Kinetics and biochemical characterization of silver nanozymes and investigating impact of storage conditions on their activity and shelf-life

In this contribution, bare silver nanozymes were synthesized by a simple method, and their optical properties, size, morphology, crystalline structure, and nanozymatic behavior were evaluated. The as-prepared nanozymes reveal a specific activity as high as 5.02 μM min-1, therefore, their biochemical characterization was performed to investigate their stability against environmental changes such as pH and temperature variations, revealing maximum nanozyme activity over pH range of 3.5-4.5 at 25-30 ℃. Thereafter, the impact of the storage conditions on the nanozyme activity and shelf-life were investigated, revealing that the activity of the as-prepared nanozymes was retained at about 75% and 63% after exposing to light and air oxygen for 7 days, respectively. Besides, based on kinetics studies, Km, and Vmax of these nanozymes were calculated as 0.05 mM and 113.6 nM sec-1, in turn, revealing their high nanozyme activity and catalytic efficiency. Finally, the shelf-life (storage stability) of the as-prepared nanozymes was investigated under common storage conditions (i.e. 4°C in the dark), revealing that 96% of the initial activity of nanozymes was saved after 10 days of storage.