An Enzyme‐Mimicking Single‐Atom Catalyst as an Efficient Multiple Reactive Oxygen and Nitrogen Species Scavenger for Sepsis Management

Abstract

Sepsis, characterized by immoderate production of multiple reactive oxygen and nitrogen species (RONS), causes high morbidity and mortality. Despite progress made with nanozymes, efficient antioxidant therapy to eliminate these RONS remains challenging, owing largely to the specificity and low activity of exploited nanozymes. Herein, an enzyme‐mimicking single‐atom catalyst, Co/PMCS, features atomically dispersed coordinatively unsaturated active Co‐porphyrin centers, which can rapidly obliterate multiple RONS to alleviate sepsis. Co/PMCS can eliminate O2.− and H2O2 by mimicking superoxide dismutase, catalase, and glutathione peroxidase, while removing .OH via the oxidative‐reduction cycle, with markedly higher activity than nanozymes. It can also scavenge .NO through formation of a nitrosyl–metal complex. Eventually, it can reduce proinflammatory cytokine levels, protect organs from damage, and confer a distinct survival advantage to the infected sepsis mice.

Catalytically potent and selective clusterzymes for modulation of neuroinflammation through single-atom substitutions

“…Surprisingly, Au 25 shows the strongest tendency toward GPx-like activity with a maximum reaction rate of 0.47 mM/min, higher than 0.34 mM/min for Au 24 Cu 1 and 0.10 mM/min for Au 24 Cd 1 (Fig. 3c), and also significantly higher than those of previously reported Mn 3 O 4 nanoflowers (0.056 mM/min) 51 and Co/PMCS (0.013 mM/min) 52 . The turnover frequency (TOF) value of Au 25 calculated by the Michaelis-Menten equation is 320 min −1 , 4.7 times higher than Au 24 Cd 1 ( Supplementary Fig.…”

“…Therefore, exploration of versatile artificial enzymes with different catalytic routes and desirable selectivity is beneficial to establish the relationship between oxidative stress and inflammation and to reveal the underlying molecular pathways of catalysis [30][31][32] . Atomic-level catalysts suffice a viable solution for the unmet need of improved catalytic activity and precisely modulated selectivity in a controllable manner, with lots of Fe-and Pt-based single-atom nanozymes developed [33][34][35][36][37][38][39][40] . In particular, Au contains excessive transition metal electronic states and rich electronic energy levels, which provide a solid basis for designing atomic-scale enzyme.…”

Single-Atom Catalysts for Biotherapy Applications: A Systematic Review

“…“Isolation-pyrolysis” is the most widely used path to fabricate SACs to disperse metal atoms on a 2D support. For instance, FeN 5 single-atom nanozymes with carbon nanoframe-confined (SA/CNF), zinc-based single atom nanozyme (PMCS SA), single iron atoms anchored in nitrogen-doped amorphous carbon (SAF NCs), Co/PMCS, PEGylated single-atom Fe-containing nanocatalysts (PSAF NCs) Fe-N/C SACs, Fe-SAs/NC were developed through the use of pyrolysis [ 15 , 17 , 18 , 19 , 20 , 21 , 22 ]. The deposition/coprecipitation strategy is also a common approach for SAC preparation, which was used to prepare carbon dot-supported atomically dispersed gold (MitoCAT-g), porphyrin-like single-atom Fe(III) metal-organic framework (P-MOF), and Pt/CeO 2 [ 23 , 24 , 25 ].…”

Advances in Single‐Atom Nanozymes Research†

“…developed a Co‐PMCS SAzyme featuring with atomically dispersed active Co‐porphyrin centers (Figure 7a) and found that it simultaneously has SOD, CAT and GPx‐like properties (Figure 7b). [ 26 ] The engineered Co‐PMCS SAzymes exhibited the excellent antioxidative ability for scavenging the intracellularly generated free radicals. SOD‐like activity of Co‐PMCS could catalyze the disproportionation of O 2 · – to H 2 O 2 and O 2 .…”

“…[ 24 ] SAzymes thus have shown a promise to serve as direct surrogates of traditional enzymes by mimicking the highly evolved catalytic center of natural enzymes. [ 25‐27 ] In this review, we focus on recent advances of single‐atom nanozymes, and summarize their significant applications from in vitro detection to in vivo monitoring and therapy.…”