Dual Activities of Flower‐Like Gold‐Iron Oxide Nanozyme for Peroxidase‐Mimicking and Glucose Detection

Nanozymes, constituting of inorganic nanomaterials, are the sustainable and cost-effective alternatives of the naturally abundant enzymes. For more than a decade, nanozymes have shown astonishingly enhanced enzymatic activity as compared to its naturally occurring counterpart and emerged as a potential platform in biomedical science. The current study reports a novel flower shaped gold-iron oxide nanocomposite prepared via a facile and green solution phase redox mediated synthesis. The precursor gold salt conversion to nanometallic Au(0) is mediated by iron metal powder, which acts both as reductant and metal source in the resultant gold nanoparticle decorated iron oxide nanocomposite. Calcination of the synthesized nanocomposites leads to morphological evolution into unique flower shape with improved homogeneity between gold and iron components along with metal surface exposure. The gold-iron oxide nanocomposites have been utilized first time for peroxidase mimicking study and exhibit enhanced catalytic activity at 25 °C with low Michaelis-Menten constant (K_m) and higher maximum reaction velocity (V_max) as compared to the natural enzyme Horseradish peroxidase (HRP). In addition, combined assembly of this nanozyme with natural enzyme glucose oxidase also serves a potential platform for the visible colorimetric detection and quantification of glucose with limit of detection (LOD) of 15 μM.