Green Synthesis of Triangular ZnO Nanoparticles Using Azadirachta indica Leaf Extract and Its Shape Dependency for Significant Antimicrobial Activity: Joint Experimental and Theoretical Investigation

The present study reports the green synthesis of triangular ZnO nanoparticles (G-ZnO NPs) using Azadirachta indica leaves extract, and a shape dependent density functional investigation for ZnO NPs on their antimicrobial activity. The X-ray diffraction (XRD) analysis shows the synthesized G-ZnO NPs are well crystalline in nature and calculated grain size is found to be 60-65 nm. The Fourier transforms infrared spectroscopy (FT-IR) represents that the functional group and capping agents are well attached to the nanoparticles, and the bands located near 500.8 cm(-1), 459.07 cm(-1) and 418.57 cm(-1) represents G-ZnO NPs. Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDS) confirmed the presence of the synthesized G-ZnO nanoparticles with an average size range 100-200 nm. The synthesized G-ZnO NPs are found to be in the triangular shape. A detail theoretical investigation under density functional framework shows that our synthesized triangular ZnO nanoparticles are better candidate for biological interactions compared to the prototypical spherical counterpart. The synthesized G-ZnO nanoparticles using A. indica leaves extract in triangular shape are found to show significant antimicrobial activity against Escherichia coli and Bacillus subtilis indicating a better alternative to the typical chemical methods.

Automated summary

This study reports on the green synthesis of triangular ZnO nanoparticles using Azadirachta indica leaves extract and investigates their antimicrobial activity in a shape-dependent manner. The synthesized triangular ZnO nanoparticles show good crystalline nature and significant antimicrobial activity against Escherichia coli and Bacillus subtilis.