Cytotoxicity and antimicrobial activity of naturally and chemically synthesized zinc oxide nanoparticles

Abstract EN

Background/aim Zinc oxide (ZnO) is a polar inorganic compound with numerous applications, for example, as an antimicrobial agent.

The present study aims to synthesize ZnO nanoparticles (NPs) by two different methods, and then determine the antimicrobial activity of ZnO NPs from both methods.

It then focuses on comparison between the cytotoxicity of both ZnO NPs.

Materials and methods ZnO NPs were synthesized using natural and chemical methods.

The synthesized and prepared ZnO NPs were detected by precipitation in both methods using de Man, Rogosa, and Sharpe broth and alkaline medium, respectively.

The characterization of ZnO NPs was performed using ultraviolet spectroscopy, zeta potential, and transmission electron microscopy (TEM) to decide properties of NPs.

Viability tests are essential for assessing the effect of toxicants on cells.

To measure cell viability following NP exposure, MTT assay was used.

Results Results of ultraviolet and TEM experiments for both NPs indicated absorbance at 356–360 nm, which is typical for ZnO NPs.

Results show that naturally prepared ZnO NPs had an average size within 7.8 nm; they were small spherical particles with a narrow size distribution relatively with smooth surfaces.

The chemically prepared ZnO NPs’ TEM images showed an average size of 27.6 nm.

Zeta value of naturally synthesized ZnO NPs was estimated to be −25.30 mV at pH=7.

However, the value of zeta potential in chemical preparation strategy showed −18.6 mV.

Results revealed that toxicity of naturally synthesized ZnO NPs was less than that of chemically prepared ZnO NPs.

Furthermore, the decline in cytotoxicity attributed to ZnO NP exposure was dependent on the concentration of ZnO NPs.

The antimicrobial activity results of ZnO NPs showed that the ZnO NPs produced from both methods recorded antimicrobial activities against the pathogenic strain models used.

Conclusion The microbial synthesized ZnO NPs within size 7.8 nm when used at concentration 625 μg/ml as antimicrobial agent recorded the lowest cytotoxicity when compared with chemically synthesized.

So that natural synthesis of ZnO was recommended.