Nanoscale mineral as a novel class enzyme mimic (mineralzyme) with total antioxidant capacity detection: Colorimetric and smartphone-based approaches

Abstract

Nanozymes, synthetic nano-scale materials with enzyme-like behavior, have shown remarkable advancements and widespread utilization across various applications. However, the majority of nanozymes require precursor of synthetic-chemicals, which are sometimes expensive and undergo complicated preparations and tedious purification procedures. Therefore, it is of utmost significance to find an enzyme mimic that is affordable, abundant, highly efficient, and sustainable for various applications in biomedicine, environmental sciences, and the food industry. We prove the efficient peroxidase-like activities of the earthly available mineral, barunite-II. The braunite-II mineral micro-nanoparticles (NB) were prepared via physical milling. The enzyme mimetic activity of mineral nanoparticles, referred to as “mineralzyme,” could oxidize the chromogenic blue color of TMB (3,3′,5,5′-tetramethylbenzidine) to oxTMB (3,3′,5,5′-tetramethylbenzidine oxide). Michaelis-Menten constant (K) and maximum velocity (V) were 135 mM and 62.73 mM min for TMB as a substrate, 139.2 mM, and 2.69 mM min for HO as a substrate. The K values are much lower than those for HRP. We accurately quantified the total antioxidant capacity in seminal fluid samples from infertile patients using the peroxidase activity of the mineral nanoparticles. This investigation will open new avenues to explore the realm of mineralzyme, revealing its significant potential for a wide range of applications involving diverse enzymatic behaviors.