Facile microwave-assisted green synthesis and characterization of flower shaped zinc oxide nanoclusters using Centella asiatica (Linn.) leaf extract and evaluation of its antimicrobial activity and in vivo toxic effects on Artemia nauplii.

Abstract

Green synthesized nanomaterials play a vital role in nanotechnology was due to its diverse applications. In the current study, flower shaped nanoclusters of zinc oxide nanoparticles (ZnONPs) was fabricated using the leaf extract of Centella asiatica (Linn.) by microwave-assisted method. The physico-chemical characterization of the green synthesized ZnONPs were further conducted by the UV-Vis spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and transmission electron microscopy analysis. The UV-Vis spectrum of the synthesized ZnONPs has showed characteristic absorption maximum at 363 nm. The XRD pattern of the same could confirm to have the crystalline nature of ZnONPs. Additionally, the FT-IR spectra have revealed the presence of characteristic stretching and bending vibrations of the Zn-O bond, along with those of phytochemicals that might have involved in ZnONPs stabilization. By the HR-TEM imaging, agglomeration of the nanoparticles and thereby the formation of flower-like clusters could be observed. Furthermore, the synthesized ZnONPs have remarkable antimicrobial activity against S. aureus and E. coli with inhibition zones of 15 ± 0.4 and 16.5 ± 1.0 mm respectively. The green synthesized ZnONPs showed no significant toxicity toward Artemia nauplii. Hence, the results of the study indicate the promising potential of the synthesized ZnO nanoclusters.