Carya Illinoinensis-mediated Green Synthesis and Antimicrobial Screening of Zirconium Oxide Nanoparticles: The Promising Antimicrobial Agent
Authors: Rehman Wajid , Rehman Asra , Rasheed Liaqat , Hussain Rafaqat , Iqbal Shahid , Saboor Abdul , AlAsmari Abdullah F. , Alasmari Fawaz , Khan Momin 
Published: September 2024

Background:

The synthesis of metal-based nanoparticles through conventional methods
involves harsh conditions, high costs, and severe environmental threats. To overcome these issues,
researchers are nowadays focusing on eco-friendly and low-cost methods for the synthesis of nanoparticles.
Finally, several plant-mediated synthesis techniques have been developed, which have
various advantages, such as low-cost, environmentally friendly, and easy application. The plant extract
not only serves as a reducing agent but also plays a role as a stabilizing agent. The plantmediated
synthesis provides new opportunities for cost-effective, environmentally-friendly nanoparticle
synthesis with high dispersity and stability. Besides, bio-generated nanoparticles derived from
plant extract have promising pharmacological applications, making them potential candidates for
future medicines.

Aims and Objectives:

The current study aimed to synthesize zirconium oxide nanoparticles using
Carya illinoinensis extract and examine their physicochemical properties. Additionally, the antimicrobial
efficacy of these nanoparticles was evaluated against various pathogens, exploring their potential
as potent antimicrobial agents.

Methods:

The synthesized nanoparticles were analyzed and characterized by various techniques like
UV-Vis spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy
(TEM), and Energy Dispersive X-ray spectroscopy (EDX). The UV-visible peak at 216 nm confirmed
the formation of ZrO2 nanoparticles. The SEM images clearly showed that nanoparticles were
spherical and relatively dispersed, with few agglomerations. The EDX spectra confirmed the existence
of zirconium and oxygen as the basic constituents of the sample. TEM images demonstrated
nanoparticles as spherical and uniformly dispersed but agglomerated with increasing precursor concentrations
and decreasing nanoparticle dispersion. Fluconazole and gentamicin were used as standards
in determining the antibacterial and antifungal activities of nanoparticles.

Results:

Considering the antifungal activity, a maximum zone of inhibition of 16 μg/ml was demonstrated
in the case of 2 mM as compared to 4 mM and 6 mM concentrations. The Carya illinoinensismediated
ZrO2 nanoparticles were screened against Gram-positive (S. aureus and P. aeruginosa) and
Gram-negative (S. typhi and E. coli) bacterial strains. The fabricated nanoparticles exhibited promising
action against all microorganisms.

Conclusion:

In the current study, zirconium oxide nanoparticles were synthesized by using Carya
illinoinensis leaves extract as a reducing agent. The antifungal and antibacterial potential of the synthesized
nanoparticles were evaluated. The green synthesis method used in this study is preferable to
the others as it is more affordable, environmentally benign, and widely accessible.