Investigating the biochemical stability and kinetic performances of SiO2@AuNPs nanocomposite as high throughput peroxidase alternativesAuthor(s): Saeed Reza Hormozi Jangi
In this study, biochemical properties (pH-, cycling-, & shelf-stability) and kinetics parameters of silicone dioxide@gold (SiO2@AuNPs) nanocomposite as the high throughput peroxidase alternatives were evaluated. The as-synthesized nanocomposite was characterized by the TEM imaging method, revealing an average size of 204 nm and spherical morphology. Besides, the peroxidase-like activity of the as-prepared SiO2@AuNPs nanocomposite was quantified using the standard peroxidase assay, exhibiting an enzyme-like specific activity as high as 0.0503 UI mg-1 for this nanocomposite. Considering the high peroxidase-like activity of the SiO2@AuNPs nanocomposite, their biochemical properties including, pH stability, cycling stability, shelf stability, and kinetic parameters were investigated. The results revealed that the as-mentioned SiO2@AuNPs nanocomposite revealed its maximal activity at pH=4.0 along with saving 83.3% of its maximal activity at pH=5.0. Besides, the reusability and shelf-storage studies exhibited that the SiO2@AuNPs nanocomposite retained 90% and 100% of its initial activity after 5 operational cycles and 30 days of storage, in order, to point to their high cycling and shelf-stability. The kinetic parameters of the as-prepared nanozymes were calculated using the Menten kinetic model, revealing a V max of 1.35 µM min-1 and a Km as low as 0.06 mM for the SiO2@AuNPs nanocomposite. Based on the results of this work, the as-prepared SiO2@AuNPs nanocomposite with intrinsic peroxidase-like activity shows high substrate affinity and catalytic efficiency along with excellent cycling and shelf-stability, making them suitable for application in peroxidase- mediated reactions instead of the native enzyme.