Effect of daylight and air oxygen on nanozymatic activity of unmodified silver nanoparticles: Shelf-stability

Abstract

In this work, unmodified silver nanoparticles were synthesized by a simple and cost-efficient method and then characterized by TEM imaging and UV-Vis. spectroscopy. Thereafter, their nanozymatic activity was investigated by catalyzing the oxidation of 3,3’,5,5’-tetramethyl-benzidine (TMB) as the standard peroxidase substrate. The results exhibited a specific activity as high as 5.4 µM min-1 for the as-prepared unmodified silver nanoparticles. Afterward, the effect of daylight and air oxygen on the peroxidase-like activity of these nanozymes was checked within 7 days. The results revealed that the activity of unmodified silver nanoparticles was approximately retained at about 75%, and 63% after 7 days exposing daylight and air oxygen, in order. The shelf-self of the as-prepared nanozymes was also investigated at 4 ℃ under dark conditions, revealed that these nanozymes saved about 96% of their initial activity after 10 days of storage at 4 ℃ under dark conditions. KEYWORDS:Unmodified silver nanoparticles; Peroxidase-like nanozymes; Air oxygen; Daylight; Shelf-stability