Silver Nanoparticle-Immobilized Schiff-Base Macrocycles as Nanozymes with Peroxidase Mimic Activity for Antibacterial Films

Abstract

The development of nanozymes has emerged as a promising pathway for combating bacterial infections. In this work, Ag/Schiff base nanozymes are obtained through the in situ reduction method on [2 + 3] Schiff base macrocycles using ecofriendly reductant α-tocopherol. The silver prepared was found to be nanoscale by TEM, and Ag NPs grew and dispersed uniformly on the surface of the Schiff base macrocycle due to the abundance of the C�N double bonds. The peroxidase-like catalytic activity of the Ag/Schiff base was evaluated toward 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H 2 O 2 , and the K m values of 0.350 and 0.090 mM confirm the strong affinity of Ag/Schiff base for H 2 O 2 and TMB. Moreover, the nanozyme exhibited good antibacterial properties against Streptococcus sanguinis, Pseudomonas aeruginosa, and Staphylococcus aureus, and in vivo tests confirmed that the Ag/Schiff base had negligible biotoxicity. Benefiting from the good antimicrobial and biosafety properties, the nanozymes were explored to prepare antibacterial films, and the bacterial inhibition zones demonstrated that the introduction of the Ag/Schiff base could prevent the growth of bacteria.