusters with pH-triggered catalytic selective capacity could optimize the effects of radiotherapy in the acidic tumor microenvironment, while protecting normal tissues from radiation in neutral circumstances simultaneously.

Ultrasmall carbon dot with targeting ability to nitrogen signaling molecules inhibit neuronal death by regulating the activity of endogenous enzymes.