Preparation of Zinc Oxide Nanoparticles and the Evaluation of their Antibacterial Effects

Summary

In this study, zinc oxide nanoparticles were synthesized using a precipitation method. The antibacterial effect of the synthesized particles was tested against multidrug-resistant methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa bacterial strains.

Abstract

Nosocomial bacterial infections have become increasingly challenging due to their inherent resistance to antibiotics. The emergence of multidrug-resistant bacterial strains in hospitals has been attributed to the extensive and varied use of antibiotics, further exacerbating the problem of antibiotic resistance. Metal nanomaterials have been widely studied as an alternative solution for eradicating antibiotic-resistant bacterial cells. Metallic nanoparticles attack bacterial cells through various mechanisms, such as the release of antibacterial ions, generation of reactive oxygen species, or physical disruption, against which bacteria cannot develop resistance. Among the actively researched antimicrobial metal nanoparticles, zinc oxide nanoparticles, which are FDA-approved, are known for their biocompatibility and antibacterial properties. In this study, we focused on successfully developing a precipitation method for synthesizing zinc oxide nanoparticles, analyzing the properties of these nanoparticles, and conducting antimicrobial tests. Zinc oxide nanoparticles were characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), ultraviolet/visible spectroscopy, and X-ray diffraction (XRD). Antibacterial tests were conducted using the broth microdilution test with the multidrug-resistant strains of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. This study demonstrated the potential of zinc oxide nanoparticles in inhibiting the proliferation of antibiotic-resistant bacteria.

Introduction

Multidrug-resistant (MDR) bacterial infections pose a significant global threat to human health¹. As these infections can be fatal in patients with underlying conditions, active research is attempting to address this issue². Bacteria have evolved to evade the action of various drugs. Penicillin, widely known and credited with saving millions of lives worldwide, is a β-lactam antibiotic that inhibits the synthesis of the bacterial cell wall³. However, bacteria have evolved to neutralize the efficacy of drugs through various mechanisms such as efflux pumps, transpeptidase alterations, or decrea....

Protocol

The reagents and equipment used in this study are listed in the Table of Materials.

1. Preparation of zinc oxide nanoparticles

1. Measure 200 mL of absolute ethyl alcohol and pour it into a glass round bottom flask.
2. Place the round bottom flask on a heating mantle and maintain stirring at 25-40 °C.
3. Measure 500 mg of CTAB in a 50 mL vial and add it to the ethyl alcohol in the flask. Stir until CTAB is completely dissolved.
4. Add 1.4 g of zinc acetate into the solution and stir until it is completely dissolved.
5. Raise the temperature of the solution by settin....

Results

The successful synthesis of ZnO NPs was confirmed using transmission electron microscopy (TEM), as shown in Figure 1A. The obtained ZnO NPs were observed to be round in shape, with an average particle size of 35.35 nm and a standard deviation of 6.81 nm. The precipitation of these nanoparticles was observed through a double-displacement reaction by adding NaOH solution to zinc acetate, where Zn²⁺ ions underwent hydrolysis.

Using dynamic light scattering.......

Discussion

The synthesis of ZnO NPs via precipitation is relatively simple and straightforward. To successfully synthesize ZnO NPs using this method, stirring is crucial to ensure that the precursor (zinc acetate) is fully dissolved in the solvent. Moreover, increasing the temperature helps to induce a successful double-displacement reaction. In the synthesis of ZnO NPs, there are many factors that determine the size and shape, including the precipitation agent, the concentration of the precipitation agent, and the surfact.......

Materials

Name	Company	Catalog Number	Comments
DLS	Zetasizer Pro
Ethyl alcohol, absolute	DAEJUNG	4023-2304
Microplate reader	BioTeck
Sodium Hydroxide	Sigma-Aldrich	221465
TEM	JEOL JEM-F200
TSA	DB difco	236950
TSB	DB difco	211825
XRD	NEW D8-Advance
Zinc acetate	Sigma-Aldrich	383317