N, S, and P-Co-doped Carbon Quantum Dots: Intrinsic Peroxidase Activity in a Wide pH Range and Its Antibacterial Applications

Abstract

Nanozymes have drawn significant scientific interest due to their high practical importance in terms of overcoming the instability, complicated synthesis, and high cost of protein enzymes. However, their activity is generally limited to particular pHs, especially acidic ones. Herein, we report that luminescent N, S, and P-co-doped carbon quantum dots (NSP-CQDs) act as attractive peroxidase mimetics in a wide pH range, even at neutral pH, for the peroxidase substrate 2,2′-azino-bis­(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) in the presence of H2O2. The synergistic effects of multiple heteroatoms doping in CQDs boost the catalytic activity in a wide pH range attributed to the presence of high density of active sites for enzymatic-like catalysis and accelerated electron transfer during the peroxidase-like reactions. A possible reaction mechanism for the peroxidase-like activity of CQDs is investigated based on the radical trapping experiments. Moreover, the multifunctional activity of NSP-CQDs was further utilized for antibacterial assays for both Gram-negative and Gram-positive model species, including Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively. The growths of the employed E. coli and S. aureus were found to be significantly inhibited due to the peroxidase-mediated perturbation of cell walls. The present work signifies the current advance in the rational design of N, S, and P-co-doped CQDs as highly active peroxidase mimics for novel applications in diverse fields, including catalysis, medical diagnostics, environmental chemistry, and biotechnology.

TiO2 supported single Ag atoms nanozyme for elimination of SARS-CoV2

“…Recently, Bonam et al summarized the rationale applications of nanomedicine against Coronaviruses [11] . Especially for SARS-CoV2, various nanomaterials have shown promising antiviral activity [12] , [13] . Compared to traditional materials, nanomaterials are superior because of their small size, large specific surface area, high adsorption and catalytic capacity [14] .…”

Highly Sensitive Fluorescent Detection of Acetylcholine Based on the Enhanced Peroxidase-Like Activity of Histidine Coated Magnetic Nanoparticles

“…The Lineweaver-Burk plots then were applied to determine K m and V max . Table 1 summarized the catalytic parameters of His@MNPs, unmodified pristine MNPs, HRP, and other peroxidase-like nanozymes which were recently reported [ 2 , 3 , 11 , 16 , 31 ]. According to the Table 1 , it is noticeable that the K m value (TMB) for His@MNPs was approximately 3 times higher than that of natural HRP.…”

“…Nanomaterials that can perform enzyme-like activities are defined as nanozymes and considered to be the rival for natural enzymes in aspects such as high stability, low cost, and the robustness to be stored for a relatively long time [ 10 ]. Since the first peroxidase-mimicking nanozymes, magnetic nanoparticles (MNPs), were discovered in 2007 [ 11 ], plenty of nanozymes have been developed and studied [ 10 , 12 , 13 , 14 , 15 , 16 ]. However, MNPs were still considered as fascinating materials in numerous biosensing fields [ 17 , 18 , 19 , 20 , 21 ] and biomedical applications such as drug delivery, magnetic hyperthermia, and biomedical imaging, owing to their inherent biocompatibility, low toxicity, as well as their exotic response to the magnetic field [ 22 , 23 ].…”

Carbon Dots as an Emergent Class of Antimicrobial Agents

“…Nitrogen (as well as different heteroatoms such as P, O, and S) has also been incorporated during the CD synthesis using a mixture of different starting materials [ 61 ]. For example, the addition of polyamines [ 16 , 62 ], amino acids [ 63 , 64 , 65 , 66 , 67 ], or biomass such as plant leaves and fungi [ 68 , 69 , 70 , 71 , 72 , 73 , 74 ], food [ 75 , 76 , 77 , 78 , 79 ], and industrial [ 80 ] and waste derivatives [ 81 , 82 ], among others, have been used for the preparation of doped CDs.…”