Oxalic acid capped tungsten oxide nanozyme mimicking peroxidase activity, its synthesis characterization, and kinetic data validation via spectrophotometric studies

The need for parody enzymes has attracted the interest of researchers globally. Nanomaterials have provided promising results as mimic catalysts termed nanozymes (NZMs). This article briefs the peroxidase mimicking behavior of Oxalic acid-capped WO3 nanoparticles (Ox-WO3 NPs), which were hydrothermally synthesized. The peroxidase parodying behavior of the synthesized NZMs was studied for H2O2 as substrate and PPDD-NEDA and TMB as a chromogenic reagent in Phosphate buffer at pH 6.5. The coupled product of PPDD-NEDA showed λmax=480 nm, and the method was linear between 0.2413 and 1.93 mM. The oxidized product of TMB λmax=650 nm was linear in the range of 0.1938–1.9386 mM. Km values corresponding to TMB, and PPDD-NEDA were 0.5308 and 0.3957 mM. Kinetic constants with respect to PPDD-NEDA i.e., Vmax, Kcat, Keff, and Kpow were found to be 0.1913 mM/min, 3.3639 min−1, 8.4999 mM−1 min−1, and 0.4833 min−1. The precision study for intra-day (1.27–2.49 %) and inter-day (1.09–1.52 %) has been calculated. LOD and LOQ of the reaction was found to be 56.34 and 170.73 µM respectively. Characterization of synthesized NPs were carried out with respect to morphology, crystallinity, size, zeta potential and others. The XRD of the sample revealed the crystallite size to be 42.6 nm (Williamson-Hall equation) and 35 nm (Scherrer equation), Crystal structure was identified to be a mixture of monoclinic and orthorhombic as compared with the JCPDS file and the crystallinity of the sample was found to be 79.75 %. The SEM images provided the morphology to be spherical in nature with more aggregation due to lower zeta potential value as recorded by the DLS. The elemental composition by EDS recorded the formation of WO3 NPs. The broad peak of FT-IR spectra between 2900 and 3900 cm−1 confirms the capping of oxalic acid to WO3 NPs. [Display omitted] •Synthesis of Oxalic acid capped WO3 nanoparticles (Ox-WO3 NPs) and its application in peroxidase mimics.•Study of enzyme kinetics for oxidase nanozyme (NZM) via Michaelis Menten equation.•Characterization of NPs with respect to UV-Vis, FT-IR, SEM, EDS, XRD, and DLS.•Analytical data evaluation via inter-day and intra-day precision studies.•The application of the developed method in human serum albumin (HSA) is to evaluate the effectiveness of the proposed method.