A novel TMD-based peroxidase-mimicking nanozyme: From naked eye detection of leukocytosis-related diseases to sensing different bioanalytes.

Being emerged as alternatives to natural enzymes, nanozymes have recently drawn much attention in sensing. Herein, the first multicomponent transition metal dicalchogenide (TMD)-based nanozyme (MCFS/rGO) was synthesized by a facile hydrothermal method and characterized. This peroxidase-mimic nanozyme follows the typical Michaelis-Menten kinetics, showing a higher affinity for H ₂ O ₂ substrate (K _m  = 9 μM) compared to that of natural peroxidase (K _m  = 3700 μM). The remarkable potential of the MCFS/rGO nanozyme to detect H ₂ O ₂ provided us with a great opportunity to design some simple and fast colorimetric sensing systems. Coupling the efficient peroxidase-mimicking activity of the nanozyme with the H ₂ O ₂ production capacity of white blood cells (WBCs) leads to the development of a novel, simple, rapid, and efficient colorimetric method to distinguish leukocytosis-related patients from healthy people by the naked eye. This pioneering diagnostic technique can also be utilized to quantitatively measure the WBC count. Moreover, we coupled the mentioned nanozyme-based system with the activity of glucose oxidase enzyme available in different types of honey samples, an innovative mechanism proved to be an effective quality indicator of the samples. Last but not least, the MCFS/rGO nanozyme is also able to determine the quantity of some biologically significant analytes, including glutathione (GSH), ascorbic acid (AA), and mercury ions (Hg ²⁺ ), of which the limit of detection (LOD) was 9.3 nM, 22.5 nM, and 0.32 μM, respectively. Our results, however, demonstrated the superior performance of the MCFS/rGO nanozyme to determine the first two mentioned bioanalytes compared with other TMDs. Overall, this novel nanozyme-based sensor system can be considered a suitable candidate for developing multipurpose biosensors for medical and biochemical applications.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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