Evaluation of peroxidase mimicking behaviour of VO nanozymes with various morphologies and its application as glucose sensor via cascade mechanism in human serum samples.

A simple spectrophotometric method is presented for quantifying glucose and HO using p-aminophenol sulfate-(PAP) & N-(1-Naphthyl) ethylenediamine dihydrochloride-(NEDA) as novel chromogenic reagents with different morphological VO nanoparticles (NPs) as peroxidase mimicking nanozyme. For glucose, the method was linear in the range of 0.0289 and 0.925 mM for HRP and NPs. The substrate and nanozymes interaction was established using K values, which were satisfactory. Recovery studies were performed with glucose and found between 83.98 % and 99.08 % for NPs and 88.48 to 99.35 for HRP. LOD range of 0.0194-0.0351 mM and LOQ range of 0.0588-0.1064 mM was observed with NPs, whereas for HRP, LOD was 0.02 and LOQ was 0.0607 mM. Maltose, sucrose, fructose, mannose, and galactose, considered potential interferants in glucose assay methods, provided negligible interference with the proposed method. Based on XRD data, the average crystalline size of the NPs was calculated using Scherrer's equation and Williamson-Hall plot and ranged between 29.14 and 45.42 nm, 32.5 and 45.7 nm, respectively. SEM and TEM images confirm the morphology of VO Nps were vanadium nanosheets (VNShs), nanoflowers (VNFws), and nanospheres (VNSps). DLS data revealed the Zeta potential of NPs in the range -4.5mv to 4.6mv. XPS confirms the NPs are in the VO state.