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

Abstract

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.

Interactions of Fe–N–S Co-Doped Porous Carbons with Bacteria: Sorption Effect and Enzyme-Like Properties

“…It seems that the Fe- and N-co-doped carbon materials can significantly enhance the bactericidal effect of hydrogen peroxide, even if its concentration is much lower than that used for clinical purposes [ 31 ]. If the bacteria are exposed solely to the external H 2 O 2 , or solely to the Fe/N-co-doped carbon, survival rates are high [ 4 ]. A comparison of the oxidase- and peroxidase-like activities of Fe–N–C materials showed that the oxidase-like activity is inferior to peroxidase-like activity [ 5 ].…”

“…and macroscopic objects such as porous macroparticles). Summarizing, only a few studies investigating the possible antibacterial properties of Fe-doped carbon materials have been reported so far, and in most of them the addition of H 2 O 2 is used as an external, artificial source of ROS simultaneously with the studied Fe-doped materials [4]. Simultaneous exposure of bacteria to Fe-doped materials and external (added) H 2 O 2 precludes to indicate unambiguously the factors causing bacterial damage.…”

“…ROS may be generated abiotically when hydrogen peroxide reacts with Fe-containing nanomaterials leading to the production of superoxide radicals ( • O 2 − ), hydroxyl radicals ( • OH), or singlet oxygen species ( 1 O 2 ). This process is similar to the activity of peroxidases, which catalyze the reaction of H 2 O 2 with organic substrates via ROS generation [ 3 , 4 , 5 , 6 ]. For these reasons, the possible antibiotic properties of the nanozymes as well as their implementation for nanotechnology as the ROS determination agents have been studied intensively over the last several years.…”

“…with oxygen leading to • O 2 − generation [ 19 ]. As a result, the Fe-doped carbons are able to mimic oxidase activity by producing H 2 O 2 directly from atmospheric oxygen, yet simultaneously they can act as peroxidases catalyzing the hydrogen peroxide reduction [ 3 , 4 , 5 , 6 ]. Not only heteroatom-doped carbons, but a variety of Fe-containing materials and structures (e.g., F 2 O 3 , Fe 3 S 4 , etc.…”

Ultrasmall FeS2 Nanoparticles‐Decorated Carbon Spheres with Laser‐Mediated Ferrous Ion Release for Antibacterial Therapy

“…After carbonization at 800 °C for 2 h and NaOH etching at 80 °C for 12 h, the CNSs were obtained. [18,19] Second, FeCl 3 and cysteine were added separately into ethylene glycol containing CNSs to react at 200 °C for 12 h, yielding CNSs@ FeS 2 . As shown via scanning electron microscopy (SEM) (Figure 1a), CNSs@FeS 2 had a regular spherical shape with a ≈200 nm diameter.…”