ZnO nanomaterials with enhanced antimicrobial activity obtained by Eichhornia crassipes aqueous extract‐mediated synthesis

Abstract

AbstractBACKGROUNDZinc oxide nanoparticles (ZnO NPs) were obtained through precipitation synthesis, using aqueous water hyacinth leaf extract (Eichhornia crassipes) under alkaline conditions. The effect of the extract on the physicochemical and antimicrobial properties of the ZnO was evaluated starting from concentrated extract (labeled as E100) and performing two dilutions of this concentrated extract at 50% and 25% in water (E50, and E25).RESULTSThe FTIR spectra revealed strong peaks at ≈3440 cm−1, corresponding to vibrations from OH stretching, and medium‐intense peaks at 1384 and 1327 cm−1, assigned to CC, COOH and COC vibrations, which are related to the presence of the extract; a weak band at 884 cm−1 and a broad band in the region below 600 cm−1 indicate the presence of ZnO. The hydrodynamic size of the ZnOE100, ZnOE50 and ZnOE25 samples were 202, 244 and 313 nm, respectively. No significant variations on the Eg value were observed. Field emission scanning electron microscopy images showed that the ZnO NPs have triangular‐like shapes and agglomeration of the NPs synthesized for the ZnOE25 sample. The minimum inhibitory concentration (MIC) of the ZnO NPs showed no significant effects related to the concentration the plant extract used.CONCLUSIONSVariations in particle size and zeta potential can be introduced in ZnO by varying the content of the extract; the presence of organic groups from the extract, along with a positive zeta potential value, can promote the bactericide effect of ZnO nanomaterials prepared by bio‐assisted synthesis. © 2024 Society of Chemical Industry (SCI).