Inhibitory and Stability Studies on Graphene Oxide Gold Nanozymes

In this study, peroxidase-like graphene oxide/gold nanoparticles were synthesized and characterized for their biochemical stability including pH and thermal stability by determining their relative activity as an index for their stability monitoring. Besides, the inhibitory effect of metal ions on their enzyme like activity was also studied. The results of thermal stability studies revealed a maximal activity over a wide temperature range of 20-40 ℃, revealing high thermal stability of the as-synthesized peroxidaselike graphene oxide/gold nanoparticles. The pH stability measurements revealed a maximal activity over pH= 4.5-5.5 for the as-synthesized peroxidase-like graphene oxide/gold nanoparticles, showing their wide pH range. Moreover, the inhibitory effect of silver ions (as a model metal ion) on their activity was checked at optimal pH and temperature, revealing that the activity of nanozymes was decreased by increasing the concentration of silver ions and reached about 63% upon the addition small portion of silver ions into the reaction media.