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

A biosensor comprising crystalline CuS nanoparticles(NPs) wassynthesized via a one-step simple coprecipitation route without involvementof a surfactant. The powder X-ray diffraction method has been usedto evaluate the crystalline nature and different phases consist ofthe formation of CuS NPs. Mainly hexagonal unit cells consist of theformation of CuS NP unit cells. Most of the surfaces are covered withrhombohedral microparticles with a smooth exterior and surface clustering,examined by SEM images, and the shape of NPs was spherical, havingan average size of 23 nm, as confirmed by TEM analysis. This studyhas focused on the peroxidase-mimicking activity, superoxide dismutase(SOD)-mimicking activity, and chemosensor-based colorimetric determinationand detection of epinephrine (EP) neurotransmitters with excellentselectivity. The CuS NPs catalyzed the oxidation of the oxidase substrate3, 3-5, 5 tetramethyl benzidine (TMB) with the help of supplementaryH(2)O(2) that followed Michaelis-Menten kineticswith excellent K (m) and V (max) values calculated by the Lineweaver-Burk plot.Taking advantage of the drop in absorbance upon introduction of EPfor the CuS NPs-TMB/H2O2 system, a colorimetricroute has been developed for selective and real-time detection ofEP. The sensitivity of the new colorimetric probe was vibrant, havinga linear range of 0-16 & mu;M, and achieved a low limit ofdetection of 457 nM. Moreover, the present nanosystem exhibited appreciableSOD-mimicking activity which could effectively remove O-2 (& BULL;-) from commercial cigarette smoke, alongwith it acting as a potential radical scavenger as well. The new nanosystemeffectively scavenged (OH)-O-& BULL;, O-2 (.-), and metal chelation which were investigated calorimetrically. This study focuses on the peroxidase-mimickingactivity(POD), superoxide dismutase (SOD)-mimicking activity, and chemosensor-basedcolorimetric determination and detection of epinephrine neurotransmitterswith excellent selectivity. Moreover, the present nanosystem exhibitedappreciable SOD mimicking activity which could effectively removeO2(& BULL;-) from commercial cigarette smoke, alongwith it acting as a potential radical scavenger as well. The new nanosystemeffectively scavenged (OH)-O-& BULL;, O-2 (-), and metal chelation which were investigated calorimetrically.