Nanoscale size impact of nanoparticle interaction and activity studies with urease

Herein, we provide insights into the size-dependent interactions of silver nanoparticles (AgNPs) with urease and their implications for enzyme inhibition. AgNPs with a size of 5 nm exhibited the strongest binding affinity of 66 nM, resulting in significant enzyme attachment, interfering enzyme conformation, and a consequent loss of activity. Mid-sized AgNPs, i.e., 20 and 50 nm, exhibited binding affinities of 712 and 616 nM, causing only slight structural alterations. In contrast, 100 nm AgNPs demonstrated a high binding affinity of 171 nM accompanied by a favorable enthalpic contribution and a pronounced inhibitory effect.