Bamboo‐Like Nanozyme Based on Nitrogen‐Doped Carbon Nanotubes Encapsulating Cobalt Nanoparticles for Wound Antibacterial Applications

Abstract

In this paper, an artificial nanozyme with efficient oxidase-mimicking activity is developed to investigate antibacterial performance. The bamboolike nitrogen-doped carbon nanotubes encapsulating cobalt nanoparticles (N-CNTs@Co) are synthesized by pyrolysis of cobalt cyanide cobalt at high temperature. It is found that the oxidase-mimicking activity of N-CNTs@Co is higher than that of iron-centered nanomaterials synthesized by pyrolysis of prussian blue under the same conditions, confirming that the oxidasemimicking activity is not only related to the active center, but also closely related to its morphology. In addition, the oxidase-mimicking activity of N-CNTs@Co is 12.1 times higher than that of the most reported CeO 2 . N-CNTs@Co can catalyze oxygen to produce a large number of reactive oxygen species (ROS) under acidic conditions, resulting in a favorable antibacterial effect against two representative bacteria, Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli). Because the bacterial membrane is damaged by the attack of ROS, the DNA is degraded, eventually causing the bacteria to die. Antibacterial experiments last for 20 days, nevertheless, S. aureus and E. coli do not develop resistance to N-CNTs@Co. The experiments of wound healing in vivo further confirm the high antibacterial efficiency of N-CNTs@Co.

Prospects of nano-carbons as emerging catalysts for enzyme-mimetic applications

“…4. 89,90 The more exposed surface area of tentacles of dendrites accelerates the catalysis by providing more surface-active sites. The coreshell morphology can imparts the extra activity of metallic core supported by CNTs, 91 since tubular morphology can provide both internal and external sites for enzymatic activity.…”

“…These hollow CNTs have cobalt capped in it which prevents the leakage of NPs and these tubes were acting as a nanoreactor for oxidase mimic activity. 90 The morphological changes can also enhance the catalytic activity. This concept was proved by Lin et al by doping cerium in the carbon-based GO nanozyme.…”

“…The bamboo-like stacking of particles (such as CNTs) provides not only a porous upper surface, but also a long hollow space inside the tube, which acts as active sites for the substrates. 89,90 Only a few studies are available, which focused on the influence of morphological variations on the enzymatic activity of nano-carbons. 93 Jiang et al synthesized the B-doped carbonbased core-shell structure, where the iron NPs are the core and B-doped carbon acts as a shell.…”

Efficient nanozyme engineering for antibacterial therapy

“…For example, the POD mimetic activity of truncated octahedron shaped Fe 3 O 4 NPs was superior to that of spherical-shaped ones [86]. The bamboo-like nitrogen-doped carbon nanotubes encapsulating Co nanoparticles (N-CNTs@Co NPs) possessed higher OXD-like activity than its spherical precursor CoHCF due to that the bamboo-like structure could prevent Co NPs leakage and improve its dispersion and stability [87]. Notably, the chemical state of copper in carbon supported copper nanohybrids also plays an important role in regulating the enzyme-mimicking activity of nanozymes [28].…”

Carbon Nanotubes-Based Hydrogels for Bacterial Eradiation and Wound-Healing Applications

“…He et al, developed a nitrogen-doped CNT encapsulating cobalt (N-CNTs@Co) nanoparticles for antibacterial wound-healing application [140]. The nanocomposite showed oxidase-mimicking activity, which could produce a large number of ROS in an acidic environment.…”