Label-Free Detection of Epinephrine Using Flower-like Biomimetic CuS Antioxidant Nanozymes

Abstract

A biosensor comprising crystalline CuS nanoparticles (NPs) was synthesized via a one-step simple coprecipitation route without involvement of a surfactant. The powder X-ray diffraction method has been used to evaluate the crystalline nature and different phases consist of the formation of CuS NPs. Mainly hexagonal unit cells consist of the formation of CuS NP unit cells. Most of the surfaces are covered with rhombohedral microparticles with a smooth exterior and surface clustering, examined by SEM images, and the shape of NPs was spherical, having an average size of 23 nm, as confirmed by TEM analysis. This study has focused on the peroxidase-mimicking activity, superoxide dismutase (SOD)-mimicking activity, and chemosensor-based colorimetric determination and detection of epinephrine (EP) neurotransmitters with excellent selectivity. The CuS NPs catalyzed the oxidation of the oxidase substrate 3, 3-5, 5 tetramethyl benzidine (TMB) with the help of supplementary H 2 O 2 that followed Michaelis− Menten kinetics with excellent K m and V max values calculated by the Lineweaver−Burk plot. Taking advantage of the drop in absorbance upon introduction of EP for the CuS NPs-TMB/H 2 O 2 system, a colorimetric route has been developed for selective and real-time detection of EP. The sensitivity of the new colorimetric probe was vibrant, having a linear range of 0−16 μM, and achieved a low limit of detection of 457 nM. Moreover, the present nanosystem exhibited appreciable SOD-mimicking activity which could effectively remove O 2•− from commercial cigarette smoke, along with it acting as a potential radical scavenger as well. The new nanosystem effectively scavenged • OH, O 2 .− , and metal chelation which were investigated calorimetrically.

Plasmon-Stimulated Colorimetry Biosensor Array for the Identification of Multiple Metabolites

“…Notably, the nanozyme-based colorimetric sensing platform has been considered as a promising analysis toolkit with broad-spectrum biomarker detection, including metabolites. CuS commonly utilizes the peroxidase-like nanozyme activity of decomposing hydrogen peroxide (H 2 O 2 ) into strongly oxidizing reactive oxygen species (ROS) for metabolite detection . However, the limited catalytic capability of the CuS nanozyme has severely hampered its metabolite detection.…”

Multienzyme Mimicking Cascade Mn3O4 Catalyst to Augment Reactive Oxygen Species Elimination and Colorimetric Detection: A Study of Phase Variation upon Calcination Temperature

“…Among the artificial nanozymes, POD and oxidase (OD) are in the oxido reductase family and can oxidize organic substrates such as o -phenylenediamine (OPD), 3,3′,5,5′-tetramethylbenzidine (TMB), dopamine, 2,2′,5,5′-azinobis­(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and luminal with the help of H 2 O 2 (POD) and without the involvement of H 2 O 2 (OD). SOD is another kind of antioxidant enzyme that can dismutase the superoxide radical, thereby forming H 2 O 2 , which is also considered to be a powerful reactive oxygen species (ROS). − The nanozymes that can catalyze the POD, OD, CAT, and SOD are directly regulate the intercellular ROS level and therefore are highly applicable in a synergistic artificial antioxidant defense system. A particular ROS level in the body is crucial to maintaining many biological processes, but in diseases and inflammation, the ROS level is disturbed, which can stimulate several other chronic diseases.…”